Polyphenylene ether-based composite material and preparation method thereof, antenna substrate and feed antenna

Abstract

The present invention discloses a polyphenylene ether-based composite material and a preparation method thereof, an antenna substrate and a feeding antenna. The components of the polyphenylene ether-based composite material include 20 to 30 parts of polyphenylene ether, 10 to 20 parts of auxiliary resin, 50 to 70 parts of modified high dielectric constant filler and 0.4 to 2 parts of processing aid by weight; wherein the auxiliary resin includes at least one of polystyrene and high impact polystyrene; the modified high dielectric constant filler is obtained by grafting a polymer chain on the surface of the high dielectric constant filler, and the polymer chain contains maleic anhydride and also contains at least one of a polyphenylene ether segment and a polystyrene segment. By grafting and modifying the high dielectric constant filler and combining different particle sizes to increase the filling amount, the interaction between the filler and the matrix resin is increased, and a high content of the filler in the resin matrix is ​​achieved, thereby increasing the dielectric constant, reducing the content of polar groups on the surface of the filler, and avoiding dielectric loss degradation caused by weak interface interaction.

Description

Technical Field

[0001] The present invention relates to the technical field of composite materials, and in particular to a polyphenylene ether-based composite material and a preparation method thereof, an antenna substrate and a feeding antenna. Background Art

[0002] There is a huge demand for thermoplastic polymer-based composite materials with high dielectric constant (Dk ≥ 5) and low dielectric loss (Df ≤ 0.002) in wireless communication fields such as antenna substrates and power electronics fields such as film capacitors. Antenna substrates made of polymers with high dielectric constant and low dielectric loss can miniaturize the antenna and maintain high radiation efficiency and gain. Similarly, polymer dielectrics with high dielectric constant and low dielectric loss can significantly improve the energy density and charge and discharge efficiency of film capacitors.

[0003] To prepare high dielectric constant polymers, the current main technical method is to add a large amount of high dielectric constant fillers, such as barium titanate, barium strontium titanate, etc., to the thermoplastic polymer matrix. However, on the one hand, due to the excessive amount of filler added, the mechanical properties and processing properties of the material will be significantly reduced. Therefore, the content of high dielectric constant fillers that can be filled in the polymer is limited, and the dielectric constant is difficult to be significantly improved. On the other hand, the addition of high dielectric constant fillers brings a large number of filler-polymer interface problems. The weak interaction force between the filler and the polymer interface not only leads to a decrease in the mechanical properties of the system, but also the existence of interface polarization will significantly increase the dielectric loss.

[0004] In view of this, the present invention is proposed. Summary of the invention

[0005] The purpose of the present invention is to provide a polyphenylene ether-based composite material and a preparation method thereof, an antenna substrate and a feeding antenna, so as to improve the two technical problems that the dielectric constant is difficult to significantly improve due to the limited amount of filler added and the dielectric loss is high due to the existence of an interface.

[0006] The present invention is achieved in that:

[0007] In the first aspect, the present invention provides a polyphenylene ether-based composite material, whose components, measured by weight, include 20 to 30 parts of polyphenylene ether, 10 to 20 parts of auxiliary resin, 50 to 70 parts of modified high dielectric constant filler and 0.4 to 2 parts of processing aid; wherein the auxiliary resin includes at least one of polystyrene and high impact polystyrene; the modified high dielectric constant filler is obtained by grafting a polymer chain onto the surface of the high dielectric constant filler, and the polymer chain contains at least one of a polyphenylene ether chain segment and a polystyrene chain segment.

[0008] In a second aspect, the present invention further provides a method for preparing the above-mentioned polyphenylene ether-based composite material, which comprises: melt-blending the polyphenylene ether, the auxiliary resin, the modified high dielectric constant filler and the processing aid.

[0009] In a third aspect, the present invention further provides an antenna substrate, which includes an antenna dielectric substrate, wherein the antenna dielectric substrate is prepared from the above-mentioned polyphenylene ether-based composite material, and optionally, at least one side of the antenna dielectric substrate is covered with copper foil.

[0010] In a fourth aspect, the present invention further provides a feeding antenna, which comprises the above-mentioned antenna dielectric substrate.

[0011] Optionally, the feed antenna further includes a metal base plate, an L-shaped metal feed, an SMA connector and a metal sheet, the metal base plate is provided with a through hole, the SMA connector passes through the through hole and is welded to the L-shaped metal feed, and the L-shaped metal feed is sequentially connected to the antenna dielectric substrate and the metal sheet.

[0012] The present invention has the following beneficial effects: a modified high dielectric constant filler is obtained by grafting a polymer segment containing at least one of a polyphenylene ether segment and a polystyrene segment onto a high dielectric constant filler, and the ratio of each component is reasonably set, so as to achieve interface interaction between the filler and the polyphenylene ether and polystyrene matrix, reduce interface defects, thereby increasing the filler filling amount to achieve a significant improvement in the dielectric constant of the thermoplastic polymer-based composite material, and the modified high dielectric constant filler also reduces the dielectric loss degradation caused by the weak interface interaction inside the thermoplastic polymer-based composite material, thereby improving the comprehensive performance of the thermoplastic polymer-based composite material. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0014] Figure 1 A three-dimensional schematic diagram of a feeding antenna provided in an embodiment of the present invention;

[0015] Figure 2 A side view of a feed antenna provided in an embodiment of the present invention;

[0016] Figure 3 A top view of a feeding antenna provided in an embodiment of the present invention;

[0017] Figure 4This is a microstructure diagram of the polyphenylene ether-based composite material of Example 1 of the present invention;

[0018] Figure 5 This is a diagram of the dielectric properties of the polyphenylene ether-based composite material of Example 1 of the present invention;

[0019] Figure 6 The radiation pattern of the feed antenna prepared by the polyphenylene ether-based composite material of Example 1 of the present invention;

[0020] Figure 7 This is a gain curve diagram of a feeding antenna prepared from the polyphenylene ether-based composite material of Example 1 of the present invention;

[0021] Figure 8 This is an efficiency diagram of the feeding antenna prepared using the polyphenylene ether-based composite material of Example 1 of the present invention.

[0022] Icon: 1-metal sheet; 2-antenna dielectric substrate; 3-L-shaped metal feed; 4-metal base plate; 401-through hole; 5-SMA connector 5. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be described clearly and completely below. If the specific conditions are not specified in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be purchased commercially.

[0024] The following is a detailed description of a polyphenylene ether-based composite material and a preparation method thereof, an antenna substrate and a feeding antenna provided by the present invention.

[0025] The inventors found that the current main method for preparing high dielectric constant polymers is to fill high dielectric constant ceramic fillers in the polymer to increase its dielectric constant, but there are two main problems: First, the filling amount of the filler is limited, and the dielectric constant is difficult to significantly increase. The reason is that the mechanical properties and processing properties of the material will be significantly reduced under high filling amounts, which is difficult to meet application requirements; second, while the dielectric constant is increased, the dielectric loss will also increase at the same time. The reason is that there are a large number of interfaces between the filler and the polymer, and the weakly interacting interfaces will lead to space charge polarization. In addition, the presence of polar groups such as hydroxyl groups on the surface of the filler at the interface will lead to interface polarization. In view of this, the following technical solutions are proposed.

[0026] Some embodiments of the present invention provide a polyphenylene ether-based composite material, whose components include 20 to 30 parts of polyphenylene ether, 10 to 20 parts of auxiliary resin, 50 to 70 parts of modified high dielectric constant filler and 0.4 to 2 parts of processing aid in parts by weight; wherein the auxiliary resin includes at least one of polystyrene (PS) and high impact polystyrene (HIPS); the modified high dielectric constant filler is obtained by grafting a polymer chain onto the surface of the high dielectric constant filler, and the polymer chain contains at least one of a polyphenylene ether chain segment and a polystyrene chain segment.

[0027] Thermoplastic polyphenylene oxide (PPO) is used as the main resin of the composite material, which provides excellent low dielectric loss and mechanical properties of the composite system. Polystyrene (PS) or high-impact polyphenylene oxide ethylene (HIPS) is used as the auxiliary resin of the composite material. An appropriate amount of polystyrene (PS) or high-impact polyphenylene oxide ethylene (HIPS) is added to reduce the melt viscosity of polyphenylene oxide and improve the processing performance, wherein HIPS can also improve the toughness and ductility of the composite material. The modified high dielectric constant filler is obtained by grafting a polymer segment containing at least one of a polyphenylene oxide segment and a polystyrene segment to a high dielectric constant filler, thereby realizing the interface interaction between the filler and the polyphenylene oxide and polystyrene matrix, reducing the interface defects, and then the modified high dielectric constant filler can be added in large quantities in the thermoplastic polymer-based composite material, increasing the filler filling amount, so that the dielectric constant of the thermoplastic polymer-based composite material is significantly improved. And the modified high dielectric constant filler also reduces the dielectric loss degradation caused by the weak interface interaction inside the thermoplastic polymer-based composite material. In addition, appropriate amounts of processing aids and antioxidants can improve processing performance and avoid thermal oxidative decomposition of materials during melt processing, thereby improving the overall performance of composite materials.

[0028] It should be noted that the high dielectric constant filler in the embodiment of the present invention refers to a filler with a dielectric constant Dk≥50.

[0029] In order to allow the polymer chain to fully modify the filler without affecting the high dielectric constant performance of the filler itself, in some embodiments, the mass of the polymer chain is 0.1% to 5% of the mass of the high dielectric constant filler, for example, 0.5%, 1%, 1.5%, 2%, 2.5% or 3%, etc.

[0030] Specifically, in some embodiments, the high dielectric constant filler includes but is not limited to titanium dioxide (TiO2), barium titanate (BaTiO3), barium strontium titanate (BaSrTiO3), lead zirconate titanate Pb(Zr,Ti)O3 (PZT) and calcium copper titanate (CaCu3Ti4O 12 (CCTO)). That is, the high dielectric constant filler can be any one of the above fillers, or a combination of two or more of them.

[0031] Furthermore, in some embodiments, the high dielectric constant filler is obtained by matching fillers of two particle size ranges, preferably the two particle sizes are between 10nm-100nm and 100nm-500nm, more preferably between 20nm-40nm and 150nm-350nm, and further preferably the ratio of large particle size to small particle size filler is 10-2:1, preferably 7-4:1. The filling amount is increased by surface grafting modification and matching of different particle sizes, and the dielectric loss caused by polar groups on the surface of the filler is reduced.

[0032] In some embodiments, the polymer chain is bonded to the high dielectric constant filler through an imide group, and the polymer raw material for the polymer chain includes but is not limited to at least one of polystyrene-grafted-maleic anhydride (PS-g-MAH), polystyrene-block-poly(ethylene-ran-butylene)-block-polystyrene-grafted-maleic anhydride (PS-bP(E-ran-B)-b-PS-g-MAH) and polyphenylene ether grafted maleic anhydride (PPO-g-MAH). Polystyrene and polyphenylene ether molecules are mutually soluble, so after PS-g-MAH or PS-bP(E-ran-B)-b-PS-g-MAH or PPO-g-MAH segments are grafted onto the surface of the filler, the interface interaction between the filler and the polyphenylene ether and polystyrene matrix can be significantly improved, the interface defects can be reduced, and the filler filling amount can be increased. It should be noted that the polymer raw materials used in the embodiments of the present invention are existing substances and can be obtained by commercial purchase or the like.

[0033] In some embodiments, the processing aid includes at least one of a lubricant and an antioxidant. Specifically, the lubricant includes at least one of zinc stearate and stearic acid; the antioxidant includes at least one of antioxidant 1010 (tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate] pentaerythritol) and antioxidant 168 (tris(2,4-di-tert-butyl)phenyl phosphite).

[0034] Some embodiments of the present invention also provide a method for preparing the polyphenylene ether-based composite material in the above embodiment, which comprises: melt-blending the polyphenylene ether, the auxiliary resin, the modified high dielectric constant filler and the processing aid.

[0035] Specifically, some embodiments of the present invention provide a method for preparing a polyphenylene ether-based composite material comprising the following steps:

[0036] S1. Prepare modified high dielectric constant filler.

[0037] Specifically, the surface of the high dielectric constant filler is hydroxylated, then aminated, and then the polymer chain is grafted onto the surface. The detailed operation is as follows:

[0038] (1) Hydrogenation of the filler surface. An appropriate amount of high dielectric constant filler is added to a round-bottom flask containing a 30 wt% hydrogen peroxide solution, and ultrasonically dispersed for 0.5 to 1 h to obtain a suspension, and then refluxed in an oil bath at 100 to 110° C. (e.g., 105° C.) under magnetic stirring for 4 h, and finally filtered or centrifuged, and the filler particles are washed with deionized water, and vacuum dried at 80° C. for 12 h to obtain a hydroxylated high dielectric constant filler.

[0039] (2) Amination of filler surface. Take an appropriate amount of hydroxylated high dielectric constant filler and disperse it in anhydrous ethanol. Use a high-speed shear mixer or ultrasonic dispersion to evenly disperse the filler in anhydrous ethanol to form a suspension, and adjust the solution pH to 9. Take another certain amount of deionized and anhydrous ethanol in a ratio of 9:1 to form a mixed solvent, slowly add KH550 silane coupling agent (γ-aminopropyltriethoxysilane) to mix, the amount of KH550 added is 4wt% of the filler mass, react at 60°C for 30min, and fully hydrolyze the silane coupling agent. Then, slowly add the filler suspension to the above silane coupling agent solution, and stir the mixed solution at 80°C for 3h to allow KH550 to be fully grafted on the surface of the high dielectric constant filler; finally, filter or centrifuge the inorganic filler, wash it with deionized water several times, and dry it in a vacuum oven at 120°C for 2 hours to obtain a high dielectric constant filler grafted with KH550. The grafting amount of the silane coupling agent on the surface of the high dielectric constant filler is changed by controlling the concentration of the coupling agent solution, the reaction temperature and the time.

[0040] (3) Grafting polymer chains on the filler surface. Add an appropriate amount of amino-type high dielectric constant filler into a flask filled with xylene, and ultrasonically disperse the mixture for 0.5 to 1 hour. Weigh 0.1 to 5 wt% of the mass of the amino-type high dielectric constant filler PS-g-MAH or PS-bP(E-ran-B)-b-PS-g-MAH or PPO-g-MAH and dissolve it in the xylene solution, stirring it to fully dissolve. Then, the filler suspension and the polymer solution are mixed, nitrogen is introduced for 4 minutes, the mixture is reacted in an oil bath at 140-160° C. (e.g., 150° C.) for 3 hours, and the mixture is cooled to room temperature in a nitrogen atmosphere; the high dielectric constant filler particles with polymer chains grafted on the surface are then centrifuged at a speed of 5000 rpm for 5 minutes, and the high dielectric constant filler particles are finally washed with xylene for multiple times and centrifuged. After vacuum drying at 80° C. for 12 hours, a high dielectric constant filler grafted with PS-g-MAH or PS-bP(E-ran-B)-b-PS-g-MAH or PPO-g-MAH is prepared.

[0041] S2. Prepare polyphenylene ether-based composite materials by melt blending.

[0042] Specifically, first, place the polyphenylene ether, polystyrene or high impact polystyrene, modified high dielectric constant filler and other materials in an oven at 110-125°C for about 4 hours to fully remove the moisture adsorbed in the materials, and then cool to room temperature. Secondly, weigh an appropriate amount of dried and cooled polyphenylene ether, polystyrene or high impact polystyrene, modified high dielectric constant filler, and processing aid and mix them in a blender to obtain a mixture. Then, melt blending is performed using a twin-screw extruder or a torque rheometer.

[0043] As a reference, an eight-zone twin-screw extruder is used for melt blending, and a mixture of polyphenylene ether, auxiliary resin, modified high dielectric constant filler and processing aid is added into the twin-screw extruder through a feeder for melt extrusion and granulation.

[0044] In some embodiments, the process parameters of the eight-zone twin-screw extruder include: the temperature of zone one is 260-270°C, the temperature of zone two is 270-280°C, the temperature of zone three is 275-290°C, the temperature of zone four is 275-290°C, the temperature of zone five is 265-285°C, the temperature of zone six is ​​265-285°C, the temperature of zone seven is 265-285°C, the temperature of zone eight is 265-285°C, the die head temperature is 265-285°C, and the screw speed is 450-800rpm.

[0045] Some embodiments of the present invention further provide an antenna substrate, which includes an antenna dielectric substrate, and the antenna dielectric substrate is prepared from the above-mentioned polyphenylene ether-based composite material.

[0046] In some embodiments, the antenna dielectric substrate is a double-sided board with copper foil on both sides, or a single-sided board with copper foil on one side, or a pure dielectric substrate without copper foil on both sides. The thickness of the substrate dielectric layer is 1 to 10 mm, preferably 1 to 3 mm, and the thickness of the upper and lower copper foils is 0.5 oz-2 oz, preferably 1 oz.

[0047] For reference, the preparation process of the antenna dielectric substrate is: hot pressing or injection molding the above polyphenylene ether-based composite material to prepare the antenna dielectric substrate.

[0048] Specifically, taking hot pressing as an example, the hot pressing mold used is composed of three steel plates: upper, middle and lower. The upper and lower plates are mirror steel plates, and the middle plate is a hollow frame steel plate. The size of the mold is adjusted according to actual needs. Two pieces of copper foil are placed between the middle steel plate and the upper and lower steel plates of the mold, and the size of the copper foil is cut to the same size as the upper and lower steel plates of the mold. After aligning the copper foil between the upper plate, the lower plate and the middle plate, and placing the middle plate, weigh an appropriate amount of polyphenylene ether material and place it in the hollow frame of the middle plate. Spread the pellets evenly, cover with the second copper foil, and then cover with the upper plate of the mold. After alignment, place the entire mold into a hot press for hot pressing. Set the temperature of the hot press machine to 230-270°C, preheat the mold containing the material for 5-20 minutes, then pre-press for 2-10 minutes at a pressure of 0.5-10Mpa, open the mold and deflate for 0.5-3 minutes, then pre-press for 2-5 minutes, repeat the pre-pressing and deflation 2-5 times, then increase the pressure to 10-30MPa, and keep warm and pressurized for 15-60 minutes. Next, take it out and put it on the cold press table for cold pressing for 1-5 minutes, and quickly cool it to room temperature under circulating water cooling. Finally, open the mold and trim to remove burrs and excess copper foil to prepare the antenna substrate.

[0049] The preparation process of single-sided board and pure dielectric substrate is basically the same as above, except that the process of laying the corresponding copper foil is removed.

[0050] Some embodiments of the present invention further provide a feeding antenna, which includes the antenna dielectric substrate in the above embodiment.

[0051] Specifically, see Appendix Figure 1 , Figure 2 and Figure 3 The feed antenna also includes a metal base plate 4, an L-shaped metal feed 3, an SMA connector 5 and a metal sheet 1. The metal base plate 4 is provided with a through hole 401, and the SMA connector passes through the through hole 401 and is welded to the L-shaped metal feed 3. The L-shaped metal feed 3 is sequentially connected with an antenna dielectric substrate 2 and a metal sheet 1. The length of the long side of the metal sheet 1 is (0.36±0.02)λ0, and the length of the wide side is (0.26±0.02)λ0. The antenna dielectric substrate 2 is further cut into a rectangle with a side length greater than that of the metal sheet 1 by CNC machining. The long section length of the L-shaped metal feed 3 is 0.14λ0, and the short section length is 0.05λ0. The size of the metal base plate 4 is not limited, and is preferably larger than the size of the metal sheet 1. λ0 is the wavelength in free space at a frequency of 1.8 GHz.

[0052] The features and performance of the present invention are further described in detail below in conjunction with the embodiments.

[0053] Example 1

[0054] This embodiment provides a method for preparing a polyphenylene ether-based composite material and a feed antenna, which specifically includes the following steps:

[0055] (1) Grafting modification of high dielectric constant fillers.

[0056] Weigh 100 g of titanium dioxide (TiO2) filler with a particle size of 250 nm and a particle size of 30 nm respectively, add them into a round-bottom flask containing 500 ml of a 30 wt% hydrogen peroxide solution, ultrasonically disperse for 1 hour to obtain a suspension, then reflux for 4 hours in an oil bath at 105°C under magnetic stirring, and finally filter or centrifuge, wash the filler particles with deionized water, and vacuum dry at 80°C for 12 hours to obtain hydroxylated titanium dioxide filler TiO2-OH.

[0057] The two particle sizes of TiO2-OH prepared above were separately dispersed in 100 ml of anhydrous ethanol, and TiO2-OH was uniformly dispersed in anhydrous ethanol to form a suspension by a high-speed shear mixer, and the pH of the solution was adjusted to 9. A certain amount of deionized and anhydrous ethanol was prepared into 500 ml of a mixed solvent in a ratio of 9:1, and 4 wt% of the filler mass of KH550 silane coupling agent (γ-aminopropyl triethoxysilane) was slowly added dropwise to mix, and reacted at 60°C for 30 minutes to fully hydrolyze the silane coupling agent. Then, the filler suspension was slowly added to the above silane coupling agent solution, and the mixed solution was magnetically stirred at 80°C for 3 hours to fully graft KH550 on the surface of the inorganic filler. Finally, the inorganic filler is separated by suction filtration or centrifugation, washed with deionized water for several times, and dried in a vacuum oven at 120° C. for 2 hours to obtain a titanium dioxide filler (TiO2-KH550) grafted with KH550, that is, amino functionalization is performed on the surface of TiO2.

[0058] The above two particle sizes of aminated titanium dioxide fillers (TiO2-KH550) were added to a flask containing 500 ml of xylene, and the mixture was ultrasonically dispersed for 1 hour. PS-bP(E-ran-B)-b-PS-g-MAH weighed to 2 wt% of the mass of TiO2-KH550 filler was dissolved in 10 ml of xylene solution and fully dissolved under magnetic stirring. Then, the TiO2-KH550 filler suspension and the polymer solution were mixed, nitrogen was introduced for 4 minutes, the mixture was reacted in an oil bath at 150°C for 3 hours, and the mixture was cooled to room temperature in a nitrogen atmosphere; the TiO2 filler particles with polymer chains grafted on the surface were then centrifuged at a speed of 5000 rpm for 5 minutes, and the TiO2 filler particles were finally washed with xylene for multiple times and centrifuged. After vacuum drying at 80°C for 12 hours, PS-bP(E-ran-B)-b-PS-g-MAH-grafted titanium dioxide fillers (TiO2-g-MAH-b-PS) with particle sizes of 250 nm and 30 nm, respectively, were prepared.

[0059] (2) Preparation of polyphenylene ether based composite materials.

[0060] The polyphenylene ether, polystyrene and graft-modified TiO2 filler were placed in a vacuum oven at 120° C. and dried for about 4 hours to fully remove the moisture adsorbed in the materials, and then cooled to room temperature.

[0061] The dried and cooled polyphenylene ether, polystyrene, modified inorganic filler, lubricant and antioxidant were weighed and mixed in a blender to obtain a mixture. The contents of each component are shown in Table 1.

[0062] Table 1

[0063]

[0064] The mixed material is added into the twin-screw extruder through a feeder for melt extrusion and granulation. The process parameters include: the temperature of zone 1 is 265°C, the temperature of zone 2 is 275°C, the temperature of zone 3 is 280°C, the temperature of zone 4 is 280°C, the temperature of zone 5 is 270°C, the temperature of zone 6 is 270°C, the temperature of zone 7 is 270°C, the temperature of zone 8 is 270°C, the temperature of die head is 270°C, and the screw speed is 700rpm. The extruded wire material is cut to obtain modified polyphenylene ether-based composite pellets.

[0065] (3) Preparation of antenna dielectric substrate and feeding antenna.

[0066] The modified polyphenylene ether-based composite material particles are hot-pressed to prepare the antenna dielectric substrate. The specific operation is as follows: weigh 10g of modified polyphenylene ether composite granules and place them in the hollow frame of the middle plate of the mold, spread the granules evenly, and cover the upper plate of the mold. After alignment, put the mold as a whole into the hot press for hot pressing. Set the temperature of the hot press to 250℃, preheat the mold containing the material for 10 minutes, and then pre-press for 3 minutes at a pressure of 1Mpa. After opening the mold and venting for 1 minute, pre-press for another 3 minutes. Repeat the pre-pressing and venting for 3 times, then increase the pressure to 15MPa and keep warm for 20 minutes. Then, take it out and put it into the cold press table for cold pressing for 2 minutes, and quickly cool it to room temperature under circulating water cooling. Finally, open the mold and trim to remove burrs to prepare a pure dielectric substrate without copper foil.

[0067] In this embodiment, 1oz thick copper foil is selected as the metal sheet 1, and a high degree of flatness is achieved by precision CNC numerical control processing, and a high surface finish is achieved by grinding technology. The L-shaped metal feed 3 is made of copper and is processed by wire cutting. The length of the long side of the metal sheet 1 is 60.12mm, and the length of the wide side is 43.42mm. The dielectric substrate 2 is further cut into a rectangle with a side length of 70.14mm and a thickness of 3mm by CNC numerical control processing. The long section of the L-shaped metal feed 3 is 23.38mm long and the short section is 8.36mm long. The metal base plate 4 is 1oz copper foil, with a size of 70mmx70mm. The metal sheet 1, the dielectric substrate 2, the metal feed 3, and the metal base plate 4 are mechanically assembled to obtain the following Figure 1-Figure 3 Antenna structure shown.

[0068] The polyphenylene ether-based composite material provided in this embodiment was observed by scanning electron microscopy and transmission electron microscopy, and its internal microstructure was as follows: Figure 4 As shown in the figure, the grafted modified titanium dioxide (TiO2-g-MAH-b-PS) of two particle sizes is evenly dispersed in the polymer matrix to form a dense stack. Moreover, the filler and the polymer matrix have a good interface, and there are no defects such as interface voids.

[0069] The dielectric properties of the dielectric substrate prepared from the polyphenylene ether-based composite material provided in this embodiment are as follows: Figure 5 As shown, it has stable dielectric constant and dielectric loss in the range of 0.2 GHz to 16 GHz, the dielectric constant is as high as about 6.6, and the dielectric loss is less than 0.0005. Figure 6 is the radiation pattern of the prepared antenna.

[0070] The standing wave ratio performance curve of the L-shaped feed antenna made of the polyphenylene ether-based composite material provided in this embodiment is as follows: Figure 7 As shown, the standing wave ratio curve of the antenna is lower than 2 in the range of 1.66 to 2.20 GHz.

[0071] The gain curve of the L-shaped feed antenna of the polyphenylene ether-based composite material provided in this embodiment is shown in the simulation results. Figure 7 As shown in the figure, it can be seen that the antenna gain remains stable in the range of 1.57 to 2.31 GHz, and the maximum antenna gain reaches 8.56 dBic.

[0072] The efficiency curve of the L-shaped feeding antenna of the polyphenylene ether-based composite material provided in this embodiment is shown in the simulation results. Figure 8 As shown, the maximum antenna gain reaches 98.89%, and is greater than 97.45% in the range of 1.71 to 2.11 GHz.

[0073] Example 2

[0074] This embodiment provides a method for preparing a polyphenylene ether-based composite material and a feed antenna. The grafting modification of the filler, the preparation of the dielectric antenna substrate and the antenna are the same as those in Example 1, except that a torque rheometer is used to prepare the polyphenylene ether-based composite material. The specific process is as follows:

[0075] 1) Place polyphenylene ether, polystyrene and graft-modified TiO2 filler in a vacuum oven at 120° C. and dry for about 4 hours to fully remove the moisture adsorbed in the materials, and then cool to room temperature.

[0076] 2) Weigh appropriate amounts of dried and cooled polyphenylene ether, polystyrene, modified inorganic filler, lubricant, and antioxidant and mix them in a blender to obtain a mixture. The composition of each material is the same as that in Example 1.

[0077] 3) Melt blending using a torque rheometer. The mixed mixture is added into the torque rheometer through a feeder for melt blending. The temperature of the torque rheometer is set to 270°C, the mixing time is 15 minutes, and the rotor speed is 60 rpm. The melt blended material is taken out and cut into pieces with scissors to obtain modified polyphenylene ether-based composite pellets.

[0078] Example 3

[0079] This embodiment provides a method for preparing a polyphenylene ether-based composite material and a feed antenna. In this embodiment, PPO-g-MAH is used to graft-modify the aminated titanium dioxide filler (TiO2-KH550), and the other parts are the same as those in Example 1. The graft-modification process of PPO-g-MAH on the aminated titanium dioxide filler (TiO2-KH550) is as follows:

[0080] 100g TiO2-KH550 was added to a flask containing 500ml xylene, and the mixture was ultrasonically dispersed for 1 hour. PPO-g-MAH weighing 2wt% of the mass of TiO2-KH550 filler was dissolved in 10ml xylene solution and fully dissolved under magnetic stirring. Then, the filler suspension and the polymer solution were mixed, nitrogen was introduced for 5min, reacted in an oil bath at 150°C for 4h, and cooled to room temperature in a nitrogen atmosphere; then, the TiO2 filler particles with polymer chains grafted on the surface were centrifuged by centrifuge at a speed of 5000rpm for 5min, and finally, the TiO2 filler particles were washed with xylene several times and centrifuged. After vacuum drying at 80°C for 12h, titanium dioxide fillers (TiO2-g-MAH-g-PPO) with particle sizes of 250nm and 30nm were prepared.

[0081] The dried and cooled polyphenylene ether, polystyrene, TiO2-g-MAH-g-PPO, lubricant and antioxidant were weighed and mixed in a blender to obtain a mixture. The content of each component is shown in Table 2.

[0082] Table 2

[0083]

[0084] The preparation process of the modified polyphenylene ether-based composite granules, the antenna dielectric substrate and the feeding antenna is the same as that of Example 1.

[0085] Example 4

[0086] This embodiment provides a preparation method of a polyphenylene ether-based composite material and a feeding antenna. In this embodiment, a single particle size (D50=250nm) grafted modified TiO2 is used to fill a polymer matrix, and fillers of different particle sizes are not used for mutual matching. The content of each component is shown in Table 3.

[0087] Table 3

[0088]

[0089] The preparation process of the modified polyphenylene ether-based composite granules, the antenna dielectric substrate and the feeding antenna is the same as that of Example 1.

[0090] Comparative Example 1

[0091] This comparative example provides a method for preparing a polyphenylene ether-based composite material and a feeding antenna, which is different from Example 1 in that this comparative example uses TiO2 without any modification. The contents of each component are shown in Table 4.

[0092] Table 4

[0093]

[0094]

[0095] The preparation process of the polyphenylene ether-based composite granules, the antenna dielectric substrate and the feeding antenna is the same as that of Example 1.

[0096] The dielectric properties of the polyphenylene ether-based composite materials of Examples 1 to 4 and Comparative Example 1 are compared, and the comparison results are shown in Table 5.

[0097] Table 5

[0098]

[0099] In summary, the embodiments of the present invention increase the filling amount by innovatively grafting and modifying high dielectric constant fillers and combining different particle sizes to increase the filling amount, thereby improving the interaction between the filler and the polymer matrix, achieving high-content filling of the filler in the polymer matrix, thereby improving the dielectric constant, reducing the content of polar groups on the filler surface, and avoiding dielectric loss degradation caused by weak interface interactions.

[0100] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A polyphenylene ether-based composite material, characterized in that: The components include 20 to 30 parts of polyphenylene ether, 10 to 20 parts of auxiliary resin, 50 to 70 parts of modified high dielectric constant filler and 0.4 to 2 parts of processing aid by weight; Wherein, the auxiliary resin includes at least one of polystyrene and high-impact polystyrene; the modified high dielectric constant filler is obtained by grafting a polymer chain onto the surface of the high dielectric constant filler, the polymer chain contains at least one of a polyphenylene ether segment and a polystyrene segment, and the mass of the polymer chain is 0.1% to 5% of the mass of the high dielectric constant filler; The high dielectric constant filler comprises at least one of titanium dioxide, barium titanate, barium strontium titanate, lead zirconate titanate and calcium copper titanate; The high dielectric constant filler is obtained by mixing fillers of two particle size ranges; The two particle sizes are respectively between 10nm-100nm and 100nm-500nm.

2. The polyphenylene ether-based composite material according to claim 1, characterized in that: The two particle sizes are respectively between 20nm-40nm and 150nm-350nm.

3. The polyphenylene ether-based composite material according to claim 1, characterized in that: Among the two particle sizes, the ratio of the filler of the large particle size to the small particle size is 10 to 2:

1.

4. The polyphenylene ether-based composite material according to claim 3, characterized in that: Among the two particle sizes, the ratio of the filler of the large particle size to the small particle size is 7 to 4:

1.

5. The polyphenylene ether-based composite material according to claim 1, characterized in that: The polymer chain is combined with the high dielectric constant filler through an imide group, and the polymer raw material corresponding to the polymer chain includes at least one of polystyrene-grafted-maleic anhydride, polystyrene-block-poly(ethylene-ran-butylene)-block-polystyrene-grafted-maleic anhydride and polyphenylene ether grafted maleic anhydride.

6. The polyphenylene ether-based composite material according to any one of claims 1 to 5, characterized in that: The processing aid includes at least one of a lubricant and an antioxidant.

7. The polyphenylene ether-based composite material according to claim 6, characterized in that: The lubricant includes at least one of zinc stearate and stearic acid; the antioxidant includes at least one of antioxidant 1010 and antioxidant 168.

8. A method for preparing a polyphenylene ether-based composite material according to any one of claims 1 to 7, characterized in that: It includes: The polyphenylene ether, the auxiliary resin, the modified high dielectric constant filler and the processing aid are melt-blended.

9. The method for preparing a polyphenylene ether-based composite material according to claim 8, characterized in that: Melt blending is performed using a twin-screw extruder or a torque rheometer.

10. The method for preparing a polyphenylene ether-based composite material according to claim 9, characterized in that: The mixture of the polyphenylene ether, the auxiliary resin, the modified high dielectric constant filler and the processing aid is added to the twin-screw extruder through an eight-zone twin-screw extruder for melt extrusion and granulation.

11. The method for preparing a polyphenylene ether-based composite material according to claim 10, characterized in that: The process parameters include: the temperature of zone 1 is 260-270°C, the temperature of zone 2 is 270-280°C, the temperature of zone 3 is 275-290°C, the temperature of zone 4 is 275-290°C, the temperature of zone 5 is 265-285°C, the temperature of zone 6 is 265-285°C, the temperature of zone 7 is 265-285°C, the temperature of zone 8 is 265-285°C, the die head temperature is 265-285°C, and the screw speed is 450-800rpm.

12. The method for preparing a polyphenylene ether-based composite material according to claim 8, characterized in that: The preparation steps of the modified high dielectric constant filler include: hydroxylating the surface of the high dielectric constant filler, then aminating the surface, and then grafting the polymer chain onto the surface.

13. The method for preparing a polyphenylene ether-based composite material according to claim 12, characterized in that: The high dielectric constant filler is placed in a hydrogen peroxide solution and surface hydroxylated at 100-110°C.

14. The method for preparing a polyphenylene ether-based composite material according to claim 12, characterized in that: The hydroxylated high dielectric constant filler is added with a silane coupling agent for grafting to obtain a surface amino-treated high dielectric constant filler.

15. The method for preparing a polyphenylene ether-based composite material according to claim 12, characterized in that: The aminated high dielectric constant filler is mixed and reacted with the polymer chain to obtain the modified high dielectric constant filler.

16. The method for preparing a polyphenylene ether-based composite material according to claim 15, characterized in that:The reaction temperature of the mixed reaction of the amino high dielectric constant filler and the polymer chain is 140-160°C.

17. An antenna substrate, characterized in that: The antenna substrate is prepared from the polyphenylene ether-based composite material according to any one of claims 1 to 7.

18. The antenna substrate according to claim 17, characterized in that: At least one side of the antenna substrate is covered with copper foil.

19. A feeding antenna, characterized in that: The feeding antenna includes the antenna substrate according to claim 17 or 18.

20. The feeding antenna according to claim 19, characterized in that: It also includes a metal base plate, an L-shaped metal feed, an SMA connector and a metal sheet. The metal base plate is provided with a through hole, the SMA connector passes through the through hole and is welded to the L-shaped metal feed, and the L-shaped metal feed is sequentially connected to the antenna substrate and the metal sheet.

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