Liquid crystal composite material for 5g antenna and preparation method thereof

Abstract

The application relates to the technical field, and particularly discloses a liquid crystal composite material for a 5G antenna and a preparation method thereof. The liquid crystal composite material comprises the following raw materials in parts by mass: 80-120 parts of a liquid crystal polymer, 50-80 parts of a polyphenyl ether, 10-15 parts of glass fibers, 10-15 parts of hollow nanometer microspheres, 8-10 parts of mica powder, 3-8 parts of a coupling agent, 2-5 parts of a compatilizer, and 0.5-2 parts of an antioxidant. The preparation method comprises the following steps: uniformly mixing the raw materials after drying treatment at 120-150 DEG C, melt mixing, extruding, drawing, cooling and granulating through an extrusion device, and the liquid crystal composite material is obtained. The liquid crystal composite material has the advantages of reducing the dielectric constant and dielectric loss of a propagation medium material.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, and in particular to a liquid crystal composite material for 5G antennas and its preparation method. Background Technology

[0002] Fifth-generation (5G) mobile communication technology is the latest generation of cellular mobile communication technology. It represents a leap forward in transmission speed, latency, capacity, and density across the time, spatial, and frequency domains. Its transmission rate is approximately 100 times that of 4G communication, and its latency is only 1 millisecond, 1 / 140th that of 4G. 5G technology places higher demands on materials. Due to the high propagation frequency of 5G, its signal is highly susceptible to external interference or shielding and attenuation in the propagation medium. This necessitates materials with lower dielectric constants and dielectric losses. Furthermore, 5G's electromagnetic wave coverage and signal strength are relatively poor, requiring materials with strong electromagnetic shielding capabilities. In addition, 5G's high integration and complexity, along with its multi-channel systems, necessitates materials that are lightweight, miniaturized, multifunctional, and have high thermal conductivity. Therefore, a propagation medium material for 5G antennas is required. Summary of the Invention

[0003] To reduce the dielectric constant and dielectric loss of the propagation medium material, this application provides a liquid crystal composite material for 5G antennas and a method for preparing the same.

[0004] In a first aspect, this application provides a liquid crystal composite material for 5G antennas, employing the following technical solution:

[0005] A liquid crystal composite material for 5G antennas comprises the following raw materials in parts by weight: 80-120 parts liquid crystal polymer, 50-80 parts polyphenylene ether, 10-15 parts glass fiber, 10-15 parts hollow nanospheres, 8-10 parts mica powder, 3-8 parts coupling agent, 2-5 parts compatibilizer, and 0.5-2 parts antioxidant.

[0006] Furthermore, the liquid crystal polymer is prepared by solution condensation polymerization, and the structure of the liquid crystal polymer is as follows:

[0007]

[0008] Where n = 2-10, and the polymer molecular weight is in the range of 3000-50000;

[0009] The liquid crystal polymer is prepared by a method comprising the following steps:

[0010] Take 50-100 parts of bis(4-(chlorocarbonyl)phenyl) terephthalate and 50-100 parts of a binaphthalene compound, and load them into a microwave reactor equipped with a magnetic stirrer and an argon gas inlet. First, purge with dry argon gas for 15-30 min, then gradually increase the temperature of the reactor to 190-220°C at a heating rate of 1-2°C / min using microwaves. Continue purging with argon gas and continue heating to 220-240°C for 10 h. The microwave frequency is 2350-2500 MHz and the microwave power is 400-1500 W. After cooling, add dichloromethane and filter, then add tetrahydrofuran, vacuum dry, and grind to obtain the liquid crystal polymer.

[0011] The structure of the bis(4-(chlorocarbonyl)phenyl) terephthalate is as follows:

[0012]

[0013] The binaphthyl compound is 4-4-bis(dihydroxyalkoxy)binaphthyl, and the structure of the bis(4-(chlorocarbonyl)phenyl) terephthalate is as follows, where n = 2-10:

[0014]

[0015] Furthermore, the hollow nanospheres are one or more of the following: silica hollow nanospheres, gallium nitride hollow nanospheres, and boron nitride hollow nanospheres.

[0016] Furthermore, the glass fiber is an alkali-free, untwisted roving long glass fiber, with a cross-sectional length of 10-20 micrometers, a cross-sectional width of 2-10 micrometers, and an aspect ratio of 1-5:1.

[0017] Furthermore, the mica powder comprises the following raw materials in parts by weight: 8-10 parts of T001 mica powder, 8-10 parts of 400YD mica powder, 8-10 parts of GH-605 mica powder, and 8-10 parts of GM-8 mica powder.

[0018] Furthermore, the coupling agent is two or more of the following: 3-aminopropyltriethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, isopropyltris(dioctylphosphoyloxy)titanate, and zirconium propoxide.

[0019] Furthermore, the compatibilizer is two or more of the following: maleic anhydride-grafted polyolefin, ethylene-acrylate terpolymer-grafted glycidyl ester, imide-modified acrylate, and m-isopropenyl-2,2-dimethylbenzoyl isocyanate.

[0020] Furthermore, the antioxidant is two or more of 1,3,5-tris(3,5-di-tert-butyl-4-hydroxyphenyl) isocyanate, tris(2,4-di-tert-butylphenyl) phosphite, and 2,6-di-tert-butyl-p-cresol.

[0021] Secondly, this application provides a method for preparing a liquid crystal composite material for 5G antennas, employing the following technical solution:

[0022] A method for preparing a liquid crystal composite material for 5G antennas includes the following steps: after drying the raw materials at 120-150℃, they are uniformly mixed, melt-mixed, extruded, stretched, cooled, and granulated using an extrusion device to obtain the liquid crystal composite material.

[0023] Furthermore, the temperature of the extrusion equipment is 280-300℃ in zone 1, 300-320℃ in zone 2, 300-320℃ in zone 3, 300-320℃ in zone 4, 290-310℃ in zone 5, 290-310℃ in zone 6, 270-290℃ in zone 7, 260-280℃ in zone 8, 250-270℃ in zone 9, and 240-260℃ in zone 10.

[0024] Compared with the prior art, this application has the following technical effects:

[0025] (1) Liquid crystal polymers have high strength, high modulus, high heat resistance and low dielectric properties, as well as excellent bending resistance, chemical corrosion resistance, aging resistance, high radiation resistance and molding and processing performance. They can be blended with a variety of polymers.

[0026] Polyphenylene ether (PPE) has high rigidity, high heat resistance, flame retardancy, high strength, excellent electrical properties, wear resistance, non-toxicity, and pollution resistance. Both liquid crystal polymers and PPE themselves have excellent corrosion resistance, dielectric properties, and mechanical properties. The composite material obtained by mixing them in a certain ratio not only has excellent dielectric properties, but also improves the toughness of the composite material.

[0027] (2) The hollow nanospheres have good electrical insulation properties. Their hollow structure can significantly reduce the dielectric loss and dielectric constant of the composite material. The nano-sized microspheres can also be better dispersed in the composite material, promoting the uniform distribution of phases, making the material properties more uniform and stable, and improving the comprehensive performance of the composite material.

[0028] (3) Glass fiber has good dielectric properties and heat resistance, and low moisture absorption, which improves the mechanical properties of composite materials such as impact resistance, tensile strength, and flexural strength.

[0029] (4) Mica powder is used as a functional filler for plastics, coatings, paints, rubber, etc. The proportion of mica powder disclosed in this application can improve its mechanical strength, enhance its toughness, adhesion, anti-aging and corrosion resistance. The uniform doping of mica powder can reduce the non-uniform shrinkage of the composite material, effectively prevent the warping problem of the liquid crystal composite material during processing and use, significantly improve the anti-warping performance of the liquid crystal composite material, and improve the stability of the liquid crystal composite material to a certain extent.

[0030] (5) The liquid crystal composite material treated with silane coupling agent can promote the mixing of raw materials to a certain extent, improve the friction and wear performance and mechanical properties of the composite material, and improve the stability of the composite material to a certain extent; by using compatibilizer, the interfacial tension between raw materials is reduced, the interfacial adhesion between raw materials is improved, and the compatibility of the composite material is improved; the addition of a certain antioxidant can effectively reduce the thermo-oxidative degradation of the liquid crystal composite material, improve its corrosion resistance, and maintain good mechanical properties for a long time.

[0031] (6) The preparation method of the composite material in this application has the advantages of low manufacturing cost, simple processing and easy industrial-scale production.

[0032] In summary, the liquid crystal polymer used in this application possesses high strength, high modulus, high heat resistance, and low dielectric properties, as well as excellent bending resistance, chemical corrosion resistance, aging resistance, high radiation resistance, and molding and processing performance. Polyphenylene ether (PPE) exhibits advantages such as high rigidity, high heat resistance, flame retardancy, high strength, excellent electrical properties, wear resistance, non-toxicity, and pollution resistance. Furthermore, its dielectric constant and dielectric loss are among the lowest of engineering plastics, almost unaffected by temperature and humidity. However, PPE is a Newtonian fluid with poor flowability, its viscosity is highly sensitive to temperature, and it decomposes very easily.

[0033] The composite material prepared by the proportions and methods disclosed in this application overcomes the shortcomings of polyphenylene ether, such as its extremely poor processing and molding performance and the inability of pure polyphenylene ether to be injection molded. The prepared composite material combines the excellent properties of liquid crystal polymers and polyphenylene ether, and has advantages such as excellent dielectric properties, radiation resistance, corrosion resistance, flame resistance, aging resistance, and low density, which meet the requirements of 5G antennas. Furthermore, the preparation method reduces costs, is easy to industrialize, and has good development prospects and application value. Detailed Implementation

[0034] The following examples will provide a more detailed explanation of the specific content of the present invention. It should be noted that: unless otherwise specified, the conditions in the following examples are performed under conventional conditions or conditions recommended by the manufacturer. Unless otherwise specified, the raw materials used in the following examples are all from commercially available sources.

[0035] In the embodiments of this application, the hollow nanospheres have a size of 50-500 nm; the mica powder has a particle size of 100-500 mesh.

[0036] The mica powder comprises the following raw materials in molar fractions: 8 parts T001 mica powder, 8 parts 400YD mica powder, 8 parts GH-605 mica powder, and 8 parts GM-8 mica powder.

[0037] The coupling agent is obtained by mixing 3-aminopropyltriethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, isopropyltris(dioctylphosphoyloxy)titanate and zirconium propoxide in a molar ratio of 1:1:1:1.

[0038] The compatibilizer is prepared by mixing maleic anhydride-grafted polyolefin, ethylene-acrylate terpolymer-grafted glycidyl ester, imide-modified acrylate (3 parts) and m-isopropenyl-2,2-dimethylbenzoyl isocyanate in a molar ratio of 1:1:1:

[0039] The antioxidant is obtained by mixing 1,3,5-tris(3,5-di-tert-butyl-4-hydroxyphenyl) isocyanate, tris(2,4-di-tert-butylphenyl) phosphite, and 2,6-di-tert-butyl-p-cresol in a molar ratio of 1:1:1.

[0040] The bis(4-(chlorocarbonyl)phenyl) terephthalate in this application is prepared by a method comprising the following steps: 10-50 parts of terephthalic acid and 50-300 parts of 4-hydroxybenzoyl chloride are added to a flask, followed by 10-60 drops of concentrated sulfuric acid. The mixture is heated in an oil bath to 60-100°C, mechanically stirred, and cooled under reflux using a spherical condenser. The reaction is stopped after 3-6 hours. The reaction solution is poured into sufficient ice water, stirred, and the precipitated solid is filtered and purified by column chromatography to obtain bis(4-(chlorocarbonyl)phenyl) terephthalate.

[0041] The bis(4-(chlorocarbonyl)phenyl) terephthalate used in the embodiments of this application was prepared by the following method: 30 parts of terephthalic acid and 150 parts of 4-hydroxybenzoyl chloride were added to a flask, and then 35 drops of concentrated sulfuric acid were added dropwise. The oil bath was heated to 80°C, mechanically stirred, and cooled under reflux with a spherical condenser. The reaction was stopped after 3-6 hours. The reaction solution was poured into sufficient ice water and stirred. The precipitated solid was filtered and purified by column chromatography to obtain bis(4-(chlorocarbonyl)phenyl) terephthalate.

[0042] The raw material naphthalene compound in this application embodiment, namely 4-4 bis(dihydroxyalkoxy)naphthalene, is prepared by a method including the following steps: 10-50 parts of [2,2'-binaphthyl]-6,6'-diol and 20-200 parts of n-chloroX acetate are placed in a flask containing 10-300 ml of isopropanol and 1-3 ml of water. While stirring and refluxing, argon gas is introduced to remove oxygen. While heating, 2-20 parts of 20% NaOH aqueous solution are added dropwise. The heating temperature is 60-90℃, and the reaction is carried out for 5-10 hours. The precipitate after the reaction is washed with distilled water and isopropanol, purified by column chromatography, and dried in a vacuum drying oven to obtain 4-4 bis(dihydroxyalkoxy)naphthalene.

[0043] When n=2 in the naphthalene compound, the n-chloroX ester of acetate in the raw material is 2-chloroethyl acetate;

[0044] When n=4 in the naphthalene compound, the n-chloroX ester of acetate in the raw material is 4-chlorobutyl acetate;

[0045] When n=6 in the naphthalene compound, the n-chloroX ester of acetate in the raw material is 6-chlorohexyl acetate;

[0046] When n=8 in the naphthalene compound, the n-chloroX ester of acetate in the raw material is 8-chlorooctyl acetate.

[0047] The structural formula of [2,2'-binaphthyl]-6,6'-diol is as follows:

[0048]

[0049] The structural formula of n-chloroX acetate is as follows:

[0050]

[0051] Preparation examples of liquid crystal polymers

[0052] Preparation Example 1

[0053] A method for preparing a liquid crystal polymer includes the following steps:

[0054] Take 50 parts of bis(4-(chlorocarbonyl)phenyl) terephthalate and 50 parts of binaphthalene compound, and put them into a microwave reactor equipped with a magnetic stirrer and an argon gas conduit. First, dry argon gas is introduced for 15 min, and then the temperature of the reactor is gradually increased to 200℃ at a heating rate of 1℃ / min by microwave. Argon gas is continuously introduced, and the temperature is further increased to 220℃ for 10 h. The microwave frequency is 2450MHz and the microwave power is 900W. After cooling, dichloromethane is added and filtered, then tetrahydrofuran is added, and the mixture is dried under vacuum and ground to obtain a liquid crystal polymer.

[0055] Preparation Example 2

[0056] A method for preparing a liquid crystal polymer includes the following steps:

[0057] 100 parts of bis(4-(chlorocarbonyl)phenyl) terephthalate and 100 parts of a binaphthalene compound were placed in a microwave reactor equipped with a magnetic stirrer and an argon gas conduit. Dry argon gas was first introduced for 20 min, and then the temperature of the reactor was gradually increased to 200 °C at a heating rate of 1 °C / min using microwave. Argon gas was continuously introduced, and the temperature was further increased to 220 °C for 10 h. The microwave frequency was 2450 MHz and the microwave power was 900 W. After cooling, dichloromethane was added and filtered, followed by the addition of tetrahydrofuran. The mixture was then dried under vacuum and ground to obtain a liquid crystal polymer.

[0058] Example

[0059] Example 1

[0060] A method for preparing a liquid crystal composite material for 5G antennas includes the following steps:

[0061] 80 parts of liquid crystal polymer, 50 parts of polyphenylene ether, 10 parts of glass fiber, 10 parts of hollow nanospheres, 8 parts of mica powder, 5 parts of coupling agent, 4 parts of compatibilizer and 1 part of antioxidant were dried at 140℃ and then uniformly mixed. The mixture was then melt-blended, extruded, stretched, cooled and granulated using an extrusion equipment to obtain a liquid crystal composite material. The temperatures of the extrusion equipment were as follows: Zone 1: 280℃, Zone 2: 300℃, Zone 3: 310℃, Zone 4: 320℃, Zone 5: 310℃, Zone 6: 300℃, Zone 7: 290℃, Zone 8: 280℃, Zone 9: 270℃ and Zone 10: 260℃.

[0062] Examples 2-8

[0063] A method for preparing a liquid crystal composite material for 5G antennas is carried out according to the method in Example 1, with specific differences shown in Table 1.

[0064] Table 1:

[0065]

[0066]

[0067] Comparative Example

[0068] Comparative Example 1

[0069] A method for preparing a liquid crystal composite material for 5G antennas is carried out according to the method in Example 4, except that no nano-hollow microspheres are added to the raw materials.

[0070] Performance testing

[0071] The performance tests of the above embodiments and comparative examples were carried out, and the test results are shown in Table 2.

[0072] Table 2:

[0073]

Claims

1. A liquid crystal composite material for a 5G antenna, characterized by, Raw materials including the following components in the amount of parts by weight: liquid crystal polymer 80-120 parts, polyphenyl ether 50-80 parts, glass fiber 10-15 parts, hollow nanometer microspheres 10-15 parts, mica powder 8-10 parts, coupling agent 3-8 parts, compatibilizer 2-5 parts, antioxidant 0.5-2 parts; The liquid crystal polymer is prepared by a solution condensation polymerization method, and the structure of the liquid crystal polymer is as follows: wherein n=2-10, and the polymer molecular weight is in the range of 3000-50000; The liquid crystal polymer is prepared by a method including the following steps: Take 50-100 parts of bis(4-(chlorocarbonyl)phenyl) terephthalate and 50-100 parts of binaphthalene compound, and load them into a microwave reactor with a magnetic stirring device and an argon gas conduit. First, dry argon is introduced for 15-30 minutes. Then, the reactor is gradually heated to 190-220°C at a temperature increasing rate of 1-2°C / min by microwave. The argon gas is continuously introduced, and the temperature is continuously increased to 220-240°C for 10 hours. The microwave frequency is 2350-2500 MHz, and the microwave power is 400-1500 W. After cooling, dichloromethane is added for filtration. Then, tetrahydrofuran is added, and vacuum drying is performed. Grinding obtains the liquid crystal polymer. The structure of the bis(4-(chlorocarbonyl)phenyl) terephthalate is as follows: ； The binaphthalene compound is 4-4 bis(dihydroxyalkoxy) binaphthalene. The structure of the bis(4-(chlorocarbonyl)phenyl) terephthalate is as follows, and n=2-10. ； The hollow nanometer microspheres are one or more of silicon dioxide nanometer hollow microspheres, gallium nitride hollow nanometer microspheres, and boron nitride hollow nanometer microspheres. The glass fiber is alkali-free and twist-free roving long glass fiber. The cross-sectional length of the glass fiber is 10-20 microns, the cross-sectional width is 2-10 microns, and the flatness ratio is 1-5:

1.

2. The liquid crystal composite for 5G antenna according to claim 1, characterized in that: The mica powder includes the following raw materials in the amount of parts by weight: T001 mica powder 8-10 parts, 400YD mica powder 8-10 parts, GH-605 mica powder 8-10 parts, and GM-8 mica powder 8-10 parts. 3.The liquid crystal composite material for 5G antenna of claim 1, wherein: The coupling agent is two or more of 3-aminopropyl triethoxysilane, γ-methacryloyloxypropyl trimethoxysilane, isopropyl tri(dioctyl phosphoric acyloxy) titanate, and n-propyl alcohol zirconium. 4.The liquid crystal composite material for 5G antenna of claim 1, wherein: The compatibilizer is two or more of maleic anhydride grafted polyolefin, ethylene-acrylate terpolymer grafted glycidyl ester, imide modified acrylate, and m-isopropenyl-2,2-dimethyl benzoyl isocyanate.

5. The liquid crystal composite material for 5G antenna according to claim 1, characterized in that: The antioxidant is two or more of 1,3,5-tris(3,5-di-tert-butyl-4-hydroxyphenyl) isocyanate, tris(2,4-di-tert-butylphenyl) phosphite, and 2,6-di-tert-butyl-p-cresol.

6. The method of claim 1-5, wherein the liquid crystal composite for 5G antenna is prepared by the following steps: 1) mixing the liquid crystal material, the polymer material and the magnetic material to obtain a mixture; 2) coating the mixture on a substrate to obtain a liquid crystal composite; 3) curing the liquid crystal composite to obtain the liquid crystal composite for 5G antenna. The method includes the following steps: uniformly mixing the raw materials after drying treatment at 120-150°C, melt mixing, extruding, drawing, cooling, and granulating by extrusion equipment to obtain the liquid crystal composite material.

7. The method for preparing a liquid crystal composite material for a 5G antenna according to claim 6, characterized in that: The temperature of the first zone of the extrusion equipment is 280-300℃, the temperature of the second zone is 300-320℃, the temperature of the third zone is 300-320℃, the temperature of the fourth zone is 300-320℃, the temperature of the fifth zone is 290-310℃, the temperature of the sixth zone is 290-310℃, the temperature of the seventh zone is 270-290℃, the temperature of the eighth zone is 260-280℃, the temperature of the ninth zone is 250-270℃, and the temperature of the tenth zone is 240-260℃.

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