Polypropylene material for lens antenna and preparation method thereof

Abstract

The invention relates to the technical field of high polymer materials, and provides a polypropylene material for a lens antenna and a preparation method of the polypropylene material. The polypropylene material for the lens antenna comprises the following raw materials in parts by weight: 70-90 parts of polypropylene, 15-20 parts of polyimide, 10-15 parts of modified hollow glass beads, 2-5 parts of a compatilizer, 1-2 parts of a nucleating agent, 0.4-1 part of an antioxidant, 0.5-1 part of a lubricant and 3-7 parts of a foaming agent, wherein the modified hollow glass beads are obtained by modifying hollow glass beads with 4-amino-2-hydroxytoluene. According to the technical scheme, the problem that the dielectric constant of a lens material in the related technology is large is solved.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, specifically to a polypropylene material for lens antennas and its preparation method. Background Technology

[0002] With the rapid development of technologies such as 5G communication and millimeter-wave radar, lens antennas, due to their advantages such as low profile, high gain, and narrow beamwidth, are widely used in communication base stations, autonomous driving, and satellite communication, placing higher demands on signal transmission accuracy and low attenuation. The core component of a lens antenna is the lens, commonly made from polymers such as polytetrafluoroethylene (PTFE), polystyrene, and polypropylene. For lenses, the dielectric constant of the material is a key indicator determining the antenna's signal transmission efficiency and operational stability. A higher dielectric constant results in slower electromagnetic wave transmission speeds and more significant phase delays, not only reducing antenna gain and sensitivity but also necessitating a larger lens volume to compensate for the focusing effect.

[0003] Among various lens materials, polypropylene is widely used in low- and mid-frequency lenses due to its low cost and good processability. However, its dielectric constant remains relatively high in high-frequency lenses, making it difficult to meet the performance requirements of high-frequency lens antennas. Existing technologies often use inorganic fillers such as hollow glass microspheres to reduce the dielectric constant. However, these inorganic fillers are prone to agglomeration in the polypropylene matrix, resulting in a less than expected reduction in dielectric constant. Therefore, a polypropylene material for lens antennas and its preparation method are needed. Summary of the Invention

[0004] This invention proposes a polypropylene material for lens antennas and its preparation method, which solves the problem of high dielectric constant of lens materials in related technologies.

[0005] The technical solution of the present invention is as follows: This invention proposes a polypropylene material for lens antennas, comprising the following raw materials in parts by weight: 70-90 parts polypropylene, 15-20 parts polyimide, 10-15 parts modified hollow glass microspheres, 2-5 parts compatibilizer, 1-2 parts nucleating agent, 0.4-1 part antioxidant, 0.5-1 part lubricant, and 3-7 parts foaming agent; wherein the modified hollow glass microspheres are obtained by modifying hollow glass microspheres with 4-amino-2-hydroxytoluene.

[0006] As a further technical solution, the mass of 4-amino-2-hydroxytoluene in the raw material of the modified hollow glass microspheres is 4% to 5% of the mass of the hollow glass microspheres, preferably 4.5%.

[0007] In the modified hollow glass microspheres of polypropylene material for lens antennas of this invention, when the mass of 4-amino-2-hydroxytoluene is 4% to 5% of the mass of the hollow glass microspheres, the dielectric constant of the polypropylene material for lens antennas can be further reduced. When the mass of 4-amino-2-hydroxytoluene is less than 4% of the mass of the hollow glass microspheres, the modifier cannot completely cover the surface of the hollow glass microspheres, resulting in insufficient modification effect, easy agglomeration of microspheres, and difficulty in effectively reducing the dielectric constant. When the mass of 4-amino-2-hydroxytoluene is greater than 5% of the mass of the hollow glass microspheres, the excess modifier will form a free state in the system, leading to defects inside the material and affecting the performance of the lens antenna material. When the mass of 4-amino-2-hydroxytoluene is 4% to 5% of the mass of the hollow glass microspheres, the modifier 4-amino-2-hydroxytoluene can form a uniform and dense modified layer on the surface of the hollow glass microspheres, thereby improving the dispersibility of the hollow glass microspheres and effectively reducing the dielectric constant of the polypropylene material for lens antennas.

[0008] As a further technical solution, the preparation method of the modified hollow glass microspheres includes the following steps: dispersing 4-amino-2-hydroxytoluene in a solvent, then adding hollow glass microspheres and mixing, and drying to obtain modified hollow glass microspheres.

[0009] As a further technical solution, the mass-to-volume ratio of the hollow glass microspheres to the solvent is 1g:9mL.

[0010] As a further technical solution, the solvent is anhydrous ethanol.

[0011] As a further technical solution, the particle size of the hollow glass microspheres is 10~50μm.

[0012] As a further technical solution, the polyimide includes a first polyimide and a second polyimide, wherein the first polyimide and the second polyimide have different densities.

[0013] As a further technical solution, the density of the first polyimide is 1.73 g / cm³. 3 The density of the second polyimide is 1.44 g / cm³. 3 .

[0014] In this invention, the mechanical strength of the polypropylene material for lens antennas can be improved by adding a polyimide composed of two polyimides with different densities. The first polyimide, with a higher density, has a relatively denser molecular chain stacking structure and better mechanical properties. When introduced into the polypropylene matrix as a reinforcing component, it can improve the overall load-bearing capacity of the material system. The second polyimide, with a lower density, has larger molecular chain gaps and better interfacial compatibility with the polypropylene matrix. Furthermore, the two polyimides of different densities can form a differentiated distribution in the polypropylene matrix, allowing for better stress transmission and dispersion when the material is under stress. This avoids mechanical property degradation caused by localized stress concentration, further improving the mechanical strength of the polypropylene material for lens antennas.

[0015] As a further technical solution, the mass ratio of the first polyimide to the second polyimide is 3~7:4.

[0016] As a further technical solution, the compatibilizer includes one or two of maleic anhydride-grafted polypropylene and styrene-maleic anhydride copolymer.

[0017] As a further technical solution, the nucleating agent includes one or both of NA-11 nucleating agent and NA-21 nucleating agent.

[0018] As a further technical solution, the antioxidant includes one or more of antioxidant 1010, antioxidant 1076, and antioxidant 168.

[0019] As a further technical solution, the lubricant includes one or more of polyethylene wax, butyl stearate, and pentaerythritol tetrastearate.

[0020] As a further technical solution, the foaming agent includes one or two of azodicarbonamide and 4,4'-oxobisbenzenesulfonylhydrazine.

[0021] This invention also proposes a method for preparing polypropylene material for lens antennas, comprising the following steps: S1. Mix the remaining raw materials except for the foaming agent, and then melt-extrude them to obtain the mixture; S2. After mixing the mixture with the foaming agent, the lens antenna is made of polypropylene material through injection molding.

[0022] As a further technical solution, in step S1, the mixing time is 2-3 minutes.

[0023] As a further technical solution, in step S1, the mixing speed is 250~350 rpm.

[0024] As a further technical solution, a screw extruder is used for melt extrusion, wherein the screw speed of the screw extruder is 100~200 rpm, the barrel temperature is 160~200℃, and the die temperature is 200~220℃.

[0025] The working principle and beneficial effects of this invention are as follows: In this invention, the polypropylene material for lens antennas utilizes 4-amino-2-hydroxytoluene to modify hollow glass microspheres. This significantly improves the dispersibility of the microspheres within the polypropylene matrix, thereby effectively addressing the issue of the high dielectric constant of the polypropylene material. Specifically, the amino and hydroxyl groups contained in the 4-amino-2-hydroxytoluene molecule can form stable connections with the hydroxyl groups on the surface of the hollow glass microspheres through hydrogen bonds, constructing an organic modified layer on the microsphere surface. This modified layer can significantly reduce the aggregation phenomenon between hollow glass microspheres, allowing them to be uniformly dispersed within the polypropylene matrix. This enables the hollow glass microspheres to fully exert their effect of reducing the dielectric constant, meeting the requirements for lens antenna applications. Detailed Implementation

[0026] 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.

[0027] In the following examples and comparative examples, polypropylene, grade HG385MO, was purchased from Dongguan Shanjin Plastic Raw Materials Co., Ltd.; hollow glass microspheres, particle size 20μm; maleic anhydride-grafted polypropylene, model MP101, was purchased from Dongguan Kangjin New Material Technology Co., Ltd.; styrene-maleic anhydride copolymer, item number SMA003, was purchased from Guangdong Ruihua New Material Co., Ltd.; polyethylene wax, item number CJ-95, was purchased from Linyi Chengju Chemical Co., Ltd.; and the first polyimide had a density of 1.73 g / cm³. 3 The material, SP-2512, was purchased from Guangzhou Jiushun New Materials Co., Ltd.; the second polyimide has a density of 1.44 g / cm³. 3 The product, designated SCP-50094DF, was purchased from Guangzhou Jiushun New Materials Co., Ltd.

[0028] Example 1 A method for preparing polypropylene material for lens antennas includes the following steps: S1. 70 parts polypropylene, 15 parts polyimide, 10 parts modified hollow glass microspheres, 2 parts maleic anhydride-grafted polypropylene, 1 part NA-11 nucleating agent, 0.4 parts antioxidant 1010, and 0.5 parts polyethylene wax were mixed at 300 rpm for 3 minutes. The mixture was then melt-extruded using a screw extruder at 150 rpm, a barrel temperature of 180°C, and a die temperature of 210°C to obtain the mixture. The polyimide in this mixture was only the first polyimide (density 1.73 g / cm³). 3 ); S2. After mixing the mixture with 3 parts of azodicarbonamide, the mixture is foamed and injection molded to obtain polypropylene material for lens antennas; The method for preparing modified hollow glass microspheres includes the following steps: dispersing 4-amino-2-hydroxytoluene in anhydrous ethanol, then adding hollow glass microspheres and mixing, and drying to obtain modified hollow glass microspheres; wherein, the mass of 4-amino-2-hydroxytoluene is 4% of the mass of hollow glass microspheres, and the mass-volume ratio of hollow glass microspheres to anhydrous ethanol is 1g:9mL.

[0029] Example 2 Compared with Example 1, the only difference in Example 2 is that the preparation method of the polypropylene material for the lens antenna in this example includes the following steps: S1. 80 parts polypropylene, 18 parts polyimide, 13 parts modified hollow glass microspheres, 4 parts maleic anhydride-grafted polypropylene, 1.5 parts NA-21 nucleating agent, 0.7 parts antioxidant 1076, and 0.8 parts butyl stearate were mixed at 300 rpm for 3 minutes. The mixture was then melt-extruded using a screw extruder at 150 rpm, a barrel temperature of 180°C, and a die temperature of 210°C to obtain the mixture. The polyimide in this mixture was only the first polyimide (density 1.73 g / cm³). 3 ); S2. After mixing the mixture with 5 parts of azodicarbonamide, the polypropylene material for lens antennas is obtained by foaming injection molding.

[0030] Example 3 Compared with Example 1, the only difference in Example 3 is that the preparation method of the polypropylene material for the lens antenna in this example includes the following steps: S1. 90 parts polypropylene, 20 parts polyimide, 15 parts modified hollow glass microspheres, 5 parts styrene-maleic anhydride copolymer, 2 parts NA-11 nucleating agent, 1 part antioxidant 168, and 1 part pentaerythritol tetrastearate were mixed at 300 rpm for 3 minutes. The mixture was then melt-extruded using a screw extruder at 150 rpm, a barrel temperature of 180°C, and a die temperature of 210°C to obtain the mixture. The polyimide in this mixture is only the first polyimide (density 1.73 g / cm³). 3 ); S2. After mixing the mixture with 7 parts of 4,4'-oxybisbenzenesulfonylhydrazine, the mixture is foamed and injection molded to obtain polypropylene material for lens antennas.

[0031] Example 4 Compared with Example 1, the only difference in Example 4 is that in the preparation method of the modified hollow glass microspheres in this example, the mass of 4-amino-2-hydroxytoluene is 4.5% of the mass of the hollow glass microspheres.

[0032] Example 5 Compared with Example 1, the only difference in Example 5 is that in the preparation method of the modified hollow glass microspheres in this example, the mass of 4-amino-2-hydroxytoluene is 5% of the mass of the hollow glass microspheres.

[0033] Example 6 Compared to Example 1, the only difference in Example 6 is that the polyimide in this example is composed of a first polyimide with a mass ratio of 3:4 (density 1.73 g / cm³). 3 ) and second polyimide (density 1.44 g / cm³) 3 )composition.

[0034] Example 7 Compared to Example 1, the only difference in Example 7 is that the polyimide in this example is composed of a first polyimide with a mass ratio of 5:4 (density 1.73 g / cm³). 3 ) and second polyimide (density 1.44 g / cm³) 3 )composition.

[0035] Example 8 Compared to Example 1, the only difference in Example 8 is that the polyimide in this example is composed of a first polyimide with a mass ratio of 7:4 (density 1.73 g / cm³). 3 ) and second polyimide (density 1.44 g / cm³) 3 )composition.

[0036] Example 9 Compared to Example 1, the only difference in Example 9 is that the polyimide in this example is only a second polyimide (with a density of 1.44 g / cm³). 3 ).

[0037] Comparative Example 1 Compared with Example 1, the only difference in Comparative Example 1 is that the modified hollow glass microspheres were replaced with an equal amount of hollow glass microspheres.

[0038] The polypropylene lens antennas prepared in Examples 1-9 were tested according to the following method: 1. Dielectric constant: The dielectric constant of the polypropylene material used for the lens antenna was tested according to the test method specified in standard GB / T 1409-2006 "Recommended method for measuring the permittivity and dielectric loss factor of electrical insulating materials at power frequency, audio frequency and high frequency (including meter wave wavelength)". The test conditions were 100mm×100mm×3mm, 23℃, and 2.5GHz.

[0039] 2. Tensile strength test: The tensile strength of the polypropylene material for the lens antenna was tested according to the test method specified in ISO 527-2:2012 "Determination of tensile properties of plastics - Part 2: Test conditions for molding and extrusion plastics". The tensile strength was tested at a tensile rate of 10 mm / min.

[0040] The test results are shown in Tables 1 and 2: Table 1. Test results of dielectric constant of polypropylene material for lens antennas

[0041] As shown in Table 1, the comparison between Examples 1-5 and Comparative Example 1 indicates that the addition of 4-amino-2-hydroxytoluene-modified hollow glass microspheres can reduce the dielectric constant of the polypropylene material used in lens antennas.

[0042] Table 2. Test results of dielectric constant of polypropylene material for lens antennas

[0043] As shown in Table 2, the comparison of Examples 1, 6-9 indicates that when the polyimide is composed of a first polyimide and a second polyimide, the tensile strength of the polypropylene material used for lens antennas can be improved.

[0044] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A polypropylene material for a lens antenna, characterized by, The raw material comprises the following components in parts by weight: polypropylene 70-90 parts, polyimide 15-20 parts, modified hollow glass microbeads 10-15 parts, compatibilizer 2-5 parts, nucleating agent 1-2 parts, antioxidant 0.4-1 part, lubricant 0.5-1 part, and foaming agent 3-7 parts. The modified hollow glass microbeads are obtained by modifying hollow glass microbeads with 4-amino-2-hydroxytoluene.

2. The polypropylene material for a lens antenna according to claim 1, wherein The mass of 4-amino-2-hydroxytoluene in the raw material of the modified hollow glass microbeads is 4%-5% of the mass of the hollow glass microbeads.

3. The polypropylene material for a lens antenna according to claim 1, wherein The preparation method of the modified hollow glass microbeads comprises the following steps: dispersing 4-amino-2-hydroxytoluene in a solvent, then adding hollow glass microbeads, and drying to obtain the modified hollow glass microbeads.

4. The polypropylene material for a lens antenna according to claim 1, wherein The particle size of the hollow glass microbeads is 10-50 μm.

5. The polypropylene material for a lens antenna according to claim 1, wherein The polyimide comprises a first polyimide and a second polyimide, and the first polyimide and the second polyimide have different densities.

6. The polypropylene material for a lens antenna according to claim 5, wherein The first polyimide has a density of 1.73 g / cm 3 The second polyimide has a density of 1.44 g / cm 3 .

7. The polypropylene material for a lens antenna according to claim 5, wherein The mass ratio of the first polyimide to the second polyimide is 3-7:

4.

8. A process for the preparation of a polypropylene material for lens antennas, for the preparation of a polypropylene material for lens antennas as claimed in any one of claims 1-7, characterized in that, The method comprises the following steps: S1, mixing the remaining raw materials except the foaming agent, and then melt extruding to obtain a mixture; S2, mixing the mixture with the foaming agent, and then foaming injection molding to obtain the polypropylene material for a lens antenna.

9. A method for preparing a polypropylene material for a lens antenna according to claim 8, characterized in that, In step S1, the mixing time is 2-3 min.

10. A method for preparing a polypropylene material for a lens antenna according to claim 8, characterized in that, The melt extrusion is performed by using a screw extruder, the screw rotation speed of the screw extruder is 100-200 rpm, the barrel temperature is 160-200 ℃, and the die temperature is 200-220 ℃.

Images