Polypropylene wave-absorbing material and preparation method thereof

Abstract

The application relates to the technical field of composite materials, and particularly discloses a polypropylene wave-absorbing material and a preparation method thereof. The polypropylene wave-absorbing material provided by the application comprises the following components in parts by weight: 85-95 parts of polypropylene, 5-12 parts of inorganic wave-absorbing composite filler, 2-4 parts of a compatilizer, 0.1-0.2 parts of an antioxidant, and 0.03-0.06 parts of a lubricant; the inorganic wave-absorbing composite filler is a mixture of carbon fibers, tantalum pentoxide and glass microbeads; further, the weight ratio of the carbon fibers, the tantalum pentoxide and the glass microbeads is 1:(0.2-0.3):(0.3-0.4); and the application further provides a preparation method of the polypropylene wave-absorbing material. The polypropylene wave-absorbing material provided by the application has the advantages of light texture, excellent electromagnetic wave absorption effect, high-temperature resistance and the like, and has a wide application prospect in the fields of automobiles and electronic equipment.

Description

Technical Field

[0001] The present application relates to the technical field of composite materials, and in particular to a polypropylene absorbing material and a preparation method thereof. Background Art

[0002] With the rapid advancement of technology, electromagnetic waves are increasingly being used in various fields, such as communications, electronic devices, and automobiles. Electromagnetic wave absorbing materials are crucial for ensuring the proper functioning of equipment and reducing electromagnetic interference. Their performance directly impacts the stability and reliability of the entire system. Furthermore, the continuous trend toward miniaturization and lightweighting in automobiles and electronic devices has created an increasingly urgent need to develop high-performance electromagnetic wave absorbing materials that can adapt to this trend.

[0003] Currently, the preparation of electromagnetic wave absorbing materials mainly includes the following methods: first, filling the material with microbeads to improve the material's electromagnetic wave absorption performance; second, covering the material surface with a layer of metal to enhance the reflection and absorption of electromagnetic waves; and third, evenly dispersing metal particles in the material to change the material's electromagnetic properties. However, while these methods can improve the material's wave absorption properties to a certain extent, they often increase the weight of the accessories, which is contrary to the development trend of miniaturization and lightweighting of automobiles and electronic equipment. More seriously, under certain high-temperature conditions, these absorbing materials are not ideal for electromagnetic wave absorption, which may in turn increase signal interference between different receivers and affect the normal operation of the equipment.

[0004] Therefore, there is an urgent need to improve existing absorbing materials to achieve lightweight while ensuring good electromagnetic wave absorption effect. Summary of the Invention

[0005] In order to overcome the problems of existing absorbing materials such as heavy weight and unsatisfactory electromagnetic wave absorption effect, the present application provides a polypropylene absorbing material and a preparation method thereof.

[0006] The polypropylene absorbing material provided in this application adopts the following technical solution:

[0007] A polypropylene wave-absorbing material comprises the following components in parts by weight: 85-95 parts of polypropylene, 5-12 parts of inorganic wave-absorbing composite filler, 2-4 parts of compatibilizer, 0.1-0.2 parts of antioxidant, and 0.03-0.06 parts of lubricant.

[0008] The inorganic wave-absorbing composite filler is a mixture of carbon fiber, tantalum pentoxide and glass microbeads.

[0009] This application provides a polypropylene absorbing material. By using a mixture of carbon fiber, tantalum pentoxide, and glass microspheres as the primary absorber, this material not only achieves excellent electromagnetic wave absorption (low transmission and low reflection) but also significantly reduces its weight, achieving lightweighting. This lightweight material is well-suited to the trend toward miniaturization and lightweighting in automotive and electronic equipment, meeting the stringent weight requirements. Furthermore, the polypropylene absorbing material provided in this application exhibits excellent heat resistance, absorbing electromagnetic waves effectively in ordinary environments and adapting to specific high-temperature operating scenarios (such as the high temperatures around headlights in a vehicle). In summary, the polypropylene absorbing material provided in this application demonstrates outstanding performance in multiple aspects, including weight, absorption, anti-interference, and high-temperature resistance, and possesses broad applicability and market prospects.

[0010] In this application, carbon fibers can effectively absorb electromagnetic waves within a wide high-frequency band (75-110 GHz), reducing their reflection and propagation. Furthermore, carbon fibers are lightweight and high-temperature resistant, meeting the lightweight and excellent high-temperature electromagnetic wave absorption requirements of polypropylene absorbers. Tantalum pentoxide has a high dielectric constant and polarization loss. Its excellent dielectric properties enhance the polarization loss of electromagnetic waves, achieving excellent electromagnetic wave absorption. Furthermore, nano-tantalum pentoxide has a small particle size (nanoscale) and a high specific surface area, which increases multiple scattering, reduces electromagnetic wave reflection, and significantly attenuates the energy of transmitted waves, thereby improving electromagnetic wave absorption and effectively preventing signal interference between different receivers. However, the large variation in aspect ratio of carbon fibers can lead to significant orientation issues after molding, resulting in significant differences in shrinkage in the flow direction and perpendicular to the flow direction, making the material susceptible to deformation. Glass microspheres, on the other hand, are spherical in shape, which alleviates these orientation issues during molding, making the material less susceptible to deformation and improving the stability of the resulting polypropylene absorber.

[0011] In some embodiments, the weight proportion of the inorganic wave absorbing composite filler may be 5-8 parts, 5-10 parts, 8-10 parts, 8-12 parts or 10-12 parts.

[0012] In a specific embodiment, the weight proportion of the inorganic wave absorbing composite filler may be 5 parts, 8 parts, 10 parts or 12 parts.

[0013] Optionally, the polypropylene absorbing material comprises the following components in parts by weight: 85-95 parts of polypropylene, 8-10 parts of inorganic absorbing composite filler, 2-4 parts of compatibilizer, 0.1-0.2 parts of antioxidant, and 0.03-0.06 parts of lubricant.

[0014] Optionally, the weight ratio of the carbon fiber, tantalum pentoxide and glass microbeads is 1:(0.2-0.3):(0.3-0.4).

[0015] In this application, the inventors discovered that the compounding ratio of carbon fiber, tantalum pentoxide and glass microbeads in the inorganic absorbing composite filler affects the electromagnetic wave absorption performance of the polypropylene absorbing material. Through experimental research, they found that by further controlling the weight ratio of carbon fiber, tantalum pentoxide and glass microbeads within the above range, the obtained polypropylene absorbing material has a maximum reflection loss of ≤-8.0 dB and a minimum of ≤-17.0 dB in the 75-110 GHz frequency band; the maximum transmission loss is ≤-20.0 dB and the minimum is ≤-35.0 dB.

[0016] In some embodiments, the weight ratio of the carbon fiber, tantalum pentoxide and glass microspheres can be 1: (0.1-0.2): 0.35, 1: (0.1-0.25): 0.35, 1: (0.1-0.3): 0.35, 1: (0.1-0.4): 0.35, 1: (0.2-0.25): 0.35, 1: (0.2-0.3): 0.35, 1: (0.2-0.4): 0.35, 1: (0.25-0.3): 0.35, 1: (0.25-0.4): 0.35, 1: (0.3-0.4): 0.35, 1: 0.25: (0.2-0.3), 1: 0.25: (0.2-0.35), 1: 0.25: (0.2-0.4), 1: 0.25: (0.2-0.5), 1: 0.25: (0.3-0.35), 1: 0.25: (0.3-0.4), 1: 0.25: (0.3-0.5), 0.25: (0.35-0.4), 1: 0.25: (0.35-0.5) or 1: 0.25: (0.4-0.5).

[0017] In a specific embodiment, the weight ratio of the carbon fiber, tantalum pentoxide and glass microspheres is 1:0.1:0.35, 1:0.2:0.35, 1:0.25:0.35, 1:0.3:0.35, 1:0.4:0.35, 1:0.25:0.2, 1:0.25:0.3, 1:0.25:0.4 or 1:0.25:0.5.

[0018] Optionally, the weight ratio of the carbon fiber, tantalum pentoxide and glass microbeads is 1:0.25:0.35.

[0019] Optionally, the melt index of the polypropylene is 30 g / 10 min.

[0020] Optionally, the compatibilizer is a maleic anhydride grafted compatibilizer.

[0021] Optionally, the antioxidant is antioxidant 1010 and antioxidant 168.

[0022] Optionally, the lubricant is calcium stearate.

[0023] In a second aspect, the present application provides a method for preparing a polypropylene absorbing material, comprising the following steps: adding polypropylene, a compatibilizer, an antioxidant and a lubricant according to parts by weight from the main feed port of a twin-screw extruder, adding an inorganic absorbing composite filler from the side feed port of the twin-screw extruder, and obtaining a polypropylene absorbing material through melt blending, extrusion, cooling and granulation.

[0024] In a third aspect, the present application provides an application of the polypropylene absorbing material in automobiles.

[0025] In summary, this application has the following beneficial effects:

[0026] 1. This application utilizes a mixture of carbon fiber, tantalum pentoxide, and glass microspheres as an inorganic absorbing composite filler. By mixing this with polypropylene, an antioxidant, and the like, a lightweight, high-temperature resistant polypropylene absorbing material is prepared. This polypropylene absorbing material can meet the miniaturization and lightweight requirements of automotive and electronic equipment and has great potential for application.

[0027] 2. This application further controls the weight ratio of carbon fiber, tantalum pentoxide, and glass microbeads within the above range, and the obtained polypropylene absorbing material has better electromagnetic wave absorption performance. Its maximum reflection loss in the 75-110 GHz frequency band is ≤-8.0 dB, and its minimum is ≤-17.0 dB; its maximum transmission loss is ≤-20.0 dB, and its minimum is ≤-35.0 dB. DETAILED DESCRIPTION

[0028] The present application provides a polypropylene absorbing material, comprising the following components in parts by weight: 85-95 parts of polypropylene, 5-12 parts of an inorganic absorbing composite filler, 2-4 parts of a compatibilizer, 0.1-0.2 parts of an antioxidant, and 0.03-0.06 parts of a lubricant. Furthermore, the polypropylene absorbing material comprises the following components in parts by weight: 85-95 parts of polypropylene, 8-10 parts of an inorganic absorbing composite filler, 2-4 parts of a compatibilizer, 0.1-0.2 parts of an antioxidant, and 0.03-0.06 parts of a lubricant.

[0029] The inorganic wave-absorbing composite filler is a mixture of carbon fiber, tantalum pentoxide and glass microspheres; further, the weight ratio of the carbon fiber, tantalum pentoxide and glass microspheres is 1: (0.2-0.3): (0.3-0.4).

[0030] The preparation method of the polypropylene absorbing material provided in the present application comprises the following steps: adding polypropylene, a compatibilizer, an antioxidant and a lubricant according to parts by weight from the main feed port of a twin-screw extruder, adding an inorganic absorbing composite filler from the side feed port of the twin-screw extruder, and obtaining the polypropylene absorbing material through melt blending, extrusion, cooling and granulation.

[0031] In the examples of this application, the polypropylene is copolymerized polypropylene with a melt index of 30 g / 10 min, the carbon fiber model is CFD1-0406, the CAS number of tantalum pentoxide is 1314-61-0, and the particle size is 2000 mesh, the glass microspheres are hollow, and the particle size is 300 mesh, the compatibilizer is a maleic anhydride-grafted polypropylene compatibilizer with the brand name C9021TF, the antioxidants are antioxidant 1010 and antioxidant 168, and the lubricant is calcium stearate. All raw materials, reagents, and solvents used in this application are commercially available.

[0032] The present application is further described in detail below with reference to embodiments and performance testing.

[0033] Examples 1-4

[0034] Examples 1-4 each provide a polypropylene absorbing material.

[0035] The difference between the above embodiments is that the amount of inorganic absorbing composite filler added to the polypropylene absorbing material is shown in Table 1 below.

[0036] The preparation method of the polypropylene absorbing material provided in Examples 1-4 comprises the following steps: adding 9 kg of polypropylene, 300 g of maleic anhydride grafted POE compatibilizer, 10 g of antioxidant 1010, 5 g of antioxidant 168, and 5 g of lubricant according to parts by weight from the main feed port of a twin-screw extruder; adding an inorganic absorbing composite filler (carbon fiber, tantalum pentoxide, and glass microbeads in a weight ratio of 1:0.25:0.35) from the side feed port of the twin-screw extruder; and obtaining the polypropylene absorbing material through melt blending, extrusion, cooling, and granulation.

[0037] Table 1 Addition amount of inorganic absorbing composite filler in the polypropylene absorbing material of Examples 1-4

[0038] Example Addition amount of inorganic absorbing composite filler (g) 1 500 2 800 3 1000 4 1200

[0039] Examples 5-12

[0040] Examples 5-12 each provide a polypropylene absorbing material.

[0041] The difference between the above embodiment and embodiment 2 is that the weight ratio of carbon fiber, tantalum pentoxide and glass beads in the inorganic wave absorbing composite filler is shown in Table 2 below.

[0042] Table 2 Weight ratio of carbon fiber, tantalum pentoxide and glass microspheres in the inorganic wave absorbing composite fillers of Examples 2, 5-12

[0043] Example Weight ratio of carbon fiber, tantalum pentoxide and glass microspheres 2 1：0.25：0.35 5 1：0.1：0.35 6 1：0.2：0.35 7 1：0.3：0.35 8 1：0.4：0.35 9 1：0.25：0.2 10 1：0.25：0.3 11 1：0.25：0.4 12 1：0.25：0.5 Comparative Example 1

[0044] Comparative Example 1 provides a polypropylene absorbing material.

[0045] The difference between the comparative example and Example 2 is that the inorganic absorbing material used in the polypropylene absorbing material is carbon fiber. Comparative Example 2

[0046] Comparative Example 2 provides a polypropylene absorbing material.

[0047] The difference between the comparative example and Example 2 is that the inorganic absorbing material used in the polypropylene absorbing material is tantalum pentoxide. Comparative Example 3

[0048] Comparative Example 3 provides a polypropylene absorbing material.

[0049] The difference between the comparative example and Example 2 is that the inorganic absorbing material used in the polypropylene absorbing material is carbon fiber and tantalum pentoxide in a weight ratio of 1:0.25. Comparative Example 4

[0050] Comparative Example 4 provides a polypropylene absorbing material.

[0051] The difference between the comparative example and Example 2 is that the inorganic absorbing material used in the polypropylene absorbing material is carbon fiber and glass beads in a weight ratio of 1:0.35. Comparative Example 5

[0052] Comparative Example 5 provides a polypropylene absorbing material.

[0053] The difference between the comparative example and Example 2 is that the inorganic absorbing material used in the polypropylene absorbing material is tantalum pentoxide and glass microbeads in a weight ratio of 1:1.4.

[0054] Performance testing

[0055] Various performance tests were performed on the polypropylene absorbing materials obtained in Examples 1-12 and Comparative Examples 1-5. The results are shown in Table 3 below.

[0056] (1) Density: The density of polypropylene absorbing materials is tested according to ISO1183 standard;

[0057] (2) Reflection loss: The polypropylene absorbing material was prepared into an absorbing patch with a size of 300 mm × 300 mm × 0.5 mm. The reflection loss in the 75-110 GHz frequency band was tested with reference to the GJB 2038A-2011 standard.

[0058] (3) Heat deformation temperature: The heat deformation temperature of polypropylene absorbing material under 1.82MPa is tested according to ISO75 standard.

[0059] Table 3 Performance test results of the absorbing materials obtained in Examples 1-12 and Comparative Examples 1-5

[0060] / <![CDATA[Density (g / cm 3 ).]]> Reflection loss (dB) Transmission loss (dB) Heat deformation temperature (℃) Example 1 0.930 -6.3~-14.6 -15.7~-31.6 143 Example 2 0.942 -9.6~-18.1 -25.5~-38.5 150 Example 3 0.952 -8.8~-17.7 -20.2~-35.7 156 Example 4 0.960 -5.7~-14.1 -16.4~-28.8 158 Example 5 0.940 -5.4~-13.9 -18.2~-32.5 154 Example 6 0.942 -7.6~-17.4 -23.1~-35.2 151 Example 7 0.942 -9.1~-17.8 -24.3~-36.7 153 Example 8 0.944 -6.6~-15.2 -19.5~-29.6 149 Example 9 0.946 -6.8~-15.8 -21.2~-29.3 146 Example 10 0.944 -7.5~-17.7 -22.6~-35.8 152 Example 11 0.942 -8.7~-18.3 -25.7~-37.1 150 Example 12 0.940 -5.9~-15.6 -17.4~-27.3 153 Comparative Example 1 0.918 -4.8~-8.3 -8.5~-13.7 141 Comparative Example 2 1.054 -3.6~-7.4 -9.5~-12.3 146 Comparative Example 3 0.966 -5.8~-9.6 -10.1~-17.2 138 Comparative Example 4 0.938 -5.2~-8.8 -9.2~-18.4 140 Comparative Example 5 0.950 -4.2~-7.9 -8.6~-14.1 143

[0061] According to the test results in Table 3, the density of the polypropylene absorbing material obtained in Examples 1-12 of the present application is 0.930-0.960 g / cm 3 , the reflection loss in the 75-110 GHz frequency band is -5.4~-18.3 dB, the transmission loss is -15.7~-38.5 dB, and the thermal deformation temperature is 143-158 ° C; while the density of the polypropylene absorbing material obtained in Comparative Examples 1-5 is 0.918-1.054 g / cm 3 In the 75-110 GHz frequency band, the reflection loss is -3.6 to -8.8 dB, the transmission loss is -8.5 to -18.4 dB, and the heat distortion temperature is 138-146°C. Therefore, this application demonstrates that the polypropylene absorbing material produced by using a mixture of carbon fiber, tantalum pentoxide, and glass microspheres as an inorganic absorbing composite filler has the advantages of low density, low reflection loss, and a high heat distortion temperature, meeting the requirements for absorbing materials used in automobiles and electronic devices.

[0062] The test results of Examples 1-4 show that the maximum reflection loss of the polypropylene absorbing materials obtained in Examples 1 and 4 in the 75-110 GHz frequency band is only -5.7~-6.3 dB, and the minimum is only -14.1~-14.6 dB, and the maximum transmission loss is only -15.7~-16.4 dB, and the minimum is only -28.8~-31.6 dB; while the maximum reflection loss of the polypropylene absorbing materials obtained in Examples 2-3 in the 75-110 GHz frequency band is -8.8~-9.6 dB (≤-8.0 dB), and the minimum is only -17.7~-18.1 dB (≤-17.0 dB), the maximum transmission loss is -20.2~-25.5 dB (≤-20.0 dB), and the minimum is -35.7~-38.5 dB (≤-35.0 dB). Therefore, it is shown that the present application further controls the addition amount of the inorganic absorbing composite filler within the range of 8-10 parts, and the obtained polypropylene absorbing material has better electromagnetic wave absorption performance.

[0063] The test results of Example 2 and Examples 5-12 show that the maximum reflection loss of the polypropylene absorbing materials obtained in Example 5, Examples 8-9, and Example 12 in the 75-110 GHz frequency band is only -5.4~-6.8 dB, and the minimum is only -13.9~-15.8 dB, and the maximum transmission loss is only -17.4~-21.2 dB, and the minimum is only -27.3~-32.5 dB; while the maximum reflection loss of the polypropylene absorbing materials obtained in Example 2, Examples 6-7, and Examples 10-11 in the 75-110 GHz frequency band is -7.5~-9.6 dB (≤-8.0 dB), and the minimum is -17.4~-18.3 dB (≤-17.0 dB), and the maximum transmission loss is -22.6~-25.7 dB (≤-20.0 dB), and the minimum is -35.2~-38.5 dB (≤-35.0 dB). Therefore, it is shown that the present application further controls the weight ratio of carbon fiber, tantalum pentoxide and glass microbeads in the inorganic absorbing composite filler within the range of 1: (0.2-0.3): (0.3-0.4), and the obtained polypropylene absorbing material has better electromagnetic wave absorption performance.

[0064] Although the present invention has been described in detail above using general descriptions and specific embodiments, it will be apparent to those skilled in the art that modifications and improvements may be made based on the present invention. Therefore, such modifications and improvements, which do not depart from the spirit of the present invention, are intended to be within the scope of protection claimed herein.

Claims

1. A polypropylene absorbing material, characterized in that: The invention comprises the following components in parts by weight: 85-95 parts of polypropylene, 8-10 parts of inorganic wave-absorbing composite filler, 2-4 parts of compatibilizer, 0.1-0.2 parts of antioxidant, and 0.03-0.06 parts of lubricant; The inorganic wave-absorbing composite filler is a mixture of carbon fiber, tantalum pentoxide and glass microspheres; the weight ratio of the carbon fiber, tantalum pentoxide and glass microspheres is 1: (0.2-0.3): (0.3-0.4).

2. The polypropylene absorbing material according to claim 1, characterized in that: The weight ratio of the carbon fiber, tantalum pentoxide and glass microbeads is 1:0.25:0.

35.

3. The polypropylene absorbing material according to claim 1, characterized in that: The melt index of the polypropylene is 30 g / 10 min.

4. The polypropylene absorbing material according to any one of claims 1 to 3, characterized in that: The compatibilizer is a maleic anhydride grafted compatibilizer.

5. The polypropylene absorbing material according to any one of claims 1 to 3, characterized in that: The antioxidants are antioxidant 1010 and antioxidant 168.

6. The polypropylene absorbing material according to any one of claims 1 to 3, characterized in that: The lubricant is calcium stearate.

7. The method for preparing a polypropylene absorbing material according to any one of claims 1 to 6, wherein: The method comprises the following steps: adding polypropylene, a compatibilizer, an antioxidant and a lubricant according to parts by weight from a main feed port of a twin-screw extruder, adding an inorganic absorbing composite filler from a side feed port of the twin-screw extruder, and performing melt blending, extrusion, cooling and granulation to obtain a polypropylene absorbing material.

8. Use of the polypropylene absorbing material according to any one of claims 1 to 6 in automobiles.