Polypropylene wave-absorbing material and preparation method thereof

Abstract

The invention 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 invention is prepared from the following components in parts by weight: 85 to 95 parts of polypropylene, 5 to 12 parts of inorganic wave-absorbing composite filler, 2 to 4 parts of compatilizer, 0.1 to 0.2 part of antioxidant and 0.03 to 0.06 part of lubricant, the inorganic wave-absorbing composite filler is a mixture of carbon fibers, tantalum pentoxide and glass beads; furthermore, the weight ratio of the carbon fibers to the tantalum pentoxide to the glass beads is 1: (0.2-0.3): (0.3-0.4); the invention also provides a preparation method of the polypropylene wave-absorbing material. The polypropylene wave-absorbing material provided by the invention has the advantages of light weight, excellent electromagnetic wave absorbing effect, high temperature resistance and the like, and has wide application prospects in the fields of automobiles, electronic equipment and the like.

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: 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.

[0007] The inorganic wave-absorbing composite filler is a mixture of carbon fiber, tantalum pentoxide and glass microbeads.

[0008] The present application provides a polypropylene absorbing material. By using a mixture of carbon fiber, tantalum pentoxide and glass microbeads as the main absorber, the polypropylene absorbing material can not only achieve excellent electromagnetic wave absorption effect (low transmission, low reflection), but also significantly reduce the weight of the polypropylene absorbing material, thereby achieving lightweight absorbing material. For the development trend of miniaturization and lightweight of automobiles and electronic equipment, this lightweight material can better adapt to and meet their strict requirements on material weight. In addition, the polypropylene absorbing material provided by the present application also has good heat resistance. It can not only play a good electromagnetic wave absorption role in ordinary environments, but also adapt to some special high-temperature working scenarios (such as the high temperature around the headlights in the car). In summary, the polypropylene absorbing material provided by the present application has excellent performance in many aspects such as weight, absorbing effect, anti-interference and high temperature resistance, and has wide applicability and market prospects.

[0009] In the present application, carbon fiber can effectively absorb electromagnetic waves in a wide high frequency band (75-110GHz), reducing the reflection and propagation of electromagnetic waves; in addition, carbon fiber also has the characteristics of light weight and high temperature resistance, which can meet the lightweight and excellent use requirements of high-temperature electromagnetic wave absorption effect required by polypropylene absorbing materials. Tantalum pentoxide has a high dielectric constant and polarization loss, and its excellent dielectric properties can enhance the polarization loss of electromagnetic waves and achieve good electromagnetic wave absorption effect; in addition, nano tantalum pentoxide also has a small particle size (nanoscale) and a high specific surface area, which is conducive to increasing multiple scattering, reducing the reflection of electromagnetic waves, and greatly attenuating the energy of the transmitted wave, thereby improving the electromagnetic wave absorption effect and effectively avoiding signal interference between different receivers. However, the aspect ratio of carbon fiber is relatively different, and it will have obvious orientation problems after molding. The shrinkage difference between the flow direction and the perpendicular flow direction is large, which makes the material easy to deform; and the glass microbeads are spherical in size, which can alleviate the molding orientation problem of the material, making the material not easy to deform, and the stability of the obtained polypropylene absorbing material is better.

[0010] 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.

[0011] In a specific embodiment, the weight of the inorganic absorbing composite filler can be 5 parts, 8 parts, 10 parts Or 12 servings.

[0012] 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.

[0013] Optionally, the weight ratio of the carbon fiber, tantalum pentoxide and glass microbeads is 1:(0.2-0.3):(0.3-0.4).

[0014] 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 ≤-8.0dB and a minimum of ≤-17.0dB in the 75-110GHz frequency band; the maximum transmission loss is ≤-20.0dB and the minimum is ≤-35.0dB.

[0015] 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).

[0016] 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.

[0017] Optionally, the weight ratio of the carbon fiber, tantalum pentoxide and glass microbeads is 1:0.25:0.35.

[0018] Optionally, the melt index of the polypropylene is 30 g / 10 min.

[0019] Optionally, the compatibilizer is a maleic anhydride grafted compatibilizer.

[0020] Optionally, the antioxidant is antioxidant 1010 and antioxidant 168.

[0021] Optionally, the lubricant is calcium stearate.

[0022] 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.

[0023] In a third aspect, the present application provides an application of the polypropylene absorbing material in automobiles.

[0024] In summary, this application has the following beneficial effects: 1. This application uses a mixture of carbon fiber, tantalum pentoxide, and glass microbeads as an inorganic absorbing composite filler. By mixing it with polypropylene, antioxidants, etc., a polypropylene absorbing material with a light texture, excellent electromagnetic wave absorption effect, and high temperature resistance is prepared. This polypropylene absorbing material can meet the requirements of miniaturization and lightweight use in automobiles and electronic equipment, and has good application prospects.

[0025] 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 the minimum is ≤-17.0 dB; the maximum transmission loss is ≤-20.0 dB, and the minimum is ≤-35.0 dB. DETAILED DESCRIPTION

[0026] 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. Wherein, the inorganic 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).

[0027] 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.

[0028] 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.

[0029] The present application is further described in detail below with reference to embodiments and performance testing.

[0030] Examples 1-4 Examples 1-4 each provide a polypropylene absorbing material.

[0031] 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.

[0032] The preparation method of the polypropylene absorbing material provided in Examples 1-4 comprises the following steps: 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 are added from the main feed port of a twin-screw extruder according to parts by weight, and an inorganic absorbing composite filler (carbon fiber, tantalum pentoxide, and glass microbeads in a weight ratio of 1:0.25:0.35) is added from the side feed port of the twin-screw extruder. After melt blending, extrusion, cooling, and granulation, a polypropylene absorbing material is obtained.

[0033] Table 1 Addition amount of inorganic absorbing composite filler in polypropylene absorbing materials of Examples 1-4 Example Addition amount of inorganic absorbing composite filler (g) 1 500 2 800 3 1000 4 1200 Examples 5-12 Examples 5-12 each provide a polypropylene absorbing material.

[0034] 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.

[0035] Table 2 Weight ratio of carbon fiber, tantalum pentoxide and glass microspheres in the inorganic wave absorbing composite fillers of Examples 5-12 Comparative Example 1 Comparative Example 1 provides a polypropylene absorbing material.

[0036] The difference between the comparative example and Example 2 is that the inorganic absorbing material used in the polypropylene absorbing material is carbon fiber.

[0037] Comparative Example 2 Comparative Example 2 provides a polypropylene absorbing material.

[0038] The difference between the comparative example and Example 2 is that the inorganic absorbing material used in the polypropylene absorbing material is tantalum pentoxide.

[0039] Comparative Example 3 Comparative Example 3 provides a polypropylene absorbing material.

[0040] 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.

[0041] Comparative Example 4 Comparative Example 4 provides a polypropylene absorbing material.

[0042] 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.

[0043] Comparative Example 5 Comparative Example 5 provides a polypropylene absorbing material.

[0044] 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.

[0045] Performance testing 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.

[0046] (1) Density: The density of polypropylene absorbing materials is tested according to ISO1183 standard; (2) Reflection loss: Polypropylene absorbing material was prepared into an absorbing patch with a size of 300 mm × 300 mm × 0.5 mm. Referring to the GJB 2038A-2011 standard, its reflection loss in the 75-110 GHz frequency band was tested.

[0047] (3) Heat deformation temperature: The heat deformation temperature of polypropylene absorbing material under 1.82 MPa is tested according to ISO75 standard.

[0048] Table 3 Performance test results of the absorbing materials obtained in Examples 1-12 and Comparative Examples 1-5 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 75-110GHz frequency band is -5.4 to -18.3dB, the transmission loss is -15.7 to -38.5dB, and the thermal deformation temperature is 143-158°C; while the density of the polypropylene absorbing material obtained in Comparative Examples 1-5 is 0.918-1.054g / 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 high heat distortion temperature, meeting the requirements for absorbing materials in automobiles and electronic equipment.

[0049] 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 to -6.3 dB, and the minimum is only -14.1 to -14.6 dB. The maximum transmission loss is only -15.7 to -16.4 dB, and the minimum is only -28.8 to -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 to -9.6 dB (≤-8.0 dB), and the minimum is only -17.7 to -18.1 dB (≤-17.0 dB). The maximum transmission loss is -20.2 to -25.5 dB (≤-20.0 dB), and the minimum is -35.7 to -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.

[0050] The test results of Example 2 and Examples 5-12 show that the maximum reflection loss of the polypropylene absorbing material obtained in Example 5, Examples 8-9, and Example 12 in the 75-110 GHz frequency band is only -5.4 to -6.8 dB, and the minimum is only -13.9 to -15.8 dB, and the maximum transmission loss is only -17.4 to -21.2 dB, and the minimum is only -27.3 to -32.5 dB; while the maximum transmission loss of Example 2 and Examples 8-9 and Example 12 in the 75-110 GHz frequency band is only -5.4 to -6.8 dB, and the minimum is only -13.9 to -15.8 dB. The polypropylene absorbing materials obtained in Examples 6-7 and 10-11 exhibited a maximum reflection loss of -7.5 to -9.6 dB (≤-8.0 dB) and a minimum of -17.4 to -18.3 dB (≤-17.0 dB) in the 75-110 GHz frequency band. The maximum transmission loss was -22.6 to -25.7 dB (≤-20.0 dB) and a minimum of -35.2 to -38.5 dB (≤-35.0 dB). This demonstrates that the present invention further controls the weight ratio of carbon fiber, tantalum pentoxide, and glass microspheres in the inorganic absorbing composite filler within the range of 1:(0.2-0.3):(0.3-0.4), resulting in a polypropylene absorbing material with improved electromagnetic wave absorption performance.

[0051] 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, 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; The inorganic wave-absorbing composite filler is a mixture of carbon fiber, tantalum pentoxide and glass microbeads.

2. The polypropylene absorbing material according to claim 1, characterized in that: The polypropylene wave-absorbing material 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.

3. 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: (0.2-0.3): (0.3-0.4).

4. The polypropylene absorbing material according to claim 3, characterized in that: The weight ratio of the carbon fiber, tantalum pentoxide and glass microbeads is 1:0.25:0.

35.

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

6. The polypropylene absorbing material according to any one of claims 1 to 5, characterized in that: The compatibilizer is a maleic anhydride grafted compatibilizer.

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

8. The polypropylene absorbing material according to any one of claims 1 to 5, characterized in that: The lubricant is calcium stearate.

9. The method for preparing a polypropylene absorbing material according to any one of claims 1 to 8, wherein: The following steps are involved: Polypropylene, compatibilizer, antioxidant and lubricant are added from the main feeding port of the twin-screw extruder according to weight parts, and inorganic absorbing composite filler is added from the side feeding port of the twin-screw extruder. After melt blending, extrusion, cooling and granulation, polypropylene absorbing material is obtained.

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

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