Electromagnetic shielding PC material and preparation method and application thereof

Abstract

The invention relates to an electromagnetic shielding PC material and a preparation method thereof. The electromagnetic shielding PC material is prepared from the following components in parts by weight: 53-70 parts of PC resin, 25-40 parts of conductive filler, 2-4 parts of magnesium oxide, 3-5 parts of a flexibilizer, 0.3-0.5 part of an antioxidant and 0.3-0.5 part of a lubricant. According to the electromagnetic shielding PC material disclosed by the invention, the dispersion effect of the conductive filler in the material can be improved by adding magnesium oxide, so that a good conductive path is formed in the material, and an excellent electromagnetic shielding effect is established.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer materials, and in particular to an electromagnetic shielding PC material and a preparation method and application thereof. Background Art

[0002] With the rapid development of science and technology and the electronics industry, various digital and high-frequency electronic and electrical equipment radiate a large number of electromagnetic waves of different wavelengths and frequencies into space when working, which leads to new environmental pollution: electromagnetic interference (EMI). When electronic equipment is working, it does not want to be interfered by external electromagnetic waves, nor does it want to radiate electromagnetic waves to interfere with external equipment and cause radiation hazards to the human body. This requires electromagnetic shielding to block the propagation path of electromagnetic waves. The attenuation of electromagnetic shielding is mainly based on the reflection and absorption principles of electromagnetic waves.

[0003] Electromagnetic waves can be reflected, absorbed and penetrated by humans, animals and plants. This biological effect of non-ionizing radio frequency radiation has always been of concern to humans, because under certain conditions, electromagnetic radiation can lead to dysfunction of the central nervous system and autonomic nerve function, eye damage, cancer or immunodeficiency diseases. Generally, it is safe for the human body to be in an environment with a field strength of less than 631V / m. Another danger of electromagnetic radiation is radio frequency burns. Metal objects in a strong electromagnetic field (such as metal conductors under the transmitting antenna, cranes and metal railings of ships, etc.) will have dangerous induced voltages, and when the human body touches them, it may be burned or feel an electric shock.

[0004] Electromagnetic radiation is dangerous. Strong fields are more serious than weak fields, high frequencies are more serious than low frequencies, and long durations are more serious than short durations. Humans should stay away from high-power devices, but should not ignore the dangers of low power. For example, the electromagnetic radiation from mobile phones close to the brain is not small, the electromagnetic radiation of many unqualified home appliances exceeds the standard, and the non-thermal effects of some low-frequency devices should not be ignored. Electromagnetic shielding materials are becoming more and more important for the increasingly serious electromagnetic pollution materials. Summary of the invention

[0005] Based on this, the purpose of the present invention is to provide an electromagnetic shielding PC material and its preparation method and application, which can enclose the area that needs protection, effectively reduce the electromagnetic interference leaked by space propagation, and at the same time prevent the influence of external electromagnetic interference on electronic equipment.

[0006] To achieve the above object, the present invention adopts the following technical solutions: The present invention first provides an electromagnetic shielding PC material, which is prepared from the following components in parts by weight: 53-70 parts of PC resin, 25-40 parts of conductive filler, 2-4 parts of magnesium oxide, 3-5 parts of toughening agent, 0.3-0.5 parts of antioxidant, and 0.3-0.5 parts of lubricant.

[0007] As a further improvement of the above solution of the present invention, the PC resin is aromatic polycarbonate.

[0008] As a further improvement of the above solution of the present invention, the conductive filler is at least one of carbon fiber, conductive graphite, and stainless steel fiber.

[0009] As a further improvement of the above solution of the present invention, the toughening agent is at least one of a terpolymer of methyl methacrylate-butadiene-styrene, an ethylene-methyl acrylate copolymer, polyethylene, and ethylene-butyl acrylate-glycidyl methacrylate.

[0010] As a further improvement of the above solution of the present invention, the antioxidant is at least one of a hindered phenol antioxidant, a thioester antioxidant, and a phosphite antioxidant.

[0011] As a further improvement of the above solution of the present invention, the lubricant is at least one of polyethylene wax, silicone masterbatch, montan wax, and pentaerythritol stearate.

[0012] The present invention also provides a method for preparing the electromagnetic shielding PC material as described above, which comprises the following steps: mixing PC resin, magnesium oxide, toughening agent, antioxidant and lubricant in proportion under a protective atmosphere, feeding the mixture into an extruder from a main feeding port, feeding a conductive filler into the extruder from a side feeding port in proportion, melting, extruding and granulating to obtain the electromagnetic shielding PC material.

[0013] As a further improvement of the above solution of the present invention, the barrel temperature of the extruder is 240-260° C., the screw speed is 400-600 r / min, and the vacuum degree is -0.04--0.1 MPa.

[0014] The present invention also provides an application of the electromagnetic shielding PC material as mentioned above in preparing an electronic product housing.

[0015] Compared with the prior art, the present invention has the following beneficial effects: In the electromagnetic shielding PC material of the present invention, by adding magnesium oxide, the dispersion effect of the conductive filler in the material can be improved, thereby forming a good conductive path in the material, thereby establishing an excellent electromagnetic shielding effect.

[0016] The electronic shielding PC material prepared by the present invention has an electromagnetic shielding effect of >60db and a cantilever beam notch impact strength of ≥10 KJ / m by adding magnesium oxide.2 , melt index ≥10g / 10min, can meet the injection molding requirements of electronic components with high electromagnetic shielding requirements. DETAILED DESCRIPTION

[0017] For ease of understanding of the present invention, the present invention will be described more fully below in conjunction with specific embodiments. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thoroughly understood.

[0018] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0019] The specific information of the raw materials used in the following examples and comparative examples is as follows: Aromatic polycarbonate: 1250Y, produced by Teijin, Japan; Ethylene-methyl acrylate copolymer: EMA 1330AC, produced by DuPont Chemical; Methyl methacrylate-butadiene-styrene terpolymer: MBS 2690, produced by Dow Chemical; Polyethylene: HDPS 5000S, produced by Sinopec.

[0020] Conductive filler: carbon fiber and conductive graphite are produced by Yiruishi, and stainless steel fiber is produced by Hunan Huitong; Magnesium oxide is produced by Hebei Xintao New Materials.

[0021] The above raw materials are only for illustrating the sources and components of the raw materials used in the experiments of the present invention so as to fully disclose the information, and do not mean that the present invention cannot be realized by using other similar reagents or reagents provided by other suppliers.

[0022] Example 1 This embodiment provides an electromagnetic shielding PC material, which includes the following raw materials in parts by weight: 70 parts of aromatic polycarbonate, 25 parts of conductive filler, 2 parts of magnesium oxide, 3 parts of methyl methacrylate-butadiene-styrene terpolymer, 0.1 parts of antioxidant 1076, 0.1 parts of antioxidant DLTP, 0.1 parts of antioxidant 168, and 0.3 parts of pentaerythritol stearate. Among them, the conductive filler is carbon fiber.

[0023] The preparation method of the electromagnetic shielding PC material of this embodiment comprises the following steps: (1) Add aromatic polycarbonate, methyl methacrylate-butadiene-styrene terpolymer, magnesium oxide, antioxidant 1076, antioxidant 168, antioxidant DLTP, and pentaerythritol stearate into a nitrogen-protected mixer and mix at high speed for 6 minutes; (2) The mixed material of step (1) is fed into a parallel twin-screw extruder for melting, and a conductive filler is added through a side feed port. The mixture is extruded and granulated to obtain an electromagnetic shielding PC material; wherein the barrel temperature of the extruder is 240° C., the screw speed is 400 r / min, the melt pressure is 1.5 MPa, and the vacuum degree is -0.04 MPa to obtain an electromagnetic shielding PC material.

[0024] Example 2 This embodiment provides an electromagnetic shielding PC material, which includes the following raw materials in parts by weight: 70 parts of aromatic polycarbonate, 25 parts of conductive filler, 2 parts of magnesium oxide, 2 parts of ethylene-methyl acrylate copolymer, 1 part of methyl methacrylate-butadiene-styrene terpolymer, 0.1 parts of antioxidant 1076, 0.2 parts of antioxidant DLTP, 0.2 parts of antioxidant 168, and 0.3 parts of pentaerythritol stearate. The conductive filler is conductive graphite.

[0025] The preparation method of the electromagnetic shielding PC material of this embodiment comprises the following steps: (1) Add aromatic polycarbonate, magnesium oxide, ethylene-methyl acrylate copolymer, methyl methacrylate-butadiene-styrene terpolymer, antioxidant 1076, antioxidant DLTP, antioxidant 168, and pentaerythritol stearate into a nitrogen-protected mixer and mix at high speed for 6 minutes; (2) The mixed material of step (1) is fed into a parallel twin-screw extruder for melting, and a conductive filler is added through a side feed port. The mixture is extruded and granulated to obtain an electromagnetic shielding PC material; wherein the barrel temperature of the extruder is 280°C, the screw speed is 600 r / min, the melt pressure is 1.5 MPa, and the vacuum degree is -0.1 MPa to obtain an electromagnetic shielding PC material.

[0026] Example 3 This embodiment provides an electromagnetic shielding PC material, which includes the following raw materials in parts by weight: 53 parts of aromatic polycarbonate, 40 parts of conductive filler, 4 parts of magnesium oxide, 2 parts of polypropylene, 0.1 parts of antioxidant 1076, 0.2 parts of antioxidant DLTP, 0.2 parts of antioxidant 168, and 0.5 parts of montan wax. The conductive filler is stainless steel fiber.

[0027] The preparation method of the electromagnetic shielding PC material of this embodiment comprises the following steps: (1) Add 10 parts of aromatic polycarbonate, magnesium oxide, polypropylene, antioxidant 1076, antioxidant DLTP, antioxidant 168, and montan wax into a nitrogen-protected mixer and mix at high speed for 2 minutes; (2) The mixed material of step (1) is fed into a parallel twin-screw extruder for melting, and a conductive filler is added through a side feed port. The mixture is extruded and granulated to obtain an electromagnetic shielding PC material; wherein the barrel temperature of the extruder is 260° C., the screw speed is 400 r / min, the melt pressure is 1.5 MPa, and the vacuum degree is -0.04 MPa to obtain an electromagnetic shielding PC material.

[0028] Comparative Example This comparative example adopts the same implementation method as Example 3, and the difference from Example 3 is that the electromagnetic shielding PC material of this comparative example includes the following raw materials in parts by weight: 70 parts of aromatic polycarbonate, 25 parts of conductive filler, 5 parts of polypropylene, 0.1 parts of antioxidant 1076, 0.2 parts of antioxidant DLTP, 0.2 parts of antioxidant 168, and 0.5 parts of montan wax.

[0029] The amounts of the raw materials used in Examples 1-3 and Comparative Examples are shown in Table 1.

[0030] Table 1 Amount of each raw material used in Examples 1-3 and Comparative Examples (parts by weight)

[0031] Test Case The electromagnetic shielding PC materials prepared in the above Examples 1-3 and the comparative example were subjected to performance tests. The performance test standards and test results are shown in Table 2.

[0032] Table 2 Performance test

[0033] According to the results in Table 2: After adding magnesium oxide, the electromagnetic shielding effect of this application is significantly improved, and the test data is stable, so it can be used commercially.

[0034] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0035] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. An electromagnetic shielding PC material, characterized in that: The invention is prepared from the following components in parts by weight: 53-70 parts of PC resin, 25-40 parts of conductive filler, 2-4 parts of magnesium oxide, 3-5 parts of toughening agent, 0.3-0.5 parts of antioxidant and 0.3-0.5 parts of lubricant.

2. The electromagnetic shielding PC material according to claim 1, characterized in that: The PC resin is aromatic polycarbonate.

3. The electromagnetic shielding PC material according to claim 1, characterized in that: The conductive filler is at least one of carbon fiber, conductive graphite and stainless steel fiber.

4. The electromagnetic shielding PC material according to claim 1, characterized in that: The toughening agent is at least one of a terpolymer of methyl methacrylate-butadiene-styrene, an ethylene-methyl acrylate copolymer, polyethylene, and ethylene-butyl acrylate-glycidyl methacrylate.

5. The electromagnetic shielding PC material according to claim 1, characterized in that: The antioxidant is at least one of a hindered phenol antioxidant, a thioester antioxidant, and a phosphite antioxidant.

6. The electromagnetic shielding PC material according to claim 1, characterized in that: The lubricant is at least one of polyethylene wax, silicone masterbatch, montan wax and pentaerythritol stearate.

7. A method for preparing the electromagnetic shielding PC material according to any one of claims 1 to 6, characterized in that: It includes the following steps: PC resin, magnesium oxide, toughening agent, antioxidant and lubricant are mixed in proportion under a protective atmosphere and fed into an extruder from a main feed port. Conductive fillers are fed into the extruder from a side feed port in proportion, melted, extruded and granulated to obtain electromagnetic shielding PC material.

8. The method for preparing the electromagnetic shielding PC material according to claim 7, characterized in that: The barrel temperature of the extruder is 240-260° C., the screw speed is 400-600 r / min, and the vacuum degree is -0.04--0.1 MPa.

9. Use of the electromagnetic shielding PC material according to any one of claims 1 to 6 in preparing electronic product housings.

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