Composite material with shielding function, preparation method thereof and interphone shell

Abstract

The invention discloses a composite material with a shielding function, a preparation method thereof and an interphone shell. The composite material comprises a polycarbonate-acrylonitrile-butadiene-styrene copolymer, a modified conductive filler, maleic anhydride grafted polyethylene, polyaryletherketone, a flame retardant, an antioxidant, glass microfibers and a compatilizer, wherein the modified conductive filler is aluminum oxide ceramic particles subjected to chemical copper plating and graft polymerization treatment. The preparation method comprises the steps of modified conductive filler preparation, step-by-step raw material mixing, twin-screw extrusion granulation and drying. The interphone shell is prepared from the composite material through injection molding, and the injection molding process comprises the steps of raw material drying, injection molding machine preheating, charging and injection molding, and demolding and finishing. The composite material is stable in electromagnetic shielding performance and has good mechanical strength and heat resistance; the preparation method can improve the dispersity of the components and is adaptive to conventional equipment; the interphone shell can block electromagnetic wave interference, is suitable for being used in multiple environments, and meets the requirements of an electronic equipment shell for shielding and structural performance.

Description

Technical Field

[0001] This invention relates to the field of composite material technology, specifically to a composite material with shielding function, its preparation method, and a walkie-talkie housing. Background Technology

[0002] As electronic devices become more high-frequency and integrated, electromagnetic interference problems are becoming increasingly prominent. As communication devices, walkie-talkies need to have both electromagnetic shielding and structural protection functions in their casings. Traditional metal shielding materials are difficult to adapt to the needs of lightweight equipment due to their high density, difficulty in processing, and susceptibility to corrosion.

[0003] Existing resin-based shielding composite materials mostly use a single resin matrix, making it difficult to simultaneously achieve good heat resistance and mechanical properties, and they are prone to performance degradation under high-temperature environments. Conductive fillers often face problems such as uneven dispersion and weak bonding with the matrix, resulting in unstable shielding effectiveness, especially with significant fluctuations in shielding performance over a wide frequency range. In terms of manufacturing processes, one-step mixing methods are prone to component agglomeration, while surface electroplating processes suffer from high pollution and easy peeling of the coating. These problems make it difficult for existing materials to meet the comprehensive requirements of walkie-talkies for shielding stability, structural strength, and heat resistance in complex environments. There is an urgent need to develop composite materials that take into account multiple properties and suitable manufacturing technologies. Summary of the Invention

[0004] This invention provides a composite material with shielding function, its preparation method, and a walkie-talkie shell, solving the problems of existing resin-based materials having difficulty in balancing heat resistance and mechanical properties of a single matrix, poor dispersion of conductive fillers, and unstable shielding effectiveness; solving the process defects of one-step mixing component agglomeration, large surface electroplating pollution, and easy peeling of the plating layer; and ultimately solving the problem that existing materials cannot meet the comprehensive performance requirements of walkie-talkies in complex environments.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A composite material with shielding function, comprising the following components: 55-70 parts by weight of polycarbonate-acrylonitrile-butadiene-styrene copolymer, 20-28 parts by weight of modified conductive filler, 7-12 parts by weight of maleic anhydride grafted polyethylene, 4-8 parts by weight of polyaryletherketone, 2.2-3.0 parts by weight of flame retardant, 0.3-0.5 parts by weight of antioxidant, 3-6 parts by weight of glass microfiber, and 1.5-2.5 parts by weight of compatibilizer; The modified conductive filler is alumina ceramic particles for electroless copper plating. The plating solution used in the electroless plating process contains the following components: copper sulfate 15~18g / L, disodium ethylenediaminetetraacetate 25~30g / L, formaldehyde 8~10mL / L, sodium hydroxide 8~12g / L, nickel chloride 2~3g / L, potassium sodium tartrate 10~15g / L, and the balance is deionized water. The modified conductive filler needs to undergo surface treatment, which includes grafting glycidyl methacrylate and the conductive filler with a conductive filler under the action of an initiator to form a coating layer. This composite material is produced by mixing the components in a certain proportion and then extruding and granulating them using a twin-screw extruder. The extrusion temperature is controlled at 240~270℃, the screw speed is 300~450rpm, and the mixing process is carried out in a high-speed mixer at a mixing temperature of 60~75℃ for 30~45 minutes. This composite material has excellent electromagnetic shielding performance, effectively shielding high-frequency, mid-frequency, and low-frequency electromagnetic waves. It also has good mechanical strength and heat resistance, and can be used to manufacture electronic device housings with high electromagnetic shielding requirements.

[0006] Furthermore, the melt flow rate of the polycarbonate-acrylonitrile-butadiene-styrene copolymer is 15~25 g / 10 min (test conditions are 300℃ and 1.2 kg), and the flexural modulus is 2200~2800 MPa.

[0007] Furthermore, the alumina ceramic particles electrolessly plated with copper have a particle size distribution of 5~20 μm and a volume resistivity of 1.0 × 10⁻⁶. -4 ~5.0×10 -4 •cm; During the chemical copper plating process, the temperature of the plating solution is controlled at 40~55℃, and the plating time is 15~25 minutes.

[0008] Furthermore, the maleic anhydride-grafted polyethylene has a grafting rate of 1.5~3.0% and a melt index of 8~15 g / 10 min (test conditions: 190℃, 2.16 kg); the polyaryletherketone has a glass transition temperature of 150~180℃ and a heat distortion temperature of 180~220℃ (test conditions: 1.82 MPa).

[0009] Furthermore, the flame retardant is a compound of phosphate ester flame retardant and melamine cyanurate, with a mass ratio of 3:1 to 5:1; the antioxidant is a compound of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and tris(2,4-di-tert-butylphenyl) phosphite, with a mass ratio of 2:1 to 4:1.

[0010] Furthermore, the glass microfibers have a diameter of 8~15μm and a length of 300~600μm, and their surfaces are treated with a silane coupling agent; the compatibilizer is a compound of styrene-maleic anhydride copolymer and ethylene-methyl acrylate copolymer, with a mass ratio of 1:1~2:1.

[0011] A method for preparing a composite material with shielding function includes the following steps: S1: To prepare the modified conductive filler, alumina ceramic particles were sequentially cleaned, coarsened, sensitized, and activated. Then, they were placed in a chemical plating solution for chemical copper plating. After plating, they were dried under a nitrogen atmosphere at a temperature of 80-100℃ for 2-3 hours. Next, the dried copper-plated alumina ceramic particles were mixed with monomers and initiators and grafted under nitrogen protection at a temperature of 85-95℃ for 3-4 hours. After the reaction, the particles were filtered, washed, and dried to obtain the modified conductive filler. S2: Mix the raw materials. Weigh out the polycarbonate-acrylonitrile-butadiene-styrene copolymer, modified conductive filler, maleic anhydride grafted polyethylene, polyaryletherketone, flame retardant, antioxidant, glass microfiber and compatibilizer according to the weight parts. Put the polycarbonate-acrylonitrile-butadiene-styrene copolymer, maleic anhydride grafted polyethylene and polyaryletherketone into a high-speed mixer and stir at 60~75℃ for 10~15 minutes. S3: Add the remaining components, add the modified conductive filler, flame retardant, antioxidant, glass microfiber and compatibilizer to the high-speed mixer, and continue to stir at 60~75℃ for 20~30 minutes to obtain the mixture; S4: Extrusion granulation. The mixture is added to a twin-screw extruder, the extrusion temperature is set to 240~270℃, the screw speed is 300~450rpm, and after extrusion, it is cooled by water and pelletized to obtain composite material particles. S5: Drying treatment: Place the composite material particles in a vacuum drying oven and dry them at 100~120℃ for 4~6 hours to remove moisture and obtain a composite material with shielding function.

[0012] Further, in step S1, the roughening solution used for the roughening treatment is a mixed solution of sulfuric acid and hydrofluoric acid, with a sulfuric acid concentration of 40-50 wt% and a hydrofluoric acid concentration of 5-10 wt%, a roughening temperature of 50-60℃, and a roughening time of 20-30 minutes; the sensitization solution used for the sensitization treatment is a mixed solution of stannous chloride and hydrochloric acid, with a stannous chloride concentration of 10-15 g / L and a hydrochloric acid concentration of 5-8 wt%, a sensitization temperature of 30-40℃, and a sensitization time of 15-20 minutes; the activation solution used for the activation treatment is a mixed solution of silver nitrate and ammonia, with a silver nitrate concentration of 5-8 g / L, an activation temperature of 25-35℃, and an activation time of 10-15 minutes.

[0013] Furthermore, in step S1, the monomer used in the graft polymerization reaction is glycidyl methacrylate, the initiator is benzoyl peroxide, the monomer dosage is 8-15% of the conductive filler mass, and the initiator dosage is 0.8-1.5% of the monomer mass; in step S4, the temperature of each section of the twin-screw extruder is set as follows: feeding section 240-250℃, compression section 250-260℃, homogenization section 260-270℃, and die head temperature 255-265℃.

[0014] A walkie-talkie housing, wherein the shielding composite material is obtained by injection molding, and the injection molding process includes the following steps: S1: Raw material drying: Place the composite material particles into a hot air dryer and dry them at 110~130℃ for 3~5 hours; S2: Preheat the injection molding machine. Set the barrel temperature to 250~280℃, the nozzle temperature to 255~285℃, and the mold temperature to 60~80℃. The preheating time is 30~45 minutes. S3: Feeding injection molding, add the dried composite material particles into the injection molding machine hopper, set the injection pressure to 15~20MPa, the injection speed to 50~80mm / s, the holding pressure to 12~16MPa, the holding time to 5~10 seconds, and the cooling time to 15~25 seconds, and perform injection molding. S4: Demolding and finishing. After injection molding, open the mold and remove the shell blank. Remove the gate, flash and other excess parts to obtain the finished walkie-talkie shell. The electromagnetic shielding effectiveness of the walkie-talkie casing is 40~55dB in the frequency range of 1~1000MHz, the tensile strength is 65~80MPa, the bending strength is 95~110MPa, the notched impact strength is 65~80kJ / m², and the heat distortion temperature is 120~140℃ (test condition is 1.82MPa). Beneficial effects

[0015] The composite material of this invention employs a ternary resin matrix compounding design, which, compared to the single or binary resin matrices in existing technologies, enables synergistic complementarity of the properties of different resins. Specifically, the introduction of polyaryletherketone (PAK) enhances the overall heat resistance of the material, solving the problem of softening and performance degradation of traditional shielding composite materials under high-temperature environments. Maleic anhydride-grafted polyethylene (MPPE) enhances the compatibility between components, preventing mechanical property degradation due to poor interfacial bonding. Simultaneously, the dual-modified conductive filler, through chemical plating and graft polymerization, optimizes its own conductivity and improves its dispersibility and bonding with the resin matrix, effectively avoiding the defects of traditional conductive fillers such as easy agglomeration and unstable shielding effectiveness, ensuring stable electromagnetic shielding performance across different frequency bands. Furthermore, the synergistic effect of glass microfibers and the compound compatibilizer further enhances the mechanical properties of the material, enabling the composite material to possess excellent shielding function while also exhibiting good impact and bending resistance, meeting the structural strength requirements of electronic device housings.

[0016] The preparation method of this invention employs a step-by-step process. First, the conductive filler is finely modified, and then step-by-step mixing ensures uniform dispersion of each component. Compared to existing one-step mixing or simplified modification processes, this reduces component agglomeration and improves material performance stability. In the extrusion granulation stage, precise temperature zone control is adapted to the melting characteristics of the ternary resin matrix, avoiding high-temperature degradation or incomplete melting of the resin and ensuring the molding quality of the composite material. The entire preparation process eliminates the need for complex surface electroplating, reducing wastewater discharge and environmental pollution. It also avoids problems such as poor adhesion and easy peeling between the electroplated layer and the resin matrix, extending the material's service life. Furthermore, the process parameters are designed to be compatible with conventional production equipment, enabling industrial production without special modifications, thus lowering production barriers and costs.

[0017] The walkie-talkie housing made of composite materials in this invention inherits the excellent properties of composite materials. Its electromagnetic shielding effectiveness covers the commonly used operating frequency bands of walkie-talkies, effectively blocking external electromagnetic interference and preventing electromagnetic waves generated by internal electronic components from radiating outwards. This ensures stable communication signals and avoids signal distortion or interruption. The housing's heat resistance allows it to adapt to different temperature environments without worrying about deformation or malfunction due to high temperatures. Its excellent mechanical properties enhance the housing's resistance to drops and impacts, reducing damage caused by collisions during daily use and extending the overall lifespan of the walkie-talkie. Furthermore, the injection molding process used in the housing's manufacture is mature and produces excellent molding results, meeting the complex structural design requirements of walkie-talkie housings while balancing practicality and aesthetic integrity. Detailed Implementation

[0018] The technical solutions in the embodiments of the present invention have been clearly and completely described. 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 skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] Example 1

[0020] According to the following raw material ratios: Roughening solution: Sulfuric acid (40wt%) and hydrofluoric acid (5wt%) are mixed at a mass ratio of 8:1, with the remainder being deionized water; Chemical plating solution: copper sulfate 15~18g / L, disodium ethylenediaminetetraacetate 25~30g / L, formaldehyde 8~10mL / L, sodium hydroxide 8~12g / L, nickel chloride 2~3g / L, potassium sodium tartrate 10~15g / L, balance deionized water.

[0021] Composite material preparation, S1: Preparation of modified conductive filler. Alumina ceramic particles were coarsened sequentially with a mixed solution of sulfuric acid (40wt%) and hydrofluoric acid (5wt%) in a mass ratio of 8:1 at 50℃ for 20 minutes, then sensitized with a mixed solution of stannous chloride (10g / L) and hydrochloric acid (5wt%) at 30℃ for 15 minutes, and subsequently activated with a mixed solution of silver nitrate (5g / L) and ammonia at 25℃ for 10 minutes. The treated particles were then placed in a plating solution containing 16g / L copper sulfate, 28g / L disodium ethylenediaminetetraacetate, 9mL / L formaldehyde, 10g / L sodium hydroxide, 2.5g / L nickel chloride, 12g / L potassium sodium tartrate, and the remainder being deionized water. Copper plating was performed at 40℃ for 15 minutes, followed by drying at 80℃ under a nitrogen atmosphere for 2 hours. Glycidyl methacrylate was added at 8% by weight of the conductive filler. Add 0.8% benzoyl peroxide by monomer mass, and graft polymerize at 85℃ for 3 hours under nitrogen protection. Filter, wash, and dry to obtain modified conductive filler; S2: Weigh 55 parts by weight of PC-ABS (melt flow rate 15g / 10min, flexural modulus 2200MPa), 7 parts by weight of maleic anhydride grafted polyethylene (grafting rate 1.5%, melt index 8g / 10min), and 4 parts by weight of polyaryletherketone (glass transition temperature 150℃, heat distortion temperature 180℃), place in a high-speed mixer, and stir at 60℃ for 10 minutes; S3: Add 20 parts by weight of modified conductive filler (particle size 5μm, volume resistivity 1.0×10⁻⁶). -42.2 parts by weight of flame retardant (phosphate ester to melamine cyanurate mass ratio 3:1), 0.3 parts by weight of antioxidant (pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] to tris(2,4-di-tert-butylphenyl)phosphite mass ratio 2:1), 3 parts by weight of glass microfiber (diameter 8μm, length 300μm, silane coupling agent treated), 1.5 parts by weight of compatibilizer (styrene-maleic anhydride copolymer to ethylene-methyl acrylate copolymer mass ratio 1:1), continue stirring at 60℃ for 20 minutes; S4: add the mixture to a twin-screw extruder, feed section 240℃, compression section 250℃, homogenization section 260℃, die head temperature 255℃, screw speed 300rpm, water cooling and pelletizing after extrusion; S5: vacuum drying at 100℃ for 4 hours to obtain a composite material with shielding function.

[0022] The process for preparing the walkie-talkie casing is as follows: S1: Dry the composite material particles with hot air at 110℃ for 3 hours; S2: Preheat the injection molding machine for 30 minutes at a barrel temperature of 250℃, a nozzle temperature of 255℃, and a mold temperature of 60℃; S3: Add the particles, injection pressure of 15MPa, injection speed of 50mm / s, holding pressure of 12MPa, holding time of 5 seconds, and cooling time of 15 seconds; S4: Trim after demolding to obtain the walkie-talkie casing.

[0023] Example 2

[0024] Preparation of composite materials: S1: Alumina ceramic particle coarsening was performed using a mixed solution of sulfuric acid (45 wt%) and hydrofluoric acid (8 wt%) at a mass ratio of 8:1, treated at 55°C for 25 minutes; sensitization was performed using a mixed solution of stannous chloride (12 g / L) and hydrochloric acid (6 wt%), treated at 35°C for 18 minutes; activation was performed using a mixed solution of silver nitrate (6 g / L) and ammonia, treated at 30°C for 12 minutes; electroless copper plating temperature was 48°C (the concentration ratio of copper sulfate, disodium ethylenediaminetetraacetate, formaldehyde, sodium hydroxide, nickel chloride, and potassium sodium tartrate used in the electroless copper plating process was the same as in Example 1). Same process (same time), 20 minutes, nitrogen drying at 90℃ for 2.5 hours; graft polymerization monomer dosage is 12% of conductive filler mass, initiator dosage is 1.2%, reaction at 90℃ for 3.5 hours; S2: Weigh 62 parts by weight of PC-ABS (melt flow rate 20g / 10min, flexural modulus 2500MPa), 9 parts by weight of maleic anhydride grafted polyethylene (grafting rate 2.2%, melt index 12g / 10min), 6 parts by weight of polyaryletherketone (glass transition temperature 165℃, heat distortion temperature 200℃), stir in a high-speed mixer at 68℃ for 12 minutes; S3: Add 24 parts by weight of modified conductive filler (particle size 12μm, volume resistivity 3.0×10⁻⁶). -42.6 parts by weight of flame retardant (4:1), 0.4 parts by weight of antioxidant (3:1), 4.5 parts by weight of glass microfiber (12 μm in diameter and 450 μm in length), and 2.0 parts by weight of compatibilizer (1.5:1). Stir at 68°C for 25 minutes; S4: Twin-screw extruder feeding section 245°C, compression section 255°C, homogenization section 265°C, die head temperature 260°C, screw speed 380 rpm; S5: Vacuum drying at 110°C for 5 hours.

[0025] The process for preparing the walkie-talkie casing is as follows: S1: Drying with hot air at 120℃ for 4 hours; S2: Preheating the injection molding machine barrel temperature to 265℃, nozzle temperature to 270℃, and mold temperature to 70℃ for 38 minutes; S3: Injection pressure to 18MPa, injection speed to 65mm / s, holding pressure to 14MPa, holding time to 8 seconds, and cooling time to 20 seconds; S4: Demolding and trimming to obtain the casing.

[0026] Example 3

[0027] Preparation of composite materials: S1: Alumina ceramic particle coarsening was performed using a mixed solution of sulfuric acid (50 wt%) and hydrofluoric acid (10 wt%) at a mass ratio of 8:1, treated at 60°C for 30 minutes; sensitization was performed using a mixed solution of stannous chloride (15 g / L) and hydrochloric acid (8 wt%), treated at 40°C for 20 minutes; activation was performed using a mixed solution of silver nitrate (8 g / L) and ammonia, treated at 35°C for 15 minutes; electroless copper plating temperature was 55°C (the concentration ratio of copper sulfate, disodium ethylenediaminetetraacetate, formaldehyde, sodium hydroxide, nickel chloride, and potassium sodium tartrate in the electroless copper plating solution used in the electroless copper plating process was the same as in Example 1). Same process (same time), 25 minutes, nitrogen drying at 100℃ for 3 hours; graft polymerization monomer dosage 15%, initiator dosage 1.5%, reaction at 95℃ for 4 hours; S2: weigh 70 parts by weight of PC-ABS (melt flow rate 25g / 10min, flexural modulus 2800MPa), 12 parts by weight of maleic anhydride grafted polyethylene (grafting rate 3.0%, melt index 15g / 10min), 8 parts by weight of polyaryletherketone (glass transition temperature 180℃, heat distortion temperature 220℃), stir in a high-speed mixer at 75℃ for 15 minutes; S3: add 28 parts by weight of modified conductive filler (particle size 20μm, volume resistivity 5.0×10⁻⁶). -4 Ω·cm), 3.0 parts by weight of flame retardant (mass ratio 5:1), 0.5 parts by weight of antioxidant (mass ratio 4:1), 6 parts by weight of glass microfiber (diameter 15μm, length 600μm), 2.5 parts by weight of compatibilizer (mass ratio 2:1), stirred at 75℃ for 30 minutes; S4: twin-screw extruder feeding section 250℃, compression section 260℃, homogenization section 270℃, die head temperature 265℃, screw speed 450rpm; S5: vacuum drying at 120℃ for 6 hours.

[0028] The process for preparing the walkie-talkie casing is as follows: S1: Drying with hot air at 130℃ for 5 hours; S2: Preheating the injection molding machine barrel temperature to 280℃, nozzle temperature to 285℃, and mold temperature to 80℃ for 45 minutes; S3: Injection pressure to 20MPa, injection speed to 80mm / s, holding pressure to 16MPa, holding time to 10 seconds, and cooling time to 25 seconds; S4: Demolding and trimming to obtain the casing.

[0029] Comparative Example 1 Preparation of composite materials (resin matrix is ​​pure PC, without polyaryletherketone and maleic anhydride grafted polyethylene): S1: Conductive filler is chemically plated nickel hollow microspheres, without graft polymerization coating treatment; S2: Weigh 65 parts by weight of PC resin and 15 parts by weight of ABS resin, and stir at 50°C for 10 minutes in a high-speed mixer; S3: Add 15 parts by weight of chemically plated nickel hollow microspheres, 6 parts by weight of styrene-maleic anhydride copolymer, 3 parts by weight of polyetherimide resin, 1.8 parts by weight of flame retardant, and 0.20 parts by weight of antioxidant, and stir at 50°C for 20 minutes; S4: Extrude and pelletize using a twin-screw extruder at a temperature of 235-260°C and a screw speed of 2500 rpm; S5: Dry under nitrogen at 80°C for 3 hours.

[0030] Walkie-talkie casing preparation: injection molding temperature 230-235℃, injection molding pressure 13.0-15.0MPa, mold temperature 50-55℃, injection molding to obtain the casing.

[0031] Comparative Example 2 Preparation of composite materials (resin matrix is ​​PVC-ABS, without polyaryletherketone, conductive filler is not grafted modified): S1: The conductive filler is chemically plated nickel hollow microspheres, treated only with titanate coupling agent; S2: Weigh 60 parts by weight of PVC resin (S-1300) and 30 parts by weight of ABS resin, and stir at 45°C for 10 minutes in a high-speed mixer; S3: Add 15 parts by weight of the treated conductive filler, 8 parts by weight of plasticizer DOTP, 6 parts by weight of epoxidized soybean oil, 8 parts by weight of styrene-maleic anhydride copolymer, 2.5 parts by weight of polyoxypropylene diamine, 0.20 parts by weight of antioxidant, 1.8 parts by weight of barium stearate, and 2.5 parts by weight of calcium zinc stabilizer, and stir at 45°C for 20 minutes; S4: Extrude and pelletize at 150-165°C using a screw extruder; S5: Dry under nitrogen at 80°C for 3 hours.

[0032] Walkie-talkie casing preparation: injection molding temperature 205-215℃, injection molding pressure 12.0-15.0MPa, mold temperature 45-50℃, injection molding to obtain the casing.

[0033] Comparative Example 3 Preparation of composite materials (maleic anhydride-free grafted polyethylene and polyaryletherketone, simplified conductive filler modification process): S1: The conductive filler is chemically plated nickel hollow microspheres, treated only with silane coupling agent; S2: Weigh 60 parts by weight of PVC resin (S-1300) and 30 parts by weight of ABS resin, and stir at 45°C for 10 minutes in a high-speed mixer; S3: Add 15 parts by weight of the treated conductive filler, 8 parts by weight of plasticizer DOTP, 6 parts by weight of epoxidized soybean oil, 8 parts by weight of styrene-maleic anhydride copolymer, 2.5 parts by weight of polyoxypropylene diamine D-400, 0.20 parts by weight of antioxidant, 1.8 parts by weight of barium stearate, and 2.5 parts by weight of calcium-zinc stabilizer, and stir at 45°C for 20 minutes; S4: Extrude and pelletize at 150-165°C using a screw extruder; S5: Dry under nitrogen at 80°C for 3 hours.

[0034] Walkie-talkie casing preparation: injection molding temperature 205-215℃, injection molding pressure 12.0-15.0MPa, mold temperature 45-50℃, injection molding to obtain the casing.

[0035] The test results of the composite materials and shells of Examples 1-3 and Comparative Examples 1-3 of the present invention are shown in the table below: project Testing standards Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Melt flow rate of composite material (g / 10min) GB / T3682.1-2018 16 21 24 12 8 9 Tensile strength of composite materials (MPa) GB / T1040.1-2025 65 72 80 52 32 33 Flexural strength of composite materials (MPa) GB / T9341-2008 95 102 110 85 55 58 Notched impact strength of composite materials (kJ / m²) GB / T1043.1-2008 65 72 80 48 30 32 Heat distortion temperature of composite materials (°C) GB / T1634.2-2019 120 130 140 110 85 88 Electromagnetic shielding effectiveness of the enclosure (dB, 1MHz) GB / T25471-2010 55 53 50 40 35 36 Electromagnetic shielding effectiveness of the enclosure (dB, 500MHz) GB / T25471-2010 48 46 43 32 25 26 Electromagnetic shielding effectiveness of the enclosure (dB, 1000MHz) GB / T25471-2010 40 38 35 25 18 19 The outer casing's resistance to thermal cycling (cycles, no cracking) GB / T2423.22-2012 500 500 500 300 200 220 Example Description: The composite materials in Examples 1-3 use PC-ABS, maleic anhydride-grafted polyethylene, and polyaryletherketone to form a ternary resin matrix, combined with doubly modified chemically plated copper-alumina ceramic particles. These are prepared through stepwise mixing and precise temperature-controlled extrusion processes, and all properties are within the protection scope of this invention. Specifically, polyaryletherketone enhances heat resistance, maleic anhydride-grafted polyethylene strengthens compatibility, modified conductive fillers ensure shielding performance, and glass microfibers and compatibilizers synergistically improve mechanical properties. The resulting walkie-talkie housing exhibits excellent performance in electromagnetic shielding, mechanical properties, and heat resistance, meeting the usage requirements of walkie-talkies in various environments.

[0036] Comparative Examples: Comparative Examples 1-3 were designed according to the contents disclosed in publication numbers (CN 104194299 A, CN 104177733 A, CN104177734 A), respectively. The resin matrix did not use the ternary compound system of this invention, lacked polyarylether ketone and maleic anhydride grafted polyethylene, and the conductive filler was not double-modified (no graft polymerization coating). The preparation process parameters also followed the data in the prior art documents. The test results showed that the melt flow rate, mechanical strength, heat distortion temperature, electromagnetic shielding effectiveness, and thermal cycling resistance of the walkie-talkie shell of the composite material were significantly lower than those of the examples.

[0037] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A composite material with shielding function, characterized in that, Includes the following components: 55-70 parts by weight of polycarbonate-acrylonitrile-butadiene-styrene copolymer, 20-28 parts by weight of modified conductive filler, 7-12 parts by weight of maleic anhydride grafted polyethylene, 4-8 parts by weight of polyaryletherketone, 2.2-3.0 parts by weight of flame retardant, 0.3-0.5 parts by weight of antioxidant, 3-6 parts by weight of glass microfiber, and 1.5-2.5 parts by weight of compatibilizer; The modified conductive filler is alumina ceramic particles for electroless copper plating. The plating solution used in the electroless plating process contains the following components: copper sulfate 15~18g / L, disodium ethylenediaminetetraacetate 25~30g / L, formaldehyde 8~10mL / L, sodium hydroxide 8~12g / L, nickel chloride 2~3g / L, potassium sodium tartrate 10~15g / L, and the balance is deionized water. The modified conductive filler needs to undergo surface treatment, which includes grafting glycidyl methacrylate and the conductive filler with a conductive filler under the action of an initiator to form a coating layer.

2. The composite material with shielding function according to claim 1, characterized in that, The polycarbonate-acrylonitrile-butadiene-styrene copolymer has a melt flow rate of 15~25 g / 10 min and a flexural modulus of 2200~2800 MPa.

3. The composite material with shielding function according to claim 1, characterized in that, The alumina ceramic particles used in the electroless copper plating have a particle size distribution of 5~20μm and a volume resistivity of 1.0×10⁻⁶. -4 ~5.0×10 -4 ·cm.

4. The composite material with shielding function according to claim 1, characterized in that, The maleic anhydride-grafted polyethylene has a grafting rate of 1.5-3.0% and a melt index of 8-15 g / 10 min; the polyaryletherketone has a glass transition temperature of 150-180℃ and a heat distortion temperature of 180-220℃.

5. The composite material with shielding function according to claim 1, characterized in that, The flame retardant is a compound of phosphate ester flame retardant and melamine cyanurate, with a mass ratio of 3:1 to 5:1; the antioxidant is a compound of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and tris(2,4-di-tert-butylphenyl) phosphite, with a mass ratio of 2:1 to 4:

1.

6. The composite material with shielding function according to claim 1, characterized in that, The glass microfibers have a diameter of 8~15μm and a length of 300~600μm, and their surfaces are treated with silane coupling agents; the compatibilizer is a compound of styrene-maleic anhydride copolymer and ethylene-methyl acrylate copolymer, with a mass ratio of 1:1~2:

1.

7. A method for preparing a composite material with shielding function, used to prepare the composite material as described in any one of claims 1 to 6, characterized in that, Includes the following steps: S1: To prepare the modified conductive filler, alumina ceramic particles were sequentially cleaned, coarsened, sensitized, and activated. Then, they were placed in a chemical plating solution for chemical copper plating. After plating, they were dried under a nitrogen atmosphere at a temperature of 80-100℃ for 2-3 hours. Next, the dried copper-plated alumina ceramic particles were mixed with monomers and initiators and grafted under nitrogen protection at a temperature of 85-95℃ for 3-4 hours. After the reaction, the particles were filtered, washed, and dried to obtain the modified conductive filler. S2: Mix the raw materials. Weigh out the polycarbonate-acrylonitrile-butadiene-styrene copolymer, modified conductive filler, maleic anhydride grafted polyethylene, polyaryletherketone, flame retardant, antioxidant, glass microfiber and compatibilizer according to the weight parts. Put the polycarbonate-acrylonitrile-butadiene-styrene copolymer, maleic anhydride grafted polyethylene and polyaryletherketone into a high-speed mixer and stir at 60~75℃ for 10~15 minutes. S3: Add the remaining components, add the modified conductive filler, flame retardant, antioxidant, glass microfiber and compatibilizer to the high-speed mixer, and continue to stir at 60~75℃ for 20~30 minutes to obtain the mixture; S4: Extrusion granulation. The mixture is added to a twin-screw extruder, the extrusion temperature is set to 240~270℃, the screw speed is 300~450rpm, and after extrusion, it is cooled by water and pelletized to obtain composite material particles. S5: Drying treatment: Place the composite material particles in a vacuum drying oven and dry them at 100~120℃ for 4~6 hours to remove moisture and obtain a composite material with shielding function.

8. The method for preparing the composite material with shielding function according to claim 7, characterized in that, In step S1, the roughening solution used for roughening is a mixed solution of sulfuric acid and hydrofluoric acid, with a sulfuric acid concentration of 40-50 wt% and a hydrofluoric acid concentration of 5-10 wt%. The roughening temperature is 50-60℃, and the roughening time is 20-30 minutes. The sensitization solution used for sensitization is a mixed solution of stannous chloride and hydrochloric acid, with a stannous chloride concentration of 10-15 g / L and a hydrochloric acid concentration of 5-8 wt%. The sensitization temperature is 30-40℃, and the sensitization time is 15-20 minutes. The activation solution used for activation is a mixed solution of silver nitrate and ammonia, with a silver nitrate concentration of 5-8 g / L. The activation temperature is 25-35℃, and the activation time is 10-15 minutes.

9. The method for preparing the composite material with shielding function according to claim 7, characterized in that, In step S1, the monomer used in the graft polymerization reaction is glycidyl methacrylate, the initiator is benzoyl peroxide, the amount of monomer used is 8-15% of the mass of the conductive filler, and the amount of initiator used is 0.8-1.5% of the mass of the monomer.

10. A walkie-talkie housing, wherein the housing is injection molded from a composite material with shielding function as described in any one of claims 1 to 6, characterized in that, The injection molding process includes the following steps: S1: Raw material drying; S2: Injection molding machine preheating; S3: Feeding injection molding, injection molding; S4: Demolding and trimming to obtain the finished walkie-talkie casing.