High-thermal-conductivity high-heat-dissipation impact-resistant nylon and preparation method thereof

Abstract

The invention discloses high-heat-conductivity high-heat-dissipation impact-resistant nylon and a preparation method thereof, and belongs to the technical field of high polymer materials. The high-heat-conductivity high-heat-dissipation impact-resistant nylon is prepared from the following components in parts by weight: 50 to 60 parts of nylon 66, 12 to 15 parts of modified boron nitride, 22 parts of reinforcing filler, 5 to 6 parts of diamond powder, 8 to 10 parts of graphene nanoplatelets, 8 to 10 parts of heat dissipation filler, 2 to 4 parts of flexibilizer, 0.3 to 0.4 part of OP wax, 0.2 to 0.3 part of antioxidant 1010 and 0.2 to 0.3 part of antioxidant 168. The modified boron nitride is obtained by treating hexagonal boron nitride powder with a mixed enzyme and modifying with a modifier. The nylon provided by the invention has high thermal conductivity, high heat dissipation and impact resistance.

Description

Technical Field

[0001] The present invention belongs to the technical field of polymer materials, and in particular relates to a high thermal conductivity, high heat dissipation and impact-resistant nylon and a preparation method thereof. Background Art

[0002] With the rapid development of global technology, electronic and electrical products have become ubiquitous in every aspect of human life. However, these products generate significant amounts of heat during operation. Failure to dissipate this heat promptly and effectively can lead to performance degradation or even damage. Therefore, the development of materials with high thermal conductivity and heat dissipation properties holds significant application value in the electronic and electrical fields.

[0003] Chinese invention patent CN108892947B uses boron nitride and zinc oxide as thermally conductive fillers to modify nylon. Since the thermal conductivity of these two fillers is relatively low, a large amount of addition is required to achieve a thermal conductivity effect, and large amounts of addition will affect the performance of nylon. Patent CN104844795B uses graphene with a higher thermal conductivity. The product prepared has a high thermal conductivity and relatively average impact performance, which easily limits the application of the product. Patent CN114196202B uses multi-walled carbon nanotubes as fillers to prepare a product with a thermal conductivity of up to 13W / (m·K), but no further research on heat dissipation is conducted. Most thermally conductive materials transfer heat to the surface of the material in the form of heat transfer, and then allow the air to carry away the heat in the form of thermal convection. This heat dissipation rate is far inferior to heat dissipation by thermal radiation. Chinese invention patent CN105733191 A discloses a polymer-based composite material reinforced with high thermal conductivity materials of different dimensions and a preparation method thereof. Diamond, graphene or carbon nanotubes with ultra-high thermal conductivity are deposited on the surface of a substrate of different dimensions so that the diamond, graphene or carbon nanotubes are continuously and densely distributed on the surface of the substrate. Then, a substrate-type or self-supporting one-dimensional linear reinforcement, a two-dimensional sheet reinforcement and a three-dimensional mesh reinforcement after surface modification are compounded with a polymer matrix so that the reinforcement forms a one-dimensional, two-dimensional or three-dimensional continuous structure in the polymer. Although the number of interfaces is reduced by the one-dimensional, two-dimensional and three-dimensional reinforcements, thermal resistance is generated at the interface due to the mismatch in thermal expansion coefficients between the polymer matrix and the reinforcement, thereby limiting the improvement of thermal conductivity efficiency. Therefore, the present invention develops a high thermal conductivity, high heat dissipation and impact-resistant nylon and a preparation method thereof, which is used to solve the technical problems of insufficient direct interface bonding between the reinforcement and the polymer matrix in the prior art, resulting in insufficient thermal conductivity and heat dissipation performance of nylon and poor impact resistance. Summary of the Invention

[0004] The purpose of the present invention is to provide a high thermal conductivity, high heat dissipation and impact-resistant nylon and a preparation method thereof, which are used to solve the technical problems in the prior art of insufficient direct interface bonding between the reinforcement and the polymer matrix, resulting in insufficient thermal conductivity and heat dissipation performance and poor impact resistance of the nylon.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions: A high-thermal-conductivity, high-heat-dissipation, impact-resistant nylon is composed of the following ingredients in parts by weight: 50-60 parts of nylon 66, 12-15 parts of modified boron nitride, 22 parts of reinforcing filler, 5-6 parts of diamond powder, 8-10 parts of graphene microplatelets, 8-10 parts of heat-dissipating filler, 2-4 parts of a toughening agent, 0.3-0.4 parts of OP wax, 0.2-0.3 parts of antioxidant 1010, and 0.2-0.3 parts of antioxidant 168; the modified boron nitride is obtained by treating hexagonal boron nitride powder with a mixed enzyme and modifying it with a modifier; the reinforcing filler is a mixture of silicon carbide whiskers and glass fibers, with the mass ratio of silicon carbide whiskers to glass fibers being 10:1; the heat-dissipating filler is nano-bamboo charcoal; and the toughening agent is a mixture of polyolefin elastomer and linear low-density polyethylene, with the mass ratio of polyolefin elastomer to linear low-density polyethylene being 3:1.

[0006] Furthermore, the preparation method of the modified boron nitride comprises the following steps: (1) Enzyme treatment: Mix the mixed enzyme with hexagonal boron nitride powder, add N,N-dimethylformamide, then add deionized water, mix well, and then ultrasonicate to obtain a hexagonal boron nitride suspension; (2) Separation and purification: centrifuging the hexagonal boron nitride suspension, dialyzing it, and drying it to obtain enzyme-treated boron nitride; (3) Modification treatment: dissolve the enzyme-treated boron nitride in deionized water, add a modifier, heat, stir, then centrifuge, wash, and dry to obtain modified boron nitride.

[0007] Furthermore, in step (1), the mixed enzyme is an equal mixture of lipase and protease, the purity of hexagonal boron nitride is greater than 99%, the particle size is less than 1 μm, the mass volume ratio of the mixed enzyme to N,N-dimethylformamide is 2-8:50 mg / mL, the mass volume ratio of hexagonal boron nitride powder to N,N-dimethylformamide is 60-70:50 mg / mL, the volume ratio of deionized water to N,N-dimethylformamide is 1:1, the ultrasonic power is 400-500 W, the ultrasonic time is 4-5 hours, and the mixing time is 1-2 hours; the centrifugal speed in step (2) is 4000-5000 rpm, and the centrifugation time is 20-25 minutes; in step (3), the mass volume ratio of enzyme-treated boron nitride to deionized water is 60-80:100 mg / mL, the modifier is a mixture of silane coupling agent KH-550 and palmitoleic acid, the mass ratio of silane coupling agent KH-550 to palmitoleic acid is 2:1-2, the mass ratio of modifier to enzyme-treated boron nitride is 2-5:60-80, the heating temperature is 60-80°C, the stirring speed is 200-300 rpm, the stirring time is 2-4 hours, the drying temperature is 60-80°C, and the drying time is 12-16 hours.

[0008] A method for preparing high thermal conductivity, high heat dissipation and impact-resistant nylon comprises the following steps: S1. Premixing nylon 66, modified boron nitride, reinforcing filler, diamond powder, graphene microplatelets, heat dissipation filler, toughening agent, OP wax, antioxidant 1010 and antioxidant 168 in a high-speed mixer to obtain a premix; S2. Melt blending: adding the premix into a twin-screw extruder, melt blending, and extruding into granules to obtain thermal conductive nylon granules; S3. Molding process: The thermal conductive nylon particles are injection molded at appropriate temperature, pressure and speed to obtain high thermal conductivity, high heat dissipation and impact resistant nylon test specimens.

[0009] Furthermore, the premixing temperature in S1 is 50°C, and the premixing time is 1 hour; the premix processing temperature in S2 is 220-270°C, the screw speed is 450rpm, the extruder feed section temperature is 200-220°C, the melting section temperature is 260-270°C, the extrusion section temperature is 240-250°C, the granulation method is air-cooled granulation, and the granulation size is 2-4mm; the injection temperature in S3 is 240-270°C, the injection pressure is 50-80MPa, the injection speed is 50%-80%, the mold temperature is 80°C, and the holding time is 10 seconds.

[0010] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are: 1. The present invention adds modified boron nitride nanosheets as thermally conductive fillers and utilizes specific enzyme treatment and modification techniques to improve the dispersibility and compatibility of the filler in the nylon matrix, thereby significantly improving the thermal conductivity of the material. The addition of heat-dissipating fillers further enhances the heat dissipation capacity of the material, enabling the nylon material to maintain stable heat dissipation performance in high-temperature environments. The addition of grafted polyolefin elastomers and linear low-density polyethylene as toughening agents significantly improves the toughness and impact resistance of the material, making it less likely to break or deform when subjected to external force. The addition of antioxidants such as 1010 antioxidant and 168 antioxidant effectively inhibits oxidative degradation of the material during processing and use, thereby extending the service life of the material.

[0011] 2. The present invention utilizes enzyme treatment and the introduction of palmitoleic acid to change the interaction between boron nitride layers by utilizing enzyme activity, so that the modified boron nitride can be uniformly dispersed in the polymer matrix. The good dispersibility enables the modified boron nitride to fully contact the polymer matrix to form a continuous thermal conductive network. The synergistic effect of the silane coupling agent KH-550 and palmitoleic acid enhances the interfacial bonding force between the modified boron nitride and the polymer matrix, reduces the interfacial thermal resistance, and the reduction in interfacial thermal resistance makes heat conduction more efficient, significantly improving the thermal conductivity of the composite material. In addition, the action of the silane coupling agent KH-550 enables the modified boron nitride to form a strong chemical bond with the polymer matrix, thereby enhancing the mechanical properties of the composite material. The modified boron nitride is evenly distributed in the polymer matrix, avoiding stress concentration and improving the impact resistance of the material. DETAILED DESCRIPTION

[0012] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0013] Example 1: A high thermal conductivity, high heat dissipation and impact-resistant nylon is composed of the following components by weight: 50 kg of nylon 66, 12 kg of modified boron nitride, 2 kg of glass fiber, 5 kg of diamond powder, 8 kg of graphene microsheets, 8 kg of nano bamboo charcoal, 20 kg of silicon carbide whiskers, 1.5 kg of polyolefin elastomer, 0.5 kg of linear low-density polyethylene, 0.3 kg of OP wax, 0.2 kg of antioxidant 1010 and 0.2 kg of antioxidant 168.

[0014] The preparation method of the modified boron nitride comprises the following steps: (1) Enzyme treatment: 1 mg of lipase, 1 mg of protease and 60 mg of hexagonal boron nitride powder were mixed. The purity of hexagonal boron nitride was greater than 99% and the particle size was less than 1 μm. 50 mL of N,N-dimethylformamide was added, followed by 50 mL of deionized water. The mixture was mixed for 1-2 hours, and then ultrasonicated at a power of 400 W for 4 hours to obtain a hexagonal boron nitride suspension. (2) Separation and purification: centrifuge the hexagonal boron nitride suspension at a speed of 4000 rpm for 20 minutes, dialyze, and dry to obtain enzyme-treated boron nitride; (3) Modification treatment: 60 g of enzyme-treated boron nitride was dissolved in 100 mL of deionized water, 1 mg of silane coupling agent KH-550 and 1 mg of palmitic acid were added, and the mixture was heated to 60 °C with a stirring speed of 200 rpm for 2 hours. The mixture was then centrifuged, washed, and dried at a drying temperature of 60 °C for 12 hours to obtain modified boron nitride.

[0015] A method for preparing high thermal conductivity, high heat dissipation and impact-resistant nylon comprises the following steps: S1. Premixing: premixing nylon 66, modified boron nitride, reinforcing filler, diamond powder, graphene microplatelets, heat dissipation filler, toughening agent, OP wax, antioxidant 1010 and antioxidant 168 in a high-speed mixer at a temperature of 50° C. for 1 hour to obtain a premix; S2. Melt blending: adding the premix to a twin-screw extruder at a processing temperature of 220-270° C. and a screw speed of 450 rpm for melt blending and extrusion granulation. The extruder feed section temperature is 200-220° C., the melting section temperature is 260-270° C., and the extrusion section temperature is 240-250° C. The granulation method is air-cooled granulation, and the granulation size is 2-4 mm to obtain thermal conductive nylon granules; S3. Molding process: The thermal conductive nylon particles are injection molded at appropriate temperature, pressure and speed. The injection temperature is 240-270°C, the injection pressure is 50-80MPa, the mold temperature is 80°C, and the holding time is 10 seconds to obtain high thermal conductivity, high heat dissipation and impact-resistant nylon test specimens.

[0016] Example 2: A high thermal conductivity, high heat dissipation and impact-resistant nylon is composed of the following components by weight: 55kg of nylon 66, 13kg of modified boron nitride, 2kg of glass fiber, 5.5kg of diamond powder, 9kg of graphene microsheets, 9kg of nano bamboo charcoal, 20kg of silicon carbide whiskers, 1.5kg of polyolefin elastomer, 0.5kg of linear low-density polyethylene, 0.3kg of OP wax, 0.2kg of antioxidant 1010 and 0.25kg of antioxidant 168.

[0017] The preparation method of the modified boron nitride comprises the following steps: (1) Enzyme treatment: 2 mg of lipase, 2 mg of protease and 65 mg of hexagonal boron nitride powder were mixed. The purity of hexagonal boron nitride was greater than 99% and the particle size was less than 1 μm. 50 mL of N,N-dimethylformamide was added, followed by 50 mL of deionized water. The mixture was mixed for 1.5 hours, and then ultrasonicated at a power of 450 W for 4.5 hours to obtain a hexagonal boron nitride suspension. (2) Separation and purification: centrifuge the hexagonal boron nitride suspension at a speed of 4500 rpm for 23 minutes, dialyze, and dry to obtain enzyme-treated boron nitride; (3) Modification treatment: 70 mg of enzyme-treated boron nitride was dissolved in 100 mL of deionized water, 2 mg of silane coupling agent KH-550 and 1 mg of palmitic acid were added, and the mixture was heated to 70 ° C, stirred at a speed of 200-300 rpm, and stirred for 3 hours. The mixture was then centrifuged, washed, and dried at a drying temperature of 70 ° C and a drying time of 14 hours to obtain modified boron nitride.

[0018] A method for preparing high thermal conductivity, high heat dissipation and impact-resistant nylon comprises the following steps: S1. Premixing: premixing nylon 66, modified boron nitride, reinforcing filler, diamond powder, graphene microplatelets, heat dissipation filler, toughening agent, OP wax, antioxidant 1010 and antioxidant 168 in a high-speed mixer at a temperature of 50° C. for 1 hour to obtain a premix; S2. Melt blending: adding the premix to a twin-screw extruder at a processing temperature of 220-270° C. and a screw speed of 450 rpm for melt blending and extrusion granulation. The extruder feed section temperature is 200-220° C., the melting section temperature is 260-270° C., and the extrusion section temperature is 240-250° C. The granulation method is air-cooled granulation, and the granulation size is 2-4 mm to obtain thermal conductive nylon granules; S3. Molding process: The thermal conductive nylon particles are injection molded at appropriate temperature, pressure and speed. The injection temperature is 240-270°C, the injection pressure is 50-80MPa, the mold temperature is 80°C, and the holding time is 10 seconds to obtain high thermal conductivity, high heat dissipation and impact-resistant nylon test specimens.

[0019] Example 3: A high-thermal-conductivity high-heat-dissipation impact-resistant nylon is composed of the following ingredients by weight: 60 kg of nylon 66, 15 kg of modified boron nitride, 2 kg of glass fiber, 6 kg of diamond powder, 10 kg of graphene microsheet, 10 kg of nano-bamboo charcoal, 20 kg of silicon carbide whisker, 3 kg of polyolefin elastomer, 1 kg of linear low-density polyethylene, 0.4 kg of OP wax, 0.3 kg of antioxidant 1010, and 0.3 kg of antioxidant 168.

[0020] The preparation method of the modified boron nitride comprises the following steps: (1) Enzyme treatment: 4 mg of lipase, 4 mg of protease, and 70 mg of hexagonal boron nitride powder (purity greater than 99%, particle size less than 1 μm) are mixed, 50 mL of N,N-dimethylformamide is added, then 50 mL of deionized water is added, and the mixture is uniformly mixed for 2 hours, followed by ultrasonic treatment at a power of 500 W for 5 hours to obtain a hexagonal boron nitride suspension; (2) Separation and purification: the hexagonal boron nitride suspension is centrifuged at a speed of 5000 rpm for 25 minutes, dialyzed, and dried to obtain enzyme-treated boron nitride; (3) Modification treatment: 80 mg of enzyme-treated boron nitride is dissolved in 100 mL of deionized water, 3 mg of silane coupling agent KH-550 and 2 mg of palmitoleic acid are added, heated to 80℃, stirred at a speed of 300 rpm for 4 hours, then centrifuged, washed, and dried at a temperature of 80℃ for 16 hours to obtain modified boron nitride.

[0021] A preparation method of a high-thermal-conductivity high-heat-dissipation impact-resistant nylon comprises the following steps: S1, Pre-mixing: nylon 66, modified boron nitride, reinforcing filler, diamond powder, graphene microsheet, heat-dissipation filler, toughening agent, OP wax, antioxidant 1010, and antioxidant 168 are pre-mixed in a high-speed mixer at a temperature of 50℃ for 1 hour to obtain a pre-mixed material; S2, Melt blending: the pre-mixed material is added to a twin-screw extruder, the pre-mixed material is processed at a temperature of 220-270℃ and a screw rotation speed of 450 rpm for melt blending and extrusion granulation, the extruder feeding section temperature is 200-220℃, the melting section temperature is 260-270℃, the extrusion section temperature is 240-250℃, the granulation mode is air-cooled cutting, and the granulation size is 2-4 mm to obtain thermal-conductivity nylon particles; S3, Forming processing: the thermal-conductivity nylon particles are injection molded through appropriate temperature, pressure, and speed, the injection temperature is 240-270℃, the injection pressure is 50-80 MPa, the mold temperature is 80℃, and the holding pressure time is 10 seconds to obtain a high-thermal-conductivity high-heat-dissipation impact-resistant nylon test sample.

[0022] Comparative Example 1: Comparative Example 1 Compared with Example 3, in the preparation process of nylon in Comparative Example 1, no modified boron nitride was added, and other conditions remained unchanged.

[0023] Experimental example The properties of the nylon prepared in Examples 1-3 and Comparative Example 1 were tested as follows. Mechanical properties were tested according to GB / T 1040.2-2006, thermal conductivity was tested according to GB / T 10801.1-2002, heat dissipation was tested according to GB / T 10294-2008, and impact resistance was tested according to GB / T 18477.3-2001. The test results are shown in Table 1: Table 1 Group Tensile strength (MPa) Elongation at break (%) Bending strength (MPa) Notched impact strength (kJ / m²) Thermal conductivity W / (m·K) Thermal resistance (m²·K / W) Thermal diffusivity (mm² / s) Example 1 92 6.4 151 10.5 3.1 0.009 0.5 Example 2 99 7.1 163 11.2 3.3 0.008 0.6 Example 3 100 7.4 166 15.3 3.6 0.007 0.7 Comparative Example 1 78 5.2 132 11.6 2.1 0.02 0.35 According to the test results in Table 1, the mechanical strength, thermal conductivity, heat dissipation and impact resistance of the nylon prepared in Examples 1-3 of the present invention are significantly improved. By comparing Comparative Example 1 with Examples 1-3, it can be seen that the addition of modified boron nitride can effectively improve the mechanical strength, thermal conductivity, heat dissipation and impact resistance of nylon.

[0024] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

[0025] The preferred embodiments of the present invention disclosed above are intended only to help illustrate the present invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the present invention to specific embodiments. Obviously, many modifications and variations are possible based on the contents of this specification. These embodiments are selected and described in detail in this specification to better explain the principles and practical applications of the present invention, thereby enabling those skilled in the art to better understand and utilize the present invention. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A high thermal conductivity, high heat dissipation and impact resistant nylon, characterized in that: The invention comprises the following ingredients in parts by weight: 50-60 parts of nylon 66, 12-15 parts of modified boron nitride, 22 parts of reinforcing filler, 5-6 parts of diamond powder, 8-10 parts of graphene microsheets, 8-10 parts of heat dissipation filler, 2-4 parts of toughening agent, 0.3-0.4 parts of OP wax, 0.2-0.3 parts of antioxidant 1010 and 0.2-0.3 parts of antioxidant 168; the modified boron nitride is obtained by treating hexagonal boron nitride powder with a mixed enzyme and modifying it with a modifier.

2. The high thermal conductivity, high heat dissipation and impact-resistant nylon according to claim 1, characterized in that: The reinforcing filler is a mixture of silicon carbide whiskers and glass fibers, and the mass ratio of silicon carbide whiskers to glass fibers is 10:1; the heat dissipation filler is nano bamboo charcoal; and the toughening agent is a mixture of polyolefin elastomer and linear low-density polyethylene, and the mass ratio of polyolefin elastomer to linear low-density polyethylene is 3:

1.

3. The high thermal conductivity, high heat dissipation and impact-resistant nylon according to claim 1, characterized in that: The preparation method of the modified boron nitride comprises the following steps: (1) Enzyme treatment: Mix the mixed enzyme with hexagonal boron nitride powder, add N,N-dimethylformamide, then add deionized water, mix well, and then ultrasonicate to obtain a hexagonal boron nitride suspension; (2) Separation and purification: centrifuging the hexagonal boron nitride suspension, dialyzing it, and drying it to obtain enzyme-treated boron nitride; (3) Modification treatment: dissolve the enzyme-treated boron nitride in deionized water, add a modifier, heat, stir, then centrifuge, wash, and dry to obtain modified boron nitride.

4. The high thermal conductivity, high heat dissipation and impact-resistant nylon according to claim 3, characterized in that: In step (1), the mixed enzyme is an equal mixture of lipase and protease, the purity of hexagonal boron nitride is greater than 99%, the particle size is less than 1 μm, the mass volume ratio of the mixed enzyme to N,N-dimethylformamide is 2-8:50 mg / mL, the mass volume ratio of hexagonal boron nitride powder to N,N-dimethylformamide is 60-70:50 mg / mL, the volume ratio of deionized water to N,N-dimethylformamide is 1:1, the ultrasonic power is 400-500 W, the ultrasonic time is 4-5 hours, and the mixing time is 1-2 hours.

5. The high thermal conductivity, high heat dissipation and impact-resistant nylon according to claim 3, characterized in that: The centrifugal speed in step (2) is 4000-5000 rpm, and the centrifugal time is 20-25 minutes. In step (3), the mass volume ratio of enzyme-treated boron nitride to deionized water is 60-80:100 mg / mL, the modifier is a mixture of silane coupling agent KH-550 and palmitoleic acid, the mass ratio of silane coupling agent KH-550 to palmitoleic acid is 2:1-2, the mass ratio of modifier to enzyme-treated boron nitride is 2-5:60-80, the heating temperature is 60-80°C, the stirring speed is 200-300 rpm, the stirring time is 2-4 hours, the drying temperature is 60-80°C, and the drying time is 12-16 hours.

6. A method for preparing high thermal conductivity, high heat dissipation and impact-resistant nylon, characterized in that: The following steps are involved: S1. Premixing nylon 66, modified boron nitride, reinforcing filler, diamond powder, graphene microplatelets, heat dissipation filler, toughening agent, OP wax, antioxidant 1010 and antioxidant 168 in a high-speed mixer to obtain a premix; S2. Melt blending: adding the premix into a twin-screw extruder, melt blending, and extruding into granules to obtain thermal conductive nylon granules; S3. Molding process: The thermal conductive nylon particles are injection molded at appropriate temperature, pressure and speed to obtain high thermal conductivity, high heat dissipation and impact resistant nylon test specimens.

7. The method for preparing high thermal conductivity, high heat dissipation and impact-resistant nylon according to claim 6, characterized in that: The premixing temperature in S1 is 50°C and the premixing time is 1 hour; the premix processing temperature in S2 is 220-270°C, the screw speed is 450rpm, the extruder feed section temperature is 200-220°C, the melting section temperature is 260-270°C, the extrusion section temperature is 240-250°C, the granulation method is air-cooled granulation, and the granulation size is 2-4mm.

8. The method for preparing high thermal conductivity, high heat dissipation and impact-resistant nylon according to claim 6, characterized in that: In S3, the injection temperature is 240-270°C, the injection pressure is 50-80 MPa, the injection speed is 50%-80%, the mold temperature is 80°C, and the holding time is 10 seconds.