Heat-conducting polycarbonate composition, preparation method and application

Abstract

The invention relates to a heat-conducting polycarbonate composition as well as a preparation method and application thereof, and mainly solves the problem of poor processing and mechanical properties caused by too high dosage of a heat-conducting agent in the prior art. The heat-conducting polycarbonate composition provided by the invention is prepared from the following components in parts by weight: (i) 50 to 85 parts of polycarbonate resin; (ii) 15-45 parts of a heat conducting agent; (iii) 0.1 to 5 parts of an interface modifier; (iv) 1-5 parts of other auxiliary agents; wherein the heat-conducting agent is at least one of a linear heat-conducting agent with the length / diameter ratio being greater than or equal to 2 and less than or equal to 10, a flaky heat-conducting agent with the length / thickness ratio being greater than or equal to 10 and less than or equal to 100, and a spherical heat-conducting agent with the particle size being 0.5-50 microns. According to the technical scheme, the problems are well solved, industrial production can be achieved, and the aluminum alloy can be used for heat dissipation components of household appliances, automobiles, industries and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer composite materials and relates to a thermal conductive polycarbonate composition and a preparation method and application thereof. Background Art

[0002] At present, with the rapid development of 5G communication technology, electronic technology and manufacturing technology, the integration of electronic appliances and industrial equipment is getting higher and higher, accompanied by a surge in heat generation during operation, which directly affects the long-term stable use of the equipment. Therefore, efficient and rapid heat transfer and heat dissipation are crucial. Traditional thermal conductive materials such as metals and ceramics have high density, low design freedom and high manufacturing difficulty. Resin-based thermal conductive materials are light in weight, low in cost, easy to form, and have a wide range of substrate selection, and have developed into a research and development hotspot for thermal conductive materials. Chinese patent CN102482449 discloses a thermal conductive resin composition with a thermal conductivity of 0.6~1.5 watts / (meter•degree) prepared by high-content metal compounds and glass fibers. Chinese patent CN103119092 reports the preparation of a thermal conductive resin composition with calcium fluoride and fiber filler. Chinese patent CN103965616 reports the use of boron carbide particles to make a thermal conductive resin with a thermal conductivity of 2.1~4.2 watts / (meter•degree). A large amount of inorganic fillers are added in the above patents, which is bound to be unfavorable to the processing and mechanical properties of the materials. It is of great significance to develop a thermally conductive resin composition with high thermal conductivity, light weight and excellent performance. Summary of the invention

[0003] The present invention aims to solve the problem in the prior art that excessive dosage of thermal conductor leads to poor processing and mechanical properties, and provides a thermally conductive polycarbonate composition that meets the application requirements of heat dissipation components in home appliances, automobiles, industry, etc.

[0004] In order to solve the above technical problems, the present invention provides a thermally conductive polycarbonate composition, which comprises the following components in parts by weight: (i) 75 to 85 parts of a polycarbonate resin; (ii) 15 to 25 parts of a thermal conductive agent; (iii) 0.1 to 5 parts of an interfacial modifier; (iv) 1 to 10 parts of other additives; Among them, the thermal conductor is at least one of a linear thermal conductor with a length / diameter ratio of 2≤≤10, a sheet thermal conductor with a length / thickness ratio of 10≤≤100, and a spherical thermal conductor with a particle size of 0.5~50 microns, preferably a combination of at least one of a linear thermal conductor with a length / diameter ratio of 2≤≤10, a sheet thermal conductor with a length / thickness ratio of 10≤≤100 and a spherical thermal conductor with a particle size of 0.5~50 microns, and more preferably a combination of a linear thermal conductor with a length / diameter ratio of 2≤≤10, a sheet thermal conductor with a length / thickness ratio of 10≤≤100 and a spherical thermal conductor with a particle size of 1~35 microns.

[0005] In the above technical solution, the polycarbonate resin is selected from at least one of bisphenol A polycarbonate and its derivatives; The number average molecular weight of the polycarbonate resin is 17000-27000 g / mol, preferably 19000-25000 g / mol; The derivative of bisphenol A polycarbonate has a structure represented by formula (I) with a molar percentage of 0.05-3%: Formula (I); Wherein, R1, R2, and R3 are arbitrarily selected from C1 to C 24 X is selected from N, a C1~C6 hydrocarbon group.

[0006] In the above technical solution, the linear thermal conductor is selected from at least one of glass fiber, carbon fiber and carbon nanotube; The flaky thermal conductor is selected from at least one of graphite and graphene; The spherical thermal conductor is selected from at least one of glass beads, alumina and aluminum nitride; The combination of thermal conductors is preferably a combination of carbon nanotubes and aluminum oxide, a combination of graphene and aluminum oxide, or a combination of carbon nanotubes, graphene and aluminum oxide.

[0007] In the above technical solution, the interface modifier is selected from at least one of a silane coupling modifier and a titanate coupling modifier.

[0008] In the above technical solution, the other additives include antioxidants, release agents, and toughening agents; The antioxidant is selected from at least one of the trade names 1010, 1076, and 168; The release agent is selected from at least one of silicone oil, carbon tetrachloride and white oil; The toughening agent is selected from at least one of methacrylate C1~C6 alkyl ester / butadiene / styrene copolymer, acrylate C1~C6 alkyl ester / butadiene / styrene copolymer, acrylate C1~C6 alkyl ester / butadiene copolymer, butadiene / styrene copolymer; The toughening agent has a core-shell structure.

[0009] At the same time, the present invention also provides a method for preparing a thermally conductive polycarbonate composition, which is simple and easy to implement and can be easily industrially prepared.

[0010] In the above technical solution, the method for preparing the thermally conductive polycarbonate composition comprises the following steps: The surface of the thermal conductor is pretreated by using an interface modifier; polycarbonate resin, the pretreated thermal conductor and other additives are mixed and introduced into an extruder for melting, kneading, extrusion and granulation to obtain a thermally conductive polycarbonate composition.

[0011] In the above technical solution, the melting temperature is 240-290° C.; the rotation speed of the extruder is 350-900 rpm.

[0012] In the above technical solution, the thermal conductivity of the thermally conductive polycarbonate composition is 5-15 W / (m•degree), the density is 1.25-1.45 g / cm3, and the notched impact strength is above 20 kJ / m2.

[0013] In addition, the present invention also provides an application of the thermally conductive polycarbonate composition, which is used for but not limited to application in heat dissipation components of household appliances, automobiles, industry, etc.

[0014] Advantages of this patented invention method: (i) A combination of a linear thermal conductor with a specific length / diameter ratio, a flake thermal conductor with a specific length / thickness ratio, and a spherical thermal conductor with a specific particle size range is used to give the thermally conductive polycarbonate composition excellent thermal conductivity and thermal conduction performance.

[0015] (ii) By using bisphenol A polycarbonate and polycarbonate having a branched structure, a thermally conductive polycarbonate composition having excellent processing performance can be obtained.

[0016] (iii) Using interface modifiers and other processing aids together with polycarbonate resin and thermal conductive agent to construct a thermal conductive polycarbonate composition with excellent comprehensive performance, achieving good technical results.

[0017] The properties of the composition in the method of the present invention are determined as follows: Density: Measured by electronic density meter.

[0018] Melt flow index: measured according to ASTM D1238 standard, conditions 300 degrees, 1.2 kg.

[0019] Flexural modulus: measured according to ISO178 standard.

[0020] Notched impact strength: measured according to ISO179 standard.

[0021] Thermal conductivity: measured according to ASTM E1461.

[0022] The present invention will be further described below through specific examples. DETAILED DESCRIPTION

[0023] [Examples 1 to 7] In the pretreatment kettle, the surface of the thermal conductor is pretreated with an interfacial modifier, which is achieved by stirring at room temperature for 2 hours at a stirring rate of 300 rpm; the polycarbonate resin, the pretreated thermal conductor, and other additives are mixed at high speed in a high-speed mixer, introduced into a twin-screw extruder for melting, kneading, extrusion, and granulation to obtain a thermally conductive polycarbonate composition with a melting temperature of 268°C and an extruder speed of 600 rpm. The dosage ratios (by weight) of each component of Examples 1-7 and the performance test results of the thermally conductive polycarbonate composition are shown in Table 1.

[0024] [Comparative Example 1] In the pretreatment kettle, the surface of the thermal conductor is pretreated with an interfacial modifier, which is achieved by stirring at room temperature for 2 hours at a stirring rate of 300 rpm; the polycarbonate resin, the pretreated thermal conductor, and other additives are mixed at high speed in a high-speed mixer, introduced into a twin-screw extruder for melting, kneading, extrusion, and granulation to obtain a thermally conductive polycarbonate composition with a melting temperature of 268°C and an extruder speed of 600 rpm. The dosage ratio (by weight) of each component of Comparative Example 1 and the performance test results of the thermally conductive polycarbonate composition are shown in Table 1.

[0025] Table 1 The number average molecular weight of the bisphenol A polycarbonate in Table 1 is 25000 g / mol; the copolycarbonate contains 0.15% by mole of the structure shown in formula (II): Formula (II); The number average molecular weight of the copolycarbonate is 19000 g / mol; the length / diameter ratio of the carbon nanotubes is 10; the particle size of the aluminum oxide (D 50 ) is 20 microns; the length / thickness ratio of graphene is 45; and the molar ratio of butyl acrylate / butadiene / styrene copolymer is 20 / 25 / 55.

[0026] As can be seen from Table 1, by using graphene with a specific length / thickness ratio, carbon nanotubes with a specific length / diameter ratio, and alumina with a specific particle size range and their combination, a thermally conductive polycarbonate composition with a thermal conductivity of up to 10.6 W / (m•deg.), a density of 1.26 g / cm3, and a notched impact strength of 27.5 kJ / m2 can be prepared. Compared with a single spherical alumina thermally conductive polycarbonate material, the thermal conductivity is increased by more than 8 times, the density is reduced by 8%, and the notched impact strength is increased by 10%. In addition, the copolycarbonate has a certain content of the structure of formula (II), forming a certain branched molecular chain in the resin, giving the composition good processing flowability, reflecting the advantages of the present technical invention.

[0027] [Examples 8-10] In the pretreatment kettle, the surface of the thermal conductor is pretreated with an interfacial modifier, which is achieved by stirring at room temperature for 2 hours at a stirring rate of 300 rpm; the polycarbonate resin, the pretreated thermal conductor, and other additives are mixed at high speed in a high-speed mixer, introduced into a twin-screw extruder for melting, kneading, extrusion, and granulation to obtain a thermally conductive polycarbonate composition with a melting temperature of 268°C and an extruder speed of 600 rpm. The dosage ratios (by weight) of each component of Examples 8-10 and the performance test results of the thermally conductive polycarbonate composition are shown in Table 2.

[0028] [Comparative Examples 2 to 5] In the pretreatment kettle, the surface of the thermal conductor is pretreated with an interfacial modifier, which is achieved by stirring at room temperature for 2 hours at a stirring rate of 300 rpm; the polycarbonate resin, the pretreated thermal conductor, and other additives are mixed at high speed in a high-speed mixer, introduced into a twin-screw extruder for melting, kneading, extrusion, and granulation to obtain a thermally conductive polycarbonate composition with a melting temperature of 268°C and an extruder speed of 600 rpm. The dosage ratios (by weight) of the components of Comparative Examples 2-5 and the performance test results of the thermally conductive polycarbonate composition are shown in Table 2.

[0029] Table 2 In Table 2, the number average molecular weight of bisphenol A polycarbonate is 21000 g / mol; the length / diameter ratio of carbon nanotube 1 is 8; the length / diameter ratio of carbon nanotube 2 is 1.5; the particle size of aluminum oxide 1 (D 50 ) is 10 microns; the particle size of aluminum oxide 2 (D 50 ) is 100 microns; the length / thickness ratio of graphene 1 is 30; the length / thickness ratio of graphene 2 is 120; the molar ratio of methyl methacrylate / butadiene / styrene copolymer is 10 / 20 / 70.

[0030] As can be seen from Table 2, the combination of carbon nanotubes of specific sizes and alumina in Example 8 is compared with Comparative Example 2, the combination of graphene and alumina of specific sizes in Example 9 is compared with Comparative Examples 3 and 4, and the combination of carbon nanotubes, graphene and alumina of specific sizes in Example 10 is compared with Comparative Example 5. The composition prepared by the method of the present invention has high thermal conductivity, low density and high notched impact strength, which are superior to the thermal conductor system beyond the protection size range of the present invention, and the comprehensive performance is far better than the alumina system with a higher usage in Comparative Example 5, which reflects the advantages of the protection scope of the present invention.

Claims

1. A thermally conductive polycarbonate composition comprising the following components in parts by weight: (i) 75 to 85 parts of a polycarbonate resin; (ii) 15 to 25 parts of a thermal conductive agent; (iii) 0.1 to 5 parts of an interfacial modifier; (iv) 1 to 10 parts of other additives; The thermal conductor is at least one of a linear thermal conductor with a length / diameter ratio of 2≤≤10, a sheet thermal conductor with a length / thickness ratio of 10≤≤100, and a spherical thermal conductor with a particle size of 0.5-50 microns.

2. The thermally conductive polycarbonate composition according to claim 1, characterized in that: The thermal conductor is a combination of at least one of a linear thermal conductor with a length / diameter ratio of 2≤≤10 and a sheet thermal conductor with a length / thickness ratio of 10≤≤100 and a spherical thermal conductor with a particle size of 0.5-50 microns.

3. The thermally conductive polycarbonate composition according to claim 1, characterized in that: The thermal conductor is a combination of at least one of a linear thermal conductor with a length / diameter ratio of 2≤≤10 and a sheet thermal conductor with a length / thickness ratio of 10≤≤100 and a spherical thermal conductor with a particle size of 1-35 microns.

4. The thermally conductive polycarbonate composition according to claim 1, characterized in that: The polycarbonate resin is selected from at least one of bisphenol A polycarbonate and its derivatives; The number average molecular weight of the polycarbonate resin is 17000-27000 g / mol.

5. The thermally conductive polycarbonate composition according to claim 1, characterized in that: The linear thermal conductor is selected from at least one of glass fiber, carbon fiber, and carbon nanotube; The flaky thermal conductor is selected from at least one of graphite and graphene; The spherical thermal conductor is selected from at least one of glass beads, aluminum oxide, and aluminum nitride.

6. The thermally conductive polycarbonate composition according to claim 1, characterized in that: The interface modifier is selected from at least one of a silane coupling modifier and a titanate coupling modifier.

7. The thermally conductive polycarbonate composition according to claim 1, characterized in that: The other additives include antioxidants, release agents, and toughening agents; The antioxidant is selected from at least one of the trade names 1010, 1076, and 168; The release agent is selected from at least one of silicone oil, carbon tetrachloride and white oil; The toughening agent is selected from at least one of methacrylate C1~C6 alkyl ester / butadiene / styrene copolymer, acrylate C1~C6 alkyl ester / butadiene / styrene copolymer, acrylate C1~C6 alkyl ester / butadiene copolymer, butadiene / styrene copolymer; The toughening agent has a core-shell structure.

8. The thermally conductive polycarbonate composition according to any one of claims 1 to 7, characterized in that: The thermally conductive polycarbonate composition has a thermal conductivity of 5 to 15 W / (m•degree), a density of 1.25 to 1.45 g / cm3, and a notched impact strength of more than 20 kJ / m2.

9. The method for preparing the thermally conductive polycarbonate composition according to any one of claims 1 to 8, characterized in that: The following steps are involved: The surface of the thermal conductor is pretreated by using an interface modifier; polycarbonate resin, the pretreated thermal conductor and other additives are mixed and introduced into an extruder for melting, kneading, extrusion and granulation to obtain a thermally conductive polycarbonate composition.

10. The use of the thermally conductive polycarbonate composition according to any one of claims 1 to 8 is used for, but not limited to, household appliances, automobiles, and industrial heat dissipation parts.

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