Polyphenyl ether conductive composite material and preparation method thereof

Abstract

The invention relates to the technical field of engineering plastics, and provides a polyphenyl ether conductive composite material and a preparation method thereof. According to the polyphenyl ether conductive composite material provided by the invention, the carbon nanotube composite material is adopted to replace a traditional carbon-based conductive agent to serve as the conductive filler to be added into the resin base material, the addition amount of the conductive filler is reduced, and meanwhile, the wear resistance of the material can be improved due to the fact that the carbon nanotubes have fibrous structures, so that the effect of reducing dust falling is achieved. The modified carbon nanotube comprises a mixture of a multi-walled carbon nanotube, graphene and calcium silicate, the graphene with a two-dimensional structure can improve the interface energy between the carbon nanotube and a resin base material, and meanwhile, the calcium silicate can fill gaps between the carbon nanotube and the graphene as well as between the carbon nanotube and the resin base material, so that the stripping between the carbon nanotube and the base material is reduced, and the service life of the carbon nanotube is prolonged. The connection is tight. Moreover, the modified carbon nanotubes and polystyrene form a composite material, so that the dispersion of the carbon nanotubes is improved, and the processability is improved.

Description

Technical Field

[0001] The present application belongs to the technical field of engineering plastics, and in particular relates to a polyphenylene ether conductive composite material and a preparation method thereof. Background Art

[0002] There are tens of thousands of circuits inside high-performance integrated circuits, and the internal circuits are complex, subtle, and precise. These fine and precise circuits etched and buried on silicon-based semiconductor wafers must be properly protected to avoid damage during production and transportation. Chip trays are widely used in semiconductor chip manufacturing, testing, and packaging. They can protect chips from static electricity, vibration, high temperature, and other factors to ensure the quality and reliability of chips. Therefore, the tray material must have excellent static dissipation capabilities.

[0003] Semiconductor chip trays and integrated circuit trays need to have excellent mechanical properties, good electrostatic dissipation, high heat resistance, dimensional stability, and low warping. Polyphenylene oxide resin (PPO) has the advantages of excellent mechanical properties, heat resistance, electrical insulation, and low creep at high temperatures. At the same time, PPO has low density and hygroscopicity, high strength, and good dimensional stability. Existing semiconductor trays and integrated circuit trays mainly use resins such as PPO, polysulfone (PSF) or polyethersulfone (PES) as the matrix.

[0004] In order to provide conductivity to the tray and prevent the tray from accumulating static electricity, the traditional practice is to add conductive fillers such as carbon black or carbon fiber to the matrix resin material. Although carbon fiber has a reinforcing effect on the resin, the amount of carbon fiber added is large, which puts great cost pressure. Carbon black is relatively cheap, but the amount added is generally about 20%-30% of the mass fraction, resulting in serious dusting, which can cause IC burnout and low process yield. Application Contents

[0005] The purpose of the present application is to provide a polyphenylene ether conductive composite material and a preparation method thereof, aiming to solve the problems of large amount of conductive filler added and serious dusting in existing pallet materials. Technical Solutions

[0006] In order to achieve the above application purpose, the technical solution adopted in this application is as follows:

[0007] In a first aspect, the present application provides a polyphenylene ether conductive composite material, comprising the following components in parts by weight:

[0008] 40-70 parts of polyphenylene ether;

[0009] 10 to 30 parts of carbon nanotube composite material;

[0010] 1 to 3 parts of toughening agent;

[0011] 2 to 4 parts of dispersant;

[0012] 20-30 parts of inorganic filler;

[0013] Antioxidant 0.1-1 part;

[0014] The carbon nanotube composite material comprises modified carbon nanotubes and high-impact polystyrene, and the modified carbon nanotubes comprise multi-walled carbon nanotubes, graphene and calcium silicate.

[0015] In some embodiments, the mass ratio of the modified carbon nanotubes to the high impact polystyrene is (10-20):(80-90).

[0016] In some embodiments, the mass ratio of the multi-walled carbon nanotubes, the graphene, and the calcium silicate is 1:(0.1-0.5):(0.5-2).

[0017] In some embodiments, the multi-walled carbon nanotubes have at least one of the following (1)-(5):

[0018] (1) The multi-walled carbon nanotubes have an inner diameter of 1 to 2 nm, an outer diameter of 8 to 25 nm, a length of 1 to 100 μm, an aspect ratio of 5000 to 10000:1, and a bulk density of 0.15 to 0.4 g / cm 3 , with a specific surface area of ​​190 to 270 m 2 / g;

[0019] (2) The thermal conductivity of the multi-walled carbon nanotubes is 300 to 6000 W / mk;

[0020] (3) The initial decomposition temperature of the multi-walled carbon nanotubes is 500-600°C;

[0021] (4) The particle size D97 of the multi-walled carbon nanotubes is ≤50 μm, and the particle size Dmax is ≤300 μm;

[0022] (5) The powder resistivity of the multi-walled carbon nanotubes is 30 to 60 mΩ·cm;

[0023] (6) The Raman spectrum intensity of the multi-walled carbon nanotubes is D / I G ≤1.2.

[0024] In some embodiments, the weight average molecular weight of the high impact polystyrene is 150,000 to 300,000 g / mol.

[0025] In some embodiments, the inorganic filler includes at least one of talc, calcium carbonate, silica fume, mica powder, kaolin, wollastonite, and attapulgite; and the particle size of the inorganic filler is 1000 to 3000 meshes.

[0026] In some embodiments, the antioxidant includes at least one of a hindered phenol antioxidant and a phosphite antioxidant.

[0027] In some embodiments, the polyphenylene ether conductive composite material has at least one of the following (1)-(3):

[0028] (1) The surface resistivity of the polyphenylene ether conductive composite material is 10 6 ~10 8 Ω / sq;

[0029] (2) The polyphenylene ether conductive composite material has a melt index of 6 to 13 g / 10 min under the test conditions of 300° C. and 10 kg;

[0030] (3) The density of the polyphenylene ether conductive composite material is 1.07 to 1.1 g / cm 3 .

[0031] In a second aspect, the present application provides a method for preparing a polyphenylene ether conductive composite material, comprising the following steps:

[0032] Mixing the multi-walled carbon nanotubes with the graphene and the calcium silicate to obtain the modified carbon nanotubes;

[0033] Dispersing the modified carbon nanotubes and the high impact polystyrene to obtain the carbon nanotube composite material;

[0034] The carbon nanotube composite material is mixed with the polyphenylene ether, the toughening agent, the dispersant, the inorganic filler and the antioxidant, and then melt-extruded and granulated to obtain the polyphenylene ether conductive composite material.

[0035] In some embodiments, the step of mixing the multi-walled carbon nanotubes with the graphene and the calcium silicate to obtain the modified carbon nanotubes includes: mixing the multi-walled carbon nanotubes, the graphene, the calcium silicate, a binder and a solvent, then ball milling to obtain a mixed slurry, and drying the mixed slurry to obtain the modified carbon nanotubes.

[0036] In some embodiments, the conditions of the ball milling treatment include: the grinding medium includes zirconia balls and / or agate balls; the size of the grinding medium is 0.5-1.0 mm; the filling rate of the grinding medium is 60%-85%; and the stirring rate is 500-900 r / min.

[0037] In some embodiments, the step of dispersing the modified carbon nanotubes and the high impact polystyrene to obtain the carbon nanotube composite material includes: adding the modified carbon nanotubes and the high impact polystyrene into tetrahydrofuran for dispersion, and removing the solvent in vacuum to obtain the carbon nanotube composite material.

[0038] In some embodiments, the process conditions of melt extrusion granulation include: an extrusion temperature of 250-300° C., a main engine speed of 400-1000 rpm / min, and melt extrusion granulation by a twin-screw extruder.

[0039] The polyphenylene ether conductive composite material provided in the first aspect of the present application adopts a modified carbon nanotube composite material to replace the traditional carbon-based conductive agent as a conductive filler added to the resin substrate. Since the amount of modified carbon nanotubes added is only 1 / 10 of the amount of carbon black added, and since the carbon nanotubes have a fibrous structure, the wear resistance of the material can be improved, thereby achieving the purpose of lower dusting. The modified carbon nanotubes of the present application include multi-walled carbon nanotubes, graphene and calcium silicate, wherein the multi-walled carbon nanotubes are used as one-dimensional conductive fillers, and the graphene with a two-dimensional structure is matched. The graphene can improve the interface energy between the carbon nanotubes and the resin substrate to a certain extent, and the calcium silicate can fill the gap between the carbon nanotubes and the graphene and the resin substrate, reduce the peeling between the carbon nanotubes and the substrate, and connect tightly. Moreover, the present application forms a composite material with modified carbon nanotubes and polystyrene, and the composite material is an antistatic material with a high degree of uniformity, which is easy to add and easy to disperse, further improves the dispersion of carbon nanotubes, and improves processing performance.

[0040] The second aspect of the present application provides a method for preparing a polyphenylene ether conductive composite material. The method comprises the following steps: mixing multi-walled carbon nanotubes with graphene and calcium silicate to obtain modified carbon nanotubes, improving the interface energy between the carbon nanotubes and a resin substrate, and then compounding the modified carbon nanotubes with high-impact polystyrene to obtain a composite material, thereby improving the dispersibility of the carbon nanotubes. Finally, the modified carbon nanotube composite material is mixed with other raw materials and melt-granulated to obtain the polyphenylene ether conductive composite material. The method is simple to operate and has strong operability. It is not only easy to control product quality, but also low in cost. Embodiments of the present invention

[0041] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present application.

[0042] It should be noted that when a component is referred to as being "fixed on" or "disposed on" another component, it may be directly on the other component or indirectly on the other component. When a component is referred to as being "connected to" another component, it may be directly or indirectly connected to the other component. The orientation or positional relationship indicated by the terms "upper", "lower", "left", "right", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to the specific circumstances. The terms "first" and "second" are only used for the purpose of convenience of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features. The meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0043] Semiconductor chip trays require materials with properties such as conductivity, antistatic, high temperature resistance, and high strength. In order to make the tray conductive and antistatic, the traditional method is to add carbon black or carbon fiber to the tray resin substrate, but the amount of carbon black and carbon fiber added is large, dust is serious, and the cost is high.

[0044] Based on this, the first aspect of the embodiment of the present application provides a polyphenylene ether conductive composite material, comprising the following components in parts by weight:

[0045] 40-70 parts of polyphenylene ether;

[0046] 10 to 30 parts of carbon nanotube composite material;

[0047] 1 to 3 parts of toughening agent;

[0048] 2 to 4 parts of dispersant;

[0049] 20-30 parts of inorganic filler;

[0050] Antioxidant 0.1-1 part;

[0051] The carbon nanotube composite material includes modified carbon nanotubes and high-impact polystyrene; the modified carbon nanotubes include multi-walled carbon nanotubes, graphene and calcium silicate.

[0052] The polyphenylene ether conductive composite material provided in the first aspect of the present application adopts modified carbon nanotubes to replace the traditional carbon-based conductive agent as a conductive filler added to the resin substrate. Since the amount of modified carbon nanotubes added is only 1 / 10 of the amount of carbon black added, and since the carbon nanotubes have a fibrous structure, the wear resistance of the material can be effectively improved, thereby achieving the purpose of low dust. The modified carbon nanotubes of the present application include multi-walled carbon nanotubes, graphene and calcium silicate, wherein the multi-walled carbon nanotubes are used as one-dimensional conductive fillers, and the graphene with a two-dimensional structure is matched. The graphene can improve the interface energy between the carbon nanotubes and the resin substrate to a certain extent, and the calcium silicate can fill the gap between the carbon nanotubes and the graphene and the resin substrate, further reducing the peeling between the carbon nanotubes and the substrate, and the connection is tight. Moreover, the present application forms a composite material with modified carbon nanotubes and polystyrene, and the composite material is an antistatic material with a high degree of uniformity, which is easy to add and easy to disperse, thereby improving the dispersion of carbon nanotubes and improving processing performance. At the same time, the components of the embodiments of the present application also include polyphenylene ether, which is called "Polyphenylene Oxide" in English, abbreviated as "PPO", and is one of the five general engineering plastics. The dielectric constant and dielectric loss of polyphenylene ether are one of the smallest varieties among engineering plastics, and are almost unaffected by temperature and humidity. It has excellent high temperature resistance, low warping, good stability, antistatic and other properties. When the components of the polyphenylene ether conductive composite material are within the above range, a polyphenylene ether conductive composite material for pallets with good antistatic and conductive properties can be obtained.

[0053] In some embodiments, the weight percentage of the polyphenylene ether includes, but is not limited to, any one of 40 parts, 45 parts, 50 parts, 55 parts, 60 parts, 65 parts, and 70 parts, or any range between two parts. In the embodiments of the present application, the weight percentage of the polyphenylene ether is controlled within the above range, and specific weight percentages of carbon nanotube composite materials, toughening agents, inorganic fillers and other components are compounded to obtain a polyphenylene ether conductive composite material with good wear resistance, less dust and good uniformity.

[0054] In some embodiments, the carbon nanotube composite material includes modified carbon nanotubes and high impact polystyrene, wherein the mass ratio of the modified carbon nanotubes to the high impact polystyrene is (10-20):(80-90).

[0055] As an example, the mass ratio of the modified carbon nanotubes to the high impact polystyrene can be typical but non-limiting values ​​such as 10:90, 12:88, 14:86, 16:84, 18:82, 20:80, etc. By controlling the mass ratio of the modified carbon nanotubes to the high impact polystyrene within the above range, the dispersibility of the modified carbon nanotubes can be further improved and the processing performance can be improved.

[0056] In some embodiments, the modified carbon nanotubes include multi-walled carbon nanotubes, graphene and calcium silicate. The mass ratio of multi-walled carbon nanotubes, graphene and calcium silicate is 1: (0.1-0.5): (0.5-2). As an example, the mass ratio of multi-walled carbon nanotubes, graphene and calcium silicate can be 1: 0.1: 0.5, 1: 0.2: 0.6, 1: 0.3: 0.8, 1: 0.4: 1.0, 1: 0.5: 1.5, 1: 0.5: 2 and other typical but non-limiting values. By controlling the mass ratio of multi-walled carbon nanotubes, graphene and calcium silicate within the above range, the interfacial energy between the carbon nanotubes and the resin substrate can be better improved, while further reducing the peeling between the carbon nanotubes and the substrate and reducing the dusting phenomenon.

[0057] In some embodiments, the inner diameter of the multi-walled carbon nanotube is 1-2 nm, the outer diameter is 8-25 nm, the length is 1-100 μm, the aspect ratio is 5000-10000:1, and the bulk density is 0.15-0.4 g / cm 3 , with a specific surface area of ​​190 to 270 m 2 / g. As an example, the aspect ratio of multi-walled carbon nanotubes can be any one of 5000, 6000, 7000, 8000, 9000, 10000 or any range between two values. As one of the core indicators affecting conductivity, the aspect ratio of carbon nanotubes directly determines the product performance of carbon nanotubes. The thinner the diameter of carbon nanotubes and the longer the length, the better the conductivity.

[0058] In some embodiments, the thermal conductivity of the multi-walled carbon nanotubes is 300 to 6000 W / mk. As an example, the thermal conductivity of the multi-walled carbon nanotubes can be any one of 300 W / mk, 1000 W / mk, 2000 W / mk, 3000 W / mk, 4000 W / mk, 5000 W / mk, 6000 W / mk or a range between any two of them. The thermal conductivity of the carbon nanotubes is closely related to their structure and size. By controlling the thermal conductivity of the multi-walled carbon nanotubes within the above range, the purpose of controlling the purity, length and other properties of the carbon nanotubes can be achieved.

[0059] In some embodiments, the initial decomposition temperature of the multi-walled carbon nanotubes is 500-600° C. As an example, the initial decomposition temperature of the multi-walled carbon nanotubes can be any one of 500° C., 510° C., 520° C., 530° C., 540° C., 550° C., 560° C., 570° C., 580° C., 590° C., and 600° C., or a range of values ​​between any two of them. The initial decomposition temperature of the carbon nanotubes is affected by their thermal stability, structure, impurities, and defects. By controlling the initial decomposition temperature of the multi-walled carbon nanotubes within the above range, the specifications and quality of the carbon nanotubes can also be evaluated, and thus can also be used as a basis for material selection.

[0060] In some embodiments, the particle size D97 of the multi-walled carbon nanotubes is ≤50 μm, and the particle size Dmax is ≤300 μm. Particle size D97 refers to the particle size corresponding to when the cumulative particle size distribution number of a sample reaches 97%. Its physical meaning is that particles with a particle size smaller than it account for 97%. This is a widely used data indicating the coarse end particle size index of a powder. Particle size Dmax represents the largest particle size in the particle size distribution. It can reflect the maximum particle size existing in the particle sample and, to a certain extent, reflects the width of the particle size distribution range. Particle size Dmax combined with particle size D97 can effectively evaluate the characteristics and quality of carbon nanotube particles.

[0061] In some embodiments, the powder resistivity of the multi-walled carbon nanotubes is 30 to 60 mΩ·cm. As an example, the powder resistivity of the multi-walled carbon nanotubes can be any one of 30 mΩ·cm, 35 mΩ·cm, 40 mΩ·cm, 45 mΩ·cm, 50 mΩ·cm, 55 mΩ·cm, 60 mΩ·cm, or a range of values ​​between any two of them. The resistivity of the carbon nanotubes represents the resistance encountered when the current passes through a unit length of the carbon nanotubes, and its resistivity is determined by the structure and conductive properties of the carbon nanotubes. Controlling the powder resistivity of the multi-walled carbon nanotubes within the above range can further improve the conductive properties of the polyphenylene ether conductive composite material.

[0062] In some embodiments, the Raman spectrum intensity of the multi-walled carbon nanotubes is D / I G ≤1.2. Raman spectroscopy can characterize the lattice defects, morphology and other structural information of carbon nanotubes. D / I G The ratio is related to the disorder and destruction of the structure of the carbon nanotubes. This ratio can be used to describe the defects of the crystal. The larger the ratio, the more defects the crystal has. Selecting multi-walled carbon nanotubes with a Raman spectrum intensity ratio within the above range can further control the quality of the multi-walled carbon nanotubes and reduce defects.

[0063] In some embodiments, the weight average molecular weight of high impact polystyrene is 150000-300000 g / mol. As an example, the weight average molecular weight of high impact polystyrene can be any one of 150000-200000 g / mol, 180000-250000 g / mol, 230000-280000 g / mol, 250000-300000 g / mol, or a range between any two values. The weight average molecular weight can reflect the length and molecular weight distribution of the polymer chain. The weight average molecular weight is often used to evaluate the mechanical properties and processing properties of polymers. The use of high impact polystyrene within the above weight average molecular weight range can not only better improve the dispersibility and processability of carbon nanotubes, but also better improve the processability of polyphenylene ether, so that the obtained polyphenylene ether conductive composite material has better performance.

[0064] In some embodiments, the toughening agent includes at least one of maleic anhydride grafted hydrogenated styrene-butadiene-styrene copolymer, succinic anhydride grafted hydrogenated styrene-butadiene-styrene copolymer, maleic anhydride grafted hydrogenated styrene-isoprene-styrene copolymer, and succinic anhydride grafted hydrogenated styrene-isoprene-styrene copolymer. The toughening agent can improve the dispersibility and interfacial compatibility of the inorganic powder in the resin matrix, improve the impact resistance of the composite material, and enhance toughness.

[0065] In some embodiments, the dispersant includes at least one of polyvinyl pyrrolidone, fatty alcohol polyoxyethylene ether, sodium dodecylbenzene sulfonate, and sodium dodecyl sulfate. The above dispersants have excellent properties of efficient cleaning and stable dispersion. Adding at least one of the above dispersants can further improve the dispersibility of carbon nanotubes, inorganic fillers, etc. in the resin material.

[0066] In some embodiments, the inorganic filler includes at least one of talc, calcium carbonate, silica fume, mica powder, kaolin, wollastonite, and attapulgite. The above-mentioned inorganic filler has the performance characteristics of high hardness, high wear resistance and high temperature resistance. The above-mentioned inorganic filler can better improve the strength and hardness of the polyphenylene ether conductive composite material and improve the wear resistance. In some embodiments, the particle size of the inorganic filler is 1000 to 3000 mesh. As an example, the particle size of the inorganic filler can be any value of 1000 mesh, 1300 mesh, 1500 mesh, 1800 mesh, 2000 mesh, 2300 mesh, 2500 mesh, 2800 mesh, 3000 mesh or any range value between the two. The particle size of the filler reflects the particle size. The larger the mesh size, the smaller the particle size, the larger the contact area with the substrate, and the greater the filling density.

[0067] In some embodiments, the antioxidant includes at least one of a hindered phenol antioxidant and a phosphite antioxidant. As an example, the antioxidant may include at least one of 1010, 168, 1076, 1330, 1035, 3144, 1024, and 126. The above antioxidants may be used to better inhibit or slow down the aging degradation of the polyphenylene ether conductive composite material.

[0068] In some embodiments, the surface resistivity of the top and bottom surfaces of the molded product made by using the polyphenylene ether conductive composite material of the embodiment of the present application is 10 6 ~10 8 Ω / sq. Surface resistivity is a physical quantity that measures the conductive properties of an object's surface. The polyphenylene ether conductive composite material of the embodiment of the present application requires antistatic properties. The surface resistivity of the top and bottom surfaces of the product made using the polyphenylene ether conductive composite material of the embodiment of the present application is within the above range, meeting the performance requirements of the semiconductor tray.

[0069] In some embodiments, the polyphenylene ether conductive composite material of the present application embodiment has a melt index of 6 to 13 g / 10 min under the test conditions of 300°C and 10 kg. Melt index is an index used to measure the fluidity of thermoplastic materials in a molten state. The melt index of a material can be used as an important parameter to measure the fluidity during molding, the molecular weight of the material, and the molding process conditions. The polyphenylene ether conductive composite material within the above melt index range is suitable for the production of semiconductor trays.

[0070] In some embodiments, the density of the polyphenylene ether conductive composite material of the present application embodiment is 1.07-1.1 g / cm 3 The polyphenylene ether conductive composite material has the advantages of low density, low weight and high strength, meeting the performance requirements of semiconductor trays.

[0071] A second aspect of the present application provides a method for preparing a polyphenylene ether conductive composite material, comprising the following steps:

[0072] S1: Mixing multi-walled carbon nanotubes with graphene and calcium silicate to obtain modified carbon nanotubes;

[0073] S2: dispersing the modified carbon nanotubes and high impact polystyrene to obtain a carbon nanotube composite material;

[0074] S3: The carbon nanotube composite material is mixed with polyphenylene ether, a toughening agent, a dispersant, an inorganic filler and an antioxidant, and then melt-extruded and granulated to obtain a polyphenylene ether conductive composite material.

[0075] The second aspect of the embodiment of the present application provides a method for preparing a polyphenylene ether conductive composite material. The method comprises the following steps: mixing multi-walled carbon nanotubes with graphene and calcium silicate to obtain modified carbon nanotubes, improving the interface energy between the carbon nanotubes and a resin substrate, and then compounding the modified carbon nanotubes with high-impact polystyrene to obtain a composite material, thereby improving the dispersibility of the carbon nanotubes. Finally, the modified carbon nanotube composite material is mixed with other raw materials and melt-granulated to obtain the polyphenylene ether conductive composite material. The method is simple to operate and has strong operability. It is not only easy to control product quality, but also low in cost.

[0076] Step S1:

[0077] The modified carbon nanotubes are obtained by mixing multi-walled carbon nanotubes with graphene and calcium silicate.

[0078] In some embodiments, the step of mixing multi-walled carbon nanotubes with graphene and calcium silicate to obtain modified carbon nanotubes includes: mixing multi-walled carbon nanotubes, graphene, calcium silicate, a binder and a solvent, then ball milling to obtain a mixed slurry, and drying the mixed slurry to obtain modified carbon nanotubes.

[0079] As an example, multi-walled carbon nanotubes are dispersed in a solvent, and then graphene and calcium silicate are added, and then an appropriate amount of binder is added, mixed evenly and then ball milled. The solvent here can be water, ethanol or other solvents. The amount of binder added is 0.5-1wt% of the total mass of multi-walled carbon nanotubes, graphene and calcium silicate. As an example, the amount of binder added can be any one of 0.5wt%, 0.6wt%, 0.7wt%, 0.8wt%, 0.9wt%, 1.0wt% of the total mass of multi-walled carbon nanotubes, graphene and calcium silicate, or a range value between any two. In some embodiments, the binder includes at least one of polyethylene glycol, polyvinyl alcohol, polyacrylic acid, polyvinyl pyrrolidone, polyvinylidene fluoride, and polyurethane binders. Adding the above-mentioned binder can combine multi-walled carbon nanotubes, graphene and calcium silicate, so that graphene and calcium silicate modify multi-walled carbon nanotubes and improve the interfacial energy between multi-walled carbon nanotubes and resin substrates.

[0080] In some embodiments, before the multi-walled carbon nanotubes are dispersed in the solvent, the multi-walled carbon nanotubes are first dispersed in a silane coupling agent solution, mixed evenly, and then ball-milled and dried. This can make the composite of the multi-walled carbon nanotubes, graphene and calcium carbonate more uniform and more stable.

[0081] In some embodiments, the conditions of ball milling treatment include: the grinding medium uses 0.5-1.0 mm zirconium oxide balls and / or agate balls; the filling rate of the grinding medium is 60%-85%; the stirring rate is 500-900 r / min. After ball milling, a mixed slurry is obtained, and the mixed slurry is spray-dried to form modified carbon nanotube particles with a particle size of 0.1-1 mm.

[0082] Step S2:

[0083] In some embodiments, the step of dispersing the modified carbon nanotubes and high impact polystyrene to obtain the carbon nanotube composite material includes: dispersing the modified carbon nanotubes and high impact polystyrene in tetrahydrofuran, and removing the solvent in vacuo to obtain the carbon nanotube composite material.

[0084] As an example: a certain amount of modified carbon nanotubes is ultrasonically dispersed in a tetrahydrofuran solution, and after being evenly dispersed, it is added to a tetrahydrofuran solution containing high-impact polystyrene and ultrasonically dispersed for 0.5 to 2 hours. The modified carbon nanotube composite material is obtained after vacuum drying to remove the solvent.

[0085] In some embodiments, before the dispersion process, the high impact polystyrene particles are crushed into powders with a size of ≤2000 meshes in an ultra-low temperature environment below -190°C.

[0086] In some embodiments, before the dispersion treatment, the modified carbon nanotubes are first subjected to a gas flow milling process to crush the particle size to Dmax≤300 μm. The high-impact polystyrene and the modified carbon nanotubes are first crushed into powders with smaller particle sizes, which can better improve the dispersibility of the carbon nanotubes in the high-impact polystyrene and improve the composite efficiency.

[0087] Step S3:

[0088] The carbon nanotube composite material is mixed with polyphenylene ether, a toughening agent, a dispersant, an inorganic filler and an antioxidant, and then melt-extruded and granulated to obtain a polyphenylene ether conductive composite material.

[0089] In some embodiments, before melt extrusion granulation, the toughening agent, dispersant, inorganic filler and antioxidant are placed in a high-speed mixer with a rotation speed of 200-400 rpm and mixed for 3-10 minutes to obtain a mixing aid, and then the modified carbon nanotube composite material, polyphenylene ether resin and mixing aid are respectively fed from three different loss-in-weight scales, and melt extruded and granulated by a twin-screw extruder at an extrusion temperature of 250-300°C and a main engine speed of 400-1000rpm / min.

[0090] In some embodiments, the process conditions of melt extrusion granulation include: an extrusion temperature of 250-300°C, a main engine speed of 400-1000rpm / min, and melt extrusion granulation by a twin-screw extruder. The twin-screw extruder includes a melting section, an extrusion section, a shearing section, a pressurizing section, a melt exhaust section, an extrusion section, a shearing section, a pressurizing section, a melt exhaust section, and a die. The set process conditions of the twin-screw extruder are as follows: melting section: 250-270°C; extrusion section: 270-300°C; shearing section: 270-290°C; pressurization section: 270-290°C; melt exhaust section: 270-290°C; extrusion section: 270-290°C; shearing section: 270-280°C; pressurization section: 270-290°C; melt exhaust section: 280-290°C; head temperature: 290-300°C; main engine speed 400-1000rpm / min, vacuum degree ≤-0.05MPa.

[0091] The following describes the invention in conjunction with specific embodiments.

[0092] Example 1

[0093] This embodiment provides a polyphenylene ether conductive composite material, comprising the following components in parts by weight:

[0094] 46.8 parts of polyphenylene ether;

[0095] 20 parts of carbon nanotube composite material;

[0096] 1 part of toughening agent;

[0097] 2 parts of dispersant;

[0098] 30 parts of talcum powder;

[0099] Antioxidant 1010 0.2 parts.

[0100] The carbon nanotube composite material includes modified carbon nanotubes and high-impact polystyrene, and the modified carbon nanotubes include multi-walled carbon nanotubes, graphene and calcium silicate; the mass ratio of multi-walled carbon nanotubes, graphene and calcium silicate in the modified carbon nanotubes is 1:0.1:0.5, and the mass ratio of modified carbon nanotubes to high-impact polystyrene in the carbon nanotube composite material is 10:90. The specification of the multi-walled carbon nanotubes is an aspect ratio of (7000-8000):1 and a length of 80-90 μm. The toughening agent is hydrogenated styrene-butadiene-styrene copolymer grafted with maleic anhydride. The dispersant is polyvinyl pyrrolidone.

[0101] The preparation method of the polyphenylene ether conductive composite material comprises the following steps:

[0102] S1: Disperse 5 parts by weight of multi-walled carbon nanotube powder in ethanol, add 0.5 parts by weight of graphene and 2.5 parts by weight of calcium silicate, add 0.08 parts by weight of binder polyethylene glycol, mix well and then ball mill. The grinding medium uses 0.5-1.0 mm zirconium oxide balls, the grinding medium filling rate is 65%, the stirring rate is 700 r / min, and a mixed slurry is obtained. The mixed slurry is spray-dried to obtain modified carbon nanotubes with a particle size of 0.1-1 mm.

[0103] S2: 5 parts by weight of modified carbon nanotubes are ultrasonically dispersed in a tetrahydrofuran solution, and after being evenly dispersed, they are added to a tetrahydrofuran solution containing 95 parts by weight of high-impact polystyrene, and ultrasonically dispersed for 1 hour. The modified carbon nanotube composite material is obtained after vacuum drying to remove the solvent.

[0104] S3: The modified carbon nanotube composite material, polyphenylene ether, toughening agent, dispersant, inorganic filler and antioxidant are fed from a loss-in-weight scale, and melt-extruded and granulated by a twin-screw extruder at an extrusion temperature of 250-300°C and a main engine speed of 700 rpm / min to obtain a polyphenylene ether conductive composite material.

[0105] The twin-screw extruder includes a melting section, an extrusion section, a shearing section, a pressurizing section, a melting exhaust section, an extrusion section, a shearing section, a pressurizing section, a melting exhaust section and a die head in sequence. The set process conditions of the twin-screw extruder are as follows: melting section: 260°C; extrusion section: 280°C; shearing section: 280°C; pressurizing section: 280°C; melting exhaust section: 280°C; extrusion section: 280°C; shearing section: 280°C; pressurizing section: 280°C; melting exhaust section: 290°C; die head temperature: 300°C; main engine speed 700rpm / min, vacuum degree ≤-0.05MPa.

[0106] Example 2

[0107] This embodiment provides a polyphenylene ether conductive composite material, comprising the following components in parts by weight:

[0108] 46.8 parts of polyphenylene ether;

[0109] 20 parts of carbon nanotube composite material;

[0110] 1 part of toughening agent;

[0111] 2 parts of dispersant;

[0112] 30 parts of talcum powder;

[0113] Antioxidant 1010 0.2 parts.

[0114] The carbon nanotube composite material includes modified carbon nanotubes and high-impact polystyrene, and the modified carbon nanotubes include multi-walled carbon nanotubes, graphene and calcium silicate; the mass ratio of the multi-walled carbon nanotubes, graphene and calcium silicate in the modified carbon nanotubes is 1:0.2:1; and the mass ratio of the modified carbon nanotubes to the high-impact polystyrene in the carbon nanotube composite material is 20:80. The specifications of the multi-walled carbon nanotubes, the toughening agent and the dispersant are the same as those in Example 1.

[0115] The preparation method is basically the same as that of Example 1, except that step S1: 5 parts by weight of multi-walled carbon nanotube powder is dispersed in a solvent, 1 part by weight of graphene and 5 parts by weight of calcium silicate are added, 0.11 parts by weight of a binder are added, and the mixture is mixed evenly and then ball milled.

[0116] Example 3

[0117] This embodiment provides a polyphenylene ether conductive composite material, comprising the following components in parts by weight:

[0118] 46.8 parts of polyphenylene ether;

[0119] 20 parts of carbon nanotube composite material;

[0120] 1 part of toughening agent;

[0121] 2 parts of dispersant;

[0122] 30 parts of talcum powder;

[0123] Antioxidant 1010 0.2 parts.

[0124] The carbon nanotube composite material includes modified carbon nanotubes and high-impact polystyrene, and the modified carbon nanotubes include multi-walled carbon nanotubes, graphene and calcium silicate; the mass ratio of the multi-walled carbon nanotubes, graphene and calcium silicate in the modified carbon nanotubes is 1:0.5:2; and the mass ratio of the modified carbon nanotubes to the high-impact polystyrene in the carbon nanotube composite material is 10:90. The specifications of the multi-walled carbon nanotubes, the toughening agent and the dispersant are the same as those in Example 1.

[0125] The preparation method is basically the same as that of Example 1, except that step S1: 5 parts by weight of multi-walled carbon nanotube powder is dispersed in a solvent, 2.5 parts by weight of graphene and 10 parts by weight of calcium silicate are added, 0.17 parts by weight of a binder is added, and the mixture is mixed evenly and then ball milled.

[0126] Example 4

[0127] This embodiment provides a polyphenylene ether conductive composite material, comprising the following components in parts by weight:

[0128] 46.8 parts of polyphenylene ether;

[0129] 20 parts of carbon nanotube composite material;

[0130] 1 part of toughening agent;

[0131] 2 parts of dispersant;

[0132] 30 parts of talcum powder;

[0133] Antioxidant 1010 0.2 parts.

[0134] The carbon nanotube composite material includes modified carbon nanotubes and high-impact polystyrene, and the modified carbon nanotubes include multi-walled carbon nanotubes, graphene and calcium silicate; the mass ratio of the multi-walled carbon nanotubes, graphene and calcium silicate in the modified carbon nanotubes is 1:0.2:1, and the mass ratio of the modified carbon nanotubes to the high-impact polystyrene in the carbon nanotube composite material is 20:80. The specifications of the multi-walled carbon nanotubes, the toughening agent and the dispersant are the same as those in Example 1.

[0135] The preparation method is basically the same as that of Example 2, except that step S2: 5 parts by weight of the modified carbon nanotubes are ultrasonically dispersed in a tetrahydrofuran solution, and after being uniformly dispersed, they are added to a tetrahydrofuran solution containing 100 parts by weight of high-impact polystyrene, and ultrasonically dispersed for 1 hour. The modified carbon nanotube composite material is obtained after vacuum drying to remove the solvent.

[0136] Example 5

[0137] This embodiment provides a polyphenylene ether conductive composite material, comprising the following components in parts by weight:

[0138] 68 parts of polyphenylene ether;

[0139] 27 parts of carbon nanotube composite materials;

[0140] 2 parts of toughening agent;

[0141] 3 parts of dispersant;

[0142] 30 parts of talcum powder;

[0143] Antioxidant 1010 0.5 parts.

[0144] The carbon nanotube composite material includes modified carbon nanotubes and high-impact polystyrene, and the modified carbon nanotubes include multi-walled carbon nanotubes, graphene and calcium silicate; the mass ratio of the multi-walled carbon nanotubes, graphene and calcium silicate in the modified carbon nanotubes is 1:0.2:1, and the mass ratio of the modified carbon nanotubes to the high-impact polystyrene in the carbon nanotube composite material is 20:80. The specifications of the multi-walled carbon nanotubes, the toughening agent and the dispersant are the same as those in Example 1.

[0145] The preparation method is basically the same as that of Example 2, except for the feeding amount of each component in step S2.

[0146] Comparative Example 1

[0147] This comparative example provides a polyphenylene ether conductive composite material, comprising the following components in parts by weight:

[0148] 46.8 parts of polyphenylene ether;

[0149] High impact polystyrene 18 parts;

[0150] 2 parts of multi-walled carbon nanotubes;

[0151] 1 part of toughening agent;

[0152] 2 parts of dispersant;

[0153] 30 parts of talcum powder;

[0154] Antioxidant 1010 0.2 parts.

[0155] The specifications of the multi-walled carbon nanotubes, the toughening agent and the dispersant are the same as those in Example 1.

[0156] The preparation method comprises the following steps:

[0157] The high-impact polystyrene particles are crushed into powders of ≤2000 mesh at ultra-low temperature below -190℃ ; The multi-walled carbon nanotubes are crushed to a particle size of Dmax≤300μm by a gas flow crushing process;

[0158] The toughening agent, dispersant, talcum powder and antioxidant were mixed in a high-speed mixer at a speed of 300 rpm for 5 min to obtain a mixing aid, and high-impact polystyrene, multi-walled carbon nanotubes and PPO resin were respectively fed from four different weight loss scales and melt-extruded and granulated by a twin-screw extruder at an extrusion temperature of 250-300° C. and a main engine speed of 400-1000 rpm / min. The set process conditions of the twin-screw extruder were the same as those in Example 1.

[0159] Comparative Example 2

[0160] This comparative example provides a polyphenylene ether conductive composite material, comprising the following components in parts by weight:

[0161] 46.8 parts of polyphenylene ether;

[0162] 20 parts of carbon nanotube composite material;

[0163] 1 part of toughening agent;

[0164] 2 parts of dispersant;

[0165] 30 parts of talcum powder;

[0166] Antioxidant 1010 0.2 parts.

[0167] The carbon nanotube composite material includes modified carbon nanotubes and high-impact polystyrene, and the modified carbon nanotubes contain only multi-walled carbon nanotubes and graphene, and the mass ratio of the multi-walled carbon nanotubes to the graphene is 1:0.2; the mass ratio of the modified carbon nanotubes to the high-impact polystyrene is 5:95. The specifications of the multi-walled carbon nanotubes, the toughening agent and the dispersant are the same as those in Example 1.

[0168] The preparation method of the polyphenylene ether conductive composite material is basically the same as that of Example 1, except that the preparation steps of the modified carbon nanotubes are different.

[0169] The preparation step S1 of the modified carbon nanotubes of this comparative example is as follows: 5 parts by weight of multi-walled carbon nanotube powder is dispersed in a solvent, 1 part by weight of graphene is added, 0.06 parts by weight of a binder is added, and the mixture is evenly mixed and then ball milled. The grinding medium is a 0.5-1.0 mm zirconium oxide ball, the grinding medium filling rate is 65%, the stirring rate is 700 r / min, and a mixed slurry is obtained. The mixed slurry is spray dried to obtain modified carbon nanotubes with a particle size of 0.1-1 mm.

[0170] Performance Testing

[0171] The polyphenylene ether conductive composite materials of the above-mentioned embodiments and comparative examples were compression molded into articles, injection molded into test specimens according to standard sizes, and then subjected to surface resistivity and wear resistance tests.

[0172] Surface resistivity (unit: Ω / Sq): The surface resistivity is tested by DC comparison method. The test equipment and measurement error conform to the provisions of GB / T 3048.5.

[0173] Wear amount: Wear resistance test material's wear resistance, the test method complies with the requirements of GB / T 3960-2016 "Plastic sliding friction and wear test method".

[0174] Table 1

[0175] [Table 1_sm_0001]

[0176] As shown in Table 1, compared with the comparative example, the surface resistivity of the polyphenylene ether conductive composite material of each embodiment is significantly lower, indicating that the polyphenylene ether conductive composite material of each embodiment has better antistatic effect.

[0177] It can be seen from the wear data that compared with the control example, the wear of the polyphenylene ether conductive composite material of each embodiment is significantly lower, indicating that the use of carbon nanotube composite materials instead of traditional carbon-based conductive agents as conductive fillers added to the resin substrate can improve the wear resistance of the material, thereby achieving the effect of reducing dust.

[0178] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A polyphenylene ether conductive composite material, characterized in that: The composition comprises the following components in parts by weight: 40-70 parts of polyphenylene ether; 10 to 30 parts of carbon nanotube composite material; 1 to 3 parts of toughening agent; 2 to 4 parts of dispersant; 20-30 parts of inorganic filler; Antioxidant 0.1-1 part; The carbon nanotube composite material comprises modified carbon nanotubes and high impact polystyrene. The modified carbon nanotubes include multi-walled carbon nanotubes, graphene and calcium silicate.

2. The polyphenylene ether conductive composite material according to claim 1, characterized in that: The mass ratio of the modified carbon nanotubes to the high impact polystyrene is (10-20):(80-90).

3. The polyphenylene ether conductive composite material according to claim 1 or 2, characterized in that: The mass ratio of the multi-walled carbon nanotube, the graphene and the calcium silicate is 1:(0.1-0.5):(0.5-2).

4. The polyphenylene ether conductive composite material according to claim 1 or 3, characterized in that: The multi-walled carbon nanotubes have at least one of the following (1)-(5): (1) The multi-walled carbon nanotubes have an inner diameter of 1 to 2 nm, an outer diameter of 8 to 25 nm, a length of 1 to 100 μm, an aspect ratio of 5000 to 10000:1, and a bulk density of 0.15 to 0.4 g / cm 3 , than the table Area: 190~270m 2 / g; (2) The thermal conductivity of the multi-walled carbon nanotubes is 300 to 6000 W / mk; (3) The initial decomposition temperature of the multi-walled carbon nanotubes is 500-600°C; (4) The particle size D97 of the multi-walled carbon nanotubes is ≤50 μm, and the particle size Dmax is ≤300 μm; (5) The powder resistivity of the multi-walled carbon nanotubes is 30 to 60 mΩ·cm; (6) The Raman spectrum intensity of the multi-walled carbon nanotubes is D / I G ≤1.

2.

5. The polyphenylene ether conductive composite material according to claim 1 or 2, characterized in that: The weight average molecular weight of the high impact polystyrene is 150,000 to 300,000 g / mol.

6. The polyphenylene ether conductive composite material according to claim 1, characterized in that: The inorganic filler comprises at least one of talc powder, calcium carbonate, silica fume powder, mica powder, kaolin, wollastonite and attapulgite; the particle size of the inorganic filler is 1000-3000 meshes.

7. The polyphenylene ether conductive composite material according to claim 1, characterized in that: The antioxidant includes at least one of a hindered phenol antioxidant and a phosphite antioxidant.

8. The polyphenylene ether conductive composite material according to any one of claims 1 to 7, characterized in that: The polyphenylene ether conductive composite material has at least one of the following (1)-(3): (1) The surface resistivity of the polyphenylene ether conductive composite material is 10 6 ~10 8 Ω / sq; (2) The polyphenylene ether conductive composite material has a melt index of 6 to 13 g / 10 min under the test conditions of 300° C. and 10 kg; (3) The density of the polyphenylene ether conductive composite material is 1.07 to 1.1 g / cm 3 .

9. The method for preparing the polyphenylene ether conductive composite material according to any one of claims 1 to 8, characterized in that: The following steps are involved: Mixing the multi-walled carbon nanotubes with the graphene and the calcium silicate to obtain the modified carbon nanotubes; Dispersing the modified carbon nanotubes and the high impact polystyrene to obtain the carbon nanotube composite material; The carbon nanotube composite material is mixed with the polyphenylene ether, the toughening agent, the dispersant, the inorganic filler and the antioxidant, and then melt-extruded and granulated to obtain the polyphenylene ether conductive composite material.

10. The method for preparing the polyphenylene ether conductive composite material according to claim 9, characterized in that: The step of mixing the multi-walled carbon nanotubes with the graphene and the calcium silicate to obtain the modified carbon nanotubes includes: mixing the multi-walled carbon nanotubes, the graphene, the calcium silicate, a binder and a solvent, then ball milling to obtain a mixed slurry, and drying the mixed slurry to obtain the modified carbon nanotubes.

11. The method for preparing the polyphenylene ether conductive composite material according to claim 10, characterized in that: The conditions of the ball milling treatment include: the grinding medium includes zirconia balls and / or agate balls; the size of the grinding medium is 0.5-1.0 mm; the filling rate of the grinding medium is 60%-85%; and the stirring rate is 500-900 r / min.

12. The method for preparing the polyphenylene ether conductive composite material according to claim 9, characterized in that: The step of dispersing the modified carbon nanotubes and the high impact polystyrene to obtain the carbon nanotube composite material comprises: adding the modified carbon nanotubes and the high impact polystyrene into tetrahydrofuran for dispersion, and removing the solvent in vacuum to obtain the carbon nanotube composite material.

13. The method for preparing the polyphenylene ether conductive composite material according to claim 9, characterized in that: The process conditions of melt extrusion granulation include: extrusion temperature of 250-300° C., main engine speed of 400-1000 rpm / min, and melt extrusion granulation by a twin-screw extruder.

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