A highly conductive composite system coated with black talc powder and its preparation method, as well as a modified masterbatch containing the black talc powder and its preparation method.

Abstract

This invention relates to the field of plastic modification and processing technology, and in particular to a high-conductivity composite system coated with black talc powder, its preparation method, and a modified masterbatch containing the black talc powder and its preparation method. The mass percentage composition is as follows: high-conductivity composite system coated with black talc powder 65.0–76.0 wt.%, cobalt ferrite nanoparticles 5.0–10.0 wt.%, carrier resin 15.0–20.0 wt.%, dispersant 2.0–3.0 wt.%, lubricant 0.5–1.0 wt.%. Through the technology of this invention, black talc powder is transformed from a general traditional inorganic filler into a high-end functional filler with conductive functional modification effects, thereby increasing the added value of black talc powder products and making an important contribution to the development and application of black talc powder mines in my country.

Description

Technical Field

[0001] This invention relates to the field of plastic modification and processing technology, and in particular to a highly conductive composite system coated with black talc powder, its preparation method, and a modified masterbatch containing the black talc powder and its preparation method. Background Technology

[0002] Talc is a magnesium-rich silicate mineral, mainly composed of magnesium oxide, silicon oxide, as well as aluminum oxide, iron oxide, titanium oxide, sodium oxide, and potassium oxide. It is widely used in plastic filler modification, effectively improving its strength, modulus, surface stiffness, high-temperature creep resistance, heat resistance, and dimensional stability. Black talc, like traditional talc, belongs to the 2:1 type (Si–O–Si) magnesium-rich silicate clay mineral category, but its layered structure contains varying amounts of organic carbon or graphite, resulting in its black or gray appearance. my country's black talc resources are widely distributed but relatively concentrated. Guangfeng District in Shangrao City, Jiangxi Province, boasts the world's largest black talc reserves, exceeding 1 billion tons. In recent years, black talc has received widespread attention in plastic modification and has developed into a new type of inorganic magnesium silicate filler. Due to its unique layered structure, it can strengthen, stiffen, and promote crystallization in thermoplastic plastics. Therefore, black talc powder can partially replace traditional talc powder in non-white plastic products, effectively improving the surface hardness, tensile strength and modulus, flexural strength and modulus of plastics, and also improving the warping resistance and dimensional stability of plastic products. However, the organic carbon or graphite contained in black talc powder is surrounded by its magnesium silicate layer, making it difficult to form electronic pathways with the outside environment. Therefore, it cannot exert its electrical conductivity. Currently, polymer composites formed by directly filling plastics with black talc powder cannot achieve improved electrical conductivity, and its application technology in the functional modification of thermoplastic plastics still needs further development.

[0003] On the other hand, the use of functional masterbatches to prepare modified plastics is an important measure in the current development of the field of plastic modification technology. Especially for powdered fillers such as (black) talc, calcium carbonate, kaolin, wollastonite, and montmorillonite, using pre-prepared functional masterbatches containing high concentrations of modifying additives and plastic raw materials through melt blending and extrusion granulation using a twin-screw extruder or internal mixer not only more effectively improves the dispersibility of additives in the matrix and achieves better modification effects, but also reduces dust pollution in the processing workshop, making it one of the important ways to achieve green processing of modified plastics. With the rapid development of functional design and preparation technology of plastic masterbatches, the functions of plastic masterbatches are becoming increasingly powerful and the varieties are becoming increasingly rich, and their application fields are constantly expanding. The application of masterbatches in plastic modification will inevitably become an indispensable common key technology in the future clean production of modified plastics. Summary of the Invention

[0004] The purpose of this invention is to address the current limitations of black talc powder in plastic filler modification applications. It can only exert the traditional filling and modification effects of talc powder, failing to utilize the unique conductive properties of its layered structure containing organic carbon or graphite layers to achieve functional modification of plastics. Furthermore, to broaden the application of black talc powder as an emerging inorganic filler in the field of plastic functional modification, this invention provides a highly conductive composite system coating black talc powder and a modified masterbatch containing this black talc powder.

[0005] This invention employs a highly conductive composite system formed by in-situ polymerization of polydopamine, graphene, and carbon black to coat black talc powder. Simultaneously, before in-situ polymerization, iodine is infiltrated into the interlayer of black talc powder as an electron acceptor, thereby doping the graphite layer with electron acceptors. During the in-situ polymerization and coating process of dopamine, an internal intercalation structure of conductive polymer can be formed between the black talc powder layers, which is connected to the outer highly conductive composite coating layer. This establishes an electronic pathway between the outer and inner organic carbon or graphite layers of the black talc powder, thereby achieving its high conductivity. Then, the black talc powder coated by the highly conductive composite system, cobalt ferrite (CoFe2O4) nanoparticles with high magnetic permeability, carrier resin, and additives are subjected to low-temperature intensive mixing to prepare a black talc-based plastic reinforcement and electromagnetic shielding functional modification masterbatch. This masterbatch can be applied to the filling and electromagnetic shielding functional modification of various thermoplastic plastics, thereby enabling the modified plastics to not only obtain improvements in strength, modulus, rigidity, surface hardness, dimensional stability, and thermal stability, but also to be endowed with electromagnetic shielding function, realizing the dual effect of black talc powder in plastic modification: filling reinforcement and electromagnetic shielding functionalization.

[0006] Another objective of this invention is to provide a method for preparing the above-mentioned high conductivity composite system coated with black talc powder, and a method for preparing a plastic reinforcement and electromagnetic shielding functionalized modified masterbatch containing the high conductivity composite system coated with black talc powder.

[0007] A highly conductive composite system for coating black talc powder, wherein the highly conductive composite system for coating black talc powder is a black talc powder doped with iodine electron acceptors and in situ coated with polydopamine, graphene and carbon black.

[0008] A method for coating black talc powder with a highly conductive composite system, the method comprising the following steps:

[0009] 1) Add black talc powder and iodine into a high-speed mixer according to the ratio, mix at high speed for 20 minutes in a closed environment to raise the material temperature to 80℃, then stop stirring and let stand until the material temperature drops to room temperature. Then add silane coupling agent KH-550, mix at high speed again for 10 minutes, stop stirring, let stand until the material temperature drops to room temperature and take it out.

[0010] 2) Disperse black talc powder that has been doped with iodine and surface-treated with KH-550 in tris(hydroxymethyl)aminomethane-hydrochloride buffer (pH=8.4), add dopamine hydrochloride, graphene and carbon black in sequence, and mechanically stir at room temperature. During the process, dopamine hydrochloride will gradually undergo oxidative polymerization and combine with graphene and carbon black, and automatically adhere to the surface of black talc powder through the electrostatic adsorption of KH550 to form a uniform, highly conductive composite layer. The reaction is stopped after stirring for 24 hours.

[0011] 3) The above suspension reaction liquid was filtered, and the wet powder was dried in an oven at 70°C for 10 hours to obtain a highly conductive composite system coated with black talc powder.

[0012] Furthermore, in the preparation method, the amount of iodine added in step 1) is: 10.0 g of iodine is added for every 1.0 kg of black talc powder, and the amount of silane coupling agent KH550 added is: 15.0 g of KH550 is added for every 1.0 kg of black talc powder.

[0013] Furthermore, in step 2), the amount of tris(hydroxymethyl)aminomethane-hydrochloric acid buffer added is: 5.0 L of tris(hydroxymethyl)aminomethane-hydrochloric acid buffer added for every 1.0 kg of black talc powder; the amount of dopamine hydrochloride added is: 100.0 g of dopamine hydrochloride added for every 1.0 kg of black talc powder; the amount of graphene added is: 30.0 g of graphene added for every 1.0 kg of dopamine hydrochloride; and the amount of carbon black added is: 20.0 g of carbon black added for every 1.0 kg of dopamine hydrochloride.

[0014] A modified masterbatch containing a highly conductive composite system coated with black talc powder, wherein the modified masterbatch is a special masterbatch based on a highly conductive composite system coated with black talc powder, and is specifically used for functional modification of plastic filler reinforcement and electromagnetic shielding, and its mass percentage composition is as follows:

[0015] The highly conductive composite system as described in any one of claims 1-2 is coated with 65.0-76.0 wt.% black talc powder.

[0016] Cobalt ferrite CoFe2O4 nanoparticles, 5.0–10.0 wt.%;

[0017] Carrier resin 15.0–20.0 wt.%;

[0018] Dispersant 2.0–3.0 wt.%;

[0019] Lubricant 0.5–1.0 wt.%.

[0020] Furthermore, the cobalt ferrite CoFe2O4 nanoparticles are cobalt ferrite powder particles with an average particle size of 30-50 nm and whose surface has been treated with any one of the silane coupling agents KH540, KH550 and KH560.

[0021] Furthermore, the carrier resin is any one of ethylene-1-octene copolymer, ethylene-vinyl ester copolymer, ethylene-methyl acrylate copolymer, ethylene-butyl acrylate copolymer, and ethylene-methyl acrylate-glycidyl methacrylate copolymer.

[0022] Furthermore, the dispersant is any one of stearic acid, magnesium stearate, calcium stearate, zinc stearate, aluminum stearate, oleamide, and mesoamide.

[0023] Furthermore, the lubricant is any one of oxidation-resistant polyethylene, polyethylene wax, oxidized paraffin wax, ethylene bis-stearamide, OP wax, E wax, EVA wax, and ethylene-acrylic acid copolymer wax.

[0024] Furthermore, the method includes the following steps:

[0025] 1) Weigh out the high conductivity composite system coated black talc powder, cobalt ferrite CoFe2O4 nanoparticles, carrier resin, dispersant and lubricant according to the ratio, and put them into a high-speed mixer to mix evenly to obtain a premix for later use.

[0026] 2) Put the premix prepared in step 1) into a mixer for hot mixing to obtain agglomerated blend. The mixing temperature of the mixer is 110-125℃ and the mixing time is 15-20 minutes.

[0027] 3) The agglomerated blend obtained in step 2) is fed into a single-screw extruder, and after melt blending, extrusion, air-cooled grinding and pelletizing, and bagging, a plastic reinforcement and electromagnetic shielding functionalized modified masterbatch based on black talc powder is obtained. The screw speed of the single-screw extruder is 150-200 rpm, and the barrel temperature is 150-160℃.

[0028] The beneficial effects of adopting the technical solution of the present invention are:

[0029] (1) Black talc powder is a unique new type of layered magnesium silicate mineral in my country, widely distributed in provinces such as Jiangxi, Hunan, Chongqing, and Gansu. Due to its similar chemical composition and layered structure to talc powder, black talc powder can partially replace traditional talc powder in plastic filler modification, effectively enhancing the rigidity, surface hardness, tensile and flexural strength, heat resistance, and dimensional stability of thermoplastic plastics. Moreover, its mining and production costs are much lower than those of traditional talc powder. Therefore, it has good application prospects. This patent makes full use of the structural feature of conductive graphite layers between the layers of black talc powder. First, iodine is used as an electron donor and acceptor to perform gas-phase doping of black talc powder by high-temperature and high-speed stirring in a closed cavity, so that the graphite layer obtains more conductive charge carriers. Then, dopamine hydrochloride is in situ composited with graphene and carbon black, and self-assembled and in situ oxidatively polymerized by the electrostatic attraction of aminosilane coupling agent on the surface of black talc powder, forming a highly conductive composite coating layer of polydopamine / graphene / carbon black on the surface of black talc powder. Within this coating layer, two-dimensional sheet-like graphene and three-dimensional irregularly shaped spherical carbon black are interspersed within the polydopamine matrix, creating multi-channel electron transport pathways. Furthermore, dopamine hydrochloride monomers also permeate into the intercalation layers of the black talc powder, forming a polydopamine-based conductive composite intercalation structure with the iodine-doped graphite layer. This ingenious design significantly improves the conductivity of the black talc powder. Through the technology of this invention, black talc powder is transformed from a general traditional inorganic filler into a high-end functional filler with conductive functional modification effects, thereby increasing the added value of black talc powder and making a significant contribution to the development and application of black talc powder mines in my country.

[0030] (2) By utilizing the stiffening, strengthening, and crystallization-promoting effects of black talc powder, and the conductive function of its interlayer graphite, the high conductivity composite system of this invention is used to fully utilize the conductive function of the interlayer graphite by coating the inner interlayer with the outer layer. In addition, polydopamine has natural adhesive properties. When the black talc powder coated with it is used to fill and modify plastics, it can enhance the interfacial adhesion between the black talc powder and the plastic matrix, thereby more effectively improving the mechanical properties of the filled and modified plastics. The highly conductive composite system of this invention, coated with black talc powder, is combined with CoFe2O4 nanoparticles possessing high magnetic permeability to prepare a special masterbatch for plastic modification, possessing both filling reinforcement and electromagnetic shielding functional modification effects. This not only allows black talc powder to exert the traditional reinforcing, stiffening, surface hardness, dimensional stability, and warp resistance effects of talc powder, but also utilizes the electronic pathways inherent in black talc powder itself, enabling electrons to flow freely within, between, and between powder particles of the highly conductive composite system coated with black talc powder. When combined with CoFe2O4 nanoparticles for plastic filling modification, it can effectively improve the electrical conductivity and magnetic permeability of the modified plastic, thereby achieving good electromagnetic shielding effects in both high and low frequency electromagnetic wave bands. Therefore, the technology of this invention greatly expands the filling and functional modification effects of black talc powder, achieving two benefits in one step when modifying plastics through filling.

[0031] (3) The plastic reinforcement and electromagnetic shielding functionalized modified masterbatch based on black talc powder of the present invention can be used for filling and functional modification of various plastics. Compared with plastics modified by traditional talc powder filling, it achieves high conductivity without the need to add other conductive functional fillers, and can effectively avoid the loss of mechanical properties of modified plastics caused by adding other conductive functional fillers.

[0032] (4) Design plastic modification masterbatch formulations and processing techniques that facilitate the dispersion of inorganic powder fillers, so that inorganic powders achieve excellent dispersion effects in carrier resins. By using modification masterbatch technology, the modified plastics prepared in the future can obtain better filling and functional modification effects.

[0033] (5) The plastic reinforcement and electromagnetic shielding functionalized modified masterbatch based on black talc powder prepared in this invention has the characteristics of easy dispersion and easy processing. It can be melt-blended and extruded into granulation for various plastic resins, or it can be directly applied to the injection molding of products after being simply mixed with various plastic resins in a certain ratio. The combination of modified masterbatch and other functional masterbatches and its ratio with plastic resin raw materials can be flexibly adjusted according to different performance requirements of customers to adjust its performance and cost, so as to quickly and easily achieve the product target requirements and practice the optimal design concept of plastic modification formulation and processing technology. Detailed Implementation

[0034] The following embodiments are provided to enable those skilled in the art to gain a more comprehensive understanding of the present invention, but these embodiments are not intended to limit the scope of protection of the present invention. As used herein, "an embodiment" or "an embodiment" refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that excludes other embodiments.

[0035] Example 1

[0036] A plastic reinforcement and electromagnetic shielding functionalized modified masterbatch based on black talc powder, with the following raw material mass ratio:

[0037] High conductivity composite system coated with black talc powder 76.0 kg <![CDATA[KH550 surface-treated CoFe2O4 nanoparticles]]> 6.0 kg EVA resin 15.0 kg Zinc stearate 2.5 kg Polyethylene wax 0.5 kg

[0038] Among them, the highly conductive composite system coated black talc powder is black talc powder doped with iodine electron acceptors and in situ coated with polydopamine, graphene and carbon black. The specific preparation method is as follows:

[0039] (1) Put 20.0 kg of black talc powder and 200.0 g of iodine into a high-speed mixer and mix at high speed for 20 minutes in a closed environment to raise the material temperature to 80°C. Then stop stirring and let stand until the material temperature drops to room temperature. Then add 300.0 g of silane coupling agent KH-550 and mix at high speed again for 10 minutes. Stop stirring and let stand until the material temperature drops to room temperature before taking it out.

[0040] (2) The black talc powder that has been doped with iodine and treated with KH-550 is dispersed in 100.0 L of tris(hydroxymethyl)aminomethane-hydrochloride buffer (pH=8.4), and 2.0 kg of dopamine hydrochloride, 600.0 g of graphene and 400.0 g of carbon black are added in sequence. The mixture is mechanically stirred at room temperature. During the process, dopamine hydrochloride will gradually undergo oxidative polymerization and combine with graphene and carbon black. It will also automatically adhere to the surface of the black talc powder through the electrostatic adsorption of KH550 to form a uniform highly conductive composite layer. The reaction is stopped after stirring for 24 hours.

[0041] (3) The above suspension reaction liquid was filtered and washed five times with deionized water to obtain wet powder. The wet powder was dried in an oven at 70°C for 10 hours to obtain black talc powder coated with a high conductivity composite system.

[0042] The preparation method of plastic reinforcement and electromagnetic shielding functionalized modified masterbatch based on a highly conductive composite system coated with black talc powder is as follows:

[0043] 1) Weigh out the high conductivity composite system coated black talc powder, KH550 surface-treated CoFe2O4 nanoparticles, EVA resin, zinc stearate, and polyethylene wax according to the formula, and put them into a high-speed mixer to mix evenly for later use.

[0044] 2) The premix prepared in step 1) is put into a mixer for hot mixing to obtain agglomerated blend. The mixing temperature of the mixer is 115℃ and the mixing time is 18 minutes.

[0045] 3) The agglomerated blend obtained in step 2) is fed into a single-screw extruder through a conical feeder. After melt blending, extrusion, air-cooled grinding and pelletizing, and bagging, a plastic reinforcement and electromagnetic shielding functionalized modified masterbatch based on black talc powder is obtained. The screw speed of the single-screw extruder is 190 rpm and the barrel temperature is 150-160℃.

[0046] Example 2

[0047] A plastic reinforcement and electromagnetic shielding functionalized modified masterbatch based on black talc powder, with the following raw material mass ratio:

[0048] High conductivity composite system coated with black talc powder 71.5 kg <![CDATA[KH560 surface-treated CoFe2O4 nanoparticles]]> 9.0 kg POE resin 17.0 kg Calcium stearate 2.0 kg OP wax 0.5 kg

[0049] Among them, the highly conductive composite system coated black talc powder is black talc powder doped with iodine electron acceptors and in situ coated with polydopamine, graphene and carbon black. The specific preparation method is as follows:

[0050] 1) Put 20.0 kg of black talc powder and 200.0 g of iodine into a high-speed mixer and mix at high speed for 20 minutes in a closed environment until the material temperature rises to 80°C. Then stop stirring and let stand until the material temperature drops to room temperature. Then add 300.0 g of silane coupling agent KH-550 and mix at high speed again for 10 minutes. Stop stirring and let stand until the material temperature drops to room temperature before taking it out.

[0051] 2) The black talc powder that has been doped with iodine and surface-treated with KH-550 was dispersed in 100.0 L of tris(hydroxymethyl)aminomethane-hydrochloride buffer (pH=8.4). 2.0 kg of dopamine hydrochloride, 600.0 g of graphene and 400.0 g of carbon black were added sequentially. The mixture was mechanically stirred at room temperature. During the reaction, dopamine hydrochloride gradually underwent oxidative polymerization and combined with graphene and carbon black. It also automatically adhered to the surface of the black talc powder through the electrostatic adsorption of KH550, forming a uniform, highly conductive composite layer. The reaction was stopped after stirring for 24 hours.

[0052] 3) The above suspension reaction liquid was filtered and washed five times with deionized water to obtain a wet powder. The wet powder was dried in an oven at 70°C for 10 hours to obtain a high conductivity composite system coated black talc powder.

[0053] The preparation method of plastic reinforcement and electromagnetic shielding functionalized modified masterbatch based on a highly conductive composite system coated with black talc powder is as follows:

[0054] 1) Weigh out the high conductivity composite system coated black talc powder, KH560 surface-treated CoFe2O4 nanoparticles, POE resin, calcium stearate and OP wax according to the formula, and put them into a high-speed mixer to mix evenly for later use.

[0055] 2) The premix prepared in step 1) is put into a mixer for hot mixing to obtain agglomerated blend. The mixing temperature of the mixer is 110℃ and the mixing time is 20 minutes.

[0056] 3) The agglomerated blend obtained in step 2) is fed into a single-screw extruder through a conical feeder. After melt blending, extrusion, air-cooled grinding and pelletizing, and bagging, a plastic reinforcement and electromagnetic shielding functionalized modified masterbatch based on black talc powder is obtained. The screw speed of the single-screw extruder is 195 rpm and the barrel temperature is 150-160℃.

[0057] Example 3

[0058] A plastic reinforcement and electromagnetic shielding functionalized modified masterbatch based on black talc powder, with the following raw material mass ratio:

[0059] High conductivity composite system coated with black talc powder 70.0 kg <![CDATA[KH570 surface-treated CoFe2O4 nanoparticles]]> 10.0 kg EMA resin 16.0 kg Oleamide 3.0 kg Oxidized paraffin 1.0 kg

[0060] Among them, the highly conductive composite system coated black talc powder is black talc powder doped with iodine electron acceptors and in situ coated with polydopamine, graphene and carbon black. The specific preparation method is as follows:

[0061] 1) Put 20.0 kg of black talc powder and 200.0 g of iodine into a high-speed mixer and mix at high speed for 20 minutes in a closed environment until the material temperature rises to 80°C. Then stop stirring and let stand until the material temperature drops to room temperature. Then add 300.0 g of silane coupling agent KH-550 and mix at high speed again for 10 minutes. Stop stirring and let stand until the material temperature drops to room temperature before taking it out.

[0062] 2) The black talc powder that has been doped with iodine and surface-treated with KH-550 was dispersed in 100.0 L of tris(hydroxymethyl)aminomethane-hydrochloride buffer (pH=8.4). 2.0 kg of dopamine hydrochloride, 600.0 g of graphene and 400.0 g of carbon black were added sequentially. The mixture was mechanically stirred at room temperature. During the reaction, dopamine hydrochloride gradually underwent oxidative polymerization and combined with graphene and carbon black. It also automatically adhered to the surface of the black talc powder through the electrostatic adsorption of KH550, forming a uniform, highly conductive composite layer. The reaction was stopped after stirring for 24 hours.

[0063] 3) The above suspension reaction liquid was filtered and washed five times with deionized water to obtain a wet powder. The wet powder was dried in an oven at 70°C for 10 hours to obtain a high conductivity composite system coated black talc powder.

[0064] The preparation method of plastic reinforcement and electromagnetic shielding functionalized modified masterbatch based on a highly conductive composite system coated with black talc powder is as follows:

[0065] 1) Weigh out the high conductivity composite system coated black talc powder, KH570 surface-treated CoFe2O4 nanoparticles, EMA resin, oleic acid amide, and oxidized paraffin according to the formula, and put them into a high-speed mixer to mix evenly for later use.

[0066] 2) The premix prepared in step 1) is put into a mixer for hot mixing to obtain agglomerated blend. The mixing temperature of the mixer is 120°C and the mixing time is 20 minutes.

[0067] 3) The agglomerated blend obtained in step 2) is fed into a single-screw extruder through a conical feeder. After melt blending, extrusion, air-cooled grinding and pelletizing, and bagging, a plastic reinforcement and electromagnetic shielding functionalized modified masterbatch based on black talc powder is obtained. The screw speed of the single-screw extruder is 150 rpm and the barrel temperature is 150-160℃.

[0068] Example 4

[0069] A plastic reinforcement and electromagnetic shielding functionalized modified masterbatch based on black talc powder, with the following raw material mass ratio:

[0070] High conductivity composite system coated with black talc powder 72.0 kg <![CDATA[KH550 surface-treated CoFe2O4 nanoparticles]]> 7.0 kg EBA resin 18.0 kg Stearic acid 2.5 kg E wax 0.5 kg

[0071] The highly conductive composite system-coated black talc powder is a black talc powder doped with iodine electron acceptors, which is in-situ composite-coated with polydopamine, graphene, and carbon black. The specific preparation method is as follows:

[0072] 1) Put 20.0 kg of black talc powder and 200.0 g of iodine into a high-speed mixer and mix at high speed for 20 minutes in a closed environment until the material temperature rises to 80°C. Then stop stirring and let stand until the material temperature drops to room temperature. Then add 300.0 g of silane coupling agent KH-550 and mix at high speed again for 10 minutes. Stop stirring and let stand until the material temperature drops to room temperature before taking it out.

[0073] 2) The black talc powder that has been doped with iodine and surface-treated with KH-550 was dispersed in 100.0 L of tris(hydroxymethyl)aminomethane-hydrochloride buffer (pH=8.4). 2.0 kg of dopamine hydrochloride, 600.0 g of graphene and 400.0 g of carbon black were added sequentially. The mixture was mechanically stirred at room temperature. During the reaction, dopamine hydrochloride gradually underwent oxidative polymerization and combined with graphene and carbon black. It also automatically adhered to the surface of the black talc powder through the electrostatic adsorption of KH550, forming a uniform, highly conductive composite layer. The reaction was stopped after stirring for 24 hours.

[0074] 3) The above suspension reaction liquid was filtered and washed five times with deionized water to obtain a wet powder. The wet powder was dried in an oven at 70°C for 10 hours to obtain a high conductivity composite system coated black talc powder.

[0075] The preparation method of plastic reinforcement and electromagnetic shielding functionalized modified masterbatch based on a highly conductive composite system coated with black talc powder is as follows:

[0076] 1) Weigh out the high conductivity composite system coated black talc powder, KH550 surface-treated CoFe2O4 nanoparticles, EBA resin, stearic acid, and E wax according to the formula, and put them into a high-speed mixer to mix evenly for later use.

[0077] 2) The premix prepared in step 1) is put into an internal mixer for hot mixing to obtain agglomerated blend. The mixing temperature of the internal mixer is 125°C and the mixing time is 17 minutes.

[0078] 3) The agglomerated blend obtained in step 2) is fed into a single-screw extruder through a conical feeder. After melt blending, extrusion, air-cooled grinding and pelletizing, and bagging, a plastic reinforcement and electromagnetic shielding functionalized modified masterbatch based on black talc powder is obtained. The screw speed of the single-screw extruder is 160 rpm and the barrel temperature is 150-160℃.

[0079] Example 5

[0080] A plastic reinforcement and electromagnetic shielding functionalized modified masterbatch based on black talc powder, with the following raw material mass ratio:

[0081] High conductivity composite system coated with black talc powder 68.0 kg <![CDATA[KH560 surface-treated CoFe2O4 nanoparticles]]> 10.0 kg EVA resin 19.0 kg Aluminum stearate 2.0 kg EVA wax 1.0 kg

[0082] The highly conductive composite system-coated black talc powder is a black talc powder doped with iodine electron acceptors, which is in-situ composite-coated with polydopamine, graphene, and carbon black. The specific preparation method is as follows:

[0083] 1) Put 20.0 kg of black talc powder and 200.0 g of iodine into a high-speed mixer and mix at high speed for 20 minutes in a closed environment until the material temperature rises to 80°C. Then stop stirring and let stand until the material temperature drops to room temperature. Then add 300.0 g of silane coupling agent KH-550 and mix at high speed again for 10 minutes. Stop stirring and let stand until the material temperature drops to room temperature before taking it out.

[0084] 2) The black talc powder that has been doped with iodine and surface-treated with KH-550 was dispersed in 100.0 L of tris(hydroxymethyl)aminomethane-hydrochloride buffer (pH=8.4). 2.0 kg of dopamine hydrochloride, 600.0 g of graphene and 400.0 g of carbon black were added sequentially. The mixture was mechanically stirred at room temperature. During the reaction, dopamine hydrochloride gradually underwent oxidative polymerization and combined with graphene and carbon black. It also automatically adhered to the surface of the black talc powder through the electrostatic adsorption of KH550, forming a uniform, highly conductive composite layer. The reaction was stopped after stirring for 24 hours.

[0085] 3) The above suspension reaction liquid was filtered and washed five times with deionized water to obtain a wet powder. The wet powder was dried in an oven at 70°C for 10 hours to obtain a high conductivity composite system coated black talc powder.

[0086] The preparation method of plastic reinforcement and electromagnetic shielding functionalized modified masterbatch based on a highly conductive composite system coated with black talc powder is as follows:

[0087] 1) Weigh out the high conductivity composite system coated black talc powder, KH560 surface-treated CoFe2O4 nanoparticles, EVA resin, aluminum stearate, and EVA wax according to the formula, and put them into a high-speed mixer to mix evenly for later use.

[0088] 2) The premix prepared in step 1) is put into an internal mixer for hot mixing to obtain agglomerated blend. The mixing temperature of the internal mixer is 118°C and the mixing time is 16 minutes.

[0089] 3) The agglomerated blend obtained in step 2) is fed into a single-screw extruder through a conical feeder. After melt blending, extrusion, air-cooled grinding and pelletizing, and bagging, a plastic reinforcement and electromagnetic shielding functionalized modified masterbatch based on black talc powder is obtained. The screw speed of the single-screw extruder is 200 rpm and the barrel temperature is 150-160℃.

[0090] Example 6

[0091] A plastic reinforcement and electromagnetic shielding functionalized modified masterbatch based on black talc powder, with the following raw material mass ratio:

[0092] High conductivity composite system coated with black talc powder 66.0 kg <![CDATA[KH570 surface-treated CoFe2O4 nanoparticles]]> 10.0 kg EMA–GMA resin 20.0 kg mesoamide 3.0 kg EVA wax 1.0 kg

[0093] The highly conductive composite system-coated black talc powder is a black talc powder doped with iodine electron acceptors, which is in-situ composite-coated with polydopamine, graphene, and carbon black. The specific preparation method is as follows:

[0094] 1) Put 20.0 kg of black talc powder and 200.0 g of iodine into a high-speed mixer and mix at high speed for 20 minutes in a closed environment until the material temperature rises to 80°C. Then stop stirring and let stand until the material temperature drops to room temperature. Then add 300.0 g of silane coupling agent KH-550 and mix at high speed again for 10 minutes. Stop stirring and let stand until the material temperature drops to room temperature before taking it out.

[0095] 2) The black talc powder that has been doped with iodine and surface-treated with KH-550 was dispersed in 100.0 L of tris(hydroxymethyl)aminomethane-hydrochloride buffer (pH=8.4). 2.0 kg of dopamine hydrochloride, 600.0 g of graphene and 400.0 g of carbon black were added sequentially. The mixture was mechanically stirred at room temperature. During the reaction, dopamine hydrochloride gradually underwent oxidative polymerization and combined with graphene and carbon black. It also automatically adhered to the surface of the black talc powder through the electrostatic adsorption of KH550, forming a uniform, highly conductive composite layer. The reaction was stopped after stirring for 24 hours.

[0096] 3) The above suspension reaction liquid was filtered and washed five times with deionized water to obtain a wet powder. The wet powder was dried in an oven at 70°C for 10 hours to obtain a high conductivity composite system coated black talc powder.

[0097] The preparation method of plastic reinforcement and electromagnetic shielding functionalized modified masterbatch based on a highly conductive composite system coated with black talc powder is as follows:

[0098] 1) Weigh out the high conductivity composite system coated black talc powder, KH570 surface-treated CoFe2O4 nanoparticles, EMA-GMA resin, mesoamide, and EVA wax according to the formula, and put them into a high-speed mixer to mix evenly for later use.

[0099] 2) The premix prepared in step 1) is put into a mixer for hot mixing to obtain agglomerated blend. The mixing temperature of the mixer is 125°C and the mixing time is 15 minutes.

[0100] 3) The agglomerated blend obtained in step 2) is fed into a single-screw extruder through a conical feeder. After melt blending, extrusion, air-cooled grinding and pelletizing, and bagging, a plastic reinforcement and electromagnetic shielding functionalized modified masterbatch based on black talc powder is obtained. The screw speed of the single-screw extruder is 190 rpm and the barrel temperature is 150-160℃.

[0101] To verify the modification effect of the plastic reinforcement and electromagnetic shielding functionalized modified masterbatch based on a highly conductive composite system coated with black talc powder prepared in this invention on various plastics, polypropylene and nylon 6 were specifically selected as representatives of non-polar and polar thermoplastic plastics, respectively. The plastic reinforcement and electromagnetic shielding functionalized modified masterbatch based on black talc powder prepared in Examples 1-6 were mixed with polypropylene and nylon 6 at a mass percentage of 25 wt.%, respectively, and then compounded and extruded by a twin-screw extruder. Tensile, flexural, and electromagnetic shielding test strips were injection molded according to the corresponding national standards for plastic testing. Then, tensile strength and tensile modulus were tested according to GB / T1040.2–2006, flexural strength and flexural modulus were tested according to GB / T1449–2005, and electromagnetic shielding effectiveness was tested according to GB / T32511–2016 (test frequency range: 100 kHz to 1.5 GHz). Meanwhile, the same performance tests were performed using pure polypropylene resin as Control Example 1 and pure nylon 6 resin as Control Example 2. All performance test results are shown in Table 1.

[0102] Table 1 compares the properties of the modified polypropylene special material based on the high conductivity composite system coated with black talc powder for plastic reinforcement and electromagnetic shielding prepared in Examples 1-6 with those of the control example pure polypropylene resin.

[0103]

[0104] Table 2. Comparison of various properties of the plastic reinforcement and electromagnetic shielding functionalized modified nylon 6 material based on the high conductivity composite system coated with black talc powder prepared in Examples 1-6 and the control example pure nylon 6 resin.

[0105] The data in Tables 1 and 2 show that the talc-based plastic reinforcement and electromagnetic shielding functionalized modified masterbatch prepared according to the embodiments of the present invention, after being used for filling and functionalizing polypropylene and nylon 6, exhibits significantly improved tensile strength, tensile modulus, flexural strength, and flexural modulus compared to the pure resin. Furthermore, the obtained modified masterbatch achieves high electromagnetic shielding effectiveness across a wide frequency range of 100 kHz to 1.5 GHz. This shielding effectiveness meets the electromagnetic shielding needs of general household and industrial electronic applications, a level of modification efficacy that traditional talc-filled modified polypropylene and nylon 6 cannot achieve. Utilizing the functionalized modified masterbatch technology of the present invention not only greatly simplifies the plastic modification process, improves processing efficiency, and reduces energy consumption, but also significantly enhances the dispersibility of inorganic fillers in the plastic matrix, significantly improving the modification effect and realizing the sustainable development concept of green processing in plastic preparation.

[0106] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the technical concept of the invention. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A method for preparing a highly conductive composite system coated with black talc powder, characterized in that: The method includes the following steps: 1) Add black talc powder and iodine into a high-speed mixer according to the ratio, mix at high speed for 20 minutes in a closed environment to raise the material temperature to 80℃, then stop stirring and let stand until the material temperature drops to room temperature. Then add silane coupling agent KH-550, mix at high speed again for 10 minutes, stop stirring, let stand until the material temperature drops to room temperature and take it out. 2) Black talc powder that has been doped with iodine and surface-treated with KH-550 is dispersed in a tris(hydroxymethyl)aminomethane-hydrochloride buffer solution at pH 8.

4. Dopamine hydrochloride, graphene and carbon black are added sequentially. The mixture is mechanically stirred at room temperature. During the reaction, dopamine hydrochloride will gradually undergo oxidative polymerization and combine with graphene and carbon black. It will also automatically adhere to the surface of black talc powder through the electrostatic adsorption of KH550, forming a uniform and highly conductive composite layer. The reaction is stopped after stirring for 24 hours. 3) The above suspension reaction liquid is filtered, and the wet powder is dried in an oven at 70°C for 10 hours to obtain black talc powder coated with a high conductivity composite system. The black talc powder coated with the high conductivity composite system is black talc powder doped with iodine electron acceptor and in situ coated with polydopamine, graphene and carbon black.

2. The method for preparing black talc powder coated with a highly conductive composite system according to claim 1, characterized in that: In the preparation method, the amount of iodine added in step 1) is: 10.0 g of iodine is added for every 1.0 kg of black talc powder, and the amount of silane coupling agent KH550 added is: 15.0 g of KH550 is added for every 1.0 kg of black talc powder.

3. The method for preparing black talc powder coated with a highly conductive composite system according to claim 1, characterized in that: In step 2), the amount of tris(hydroxymethyl)aminomethane-hydrochloric acid buffer added is: 5.0 L of tris(hydroxymethyl)aminomethane-hydrochloric acid buffer added for every 1.0 kg of black talc powder; the amount of dopamine hydrochloride added is: 100.0 g of dopamine hydrochloride added for every 1.0 kg of black talc powder; the amount of graphene added is: 30.0 g of graphene added for every 1.0 kg of dopamine hydrochloride; and the amount of carbon black added is: 20.0 g of carbon black added for every 1.0 kg of dopamine hydrochloride.

4. A modified masterbatch containing a highly conductive composite system coated with black talc powder, characterized in that: The modified masterbatch is a special masterbatch based on a highly conductive composite system coated with black talc powder, specifically used for functional modification of plastic filler reinforcement and electromagnetic shielding. Its mass percentage composition is as follows: The high conductivity composite system coated with black talc powder prepared by the preparation method of any one of claims 1-3 contains 65.0-76.0 wt.% of the high conductivity composite system coated with black talc powder. Cobalt ferrite CoFe2O4 nanoparticles, 5.0–10.0 wt.%; Carrier resin 15.0–20.0 wt.%; Dispersant 2.0–3.0 wt.%; Lubricant 0.5–1.0 wt.% The sum of the mass percentages of the above substances is 100 wt.%.

5. The modified masterbatch containing a highly conductive composite system coated with black talc powder according to claim 4, characterized in that: The cobalt ferrite CoFe2O4 nanoparticles are cobalt ferrite powder particles with an average particle size of 30-50 nm and whose surface has been treated with any one of the silane coupling agents KH540, KH550 and KH560.

6. The modified masterbatch containing a highly conductive composite system coated with black talc powder according to claim 4, characterized in that: The carrier resin is any one of ethylene-1-octene copolymer, ethylene-vinyl ester copolymer, ethylene-methyl acrylate copolymer, ethylene-butyl acrylate copolymer, and ethylene-methyl acrylate-glycidyl methacrylate copolymer.

7. The modified masterbatch containing a highly conductive composite system coated with black talc powder according to claim 4, characterized in that: The dispersant is any one of stearic acid, magnesium stearate, calcium stearate, zinc stearate, aluminum stearate, oleamide, and mesoamide.

8. The modified masterbatch containing a highly conductive composite system coated with black talc powder according to claim 4, characterized in that: The lubricant is any one of oxidation-resistant polyethylene, polyethylene wax, oxidized paraffin wax, ethylene bis-stearamide, OP wax, E wax, EVA wax, and ethylene-acrylic acid copolymer wax.

9. A method for preparing a modified masterbatch containing a highly conductive composite system coated with black talc powder as described in any one of claims 4-8, characterized in that: The method includes the following steps: 1) Weigh out the high conductivity composite system coated black talc powder, cobalt ferrite CoFe2O4 nanoparticles, carrier resin, dispersant and lubricant according to the ratio, and put them into a high-speed mixer to mix evenly to obtain a premix for later use. 2) Put the premix prepared in step 1) into a mixer for hot mixing to obtain agglomerated blend. The mixing temperature of the mixer is 110-125℃ and the mixing time is 15-20 minutes. 3) The agglomerated blend obtained in step 2) is fed into a single-screw extruder, and after melt blending, extrusion, air-cooled grinding and pelletizing, and bagging, a plastic reinforcement and electromagnetic shielding functionalized modified masterbatch based on black talc powder is obtained. The screw speed of the single-screw extruder is 150-200 rpm, and the barrel temperature is 150-160℃.

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