Process for the preparation of a modified talc powder for reinforced plastics

Abstract

This invention discloses a method for preparing modified talc powder for reinforcing plastics, belonging to the field of inorganic non-metallic powders and polymer composites. Talc powder is mixed with pretreated calcium oxide and an epoxy compound, and then subjected to electron beam irradiation under a carbon dioxide atmosphere to efficiently initiate surface cycloaddition reactions, generating active functional groups. A unique supported composite modifier is used to perform integrated grinding-dispersion-chemical grafting treatment on the irradiated powder. Finally, it is synergistically coated and refined with stearic acid and a toughening agent via air jet milling. This invention solves the problems of insufficient utilization of talc tailings, poor dispersibility of ordinary powders in plastics, and weak interfacial bonding. The obtained modified talc powder exhibits excellent hydrophobicity and dispersibility. When used as a filler in plastics such as polypropylene and polyethylene, it can significantly improve the tensile strength, flexural modulus, and heat distortion temperature of the composite material while reducing shrinkage, demonstrating superior overall performance.

Description

Technical Field

[0001] This invention relates to the field of inorganic non-metallic powders and polymer materials, and in particular to a method for preparing modified talc powder for reinforcing plastics. Background Technology

[0002] The development of food-grade talc powder requires high-purity, high-whiteness, high-quality talc resources. As a result, some low-grade, poor-whiteness slurries, waste materials, and scraps of secondary talc mines have not been fully and effectively utilized. After years of mining, the reserves of high-whiteness talc have gradually decreased. In order to protect and fully utilize resources, the development and utilization of secondary talc mines has become particularly important and urgent.

[0003] Meanwhile, as the application of talc becomes increasingly refined, the market demand for ordinary talc powder will be greatly compressed. What is needed are products specially designed for different application characteristics, and the development of high-end ultrafine powder and activated talc powder will be the trend. Talc, as a conventional inorganic non-metallic powder, exhibits certain oleophilic and hydrophobic properties, but its polarity differs from that of resins. When mixed with polymer resins, it is prone to agglomeration, leading to stress defects. Therefore, specific activation processes are needed to improve the surface properties of talc powder and increase its dispersibility in polymer resins, enabling its wider application in the processing and preparation of plastic products.

[0004] I. Reaction Overview: The reaction of carbon dioxide with propylene oxide to produce propylene carbonate is a significant chemical reaction in chemical production. This reaction fully utilizes carbon dioxide, a greenhouse gas, which is both environmentally friendly and produces high-value-added chemical products.

[0005] II. Reaction Type: This reaction is a cycloaddition reaction, specifically a cycloaddition reaction of an epoxide with carbon dioxide. In this process, the carbon-oxygen double bond of carbon dioxide undergoes addition with the epoxy ring of propylene oxide to form a five-membered ring propylene carbonate.

[0006] III. Reaction Process and Mechanism: Under the action of a catalyst, carbon dioxide undergoes a cycloaddition reaction with propylene oxide. The catalyst is typically a metal-organic compound or ionic liquid that can effectively activate both carbon dioxide and propylene oxide. During the reaction, the carbon-oxygen double bond of carbon dioxide is opened, and it adds to the epoxy ring of propylene oxide to form a new five-membered ring structure, namely propylene carbonate.

[0007] Electron beam irradiation is a key technology that uses electron accelerators to generate high-energy electron beams, thereby altering the properties of materials through ionization and excitation. Its core system includes a high-power electron accelerator, beam-guided irradiation transmission equipment, and an automatic control system. In the wire and cable processing industry, it can handle fan-shaped / round cables with cores ranging from 1-40mm. In the food industry, it effectively regulates flavor compounds in aquatic products and extends their shelf life.

[0008] This technology enables the disinfection of medical devices and the induction of crop mutations in the life sciences field, and enhances material performance through pre-crosslinking processes in photovoltaic module encapsulation. The electron beam energy ranges from 2.5 to 10 MeV, and its penetration capability dynamically varies with material density, combining high processing efficiency with environmental friendliness.

[0009] Grinding aids are additives that, when added in appropriate amounts to the material being ground, exert mechanical effects through their physicochemical action on the particle surface, thereby improving the material's friability and dispersibility, ultimately increasing the fineness of the powder and reducing grinding power consumption. Based on their state of application, grinding aids can be classified into solid, liquid, and gaseous grinding aids. Solid grinding aids include stearates, colloidal silica, colloidal graphite, carbon black, fly ash, and gypsum; liquid grinding aids include organosilicon, triethanolamine, ethylene glycol, propylene glycol, polyacrylates, and polycarboxylates; gaseous grinding aids include vaporized polar and non-polar substances. Summary of the Invention

[0010] The purpose of this invention is to provide a method for preparing modified talc powder for reinforcing plastics, solving the technical problem that some low-grade, poor-whiteness slurries, waste materials, and scraps of secondary talc ore are not being fully and effectively utilized. Using this talc powder to modify plastics such as polyethylene, polypropylene, and polycarbonate can effectively improve the tensile strength, heat distortion temperature, and stiffness of the composite materials, while reducing shrinkage and other comprehensive mechanical strength.

[0011] When mining food-grade talc, high-purity, high-whiteness, high-quality talc resources are required. As a result, some low-grade, poor-whiteness slurry, waste, and offcuts of secondary talc ore are not fully and effectively utilized. The raw material used in this invention is talc tailings with a specific structure. Firstly, it belongs to the waste residue category of talc mining and is cheaper than ordinary talc. Secondly, the 8-14 wt% chlorite and 1-4 wt% dolomite contained in the tailings, based on the structural characteristics of these two impurities, can impart better anti-aging properties and heat distortion characteristics to plastic composite materials than talc powder alone, when used as a plastic filler.

[0012] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A method for preparing modified talc for reinforcing plastics, the method comprising the following steps: Step 1: Take talc powder and calcium oxide powder and add epoxy compound separately by spraying at 20-40℃ and stirring speed of 500-800 r / min. Continue stirring and mixing for 5 min to obtain a fully dispersed mixed powder. The weight ratio of talc powder, calcium oxide powder and epoxy compound is 100:6:0.5. Step 2: Seal the mixed powder with a low-density polyethylene film, spread it evenly and control the powder thickness to be 2~12cm, fill it with carbon dioxide at 0.04-0.06Mpa, and treat it under electron beam irradiation for 1~9 min to obtain primary modified powder; Step 3: Add the primary modified powder, microcrystalline cellulose and supported composite modifier into a high-speed mixer, stir at 350-500 r / min for 5 min at 20-35℃ to obtain the secondary modified powder. The weight ratio of the primary modified powder, microcrystalline cellulose and supported composite modifier is 100:4:2.5. Step 4: Add the secondary modified powder into the air jet mill through the main material inlet. Add stearic acid and toughening agent into the air jet mill through the modifier material inlet. Control the feeding speed to ensure that the weight ratio of the secondary modified powder, stearic acid and toughening agent is 100:1:1.5. Then, pulverize and refine the powder with an airflow speed of 500~800m / s. Control the average particle size D50 of the output to 2~5 μm through a classifier to obtain the final modified talc powder for reinforced plastics.

[0013] Furthermore, in step 1, the talc powder is talc tailings with a particle size of 150-300 mesh, and the talc tailings contain 85-90 wt% talc, 8-14 wt% chlorite and 1-4 wt% dolomite. Further, in step 1, the calcium oxide powder is impregnated porous calcium oxide with a particle size of 250-600 mesh, a pore size of 25-40 nm, and a pore volume of 0.45-0.60 cm³. 3 / g, specific surface area is 20-80 m² 2 / g, the impregnation process is as follows: after vacuum drying of several-pore calcium oxide powder at 60 ℃ for 10 h, it is impregnated in liquid carbon dioxide for 30 min, then taken out and allowed to naturally warm to 25 ℃.

[0014] Further, in step 1, the epoxy compound is any one or a mixture of any proportions of propylene oxide, glycidyl ester type epoxy resin and epichlorohydrin. Furthermore, in step 2, the electron beam irradiation conditions are an output energy of 2.5~6.5 MeV, a beam current intensity of 10-40 mA, and an irradiation dose rate of 5~20 kGy / min.

[0015] Further, in step 3, the supported composite modifier includes porous sodium polyacrylate powder, supported 3-propionylthio-1-propyltriethoxysilane, and triethanolamine. The mass ratio of the porous sodium polyacrylate powder, supported 3-propionylthio-1-propyltriethoxysilane, and triethanolamine is 8 / 3 / 2. The porous sodium polyacrylate has a molecular weight of 10,000~12,000, a pore size of 2~5 nm, and a pore volume of 0.15~0.30 cm³. 3 / g.

[0016] Furthermore, the preparation method of the supported composite modifier is as follows: sodium polyacrylate powder, 3-propionylthio-1-propyltriethoxysilane and triethanolamine are taken in a mass ratio of 8 / 3 / 2, respectively, and after being stirred quickly and evenly, they are transferred to an oven at 40°C for activation for 30 min to obtain the swollen supported composite modifier.

[0017] Furthermore, in step 4, the toughening agent is maleic anhydride-grafted polyolefin elastomer or glycidyl methacrylate-grafted polyolefin elastomer.

[0018] An application of modified talc for reinforcing plastics: the modified talc prepared by the above method is dispersed in a polymer resin to improve the tensile strength, heat distortion temperature and stiffness of the product, reduce shrinkage and improve flexural modulus.

[0019] Furthermore, the modified talc powder is added to the plastic in the amount of 10 to 35 parts, the blending processing temperature is 150 to 320°C, and the plastic is polyethylene, polypropylene, polyvinyl chloride, acrylonitrile-butadiene-styrene terpolymer, polystyrene, polycarbonate, or polyurethane. The present invention, by adopting the above-described technical solution, has the following beneficial effects: (1) The raw material used in this invention is talc tailings with a specific structure. First, it belongs to the waste residue of talc mining and is cheaper than ordinary talc. Second, the 8-14 wt% chlorite and 1-4 wt% dolomite contained in the tailings, based on the structural characteristics of these two impurities, can be used as plastic fillers to give plastic composite materials better anti-aging properties and heat deformation characteristics than single talc powder.

[0020] (2) Although talc, as a conventional inorganic non-metallic powder, exhibits certain oleophilic and hydrophobic properties, its polarity differs from that of resins. When mixed with polymer resins, it is prone to agglomeration, leading to stress defects. Furthermore, the main chemical formula of talc is Mg3(Si4O3). 10(OH)₂ has poor reactivity. This invention, under electron beam irradiation conditions, by controlling the electron beam irradiation parameters, can specifically promote the reaction between talc powder and epoxides and carbon dioxide, enhancing the reactivity of the functional groups on the talc powder surface, thus making it more conducive to the subsequent reaction with coupling agents, stearic acid, and other surface modifiers.

[0021] (3) Since carbon dioxide is a gas, it has fewer contact sites with talc. The present invention uses porous calcium oxide treated by impregnation in liquid carbon dioxide to increase the transfer and contact between carbon dioxide and talc based on its adsorption characteristics, thereby increasing the degree of reaction.

[0022] (4) A supported composite modifier is used. Compared with conventional silane coupling agents such as γ-methacryloxypropyltrimethoxysilane (KH-570) and γ-aminopropyltriethoxysilane (KH-550), the ternary modifier of alkanolamine, sodium polyacrylate and mercaptosilane contains special mercapto groups, which can react with the primary modified talc surface functional groups (specific functional groups introduced after talc powder reacts with epoxy compounds and carbon dioxide) in a targeted manner, thereby further improving the hydrophobicity of talc. On the other hand, the synergistic mechanism in the grinding process can realize the "grinding-dispersion-coating" process in one step, improving the uniformity of powder particle size and surface activity.

[0023] (5) Conventional mercaptosilane coupling agents and triethanolamine are liquids, and their usage accounts for less than 2.5 wt% of the entire system. If they are directly added to talc powder, there will be problems such as inaccurate control of the addition amount, concentrated adhesion of a certain amount of talc by liquid silane, resulting in uneven contact and low degree of silane reaction. In this invention, sodium polyacrylate powder, which also has grinding and dispersing properties, is used to adsorb mercaptosilane and triethanolamine to obtain a solidified, swollen supported composite modifier. Under the premise of the same amount of mercaptosilane used, the surface modification degree (activation degree) and modification uniformity of talc products can be greatly improved.

[0024] (6) This invention uses both mercaptosilane and stearic acid as surface modifiers for talc. If the two modifiers are used simultaneously, there will be significant competition and interference between them, reducing the modification efficiency. This invention first adds mercaptosilane to the high-speed mixer to react the primary modified talc surface functional groups (specific functional groups introduced after the reaction of talc powder with epoxy compounds and carbon dioxide); then, in the air jet milling process, stearic acid is further used to modify the surface of the remaining reactive groups of talc; on the one hand, this can improve the degree of modification, and on the other hand, it can improve the utilization rate of the modifier.

[0025] (7) The formulation of this invention adds a certain amount of toughening agent (POE), which can effectively improve the phenomenon that while the rigidity of the composite material is increased by the lamellar talc filling, it also leads to a certain degree of decrease in elongation at break and impact strength. Based on the synergistic effect of toughening agent, modified talc and three other materials with different structures, plastic products with excellent comprehensive performance can be obtained, which have good applicability in the fields of automotive plastics and engineering plastics.

[0026] (8) The formulation of this invention contains microcrystalline cellulose, which can effectively enhance the nucleating effect of modified talc particles in the matrix resin (plastic), improve the crystallinity and transparency of the resin, and thus improve the mechanical properties of the plastic. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this invention clearer, preferred embodiments are described below to further illustrate the invention in detail. However, it should be noted that many details listed in the specification are merely to provide the reader with a thorough understanding of one or more aspects of the invention, and these aspects can be achieved even without these specific details.

[0028] Example 1: A method for preparing modified talc for reinforcing plastics includes the following steps: (1) Take 6 kg of particles with a particle size of 300 mesh, a pore size of 30 nm, and a pore volume of 0.5 cm. 3 / g, specific surface area 70 m² 2 / g of porous calcium oxide was vacuum dried at 60 ℃ for 10 h, then immersed in liquid carbon dioxide for 30 min, removed, and allowed to naturally warm to 25 ℃.

[0029] (2) Take 100 kg of talc tailings powder with a particle size of 200 mesh, containing 90 wt% talc, 9 wt% chlorite and 1 wt% dolomite, and 6 kg of impregnated porous calcium oxide powder and place them in a reactor. Under the conditions of 25℃ and a stirring speed of 800 r / min, add 0.5 kg of propylene oxide by spraying and continue stirring and mixing for 5 min to obtain a fully dispersed mixed powder. (3) The above mixed powder is sealed with a low-density polyethylene film, spread out and controlled to a thickness of 7 cm, filled with 0.05 MPa of carbon dioxide, and treated for 3 min under electron beam irradiation conditions with an output energy of 4.5 MeV, a beam current intensity of 25 mA, and an irradiation dose rate of 12 kGy / min to obtain the first-level modified powder. (4) Take 1.54 kg of porous sodium polyacrylate with a molecular weight of 12000, a pore size of 5 nm, and a pore volume of 0.30 cm³. 3 / g, 0.58 kg of 3-propionylthio-1-propyltriethoxysilane and 0.38 kg of triethanolamine were rapidly stirred until homogeneous, and then transferred to an oven at 40℃ for activation for 30 min to obtain a swollen supported composite modifier.

[0030] (5) Weigh 100 kg of primary modified powder, 4 kg of microcrystalline cellulose and 2.5 kg of supported composite modifier and add them to a high-speed mixer. Stir at 400 r / min for 5 min at 25 ℃ to obtain secondary modified powder.

[0031] (6) Weigh 100 kg of secondary modified powder and add it into the air jet mill from the main material inlet. Weigh 1 kg of stearic acid and 1.5 kg of maleic anhydride grafted polyolefin elastomer (POE-g-MAH) and add them into the air jet mill from the modifier material inlet. Control the feeding speed with a flow meter and pulverize and refine the powder with an airflow speed of 200 m / s. Control the average particle size D50 of the output to 2.5 μm with a classifier to obtain the final modified talc powder for reinforced plastics.

[0032] (7) Raise the temperature of the high-speed mixer to 135°C, and under the stirring condition of 500 r / min, add 100 kg of polypropylene, 30 kg of modified talc for reinforced plastics and 1 kg of polyethylene wax in sequence, and stir for 15 min to obtain a paste-like viscous mixture; add the obtained paste-like mixture to the screw extruder for co-extrusion, control the feeding speed in the screw extruder to 500 kg / h and the die head temperature to 180°C, and then obtain plastic masterbatch after traction, water strip cooling and cutting, and drying treatment.

[0033] Example 2: A method for preparing modified talc for reinforcing plastics includes the following steps: (1) Take 6 kg of particles with a particle size of 250 mesh, a pore size of 25 nm, and a pore volume of 0.45 cm³. 3 / g, specific surface area 20 m² 2 / g of porous calcium oxide was vacuum dried at 60 ℃ for 10 h, then immersed in liquid carbon dioxide for 30 min, removed, and allowed to naturally warm to 25 ℃.

[0034] (2) Take 100 kg of talc tailings powder with a particle size of 150 mesh, containing 87 wt% talc, 9 wt% chlorite and 4 wt% dolomite, and 6 kg of impregnated porous calcium oxide powder and place them in a reactor. Under the conditions of 25℃ and a stirring speed of 500 r / min, add 0.5 kg of propylene oxide by spraying and continue stirring and mixing for 5 min to obtain a fully dispersed mixed powder. (3) The above mixed powder is sealed with a low-density polyethylene film, spread out and controlled to a thickness of 10 cm, filled with 0.05 MPa of carbon dioxide, and treated for 1 min under electron beam irradiation conditions with an output energy of 2.5 MeV, a beam current intensity of 10 mA, and an irradiation dose rate of 5 kGy / min to obtain the first-level modified powder. (4) Take 1.54 kg of porous sodium polyacrylate with a molecular weight of 11,000, a pore size of 4 nm, and a pore volume of 0.20 cm³. 3 / g, 0.58 kg of 3-propionylthio-1-propyltriethoxysilane and 0.38 kg of triethanolamine were rapidly stirred until homogeneous, and then transferred to an oven at 40℃ for activation for 30 min to obtain a swollen supported composite modifier.

[0035] (5) Weigh 100 kg of primary modified powder, 4 kg of microcrystalline cellulose and 2.5 kg of supported composite modifier and add them to a high-speed mixer. Stir at 350 r / min for 5 min at 20℃ to obtain secondary modified powder.

[0036] (6) Weigh 100 kg of secondary modified powder and add it into the air jet mill from the main material inlet. Add 1 kg of stearic acid and 1.5 kg of maleic anhydride grafted polyolefin elastomer (POE-g-MAH) into the air jet mill from the modifier material inlet. Control the feeding speed with a flow meter and pulverize and refine it with an airflow speed of 100 m / s. Control the average particle size D50 of the output to 3 μm with a classifier to obtain the final modified talc powder for reinforced plastics.

[0037] (7) Raise the temperature of the high-speed mixer to 135°C, and under the stirring condition of 500 r / min, add 100 kg of polypropylene, 10 kg of modified talc for reinforced plastics and 1 kg of polyethylene wax in sequence, and stir for 15 min to obtain a paste-like viscous mixture; add the obtained paste-like mixture to the screw extruder for co-extrusion, control the feeding speed in the screw extruder to 500 kg / h and the die head temperature to 150°C, and then obtain plastic masterbatch after traction, water strip cooling and cutting, and drying treatment.

[0038] Example 3: A method for preparing modified talc for reinforcing plastics includes the following steps: (1) Take 6 kg of particles with a particle size of 350 mesh, a pore size of 35 nm, and a pore volume of 0.55 cm³. 3 / g, specific surface area 40 m² 2 / g of porous calcium oxide was vacuum dried at 60 ℃ for 10 h, then immersed in liquid carbon dioxide for 30 min, removed, and allowed to naturally warm to 25 ℃.

[0039] (2) Take 100 kg of talc tailings powder with a particle size of 250 mesh, containing 86 wt% talc, 9 wt% chlorite and 3 wt% dolomite, and 6 kg of impregnated porous calcium oxide powder and place them in a reactor. Under the conditions of 25℃ and a stirring speed of 600 r / min, add 0.5 kg of glycidyl ester type epoxy resin by spraying and continue stirring and mixing for 5 min to obtain a fully dispersed mixed powder. (3) The above mixed powder is sealed with a low-density polyethylene film, spread out and controlled to a thickness of 4 cm, filled with 0.05 MPa of carbon dioxide, and treated for 5 min under electron beam irradiation conditions with an output energy of 5.5 MeV, a beam current intensity of 40 mA, and an irradiation dose rate of 15 kGy / min to obtain the first-level modified powder. (4) Take 1.54 kg of porous sodium polyacrylate with a molecular weight of 10,000, a pore size of 3.5 nm, and a pore volume of 0.25 cm³. 3 / g, 0.58 kg of 3-propionylthio-1-propyltriethoxysilane and 0.38 kg of triethanolamine were rapidly stirred until homogeneous, and then transferred to an oven at 40℃ for activation for 30 min to obtain a swollen supported composite modifier.

[0040] (5) Weigh 100 kg of primary modified powder, 4 kg of microcrystalline cellulose and 2.5 kg of supported composite modifier and add them to a high-speed mixer. Stir at 30°C and 450 r / min for 5 min to obtain secondary modified powder.

[0041] (6) Weigh 100 kg of secondary modified powder and add it into the air jet mill from the main material inlet. Weigh 1 kg of stearic acid and 1.5 kg of glycidyl methacrylate grafted polyolefin elastomer (POE-g-GAH) and add them into the air jet mill from the modifier material inlet. Control the feeding speed with a flow meter and pulverize and refine the powder with an airflow speed of 200 m / s. Control the average particle size D50 of the output to 2.5 μm with a classifier to obtain the final modified talc powder for reinforced plastics.

[0042] (7) Raise the temperature of the high-speed mixer to 135°C, and under the stirring condition of 500 r / min, add 100 kg of polypropylene, 20 kg of modified talc for reinforced plastics and 1 kg of polyethylene wax in sequence, and stir for 15 min to obtain a paste-like viscous mixture; add the obtained paste-like mixture to the screw extruder for co-extrusion, control the feeding speed in the screw extruder to 500 kg / h and the die head temperature to 200°C, and then obtain plastic masterbatch after traction, water strip cooling and cutting, and drying treatment.

[0043] Example 4: A method for preparing modified talc for reinforcing plastics includes the following steps: (1) Take 6 kg of particles with a size of 400 mesh, a pore size of 38 nm, and a pore volume of 0.6 cm. 3 / g, specific surface area 50 m² 2 / g of porous calcium oxide was vacuum dried at 60 ℃ for 10 h, then immersed in liquid carbon dioxide for 30 min, removed, and allowed to naturally warm to 25 ℃.

[0044] (2) Take 100 kg of talc tailings powder with a particle size of 280 mesh, containing 88 wt% talc, 9 wt% chlorite and 4 wt% dolomite, and 6 kg of impregnated porous calcium oxide powder and place them in a reactor. Under the conditions of 25℃ and a stirring speed of 700 r / min, add 0.5 kg of propylene oxide / epoxychloropropane mixture (V / V=2 / 1) by spraying, and continue stirring and mixing for 5 min to obtain a fully dispersed mixed powder. (3) The above mixed powder is sealed with a low-density polyethylene film, spread out and controlled to a thickness of 2 cm, filled with 0.05 MPa of carbon dioxide, and treated for 9 min under electron beam irradiation conditions with an output energy of 3.5 MeV, a beam current intensity of 30 mA, and an irradiation dose rate of 20 kGy / min to obtain the first-level modified powder. (4) Take 1.54 kg of porous sodium polyacrylate with a molecular weight of 12000, a pore size of 5 nm, and a pore volume of 0.30 cm³. 3 / g, 0.58 kg of 3-propionylthio-1-propyltriethoxysilane and 0.38 kg of triethanolamine were rapidly stirred until homogeneous, and then transferred to an oven at 40℃ for activation for 30 min to obtain a swollen supported composite modifier.

[0045] (5) Weigh 100 kg of primary modified powder, 4 kg of microcrystalline cellulose and 2.5 kg of supported composite modifier and add them to a high-speed mixer. Stir at 33°C and 480 r / min for 5 min to obtain secondary modified powder.

[0046] (6) Weigh 100 kg of secondary modified powder and add it into the air jet mill from the main material inlet. Weigh 1 kg of stearic acid and 1.5 kg of maleic anhydride grafted polyolefin elastomer (POE-g-MAH) and add them into the air jet mill from the modifier material inlet. Control the feeding speed with a flow meter and pulverize and refine the powder with an airflow speed of 400 m / s. Control the average particle size D50 of the output to 2.2 μm with a classifier to obtain the final modified talc powder for reinforced plastics.

[0047] (7) Raise the temperature of the high-speed mixer to 135°C, and under the stirring condition of 500 r / min, add 100 kg of polypropylene, 25 kg of modified talc for reinforced plastics and 1 kg of polyethylene wax in sequence, and stir for 15 min to obtain a paste-like viscous mixture; add the obtained paste-like mixture to the screw extruder for co-extrusion, control the feeding speed in the screw extruder to 500 kg / h and the die head temperature to 250°C, and then obtain plastic masterbatch after traction, water strip cooling and cutting, and drying treatment.

[0048] Example 5: A method for preparing modified talc for reinforcing plastics includes the following steps: (1) Take 6 kg of porous calcium oxide with a particle size of 300 mesh, a pore size of 30 nm, a pore volume of 0.5 cm3 / g, and a specific surface area of ​​70 m2 / g. After vacuum drying at 60 ℃ for 10 h, immerse it in liquid carbon dioxide for 30 min, take it out, and allow it to naturally warm to 25 ℃.

[0049] (2) Take 100 kg of talc tailings powder with a particle size of 200 mesh, containing 90 wt% talc, 9 wt% chlorite and 1 wt% dolomite, and 6 kg of impregnated porous calcium oxide powder and place them in a reactor. Under the conditions of 25℃ and a stirring speed of 800 r / min, add 0.5 kg of propylene oxide by spraying and continue stirring and mixing for 5 min to obtain a fully dispersed mixed powder. (3) The above mixed powder is sealed with a low-density polyethylene film, spread out and controlled to a thickness of 7 cm, filled with 0.05 MPa of carbon dioxide, and treated for 3 min under electron beam irradiation conditions with an output energy of 4.5 MeV, a beam current intensity of 25 mA, and an irradiation dose rate of 12 kGy / min to obtain the first-level modified powder. (4) Take 1.54 kg of porous sodium polyacrylate with a molecular weight of 12000, a pore size of 5 nm, and a pore volume of 0.30 cm³. 3 / g, 0.58 kg of 3-propionylthio-1-propyltriethoxysilane and 0.38 kg of triethanolamine were rapidly stirred until homogeneous, and then transferred to an oven at 40℃ for activation for 30 min to obtain a swollen supported composite modifier.

[0050] (5) Weigh 100 kg of primary modified powder, 4 kg of microcrystalline cellulose and 2.5 kg of supported composite modifier and add them to a high-speed mixer. Stir at 400 r / min for 5 min at 25 ℃ to obtain secondary modified powder.

[0051] (6) Weigh 100 kg of secondary modified powder and add it into the air jet mill from the main material inlet. Weigh 1 kg of stearic acid and 1.5 kg of maleic anhydride grafted polyolefin elastomer (POE-g-MAH) and add them into the air jet mill from the modifier material inlet. Control the feeding speed with a flow meter and pulverize and refine the powder with an airflow speed of 200 m / s. Control the average particle size D50 of the output to 2.5 μm with a classifier to obtain the final modified talc powder for reinforced plastics.

[0052] (7) Raise the temperature of the high-speed mixer to 135°C, and under the stirring condition of 500 r / min, add 100 kg of acrylonitrile (A)-butadiene ((B)-styrene (S) terpolymer (ABS), 30 kg of modified talc for reinforced plastics, and 1 kg of polyethylene wax in sequence. Stir for 15 min to obtain a paste-like viscous mixture. Add the obtained paste-like mixture to a screw extruder for co-extrusion. Control the feeding speed in the screw extruder to 500 kg / h and the die head temperature to 180°C. After traction, water strip cooling and cutting, and drying treatment, obtain plastic masterbatch.

[0053] Comparative Example 1: (The difference from Example 1 is that talc powder is used instead of talc tailings) (1) Take 6 kg of particles with a particle size of 300 mesh, a pore size of 30 nm, and a pore volume of 0.5 cm. 3 / g, specific surface area 70 m² 2 / g of porous calcium oxide was vacuum dried at 60 ℃ for 10 h, then immersed in liquid carbon dioxide for 30 min, removed, and allowed to naturally warm to 25 ℃.

[0054] (2) Take 100 kg of high-purity talc powder with a particle size of 200 mesh (purity greater than 98%) and 6 kg of impregnated porous calcium oxide powder and place them in the reactor. Under the conditions of 25°C and a stirring speed of 800, add 0.5 kg of propylene oxide by spraying and continue stirring and mixing for 5 min to obtain a fully dispersed mixed powder. (3) The above mixed powder is sealed with a low-density polyethylene film, spread out and controlled to a thickness of 7 cm, filled with 0.05 MPa of carbon dioxide, and treated for 3 min under electron beam irradiation conditions with an output energy of 4.5 MeV, a beam current intensity of 25 mA, and an irradiation dose rate of 12 kGy / min to obtain the first-level modified powder. (4) Take 1.54 kg of porous sodium polyacrylate with a molecular weight of 12000, a pore size of 5 nm, and a pore volume of 0.30 cm³. 3 / g, 0.58 kg of 3-propionylthio-1-propyltriethoxysilane and 0.38 kg of triethanolamine were rapidly stirred until homogeneous, and then transferred to an oven at 40℃ for activation for 30 min to obtain a swollen supported composite modifier.

[0055] (5) Weigh 100 kg of primary modified powder, 4 kg of microcrystalline cellulose and 2.5 kg of supported composite modifier and add them to a high-speed mixer. Stir at 400 r / min for 5 min at 25℃ to obtain secondary modified powder.

[0056] (6) Weigh 100 kg of secondary modified powder and add it into the air jet mill from the main material inlet. Weigh 1 kg of stearic acid and 1.5 kg of maleic anhydride grafted polyolefin elastomer (POE-g-MAH) and add them into the air jet mill from the modifier material inlet. Control the feeding speed with a flow meter and pulverize and refine the powder with an airflow speed of 200 m / s. Control the average particle size D50 of the output to 2.5 μm with a classifier to obtain the final modified talc powder for reinforced plastics.

[0057] (7) Raise the temperature of the high-speed mixer to 135°C, and under the stirring condition of 500 r / min, add 100 kg of polypropylene, 30 kg of modified talc for reinforced plastics and 1 kg of polyethylene wax in sequence, and stir for 15 min to obtain a paste-like viscous mixture; add the obtained paste-like mixture to the screw extruder for co-extrusion, control the feeding speed in the screw extruder to 500 kg / h and the die head temperature to 180°C, and then obtain plastic masterbatch after traction, water strip cooling and cutting, and drying treatment.

[0058] Comparative Example 2: (The difference from Example 1 is the absence of carbon dioxide and epoxide) (1) Take 100 kg of talc tailings powder with a particle size of 200 mesh, containing 90 wt% talc, 9 wt% chlorite and 1 wt% dolomite, and 6 kg of talc tailings powder with a particle size of 300 mesh, a pore size of 30 nm and a pore volume of 0.5 cm. 3 / g, specific surface area 70 m² 2 / g of porous calcium oxide was placed in a reactor and stirred and mixed for 5 min at 25℃ and a stirring speed of 800 r / min to obtain a fully dispersed mixed powder. (2) The above mixed powder is sealed with a low-density polyethylene film, and the powder thickness is controlled at 7 cm. It is then treated for 3 min under electron beam irradiation conditions with an output energy of 4.5 MeV, a beam current intensity of 25 mA, and an irradiation dose rate of 12 kGy / min to obtain the first-level modified powder. (3) Take 1.54 kg of porous sodium polyacrylate with a molecular weight of 12000, a pore size of 5 nm, and a pore volume of 0.30 cm³. 3 / g, 0.58 kg of 3-propionylthio-1-propyltriethoxysilane and 0.38 kg of triethanolamine were rapidly stirred until homogeneous, and then transferred to an oven at 40℃ for activation for 30 min to obtain a swollen supported composite modifier.

[0059] (4) Weigh 100 kg of primary modified powder, 4 kg of microcrystalline cellulose and 2.5 kg of supported composite modifier and add them to a high-speed mixer. Stir at 400 r / min for 5 min at 25 ℃ to obtain secondary modified powder.

[0060] (5) Weigh 100 kg of secondary modified powder and add it into the air jet mill from the main material inlet. Weigh 1 kg of stearic acid and 1.5 kg of maleic anhydride grafted polyolefin elastomer (POE-g-MAH) and add them into the air jet mill from the modifier material inlet. Control the feeding speed with a flow meter and pulverize and refine the powder with an airflow speed of 200 m / s. Control the average particle size D50 of the output to 2.5 μm with a classifier to obtain the final modified talc powder for reinforced plastics.

[0061] (6) Raise the temperature of the high-speed mixer to 135°C, and under the stirring condition of 500 r / min, add 100 kg of polypropylene, 30 kg of modified talc for reinforced plastics and 1 kg of polyethylene wax in sequence, and stir for 15 min to obtain a paste-like viscous mixture; add the obtained paste-like mixture to the screw extruder for co-extrusion, control the feeding speed in the screw extruder to 500 kg / h and the die head temperature to 180°C, and then obtain plastic masterbatch after traction, water strip cooling and cutting, and drying treatment.

[0062] Comparative Example 3: (Compared to Example 1, the electron beam radiation treatment step was omitted) (1) Take 6 kg of particles with a particle size of 300 mesh, a pore size of 30 nm, and a pore volume of 0.5 cm. 3 / g, specific surface area 70 m² 2 / g of porous calcium oxide was vacuum dried at 60 ℃ for 10 h, then immersed in liquid carbon dioxide for 30 min, removed, and allowed to naturally warm to 25 ℃.

[0063] (2) Take 100 kg of talc tailings powder with a particle size of 200 mesh, containing 90 wt% talc, 9 wt% chlorite and 1 wt% dolomite, and 6 kg of impregnated porous calcium oxide powder and place them in a reactor. Under the conditions of 25℃ and a stirring speed of 800 r / min, add 0.5 kg of propylene oxide by spraying and continue stirring and mixing for 5 min to obtain a fully dispersed mixed powder. (3) The above mixed powder is sealed with a low-density polyethylene film, spread out and control the powder thickness at 7cm, filled with 0.05Mpa carbon dioxide, sealed and placed for 24h to obtain the first-grade modified powder. (4) Take 1.54 kg of porous sodium polyacrylate with a molecular weight of 12000, a pore size of 5 nm, and a pore volume of 0.30 cm³. 3 / g, 0.58 kg of 3-propionylthio-1-propyltriethoxysilane and 0.38 kg of triethanolamine were rapidly stirred until homogeneous, and then transferred to an oven at 40℃ for activation for 30 min to obtain a swollen supported composite modifier.

[0064] (5) Weigh 100 kg of primary modified powder, 4 kg of microcrystalline cellulose and 2.5 kg of supported composite modifier and add them to a high-speed mixer. Stir at 400 r / min for 5 min at 25℃ to obtain secondary modified powder.

[0065] (6) Weigh 100 kg of secondary modified powder and add it into the air jet mill from the main material inlet. Weigh 1 kg of stearic acid and 1.5 kg of maleic anhydride grafted polyolefin elastomer (POE-g-MAH) and add them into the air jet mill from the modifier material inlet. Control the feeding speed with a flow meter and pulverize and refine the powder with an airflow speed of 200 m / s. Control the average particle size D50 of the output to 2.5 μm with a classifier to obtain the final modified talc powder for reinforced plastics.

[0066] (7) Raise the temperature of the high-speed mixer to 135°C, and under the stirring condition of 500 r / min, add 100 kg of polypropylene, 30 kg of modified talc for reinforced plastics and 1 kg of polyethylene wax in sequence, and stir for 15 min to obtain a paste-like viscous mixture; add the obtained paste-like mixture to the screw extruder for co-extrusion, control the feeding speed in the screw extruder to 500 kg / h and the die head temperature to 180°C, and then obtain plastic masterbatch after traction, water strip cooling and cutting, and drying treatment.

[0067] Comparative Example 4: (The difference from Example 1 is that the calcium oxide impregnation treatment was omitted) (1) Take 100 kg of talc tailings powder with a particle size of 200 mesh, containing 90 wt% talc, 9 wt% chlorite and 1 wt% dolomite, add 0.5 kg of propylene oxide by spraying at 25℃ and a stirring speed of 800 r / min, and continue stirring and mixing for 5 min to obtain a fully dispersed mixed powder; (2) The above mixed powder is sealed with a low-density polyethylene film, spread out and controlled to a thickness of 7 cm, filled with 0.05 MPa of carbon dioxide, and treated for 3 min under electron beam irradiation conditions with an output energy of 4.5 MeV, a beam current intensity of 25 mA, and an irradiation dose rate of 12 kGy / min to obtain the first-level modified powder. (3) Take 1.54 kg of porous sodium polyacrylate with a molecular weight of 12000, a pore size of 5 nm, and a pore volume of 0.30 cm³. 3 / g, 0.58 kg of 3-propionylthio-1-propyltriethoxysilane and 0.38 kg of triethanolamine were rapidly stirred until homogeneous, and then transferred to an oven at 40℃ for activation for 30 min to obtain a swollen supported composite modifier.

[0068] (4) Weigh 100 kg of primary modified powder, 4 kg of microcrystalline cellulose and 2.5 kg of supported composite modifier and add them to a high-speed mixer. Stir at 400 r / min for 5 min at 25℃ to obtain secondary modified powder.

[0069] (5) Weigh 100 kg of secondary modified powder and add it into the air jet mill from the main material inlet. Weigh 1 kg of stearic acid and 1.5 kg of maleic anhydride grafted polyolefin elastomer (POE-g-MAH) and add them into the air jet mill from the modifier material inlet. Control the feeding speed with a flow meter and pulverize and refine the powder with an airflow speed of 200 m / s. Control the average particle size D50 of the output to 2.5 μm with a classifier to obtain the final modified talc powder for reinforced plastics.

[0070] (6) Raise the temperature of the high-speed mixer to 135°C, and under the stirring condition of 500 r / min, add 100 kg of polypropylene, 30 kg of modified talc for reinforced plastics and 1 kg of polyethylene wax in sequence, and stir for 15 min to obtain a paste-like viscous mixture; add the obtained paste-like mixture to the screw extruder for co-extrusion, control the feeding speed in the screw extruder to 500 kg / h and the die head temperature to 180°C, and then obtain plastic masterbatch after traction, water strip cooling and cutting, and drying treatment.

[0071] Comparative Example 5: (Compared with Example 1, the difference is that 3-propionylthio-1-propyltriethoxysilane is used directly instead of the supported composite modifier, that is, the loading treatment and grinding aid are omitted.) (1) Take 6 kg of particles with a particle size of 300 mesh, a pore size of 30 nm, and a pore volume of 0.5 cm. 3 / g, specific surface area 70 m² 2 / g of porous calcium oxide was vacuum dried at 60 ℃ for 10 h, then immersed in liquid carbon dioxide for 30 min, removed, and allowed to naturally warm to 25 ℃.

[0072] (2) Take 100 kg of talc tailings powder with a particle size of 200 mesh, containing 90 wt% talc, 9 wt% chlorite and 1 wt% dolomite, and 6 kg of impregnated porous calcium oxide powder and place them in a reactor. Under the conditions of 25℃ and a stirring speed of 800 r / min, add 0.5 kg of propylene oxide by spraying and continue stirring and mixing for 5 min to obtain a fully dispersed mixed powder. (3) The above mixed powder is sealed with a low-density polyethylene film, spread out and controlled to a thickness of 7 cm, filled with 0.05 MPa of carbon dioxide, and treated for 3 min under electron beam irradiation conditions with an output energy of 4.5 MeV, a beam current intensity of 25 mA, and an irradiation dose rate of 12 kGy / min to obtain the first-level modified powder. (4) Weigh 100 kg of primary modified powder, 4 kg of microcrystalline cellulose, and 2.5 kg of 3-propionylthio-1-propyltriethoxysilane and add them to a high-speed mixer. Stir at 400 r / min for 5 min at 25℃ to obtain secondary modified powder.

[0073] (5) Weigh 100 kg of secondary modified powder and add it into the air jet mill from the main material inlet. Weigh 1 kg of stearic acid and 1.5 kg of maleic anhydride grafted polyolefin elastomer (POE-g-MAH) and add them into the air jet mill from the modifier material inlet. Control the feeding speed with a flow meter and pulverize and refine the powder with an airflow speed of 200 m / s. Control the average particle size D50 of the output to 2.5 μm with a classifier to obtain the final modified talc powder for reinforced plastics.

[0074] (6) Raise the temperature of the high-speed mixer to 135°C, and under the stirring condition of 500 r / min, add 100 kg of polypropylene, 30 kg of modified talc for reinforced plastics and 1 kg of polyethylene wax in sequence, and stir for 15 min to obtain a paste-like viscous mixture; add the obtained paste-like mixture to the screw extruder for co-extrusion, control the feeding speed in the screw extruder to 500 kg / h and the die head temperature to 180°C, and then obtain plastic masterbatch after traction, water strip cooling and cutting, and drying treatment.

[0075] Comparative Example 6: (Compared with Example 1, the difference is that γ-methacryloyloxypropyltrimethoxysilane (KH-570) was used directly instead of the supported composite modifier, i.e., the coupling agent is different.) (1) Take 6 kg of particles with a particle size of 300 mesh, a pore size of 30 nm, and a pore volume of 0.5 cm. 3 / g, specific surface area 70 m² 2 / g of porous calcium oxide was vacuum dried at 60 ℃ for 10 h, then immersed in liquid carbon dioxide for 30 min, removed, and allowed to naturally warm to 25 ℃.

[0076] (2) Take 100 kg of talc tailings powder with a particle size of 200 mesh, containing 90 wt% talc, 9 wt% chlorite and 1 wt% dolomite, and 6 kg of impregnated porous calcium oxide powder and place them in a reactor. Under the conditions of 25℃ and a stirring speed of 800 r / min, add 0.5 kg of propylene oxide by spraying and continue stirring and mixing for 5 min to obtain a fully dispersed mixed powder. (3) The above mixed powder is sealed with a low-density polyethylene film, spread out and controlled to a thickness of 7 cm, filled with 0.05 MPa of carbon dioxide, and treated for 3 min under electron beam irradiation conditions with an output energy of 4.5 MeV, a beam current intensity of 25 mA, and an irradiation dose rate of 12 kGy / min to obtain the first-level modified powder. (4) Weigh 100 kg of primary modified powder, 4 kg of microcrystalline cellulose, and 2.5 kg of γ-methacryloxypropyltrimethoxysilane and add them to a high-speed mixer. Stir at 400 r / min for 5 min at 25℃ to obtain secondary modified powder.

[0077] (5) Weigh 100 kg of secondary modified powder and add it into the air jet mill from the main material inlet. Weigh 1 kg of stearic acid and 1.5 kg of maleic anhydride grafted polyolefin elastomer (POE-g-MAH) and add them into the air jet mill from the modifier material inlet. Control the feeding speed with a flow meter and pulverize and refine the powder with an airflow speed of 200 m / s. Control the average particle size D50 of the output to 2.5 μm with a classifier to obtain the final modified talc powder for reinforced plastics.

[0078] (6) Raise the temperature of the high-speed mixer to 135°C, and under the stirring condition of 500 r / min, add 100 kg of polypropylene, 30 kg of modified talc for reinforced plastics and 1 kg of polyethylene wax in sequence, and stir for 15 min to obtain a paste-like viscous mixture; add the obtained paste-like mixture to the screw extruder for co-extrusion, control the feeding speed in the screw extruder to 500 kg / h and the die head temperature to 180°C, and then obtain plastic masterbatch after traction, water strip cooling and cutting, and drying treatment.

[0079] Comparative Example 7: (The difference compared to Example 1 is the absence of microcrystalline cellulose) (1) Take 6 kg of particles with a particle size of 300 mesh, a pore size of 30 nm, and a pore volume of 0.5 cm. 3 / g, specific surface area 70 m² 2 / g of porous calcium oxide was vacuum dried at 60 ℃ for 10 h, then immersed in liquid carbon dioxide for 30 min, removed, and allowed to naturally warm to 25 ℃.

[0080] (2) Take 100 kg of talc tailings powder with a particle size of 200 mesh, containing 90 wt% talc, 9 wt% chlorite and 1 wt% dolomite, and 6 kg of impregnated porous calcium oxide powder and place them in a reactor. Under the conditions of 25℃ and a stirring speed of 800 r / min, add 0.5 kg of propylene oxide by spraying and continue stirring and mixing for 5 min to obtain a fully dispersed mixed powder. (3) The above mixed powder is sealed with a low-density polyethylene film, spread out and controlled to a thickness of 7 cm, filled with 0.05 MPa of carbon dioxide, and treated for 3 min under electron beam irradiation conditions with an output energy of 4.5 MeV, a beam current intensity of 25 mA, and an irradiation dose rate of 12 kGy / min to obtain the first-level modified powder. (4) Take 1.54 kg of porous sodium polyacrylate with a molecular weight of 12000, a pore size of 5 nm, and a pore volume of 0.30 cm³. 3 / g, 0.58 kg of 3-propionylthio-1-propyltriethoxysilane and 0.38 kg of triethanolamine were rapidly stirred until homogeneous, and then transferred to an oven at 40℃ for activation for 30 min to obtain a swollen supported composite modifier.

[0081] (5) Weigh 100 kg of the primary modified powder and 2.5 kg of the supported modifier and add them to the high-speed mixer. Stir at 400 r / min for 5 min at 25℃ to obtain the secondary modified powder.

[0082] (6) Weigh 100 kg of secondary modified powder and add it into the air jet mill from the main material inlet. Weigh 1 kg of stearic acid and 1.5 kg of maleic anhydride grafted polyolefin elastomer (POE-g-MAH) and add them into the air jet mill from the modifier material inlet. Control the feeding speed with a flow meter and pulverize and refine the powder with an airflow speed of 200 m / s. Control the average particle size D50 of the output to 2.5 μm with a classifier to obtain the final modified talc powder for reinforced plastics.

[0083] (7) Raise the temperature of the high-speed mixer to 135°C, and under the stirring condition of 500 r / min, add 100 kg of polypropylene, 30 kg of modified talc for reinforced plastics and 1 kg of polyethylene wax in sequence, and stir for 15 min to obtain a paste-like viscous mixture; add the obtained paste-like mixture to the screw extruder for co-extrusion, control the feeding speed in the screw extruder to 500 kg / h and the die head temperature to 180°C, and then obtain plastic masterbatch after traction, water strip cooling and cutting, and drying treatment.

[0084] Test method: Modified talc powder for reinforced plastics was prepared according to the methods described in Examples 1-5 and Comparative Examples 1-7, and then tested according to the following methods. It should be noted that the comparative examples are not prior art, but rather a scheme constructed in this application to highlight the differences in test results caused by process differences. Specific results are shown in Table 1: Contact angle testing of powder samples: The seated drop method was used. At room temperature, a small amount of sample was placed in a clean mold and pressed into a sheet under a pressure of 5 MPa. The glass slide containing the sample was placed on a platform, and liquid was dropped onto the surface of the sample using a microsyringe, ensuring that the droplet size and position were uniform and stable. Measurements were taken 3-5 times, and the average value was taken as the final test result.

[0085] Powder sample filling performance test: The obtained plastic masterbatch was added to the injection molding machine through the inlet and injection molded into standard test strips at 190℃ and 45MPa. Test conditions: tensile strength was tested according to standard ASTM-D638; IZOD notched impact strength was tested according to standard ASTM-D256; flexural strength was tested according to standard ASTM-D790; heat distortion temperature was tested according to standard ASTM-D648; and Rockwell hardness was tested according to standard ASTMD-785.

[0086] Table 1. Test results of active talc powder and its properties in reinforced plastics prepared by different methods. As can be seen from the above data, adding modified talc as an additive to plastics can improve the mechanical properties of plastics. Therefore, the modified talc prepared according to the method of the present invention has a significantly better effect than the talc prepared by the method described in the comparative example.

[0087] Matters not covered in this invention are common knowledge.

[0088] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing modified talc powder for reinforcing plastics, characterized in that, The method includes the following steps: Step 1: Take talc powder and calcium oxide powder and add epoxy compound separately by spraying at 20-40℃ and stirring speed of 500-800 r / min. Continue stirring and mixing for 5 min to obtain a fully dispersed mixed powder. The weight ratio of talc powder, calcium oxide powder and epoxy compound is 100:6:0.

5. Step 2: Seal the mixed powder with a low-density polyethylene film, spread it evenly and control the powder thickness to be 2~12cm, fill it with carbon dioxide at 0.04-0.06Mpa, and treat it under electron beam irradiation for 1~9 min to obtain primary modified powder; Step 3: Add the primary modified powder, microcrystalline cellulose and supported composite modifier into a high-speed mixer, stir at 350-500 r / min for 5 min at 20-35℃ to obtain the secondary modified powder. The weight ratio of the primary modified powder, microcrystalline cellulose and supported composite modifier is 100:4:2.

5. Step 4: Add the secondary modified powder into the air jet mill through the main material inlet. Add stearic acid and toughening agent into the air jet mill through the modifier material inlet. Control the feeding speed to ensure that the weight ratio of the secondary modified powder, stearic acid and toughening agent is 100:1:1.

5. Then, pulverize and refine the powder with an airflow speed of 500~800m / s. Control the average particle size D50 of the output to 2~5μm through a classifier to obtain the final modified talc powder for reinforced plastics.

2. The method for preparing modified talc powder for reinforced plastics according to claim 1, characterized in that: In step 1, the talc powder is talc tailings with a particle size of 150-300 mesh, which contains 85-90 wt% talc, 8-14 wt% chlorite and 1-4 wt% dolomite.

3. The method for preparing modified talc powder for reinforced plastics according to claim 1, characterized in that: In step 1, the calcium oxide powder is impregnated porous calcium oxide with a particle size of 250-600 mesh, a pore size of 25-40 nm, and a pore volume of 0.45-0.60 cm³. 3 / g, specific surface area is 20-80 m² 2 / g, the impregnation process is as follows: after vacuum drying of several-pore calcium oxide powder at 60 ℃ for 10 h, it is impregnated in liquid carbon dioxide for 30 min, then taken out and allowed to naturally warm to 25 ℃.

4. The method for preparing modified talc powder for reinforced plastics according to claim 1, characterized in that: In step 1, the epoxy compound is any one or a mixture of any proportions of propylene oxide, glycidyl ester epoxy resin, and epichlorohydrin.

5. The method for preparing modified talc powder for reinforced plastics according to claim 1, characterized in that: In step 2, the electron beam irradiation conditions are an output energy of 2.5–6.5 MeV, a beam current of 10–40 mA, and an irradiation dose rate of 5–20 kGy / min.

6. The method for preparing modified talc powder for reinforced plastics according to claim 1, characterized in that: In step 3, the supported composite modifier includes porous sodium polyacrylate powder, supported 3-propionylthio-1-propyltriethoxysilane, and triethanolamine. The mass ratio of the porous sodium polyacrylate powder, supported 3-propionylthio-1-propyltriethoxysilane, and triethanolamine is 8 / 3 / 2. The porous sodium polyacrylate has a molecular weight of 10,000–12,000, a pore size of 2–5 nm, and a pore volume of 0.15–0.30 cm³. 3 / g.

7. The method for preparing modified talc powder for reinforced plastics according to claim 1, characterized in that: In step 4, the toughening agent is maleic anhydride-grafted polyolefin elastomer or glycidyl methacrylate-grafted polyolefin elastomer.

8. An application of modified talc for reinforcing plastics, characterized in that: The modified talc powder prepared by the preparation method according to any one of claims 1-7 can be dispersed in polymer resin to improve the tensile strength, heat distortion temperature and stiffness of the product, reduce shrinkage and improve flexural modulus.

9. The application of modified talc for reinforcing plastics according to claim 8, characterized in that: The modified talc powder is added to the plastic at a rate of 10-35 parts, and the blending processing temperature is 150-320 ℃. The plastic is polyethylene, polypropylene, polyvinyl chloride, acrylonitrile-butadiene-styrene terpolymer, polystyrene, polycarbonate, or polyurethane.

Images