Preparation method of powder reinforced plastic masterbatch for vehicle

Abstract

This invention provides a method for preparing a powder-reinforced automotive plastic masterbatch, belonging to the technical field of inorganic non-metallic powders and polymer materials. This method uses the inorganic powder and sugarcane pith fiber to modify automotive plastics such as polypropylene, acrylonitrile (A)-butadiene (B)-styrene (S) terpolymer (ABS), polystyrene, and polycarbonate. This effectively improves the tensile strength, heat distortion temperature, and stiffness of automotive plastics, while reducing shrinkage and other comprehensive mechanical strength. The formulation of this invention contains sugarcane pith, which, compared to conventional wood fibers, makes it easier to obtain short fibers (<0.2 mm). Furthermore, after a special high-pressure explosion treatment, its specific surface area, pore structure, and interfiber porosity are effectively increased, thereby effectively increasing its reaction sites with stearic acid and improving its hydrophobicity. Therefore, it can be used as a hydrophobic short fiber to enhance the mechanical properties of automotive plastics.

Description

Technical Field

[0001] This invention relates to the field of inorganic non-metallic powders and polymer materials technology, and in particular to a method for preparing a powder-reinforced automotive plastic masterbatch. Background Technology

[0002] The production 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 ore 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 ore 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. The core differences between heavy calcium carbonate (HCC) and light calcium carbonate (LCC) lie in their production methods, physical properties, and applications: HCC is produced by mechanically crushing natural minerals, resulting in large particles, high bulk density, and low oil absorption; LCC is produced through chemical precipitation, resulting in fine particles, low bulk density, and high oil absorption. The density range of LCC is 2.4 to 2.7 g / cm³, while that of HCC is between 2.7 and 2.9 g / cm³. In terms of particle size, HCC is typically larger and more widely distributed, with irregular particle shapes; LCC, on the other hand, exhibits a crystalline shape and relatively smaller particle size. These differences give the two types of calcium carbonate distinct characteristics for different applications, providing more options for plastic fillers.

[0004] The particle size distribution of heavy calcium carbonate is one of its most important quality indicators, directly affecting its performance in downstream applications such as plastics, coatings, papermaking, and adhesives. (d90-d10) / d50 is a dimensionless parameter calculated based on the core characteristic particle sizes (d10, d50, d90) to quantify the breadth of the particle size distribution. It is a valuable indicator in scientific research and quality control of high-end industrial products. The smaller the ratio (e.g., close to 0.5-1.0), the smaller the absolute span of (d90 - d10) relative to the central value d50, indicating a more concentrated and uniform particle size distribution. In many applications requiring uniform performance, a value as small as possible is desirable, indicating high batch stability.

[0005] Aerogels are nanoscale porous solid materials formed by the sol-gel method, where gas replaces the liquid phase in a gel through a specific drying process. Silica aerogels are the most common type. Aerogels possess gel properties such as expansion, thixotropy, and slurry separation, and exhibit characteristics such as low density, low thermal conductivity, high porosity, high temperature resistance, and non-flammability. Aerogels have a porosity as high as 80%-99.8%, a specific surface area of ​​up to 1000 m² / g, and extremely low thermal conductivity, providing 2-8 times the thermal insulation performance of traditional materials.

[0006] Erucamide propyl dimethyl tertiary amine is an organic compound commonly used as a surfactant, emulsifier, or lubricant. It is composed of the amide group of erucic acid and propyl dimethyl tertiary amine. Because it contains both amide and tertiary amine groups, it may exhibit some polarity and hydrophilicity, while also possessing some hydrophobicity.

[0007] Sugarcane pith is a fine, spongy granular substance obtained after sugarcane is extracted from bagasse, a major byproduct of sugarcane processing. It typically comprises about 30% of the total bagasse volume. Its composition includes cellulose (45-55%), pentosans / hemicellulose (20-25%), lignin (18-25%), and soluble sugars (2-6%). Due to its short fiber length and predominantly thin-walled cell structure, sugarcane pith can impair strength, increase costs, and reduce quality in papermaking, and therefore must be removed. It is a byproduct of bagasse pulping and papermaking.

[0008] High-pressure explosion treatment of plant fibers is a technology that utilizes the physical action of high-temperature, high-pressure steam (or fluid) to rapidly, efficiently, and environmentally friendly modify plant fibers. It destroys the fiber structure through the "explosion" effect generated by instantaneous pressure release, and is widely used in materials reinforcement, pulp and paper making, and biomass conversion. It is often combined with chemical pretreatment methods such as dilute alkali and dilute acid to achieve a synergistic effect, further enhancing the treatment effect. It disrupts the dense ultrastructure of lignocellulose, making it loose and porous, significantly increasing the specific surface area, which is highly beneficial for subsequent chemical reactions or enzymatic hydrolysis processes. Summary of the Invention

[0009] The purpose of this invention is to provide a method for preparing powder-reinforced automotive plastic masterbatch. This method uses inorganic powder and sugarcane pith fiber to modify automotive plastics such as polypropylene, acrylonitrile (A)-butadiene (B)-styrene (S) terpolymer (ABS), polystyrene, and polycarbonate. This effectively improves the tensile strength, heat distortion temperature, and stiffness of automotive plastics, while reducing shrinkage and other comprehensive mechanical strength. It addresses the practical problem of limited application due to insufficient performance of existing conventional automotive plastics.

[0010] Using this inorganic powder and sugarcane pith fiber to modify automotive plastics such as polypropylene, acrylonitrile (A)-butadiene (B)-styrene (S) terpolymer (ABS), polystyrene, and polycarbonate can effectively improve the tensile strength, heat distortion temperature, and stiffness of automotive plastics, and reduce shrinkage and other comprehensive mechanical strength.

[0011] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A method for preparing a powder-reinforced automotive plastic masterbatch, the method comprising the following steps: Step 1: Take talc powder, calcium carbonate powder, barium sulfate and aerogel, and add epoxy compound 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, calcium carbonate, barium sulfate, aerogel powder and epoxy compound is 100:32:15:4. Step 2: Add the modified powder and sugarcane pith to the air jet mill through the main material inlet. Add stearic acid and toughening agent to the air jet mill through the modifier material inlet. Control the feeding speed to ensure that the weight ratio of modified powder, sugarcane pith, stearic acid and toughening agent is 100:8:1:1.5. 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 composite powder for reinforcing automotive plastics. Step 3: Place the thermoplastic resin, modified composite powder, polyethylene wax, and antioxidant in a 150℃ high-speed mixer and stir for 15 minutes to obtain a paste-like viscous mixture; add the obtained paste-like mixture to a screw extruder for co-extrusion, control the screw extruder feeding speed, die head temperature, and traction speed, cool and cut with water strips, and dry to obtain automotive plastic masterbatch. The weight ratio of the thermoplastic resin, modified composite powder, polyethylene wax, and antioxidant is 100:(20~70):1:0.5.

[0012] Further, in step 1, the talc powder is talc tailings with a particle size of 150-300 mesh, containing 85-90 wt% talc, 8-14 wt% chlorite and 1-4 wt% dolomite; the calcium carbonate powder is a heavy calcium carbonate-light calcium carbonate composite, wherein the heavy calcium carbonate has a particle size of 600-800 mesh and a particle size distribution (d90-d10) / d50≤2.2; the light calcium carbonate is nano-calcium carbonate with a particle size range of 50-80 nm; and the barium sulfate has a particle size of 3000 mesh, a purity greater than 96%, and a whiteness greater than 90.

[0013] Furthermore, in step 1, the aerogel powder is silica aerogel with a density of 0.25 mg / cm3 and a porosity of 80%.

[0014] Furthermore, the silica aerogel needs to undergo further impregnation treatment. The impregnation treatment process involves vacuum drying the silica aerogel powder at 60 °C for 10 h, then immersing it in erucamide propyl dimethyl tertiary amine at -10 °C for 30 min, and finally removing it and allowing it to naturally warm to 30 °C.

[0015] Furthermore, in step 2, the length of the sugarcane pith fiber is controlled to be 80~200μm.

[0016] Furthermore, in step 2, the sugarcane pith is a fiber with a length of 350-600 μm and a width of 10-20 μm that has undergone high-pressure explosion treatment. The high-pressure explosion treatment process is as follows: 10 kg of sugarcane pith is soaked in 100 L of 5% sodium hydroxide for 24 hours, and then poured into an ultra-high pressure explosion test machine and pressurized to 20-80 MPa before being instantly exploded and released. After 5-10 cycles, it is washed clean with tap water, filtered, and dried to obtain the sugarcane pith treated with high-pressure explosion.

[0017] Furthermore, in step 3, the toughening agent is maleic anhydride-grafted polyolefin elastomer or glycidyl methacrylate-grafted polyolefin elastomer.

[0018] Furthermore, in step 3, the thermoplastic resin includes polypropylene, acrylonitrile-butadiene-styrene terpolymer, polystyrene, and polycarbonate.

[0019] 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. Firstly, it belongs to the waste residue 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 deformation characteristics to plastic composite materials than talc powder alone, when used as plastic fillers.

[0020] 2. Erucamide propyl dimethyl tertiary amine can be used as a surface modifier and lubricant for inorganic powders. However, since it is a liquid and used in small quantities, it is not easy to mix it evenly with a large amount of inorganic powder. This invention utilizes the excellent adsorption properties of silica aerogel to adsorb the liquid erucamide propyl dimethyl tertiary amine, making the liquid modifier solid for reuse. This can increase the transfer and contact between the modifier and the inorganic powder, thereby increasing the degree of reaction.

[0021] 3. The formulation of this invention includes a certain amount of toughening agent, which can effectively mitigate the phenomenon that while the layered talc and barium sulfate fillers increase the rigidity of the composite material, they can also lead to a decrease in elongation at break and impact strength to some extent. Based on the synergistic effect of the toughening agent, modified talc, and modified barium sulfate—three materials with different structures—a plastic product with excellent comprehensive performance can be obtained, showing great applicability in the fields of automotive plastics and engineering plastics.

[0022] 4. The formulation of this invention contains sugarcane pith, which, compared to conventional wood fibers, makes it easier to obtain short fibers (<0.2 mm). Furthermore, after a special high-pressure bursting treatment, its specific surface area, pore structure, and interfiber porosity are effectively increased, thereby effectively increasing its reaction sites with stearic acid and improving its hydrophobicity. Therefore, it can be used as a hydrophobic short fiber to improve the mechanical properties of automotive plastics. Attached Figure Description

[0023] Figure 1 These are tensile strength curves of some embodiments-comparative examples of the present invention; Figure 2 These are microscopic morphology images of the powders from Example 1 (left), Comparative Example 5 (middle), and Comparative Example 6 (right) of the present invention; Figure 3 This is a contact angle diagram of a relevant embodiment of the present invention; Figure 4 This is a glass transition temperature diagram of Embodiment 1 (left) and Comparative Example 3 of the present invention; Figure 5 These are microscopic morphology images of the plastic masterbatch from Example 1 (left) and Comparative Example 3 (right) of the present invention. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and preferred embodiments. 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 present invention, and these aspects of the invention can be implemented even without these specific details.

[0025] Example 1: A method for preparing a powder-reinforced automotive plastic masterbatch includes the following steps: (1) Take 4 kg of material with a density of 0.25 mg / cm³ 3 A silica aerogel with a porosity of 80% was vacuum dried at 60 °C for 10 h, then immersed in erucamide propyl dimethyl tertiary amine at -10 °C for 30 min, and then removed and allowed to naturally warm to 30 °C.

[0026] (2) Take 100 kg of talc tailings with a particle size of 200 mesh, containing 90 wt% talc, 9 wt% chlorite and 1 wt% dolomite, 20 kg of heavy calcium carbonate with a particle size distribution of 600 mesh (d90-d10) / d50=2.1, 12 kg of nano calcium carbonate with an average particle size of 80 nm, 15 kg of barium sulfate with a particle size of 3000 mesh, a purity of 98.2% and a whiteness of 95, and 4 kg of impregnated silica aerogel powder and place them in a reactor. Under the conditions of 25℃ and a stirring speed of 800 r / min, stir and mix for 5 min to obtain a fully dispersed primary modified powder. (3) 10 kg of sugarcane pith with a length of 500 μm and a width of 12 μm was placed in 100 L of 5% sodium hydroxide and soaked for 24 hours. Then it was poured into an ultra-high pressure bursting test machine and pressurized to 50 MPa and burst instantly. After 8 cycles, it was washed with tap water, filtered, and dried to obtain the sugarcane pith treated by high pressure bursting.

[0027] (4) Weigh 100 kg of primary modified powder and 8 kg of pretreated sugarcane pith and add them to 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 to the air jet mill from the modifier material inlet. Control the feeding speed with a flow meter and grind 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 and the sugarcane pith fiber length to 120 μm with a classifier to obtain the final modified composite powder for reinforced plastics.

[0028] (5) Raise the temperature of the high-speed mixer to 155°C, and under the stirring condition of 500 r / min, add 100 kg ABS, 40 kg modified composite powder, 1 kg polyethylene wax, and 0.5 kg pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (antioxidant 1010) 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 190°C, and then obtain automotive plastic masterbatch after traction, water strip cooling and cutting, and drying treatment.

[0029] Example 2: A method for preparing a powder-reinforced automotive plastic masterbatch includes the following steps: (1) Take 4 kg of material with a density of 0.25 mg / cm³ 3 A silica aerogel with a porosity of 80% was vacuum dried at 60 °C for 10 h, then immersed in erucamide propyl dimethyl tertiary amine at -10 °C for 30 min, and then removed and allowed to naturally warm to 30 °C.

[0030] (2) Take 100 kg of talc tailings with a particle size of 300 mesh, containing 87 wt% talc, 9 wt% chlorite and 4 wt% dolomite, 10 kg of heavy calcium carbonate with a particle size distribution of 800 mesh (d90-d10) / d50=1.8, 22 kg of nano calcium carbonate with an average particle size of 70 nm, 15 kg of barium sulfate with a particle size of 3000 mesh, a purity of 99.0% and a whiteness of 97, and 4 kg of impregnated silica aerogel powder and place them in a reactor. Under the conditions of 25℃ and a stirring speed of 600 r / min, stir and mix for 5 min to obtain a fully dispersed primary modified powder. (3) Place 10 kg of sugarcane pith with a length of 450 μm and a width of 10 μm in 100 L of 5% sodium hydroxide and soak for 24 hours. Then pour it into an ultra-high pressure bursting test machine and pressurize it to 70 MPa. After bursting and releasing it instantly, after 10 cycles, wash it with tap water, filter it, and dry it to obtain the sugarcane pith treated by high pressure bursting.

[0031] (4) Weigh 100 kg of primary modified powder and 8 kg of pretreated sugarcane pith and add them to 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 to the air jet mill from the modifier material inlet. Control the feeding speed with a flow meter and grind and refine the powder with an airflow speed of 300 m / s. Control the average particle size D50 of the output to be 2.0 μm and the sugarcane pith fiber length to be 100 μm to obtain the final modified composite powder for reinforced plastics.

[0032] (5) Raise the temperature of the high-speed mixer to 155°C, and under the stirring condition of 500 r / min, add 100 kg ABS, 35 kg modified composite powder, 1 kg polyethylene wax, and 0.5 kg pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (antioxidant 1010) 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 190°C, and then obtain automotive plastic masterbatch after traction, water strip cooling and cutting, and drying treatment.

[0033] Example 3: A method for preparing a powder-reinforced automotive plastic masterbatch includes the following steps: (1) Take 4 kg of material with a density of 0.25 mg / cm³ 3 A silica aerogel with a porosity of 80% was vacuum dried at 60 °C for 10 h, then immersed in erucamide propyl dimethyl tertiary amine at -10 °C for 30 min, and then removed and allowed to naturally warm to 30 °C.

[0034] (2) Take 100 kg of talc tailings with a particle size of 100 mesh, containing 88 wt% talc, 9 wt% chlorite and 4 wt% dolomite, 30 kg of heavy calcium carbonate with a particle size distribution of 600 mesh (d90-d10) / d50=2.0, 2 kg of nano calcium carbonate with an average particle size of 80 nm, 15 kg of barium sulfate with a particle size of 3000 mesh, a purity of 97% and a whiteness of 93, and 4 kg of impregnated silica aerogel powder and place them in a reactor. Under the conditions of 25℃ and a stirring speed of 500 r / min, stir and mix for 5 min to obtain a fully dispersed primary modified powder. (4) Place 10 kg of sugarcane pith with a length of 600 μm and a width of 20 μm in 100 L of 5% sodium hydroxide and soak for 24 hours. Then pour it into an ultra-high pressure bursting test machine and pressurize it to 20 MPa. After bursting and releasing it instantly, repeat the cycle 8 times. Then wash it with tap water, filter it, and dry it to obtain the sugarcane pith treated by high pressure bursting.

[0035] (4) Weigh 100 kg of primary modified powder and 8 kg of pretreated sugarcane pith and add them to the air jet mill through 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 to the air jet mill through 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 be 5.0 μm and the sugarcane pith fiber length to be 150 μm through a classifier to obtain the final modified composite powder for reinforced plastics.

[0036] (5) Raise the temperature of the high-speed mixer to 155°C, and under the stirring condition of 500 r / min, add 100 kg ABS, 30 kg modified composite powder, 1 kg polyethylene wax, and 0.5 kg pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (antioxidant 1010) 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 220°C, and then obtain automotive plastic masterbatch after traction, water strip cooling and cutting, and drying treatment.

[0037] Example 4: A method for preparing a powder-reinforced automotive plastic masterbatch includes the following steps: (1) Take 4 kg of material with a density of 0.25 mg / cm³ 3A silica aerogel with a porosity of 80% was vacuum dried at 60 °C for 10 h, then immersed in erucamide propyl dimethyl tertiary amine at -10 °C for 30 min, and then removed and allowed to naturally warm to 30 °C.

[0038] (2) Take 100 kg of talc tailings with a particle size of 200 mesh, containing 90 wt% talc, 9 wt% chlorite and 1 wt% dolomite, 12 kg of heavy calcium carbonate with a particle size distribution of (d90-d10) / d50=1.6 of 800 mesh, 20 kg of nano calcium carbonate with an average particle size of 60 nm, 15 kg of barium sulfate with a particle size of 3000 mesh, a purity of 99% and a whiteness of 96, and 4 kg of impregnated silica aerogel powder and place them in a reactor. Under the conditions of 25℃ and a stirring speed of 800 r / min, stir and mix for 5 min to obtain a fully dispersed mixed powder. (3) 10 kg of sugarcane pith with a length of 350 μm and a width of 10 μm was placed in 100 L of 5% sodium hydroxide and soaked for 24 hours. Then it was poured into an ultra-high pressure bursting test machine and pressurized to 70 MPa and burst instantly. After 8 cycles, it was washed with tap water, filtered, and dried to obtain the sugarcane pith treated by high pressure bursting.

[0039] (4) Weigh 100 kg of secondary modified powder and 8 kg of pretreated sugarcane pith and add them to 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 to the air jet mill from the modifier material inlet. Control the feeding speed with a flow meter and grind and refine the powder with an airflow speed of 500 m / s. Control the average particle size D50 of the output to be 2.1 μm and the sugarcane pith fiber length to be 110 μm to obtain the final modified composite powder for reinforced plastics.

[0040] (5) Raise the temperature of the high-speed mixer to 155°C, and under the stirring condition of 500 r / min, add 100 kg ABS, 20 kg modified composite powder, 1 kg polyethylene wax, and 0.5 kg pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (antioxidant 1010) 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 240°C, and then obtain automotive plastic masterbatch after traction, water strip cooling and cutting, and drying treatment.

[0041] Comparative Example 1: (The difference from Example 1 is that talc powder is used instead of talc tailings) (1) Take 4 kg of material with a density of 0.25 mg / cm³ 3A silica aerogel with a porosity of 80% was vacuum dried at 60 °C for 10 h, then immersed in erucamide propyl dimethyl tertiary amine at -10 °C for 30 min, and then removed and allowed to naturally warm to 30 °C.

[0042] (2) Take 100 kg of high-purity talc powder with a particle size of 200 mesh (purity greater than 98%), 20 kg of heavy calcium carbonate with a particle size distribution of 600 mesh (d90-d10) / d50=2.1, 12 kg of nano calcium carbonate with an average particle size of 80 nm, 15 kg of barium sulfate with a particle size of 3000 mesh, a purity of 98.2% and a whiteness of 95, and 4 kg of impregnated silica aerogel powder and place them in a reactor. Under the conditions of 25℃ and a stirring speed of 800 r / min, stir and mix for 5 min to obtain a fully dispersed primary modified powder. (3) 10 kg of sugarcane pith with a length of 500 μm and a width of 12 μm was placed in 100 L of 5% sodium hydroxide and soaked for 24 hours. Then it was poured into an ultra-high pressure bursting test machine and pressurized to 50 MPa and burst instantly. After 8 cycles, it was washed with tap water, filtered, and dried to obtain the sugarcane pith treated by high pressure bursting.

[0043] (4) Weigh 100 kg of primary modified powder and 8 kg of pretreated sugarcane pith and add them to 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 to the air jet mill from the modifier material inlet. Control the feeding speed with a flow meter and grind 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 and the sugarcane pith fiber length to 120 μm with a classifier to obtain the final modified composite powder for reinforced plastics.

[0044] (5) Raise the temperature of the high-speed mixer to 155°C, and under the stirring condition of 500 r / min, add 100 kg ABS, 40 kg modified composite powder, 1 kg polyethylene wax, and 0.5 kg pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (antioxidant 1010) 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 190°C, and then obtain automotive plastic masterbatch after traction, water strip cooling and cutting, and drying treatment.

[0045] Comparative Example 2: (The difference from Example 1 is the absence of compound calcium carbonate and barium sulfate ore) (1) Take 4 kg of material with a density of 0.25 mg / cm³ 3A silica aerogel with a porosity of 80% was vacuum dried at 60 °C for 10 h, then immersed in erucamide propyl dimethyl tertiary amine at -10 °C for 30 min, and then removed and allowed to naturally warm to 30 °C.

[0046] (2) Take 100 kg of talc tailings with a particle size of 200 mesh, containing 90 wt% talc, 9 wt% chlorite and 1 wt% dolomite, and 4 kg of impregnated silica aerogel powder and place them in a reactor. Under the conditions of 25℃ and a stirring speed of 800 r / min, stir and mix for 5 min to obtain fully dispersed primary modified powder. (3) 10 kg of sugarcane pith with a length of 500 μm and a width of 12 μm was placed in 100 L of 5% sodium hydroxide and soaked for 24 hours. Then it was poured into an ultra-high pressure bursting test machine and pressurized to 50 MPa and burst instantly. After 8 cycles, it was washed with tap water, filtered, and dried to obtain the sugarcane pith treated by high pressure bursting.

[0047] (4) Weigh 100 kg of primary modified powder and 8 kg of pretreated sugarcane pith and add them to 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 to the air jet mill from the modifier material inlet. Control the feeding speed with a flow meter and grind 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 and the sugarcane pith fiber length to 120 μm with a classifier to obtain the final modified composite powder for reinforced plastics.

[0048] (5) Raise the temperature of the high-speed mixer to 155°C, and under the stirring condition of 500 r / min, add 100 kg ABS, 40 kg modified composite powder, 1 kg polyethylene wax, and 0.5 kg pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (antioxidant 1010) 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 190°C, and then obtain automotive plastic masterbatch after traction, water strip cooling and cutting, and drying treatment.

[0049] Comparative Example 3: (The difference from Example 1 is that the impregnation treatment of aerogel was omitted) (1) Take 100 kg of talc tailings with a particle size of 200 mesh, containing 90 wt% talc, 9 wt% chlorite and 1 wt% dolomite, 20 kg of heavy calcium carbonate with a particle size distribution of 600 mesh (d90-d10) / d50=2.1, 12 kg of nano calcium carbonate with an average particle size of 80 nm, and 15 kg of barium sulfate with a particle size of 3000 mesh, a purity of 98.2% and a whiteness of 95. Place them in a reactor and mix them for 5 min at 25℃ and a stirring speed of 800 r / min to obtain a fully dispersed primary modified powder. (2) 10 kg of sugarcane pith with a length of 500 μm and a width of 12 μm was placed in 100 L of 5% sodium hydroxide and soaked for 24 hours. Then it was poured into an ultra-high pressure bursting test machine and pressurized to 50 MPa and burst instantly. After 8 cycles, it was cleaned with tap water, filtered, and dried to obtain the sugarcane pith treated by high pressure bursting.

[0050] (3) Weigh 100 kg of primary modified powder and 8 kg of pretreated sugarcane pith and add them to 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 to the air jet mill from the modifier material inlet. Control the feeding speed with a flow meter and grind 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 and the sugarcane pith fiber length to 120 μm to obtain the final modified composite powder for reinforced plastics.

[0051] (4) Raise the temperature of the high-speed mixer to 155°C, and under the stirring condition of 500 r / min, add 100 kg ABS, 40 kg modified composite powder, 1 kg polyethylene wax, and 0.5 kg pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (antioxidant 1010) 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 190°C, and then obtain automotive plastic masterbatch after traction, water strip cooling and cutting, and drying treatment.

[0052] Comparative Example 4: (The difference compared to Example 1 is that erucamide propyl dimethyl tertiary amine was used directly instead of impregnated aerogel) (1) Take 100 kg of talc tailings with a particle size of 200 mesh, containing 90 wt% talc, 9 wt% chlorite and 1 wt% dolomite, 20 kg of heavy calcium carbonate with a particle size distribution of 600 mesh (d90-d10) / d50=2.1, 12 kg of nano calcium carbonate with an average particle size of 80 nm, 15 kg of barium sulfate with a particle size of 3000 mesh, a purity of 98.2% and a whiteness of 95, and 4 kg of erucamide dimethyl tertiary amine and place them in a reactor. Under the conditions of 25℃ and a stirring speed of 800 r / min, stir and mix for 5 min to obtain a fully dispersed primary modified powder. (2) 10 kg of sugarcane pith with a length of 500 μm and a width of 12 μm was placed in 100 L of 5% sodium hydroxide and soaked for 24 hours. Then it was poured into an ultra-high pressure bursting test machine and pressurized to 50 MPa and burst instantly. After 8 cycles, it was cleaned with tap water, filtered, and dried to obtain the sugarcane pith treated by high pressure bursting.

[0053] (3) Weigh 100 kg of primary modified powder and 8 kg of pretreated sugarcane pith and add them to 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 to the air jet mill from the modifier material inlet. Control the feeding speed with a flow meter and grind 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 and the sugarcane pith fiber length to 120 μm to obtain the final modified composite powder for reinforced plastics.

[0054] (4) Raise the temperature of the high-speed mixer to 155°C, and under the stirring condition of 500 r / min, add 100 kg ABS, 40 kg modified composite powder, 1 kg polyethylene wax, and 0.5 kg pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (antioxidant 1010) 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 190°C, and then obtain automotive plastic masterbatch after traction, water strip cooling and cutting, and drying treatment.

[0055] Comparative Example 5: (The difference compared to Example 1 is the absence of sugarcane pith) (1) Take 4 kg of material with a density of 0.25 mg / cm³ 3 A silica aerogel with a porosity of 80% was vacuum dried at 60 °C for 10 h, then immersed in erucamide propyl dimethyl tertiary amine at -10 °C for 30 min, and then removed and allowed to naturally warm to 30 °C.

[0056] (2) Take 100 kg of talc tailings with a particle size of 200 mesh, containing 90 wt% talc, 9 wt% chlorite and 1 wt% dolomite, and 4 kg of impregnated silica aerogel powder and place them in a reactor. Under the conditions of 25℃ and a stirring speed of 800 r / min, stir and mix for 5 min to obtain fully dispersed primary modified powder. (3) Weigh 100 kg of primary 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 composite powder for reinforced plastics.

[0057] (4) Raise the temperature of the high-speed mixer to 155°C, and under the stirring condition of 500 r / min, add 100 kg ABS, 40 kg modified composite powder, 1 kg polyethylene wax, and 0.5 kg pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (antioxidant 1010) 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 190°C, and then obtain automotive plastic masterbatch after traction, water strip cooling and cutting, and drying treatment.

[0058] Comparative Example 6: (The difference compared to Example 1 is the absence of the pith pretreatment step) (1) Take 4 kg of material with a density of 0.25 mg / cm³ 3 A silica aerogel with a porosity of 80% was vacuum dried at 60 °C for 10 h, then immersed in erucamide propyl dimethyl tertiary amine at -10 °C for 30 min, and then removed and allowed to naturally warm to 30 °C.

[0059] (2) Take 100 kg of talc tailings with a particle size of 200 mesh, containing 90 wt% talc, 9 wt% chlorite and 1 wt% dolomite, and 4 kg of impregnated silica aerogel powder and place them in a reactor. Under the conditions of 25℃ and a stirring speed of 800 r / min, stir and mix for 5 min to obtain fully dispersed primary modified powder. (3) Weigh 100 kg of primary modified powder and 8 kg of sugarcane pith and add them to 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 to 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 composite powder for reinforced plastics.

[0060] (4) Raise the temperature of the high-speed mixer to 155°C, and under the stirring condition of 500 r / min, add 100 kg ABS, 40 kg modified composite powder, 1 kg polyethylene wax, and 0.5 kg pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (antioxidant 1010) 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 190°C, and then obtain automotive plastic masterbatch after traction, water strip cooling and cutting, and drying treatment.

[0061] Test method: Modified talc powder for reinforced plastics was prepared according to the methods described in Examples 1-4 and Comparative Examples 1-6, 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.

[0062] 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 ASTM-D785.

[0063] Table 1 Test results of active talc powder prepared by different methods From Table 1 above and Figures 1-4 The data shows that adding modified talc as an additive to automotive plastics can improve the mechanical properties of automotive 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.

[0064] As can be seen from Examples 1 to 4, within the scope of the claims of this invention, the modified powders prepared all have good hydrophobicity, and their contact angles are all greater than 101°. The plastic masterbatches and injection-molded plastic products prepared by filling with the modified powder have excellent mechanical properties, with tensile strength greater than 50 MPa, notched impact strength greater than 31.9 kJ / m², flexural strength greater than 95 MPa, and glass transition temperature greater than 102°C. This indicates that the modified powder prepared by this invention can meet the experimental requirements of automotive plastics under conventional filler ratios.

[0065] Comparing Example 1 with Comparative Example 1, it can be found that replacing the talc tailings in Example 1 with high-purity talc powder resulted in a certain decrease in mechanical properties compared to Example 1. Since the talc tailings consist of 85-90 wt% talc, 8-14 wt% chlorite, and 1-4 wt% dolomite, this indicates a synergistic effect among these three components, providing a better filling effect than talc powder alone. Furthermore, talc tailings are waste materials with relatively low prices, thus serving as a means of waste utilization and cost reduction.

[0066] Comparing Example 1 with Comparative Example 2, it can be found that in the preparation of the modified powder, the absence of composite calcium carbonate and barium sulfate resulted in a final modified composite powder. Although the hydrophobicity (contact angle) of the primary modified powder did not change significantly, the mechanical properties of the filled injection-molded plastic products prepared from it decreased compared to Example 1. This indicates that talc-calcium carbonate-barium sulfate has a significant synergistic effect, improving the overall performance of the plastic products.

[0067] Comparing Example 1 with Comparative Example 4, it can be found that the contact angle of the modified powder decreased by 92.9° or 91.3° due to the absence of impregnation-treated aerogel. This indicates that the impregnation-treated aerogel can, to a certain extent, increase the transfer and contact between erucamide propyl dimethyl tertiary amine and inorganic powder, thereby increasing the degree of hydrophobicity reaction.

[0068] Comparing Example 1 with Comparative Examples 5-6, it can be observed that the overall strength of the plastic products prepared by omitting the sugarcane pith component or using untreated sugarcane pith is significantly reduced. This indicates that the sugarcane pith modified according to this method, after undergoing a special high-pressure explosion treatment, can effectively increase its specific surface area, pore structure, and interfiber porosity, thereby effectively increasing its reaction sites with stearic acid and improving its hydrophobicity. Consequently, it can be used as a hydrophobic short fiber to improve the mechanical properties of automotive plastics.

[0069] Matters not covered in this invention are common knowledge.

[0070] 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 a powder-reinforced automotive plastic masterbatch, characterized in that: The method includes the following steps: Step 1: Take talc powder, calcium carbonate powder, barium sulfate and aerogel powder and mix them at 20-40℃ and a stirring speed of 500-800 r / min for 5 min to obtain a fully dispersed mixed powder. The weight ratio of talc, calcium carbonate, barium sulfate and aerogel powder is 100:32:15:

4. Step 2: Add the modified powder and sugarcane pith to the air jet mill through the main material inlet. Add stearic acid and toughening agent to the air jet mill through the modifier material inlet. Control the feeding speed to ensure that the weight ratio of modified powder, sugarcane pith, stearic acid and toughening agent is 100:8:1:1.

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 composite powder for reinforcing automotive plastics. Step 3: Place the thermoplastic resin, modified composite powder, polyethylene wax, and antioxidant in a 150℃ high-speed mixer and stir for 15 minutes to obtain a paste-like viscous mixture; add the obtained paste-like mixture to a screw extruder for co-extrusion, control the screw extruder feeding speed, die head temperature, and traction speed, cool and cut with water strips, and dry to obtain automotive plastic masterbatch. The weight ratio of the thermoplastic resin, modified composite powder, polyethylene wax, and antioxidant is 100:(20~70):1:0.

5.

2. The method for preparing a powder-reinforced automotive plastic masterbatch according to claim 1, characterized in that: In step 1, the talc powder is talc tailings with a particle size of 150-300 mesh, containing 85-90 wt% talc, 8-14 wt% chlorite, and 1-4 wt% dolomite. The calcium carbonate powder is a heavy calcium carbonate-light calcium carbonate composite, wherein the heavy calcium carbonate particles are 600-800 mesh, and the particle size distribution is (…). d 90- d 10) / d 50≤2.2; Light calcium carbonate is nano calcium carbonate with a particle size range of 50~80 nm, barium sulfate has a particle size of 3000 mesh, purity greater than 96%, and whiteness greater than 90.

3. The method for preparing a powder-reinforced automotive plastic masterbatch according to claim 1, characterized in that: In step 1, the aerogel powder is silica aerogel with a density of 0.25 mg / cm³. 3 The porosity is 80%.

4. The method for preparing a powder-reinforced automotive plastic masterbatch according to claim 3, characterized in that: Silica aerogel needs to undergo further impregnation treatment. The impregnation treatment process involves vacuum drying the silica aerogel powder at 60 °C for 10 h, then immersing it in erucamide propyl dimethyl tertiary amine at -10 °C for 30 min, and finally removing it and allowing it to naturally warm to 30 °C.

5. The method for preparing a powder-reinforced automotive plastic masterbatch according to claim 1, characterized in that: In step 2, the length of the sugarcane pith fiber is controlled at 80~200μm.

6. The method for preparing a powder-reinforced automotive plastic masterbatch according to claim 1, characterized in that: In step 2, the sugarcane pith is a fiber with a length of 350-600 μm and a width of 10-20 μm that has undergone high-pressure explosion treatment. The high-pressure explosion treatment process is as follows: 10 kg of sugarcane pith is soaked in 100 L of 5% sodium hydroxide for 24 hours, and then poured into an ultra-high pressure explosion test machine and pressurized to 20-80 MPa for instantaneous explosion release. After 5-10 cycles, it is washed with tap water, filtered, and dried to obtain the high-pressure explosion-treated sugarcane pith.

7. The method for preparing a powder-reinforced automotive plastic masterbatch according to claim 1, characterized in that: In step 3, the toughening agent is maleic anhydride-grafted polyolefin elastomer or glycidyl methacrylate-grafted polyolefin elastomer.

8. The method for preparing a powder-reinforced automotive plastic masterbatch according to claim 1, characterized in that: In step 3, the thermoplastic resin includes polypropylene, acrylonitrile-butadiene-styrene terpolymer, polystyrene, and polycarbonate.

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