A high-impact weather-resistant toughened polypropylene composite material and a preparation method thereof

Abstract

The application relates to the technical field of composite materials, and discloses a high-impact weather-resistant toughened polypropylene composite material and a preparation method thereof. The material is prepared from the following raw materials: 40-60 parts of a copolymerized polypropylene matrix, 10-20 parts of acrylonitrile-styrene-acrylate copolymer grafted glycidyl methacrylate, 5-15 parts of hyperbranched polyester modified nano titanium dioxide, 3-10 parts of surface hydroxylated carbon fiber, 2-8 parts of a hindered amine light stabilizer compound, 1-5 parts of a thioester antioxidant, 0.5-2 parts of calcium stearate and 5-15 parts of ethylene-octene block copolymer. The hyperbranched polyester modified nano titanium dioxide is introduced to form strong interfacial interaction with the polypropylene matrix and the surface hydroxylated carbon fiber by using the rich functional groups on the surface of the hyperbranched polyester modified nano titanium dioxide, and to disperse external impact stress, so that the impact strength of the material is improved, the weather resistance of the material is enhanced, and the service life is prolonged.

Description

Technical Field

[0001] This invention relates to the field of composite material technology, specifically to a high-impact, weather-resistant, and toughened polypropylene composite material and its preparation method. Background Technology

[0002] Polypropylene is a semi-crystalline thermoplastic polymer made from propylene monomers through an addition polymerization reaction. It is usually a white, waxy solid, non-toxic, odorless, transparent in appearance, and lightweight in texture. Polypropylene is lightweight, wear-resistant, antibacterial, and easy to dye, and is widely used in clothing, blankets, and other fiber products. It also has good insulation properties and is used to manufacture the casings and parts of refrigerators, washing machines, air conditioners, and televisions.

[0003] Currently, due to the limitations of the molecular structure of polypropylene materials, they are susceptible to photo-oxidative aging during long-term outdoor use, leading to phenomena such as yellowing and embrittlement. Conventional weather-resistant modification methods cannot simultaneously ensure long-term light stability and mechanical retention, thus failing to meet high-standard weather resistance requirements. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a high-impact, weather-resistant, and toughened polypropylene composite material and its preparation method, which solves the problems mentioned in the background technology, such as yellowing and embrittlement of materials, and the difficulty of conventional weather-resistant modification methods in simultaneously ensuring long-term light stability and mechanical retention, thus failing to meet high-standard weather resistance requirements.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a high-impact, weather-resistant, and toughened polypropylene composite material, which is made from the following raw materials in parts by weight: 40-60 parts of copolymer polypropylene matrix, 10-20 parts of acrylonitrile-styrene-acrylate copolymer grafted with glycidyl methacrylate, 5-15 parts of hyperbranched polyester modified nano titanium dioxide, 3-10 parts of surface hydroxylated carbon fiber, 2-8 parts of hindered amine light stabilizer compound, 1-5 parts of thioester antioxidant, 0.5-2 parts of calcium stearate, and 5-15 parts of ethylene-octene block copolymer; The preparation method of the hyperbranched polyester modified nano-titanium dioxide includes: dispersing nano-titanium dioxide in toluene, adding γ-methacryloxypropyltrimethoxysilane, refluxing at 75-85℃ for 4-6 hours under nitrogen protection, filtering, washing and drying to obtain silane coupling agent modified nano-titanium dioxide, then adding silane coupling agent modified nano-titanium dioxide and hyperbranched polyester to xylene, ultrasonically dispersing at 80-90℃ for 30-50 minutes, then heating to 120-130℃ and refluxing for 3-5 hours, cooling and centrifuging, and vacuum drying to constant weight to obtain hyperbranched polyester modified nano-titanium dioxide; The hindered amine light stabilizer compound is composed of bis(1-octoxy-2,2,6,6-tetramethyl-4-piperidinyl) sebacate and poly{[6-[(1,1,3,3-tetramethylbutyl)amino]-1,3,5-triazine-2,4-diyl][2-(2,2,6,6-tetramethylpiperidinyl)amino]hexylene[2,2,6,6-tetramethyl-4-piperidinyl]imino} in a mass ratio of 1:(0.5-2).

[0006] Preferably, the melt flow rate of the copolymer polypropylene matrix is ​​0.5-5 g / 10 min, the grafting rate of glycidyl methacrylate in the acrylonitrile-styrene-acrylate copolymer is 1.5%-3.5%, the rubber phase content of the acrylonitrile-styrene-acrylate copolymer is 40%-60%, and the glass transition temperature is -40℃ to -30℃.

[0007] Preferably, the method for preparing the surface-hydroxylated carbon fiber includes: Carbon fibers are placed in a mixed solution of concentrated nitric acid and concentrated sulfuric acid, with a volume ratio of 1:(2-4). The solution is stirred in a water bath at 60-80℃ for 2-4 hours, then washed with deionized water until neutral, and dried in a vacuum drying oven at 80-100℃ for 12-24 hours to obtain surface-hydroxylated carbon fibers.

[0008] Preferably, the thioester antioxidant is composed of pentaerythritol tetra(3-lauryl thiopropionate) and dioctadecyl thiodipropionate in a mass ratio of 1:(1-3), and the density of the ethylene-octene block copolymer is 0.85-0.89 g / cm³. 3 The melt flow index is 0.5-3 g / 10 min.

[0009] Preferably, the material further includes 1-5 parts by weight of modified montmorillonite, wherein the method for preparing the modified montmorillonite includes: Sodium montmorillonite was dispersed in deionized water to prepare a suspension with a mass fraction of 1%-3%. Hexadecyltrimethylammonium bromide was added, with a mass ratio of hexadecyltrimethylammonium bromide to sodium montmorillonite of 1:(5-10). The mixture was stirred at 70-90℃ for 4-6 hours. After filtration, the mixture was washed with deionized water until no white precipitate was produced when tested with 0.1mol / L AgNO3 solution. After vacuum drying at 60-80℃, the mixture was ground through a 200-mesh sieve to obtain modified montmorillonite.

[0010] A method for preparing a high-impact, weather-resistant, and toughened polypropylene composite material includes the following steps: Step 1: Weigh out the following components according to the stated weight proportions: copolymer polypropylene matrix, acrylonitrile-styrene-acrylate copolymer grafted with glycidyl methacrylate, hyperbranched polyester modified nano titanium dioxide, surface hydroxylated carbon fiber, hindered amine light stabilizer compound, thioester antioxidant, calcium stearate, ethylene-octene block copolymer and modified montmorillonite. Step 2: Add the copolymer polypropylene matrix, acrylonitrile-styrene-acrylate copolymer grafted with glycidyl methacrylate, ethylene-octene block copolymer, hindered amine light stabilizer compound, thioester antioxidant and calcium stearate into a high-speed mixer and mix at 800-1200 r / min for 3-8 minutes to obtain the premix. Step 3: Add hyperbranched polyester modified nano-titanium dioxide, surface hydroxylated carbon fiber and modified montmorillonite into a mixer and mix at 180-200℃ and 30-50rpm for 5-10 minutes to obtain inorganic filler premix. Step 4: Add the premix and inorganic filler premix together to a twin-screw extruder for melt blending and extrusion. Set the temperature of each section of the extruder to 160-190℃, the main machine speed to 300-500rpm, and the feeding speed to 10-30r / min. After water cooling, the melt is stretched and pelletized to obtain a high-impact, weather-resistant, and toughened polypropylene composite material.

[0011] Preferably, in step three, the rotor of the internal mixer is of the meshing type, and the filling coefficient is 0.6-0.8; In step four, the length-to-diameter ratio of the twin-screw extruder is (36-48):1, the screw assembly contains 2-3 sets of kneading blocks, the stagger angle of the kneading blocks is 45°-90°, and the specific temperature settings for each section are as follows: Zone 1: 160-165℃, Zone 2: 170-175℃, Zone 3: 180-185℃, Zone 4: 185-190℃, Zone 5: 180-185℃, Head unit: 175-180℃.

[0012] Preferably, in step two, the mixing temperature of the high-speed mixer is 40-60℃; In step four, after the melt passes through the extruder head, it first undergoes a first stage of cooling through a water tank with a water temperature of 60-80℃, and then undergoes a second stage of cooling through a water tank with a water temperature of 20-30℃. The total cooling time for the two stages is 10-20 seconds. Afterward, the surface moisture is dried by an air knife and then pelletized. The particle size of the pelletized particles is 2-4mm.

[0013] Preferably, the process further includes a pretreatment step for surface-hydroxylated carbon fibers: Surface-hydroxylated carbon fibers are mixed with silane coupling agent KH-570 at a mass ratio of 100:(0.5~2), placed in an acetone solution, and ultrasonically dispersed at 50-70℃ for 20-40 minutes. Then, the acetone is removed by vacuum distillation, and the carbon fibers are vacuum dried at 80-100℃ to constant weight to obtain pretreated surface-hydroxylated carbon fibers. These pretreated surface-hydroxylated carbon fibers are used in step three.

[0014] Preferably, in step four, the twin-screw extruder is equipped with a vacuum exhaust device with a vacuum degree of -0.09MPa to -0.06MPa, and the exhaust port is located between the fourth and fifth zones of the extruder.

[0015] Compared with the prior art, the present invention provides a high-impact, weather-resistant, and toughened polypropylene composite material and its preparation method, which has the following beneficial effects: 1. In this invention, by introducing hyperbranched polyester-modified nano-titanium dioxide, the abundant functional groups on its surface form a strong interfacial interaction with the polypropylene matrix and surface hydroxylated carbon fibers, dispersing external impact stress, thereby improving the material's impact resistance, enhancing its weather resistance, and extending its service life.

[0016] 2. In this invention, by adding a hindered amine light stabilizer compound, free radicals generated during the oxidation of polypropylene are synergistically captured, the photo-oxidative degradation chain reaction is blocked, the color stability and mechanical property retention rate of the composite material under long-term outdoor light exposure are improved, and the weather resistance problems of polypropylene material such as easy yellowing and easy embrittlement are solved.

[0017] 3. In this invention, by compounding ethylene-octene block copolymer with surface hydroxylated carbon fiber, the toughening mechanism of the elastomer phase and the reinforcing effect of the fiber are utilized to absorb and dissipate impact energy and prevent crack propagation while maintaining the rigidity and heat resistance of polypropylene material, thereby achieving a balance between high impact resistance and weather-resistant toughening effect. Detailed Implementation

[0018] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0019] Example 1: A high-impact, weather-resistant, and toughened polypropylene composite material, made from the following raw materials by weight: 40 parts of copolymer polypropylene matrix, 10 parts of acrylonitrile-styrene-acrylate copolymer grafted with glycidyl methacrylate, 5 parts of hyperbranched polyester modified nano titanium dioxide, 3 parts of surface hydroxylated carbon fiber, 2 parts of hindered amine light stabilizer compound, 1 part of thioester antioxidant, 0.5 parts of calcium stearate, and 5 parts of ethylene-octene block copolymer. The preparation method of hyperbranched polyester modified nano-titanium dioxide includes: dispersing nano-titanium dioxide in toluene, adding γ-methacryloxypropyltrimethoxysilane, refluxing at 75°C for 4 hours under nitrogen protection, filtering, washing and drying to obtain silane coupling agent modified nano-titanium dioxide, then adding silane coupling agent modified nano-titanium dioxide and hyperbranched polyester to xylene, ultrasonically dispersing at 80°C for 30 minutes, then heating to 120°C and refluxing for 3 hours, cooling and centrifuging, and vacuum drying to constant weight to obtain hyperbranched polyester modified nano-titanium dioxide; The hindered amine light stabilizer compound consists of bis(1-octoxy-2,2,6,6-tetramethyl-4-piperidinyl) sebacate and poly{[6-[(1,1,3,3-tetramethylbutyl)amino]-1,3,5-triazine-2,4-diyl][2-(2,2,6,6-tetramethylpiperidinyl)amino]hexylene[2,2,6,6-tetramethyl-4-piperidinyl]imino} in a mass ratio of 1:0.5.

[0020] The melt flow rate of the copolymer polypropylene matrix is ​​0.5 g / 10 min. In the acrylonitrile-styrene-acrylate copolymer grafted with glycidyl methacrylate, the grafting rate of glycidyl methacrylate is 1.5%. The rubber phase content of the acrylonitrile-styrene-acrylate copolymer is 40%, and the glass transition temperature is -40℃.

[0021] Methods for preparing surface-hydroxylated carbon fibers include: Carbon fibers were placed in a mixed solution of concentrated nitric acid and concentrated sulfuric acid, with a volume ratio of 1:2. The solution was stirred for 2 hours in a water bath at 60°C, then washed with deionized water until neutral, and dried in a vacuum drying oven at 80°C for 12 hours to obtain surface-hydroxylated carbon fibers.

[0022] The thioester antioxidant is composed of pentaerythritol tetra(3-lauryl thiopropionate) and dioctadecyl thiodipropionate in a 1:1 mass ratio, and the density of the ethylene-octene block copolymer is 0.85 g / cm³. 3 The melt flow index is 0.5 g / 10 min.

[0023] The material also includes 1 part by weight of modified montmorillonite, and the preparation method of the modified montmorillonite includes: Sodium montmorillonite was dispersed in deionized water to prepare a 1% (w / w) suspension. Hexadecyltrimethylammonium bromide was added, with a mass ratio of hexadecyltrimethylammonium bromide to sodium montmorillonite of 1:5. The mixture was stirred at 70°C for 4 hours. After filtration, the mixture was washed with deionized water until no white precipitate was produced when tested with 0.1 mol / L AgNO3 solution. After vacuum drying at 60°C, the mixture was ground through a 200-mesh sieve to obtain modified montmorillonite.

[0024] A method for preparing a high-impact, weather-resistant, and toughened polypropylene composite material includes the following steps: Step 1: Weigh out the following components by weight: copolymer polypropylene matrix, acrylonitrile-styrene-acrylate copolymer grafted with glycidyl methacrylate, hyperbranched polyester modified nano titanium dioxide, surface hydroxylated carbon fiber, hindered amine light stabilizer compound, thioester antioxidant, calcium stearate, ethylene-octene block copolymer and modified montmorillonite. Step 2: Add the copolymer polypropylene matrix, acrylonitrile-styrene-acrylate copolymer grafted with glycidyl methacrylate, ethylene-octene block copolymer, hindered amine light stabilizer compound, thioester antioxidant and calcium stearate into a high-speed mixer and mix at 800 r / min for 3 minutes to obtain the premix. Step 3: Add hyperbranched polyester modified nano-titanium dioxide, surface hydroxylated carbon fiber and modified montmorillonite into a mixer and mix at 180°C and 30 rpm for 5 minutes to obtain inorganic filler premix. Step 4: Add the premix and inorganic filler premix together to a twin-screw extruder for melt blending and extrusion. The temperature of each section of the extruder is set to 160℃, the main machine speed is 300rpm, and the feeding speed is 10r / min. The melt is water-cooled, stretched, and pelletized to obtain a high-impact, weather-resistant, and toughened polypropylene composite material.

[0025] In step three, the rotor of the internal mixer is of the meshing type, and the filling factor is 0.6; In step four, the twin-screw extruder has a length-to-diameter ratio of 36:1, the screw assembly includes two sets of kneading blocks, the stagger angle of the kneading blocks is 45°, and the specific temperature settings for each section are as follows: Zone 1: 160℃, Zone 2: 170℃, Zone 3: 180℃, Zone 4: 185℃, Zone 5: 180℃, Head: 175℃.

[0026] In step two, the mixing temperature of the high-speed mixer is 40℃; In step four, after the melt passes through the extruder head, it first undergoes a first stage of cooling in a water bath at a temperature of 60°C, and then undergoes a second stage of cooling in a water bath at a temperature of 20°C. The total cooling time for the two stages is 10 seconds. Afterward, the surface moisture is dried by an air knife, and then the melt is granulated. The particle size of the granulated particles is 2mm.

[0027] It also includes a pretreatment step for surface-hydroxylated carbon fibers: Surface-hydroxylated carbon fibers were mixed with silane coupling agent KH-570 at a mass ratio of 100:0.5, placed in an acetone solution, and ultrasonically dispersed at 50°C for 20 minutes. Then, the acetone was removed by vacuum distillation, and the mixture was vacuum dried at 80°C to constant weight to obtain pretreated surface-hydroxylated carbon fibers. These pretreated surface-hydroxylated carbon fibers were used in step three.

[0028] In step four, the twin-screw extruder is equipped with a vacuum exhaust device with a vacuum degree of -0.09MPa, and the exhaust port is located between the fourth and fifth zones of the extruder.

[0029] Example 2: A high-impact, weather-resistant, and toughened polypropylene composite material, made from the following raw materials by weight: 50 parts of copolymer polypropylene matrix, 15 parts of acrylonitrile-styrene-acrylate copolymer grafted with glycidyl methacrylate, 10 parts of hyperbranched polyester modified nano titanium dioxide, 6 parts of surface hydroxylated carbon fiber, 5 parts of hindered amine light stabilizer compound, 3 parts of thioester antioxidant, 1.2 parts of calcium stearate, and 10 parts of ethylene-octene block copolymer. The preparation method of hyperbranched polyester modified nano-titanium dioxide includes: dispersing nano-titanium dioxide in toluene, adding γ-methacryloxypropyltrimethoxysilane, refluxing at 80°C for 5 hours under nitrogen protection, filtering, washing and drying to obtain silane coupling agent modified nano-titanium dioxide, then adding silane coupling agent modified nano-titanium dioxide and hyperbranched polyester to xylene, ultrasonically dispersing at 85°C for 40 minutes, then heating to 125°C and refluxing for 4 hours, cooling and centrifuging, and vacuum drying to constant weight to obtain hyperbranched polyester modified nano-titanium dioxide; The hindered amine light stabilizer compound consists of bis(1-octoxy-2,2,6,6-tetramethyl-4-piperidinyl) sebacate and poly{[6-[(1,1,3,3-tetramethylbutyl)amino]-1,3,5-triazine-2,4-diyl][2-(2,2,6,6-tetramethylpiperidinyl)amino]hexylene[2,2,6,6-tetramethyl-4-piperidinyl]imino} in a mass ratio of 1:1.2.

[0030] The melt flow rate of the copolymer polypropylene matrix is ​​1.2 g / 10 min. In the acrylonitrile-styrene-acrylate copolymer grafted with glycidyl methacrylate, the grafting rate of glycidyl methacrylate is 2.5%. The rubber phase content of the acrylonitrile-styrene-acrylate copolymer is 50%, and the glass transition temperature is -35℃.

[0031] Methods for preparing surface-hydroxylated carbon fibers include: Carbon fibers were placed in a mixed solution of concentrated nitric acid and concentrated sulfuric acid, with a volume ratio of 1:3. The solution was stirred for 3 hours in a water bath at 70°C, then washed with deionized water until neutral, and dried in a vacuum drying oven at 90°C for 18 hours to obtain surface-hydroxylated carbon fibers.

[0032] The thioester antioxidant is composed of pentaerythritol tetra(3-lauryl thiopropionate) and dioctadecyl thiodipropionate in a mass ratio of 1:2, and the density of the ethylene-octene block copolymer is 0.87 g / cm³. 3 The melt flow index is 1.7 g / 10 min.

[0033] The material also includes 3 parts by weight of modified montmorillonite, and the preparation method of the modified montmorillonite includes: Sodium montmorillonite was dispersed in deionized water to prepare a 2% (w / w) suspension. Hexadecyltrimethylammonium bromide was added, with a mass ratio of hexadecyltrimethylammonium bromide to sodium montmorillonite of 1:8. The mixture was stirred at 70°C for 5 hours. After filtration, the mixture was washed with deionized water until no white precipitate was formed when tested with 0.1 mol / L AgNO3 solution. After vacuum drying at 70°C, the mixture was ground through a 200-mesh sieve to obtain modified montmorillonite.

[0034] A method for preparing a high-impact, weather-resistant, and toughened polypropylene composite material includes the following steps: Step 1: Weigh out the following components by weight: copolymer polypropylene matrix, acrylonitrile-styrene-acrylate copolymer grafted with glycidyl methacrylate, hyperbranched polyester modified nano titanium dioxide, surface hydroxylated carbon fiber, hindered amine light stabilizer compound, thioester antioxidant, calcium stearate, ethylene-octene block copolymer and modified montmorillonite. Step 2: Add the copolymer polypropylene matrix, acrylonitrile-styrene-acrylate copolymer grafted with glycidyl methacrylate, ethylene-octene block copolymer, hindered amine light stabilizer compound, thioester antioxidant and calcium stearate into a high-speed mixer and mix at 1000 r / min for 5.5 minutes to obtain the premix. Step 3: Add hyperbranched polyester modified nano-titanium dioxide, surface hydroxylated carbon fiber and modified montmorillonite into a mixer and mix at 190℃ and 40rpm for 8 minutes to obtain inorganic filler premix. Step 4: Add the premix and inorganic filler premix together to a twin-screw extruder for melt blending and extrusion. The temperature of each section of the extruder is set to 175℃, the main machine speed is 400rpm, and the feeding speed is 20r / min. The melt is water-cooled, stretched, and pelletized to obtain a high-impact, weather-resistant, and toughened polypropylene composite material.

[0035] In step three, the rotor of the internal mixer is of the meshing type, and the filling factor is 0.7; In step four, the twin-screw extruder has a length-to-diameter ratio of 42:1, the screw assembly includes two sets of kneading blocks, the stagger angle of the kneading blocks is 65°, and the specific temperature settings for each section are as follows: Zone 1: 162℃, Zone 2: 172℃, Zone 3: 182℃, Zone 4: 187℃, Zone 5: 182℃, Head unit: 177℃.

[0036] In step two, the mixing temperature of the high-speed mixer is 50℃; In step four, after the melt passes through the extruder head, it first undergoes a first stage of cooling in a water bath at a temperature of 70°C, and then undergoes a second stage of cooling in a water bath at a temperature of 25°C. The total cooling time for the two stages is 15 seconds. Afterward, the surface moisture is dried by an air knife and then pelletized. The particle size of the pelletized particles is 3mm.

[0037] It also includes a pretreatment step for surface-hydroxylated carbon fibers: Surface-hydroxylated carbon fibers were mixed with silane coupling agent KH-570 at a mass ratio of 100:1.2, placed in an acetone solution, and ultrasonically dispersed at 60°C for 30 minutes. Then, the acetone was removed by vacuum distillation, and the mixture was vacuum dried at 90°C to constant weight to obtain pretreated surface-hydroxylated carbon fibers. These pretreated surface-hydroxylated carbon fibers were used in step three.

[0038] In step four, the twin-screw extruder is equipped with a vacuum exhaust device with a vacuum level of -0.07 MPa, and the exhaust port is located between the fourth and fifth zones of the extruder.

[0039] Example 3: A high-impact, weather-resistant, and toughened polypropylene composite material, made from the following raw materials by weight: 60 parts of copolymer polypropylene matrix, 20 parts of acrylonitrile-styrene-acrylate copolymer grafted with glycidyl methacrylate, 15 parts of hyperbranched polyester modified nano titanium dioxide, 10 parts of surface hydroxylated carbon fiber, 8 parts of hindered amine light stabilizer compound, 5 parts of thioester antioxidant, 2 parts of calcium stearate, and 15 parts of ethylene-octene block copolymer. The preparation method of hyperbranched polyester modified nano-titanium dioxide includes: dispersing nano-titanium dioxide in toluene, adding γ-methacryloxypropyltrimethoxysilane, refluxing at 85°C for 6 hours under nitrogen protection, filtering, washing and drying to obtain silane coupling agent modified nano-titanium dioxide, then adding silane coupling agent modified nano-titanium dioxide and hyperbranched polyester to xylene, ultrasonically dispersing at 90°C for 50 minutes, then heating to 130°C and refluxing for 5 hours, cooling and centrifuging, and vacuum drying to constant weight to obtain hyperbranched polyester modified nano-titanium dioxide; The hindered amine light stabilizer compound consists of bis(1-octyloxy-2,2,6,6-tetramethyl-4-piperidinyl) sebacate and poly{[6-[(1,1,3,3-tetramethylbutyl)amino]-1,3,5-triazine-2,4-diyl][2-(2,2,6,6-tetramethylpiperidinyl)amino]hexylene[2,2,6,6-tetramethyl-4-piperidinyl]imino} in a mass ratio of 1:2.

[0040] The melt flow rate of the copolymer polypropylene matrix is ​​5 g / 10 min. In the acrylonitrile-styrene-acrylate copolymer grafted with glycidyl methacrylate, the grafting rate of glycidyl methacrylate is 3.5%. The rubber phase content of the acrylonitrile-styrene-acrylate copolymer is 60%, and the glass transition temperature is -30℃.

[0041] Methods for preparing surface-hydroxylated carbon fibers include: Carbon fibers were placed in a mixed solution of concentrated nitric acid and concentrated sulfuric acid, with a volume ratio of 1:4. The solution was stirred for 4 hours in an 80°C water bath, then washed with deionized water until neutral, and dried in a vacuum drying oven at 100°C for 24 hours to obtain surface-hydroxylated carbon fibers.

[0042] The thioester antioxidant is composed of pentaerythritol tetra(3-lauryl thiopropionate) and dioctadecyl thiodipropionate in a mass ratio of 1:3. The density of the ethylene-octene block copolymer is 0.89 g / cm³. 3 The melt flow index is 3 g / 10 min.

[0043] The material also includes 5 parts by weight of modified montmorillonite, and the preparation method of the modified montmorillonite includes: Sodium montmorillonite was dispersed in deionized water to prepare a 3% (w / w) suspension. Hexadecyltrimethylammonium bromide was added, with a mass ratio of hexadecyltrimethylammonium bromide to sodium montmorillonite of 1:10. The mixture was stirred at 90°C for 6 hours. After filtration, the mixture was washed with deionized water until no white precipitate was produced when tested with 0.1 mol / L AgNO3 solution. After vacuum drying at 80°C, the mixture was ground through a 200-mesh sieve to obtain modified montmorillonite.

[0044] A method for preparing a high-impact, weather-resistant, and toughened polypropylene composite material includes the following steps: Step 1: Weigh out the following components by weight: copolymer polypropylene matrix, acrylonitrile-styrene-acrylate copolymer grafted with glycidyl methacrylate, hyperbranched polyester modified nano titanium dioxide, surface hydroxylated carbon fiber, hindered amine light stabilizer compound, thioester antioxidant, calcium stearate, ethylene-octene block copolymer and modified montmorillonite. Step 2: Add the copolymer polypropylene matrix, acrylonitrile-styrene-acrylate copolymer grafted with glycidyl methacrylate, ethylene-octene block copolymer, hindered amine light stabilizer compound, thioester antioxidant and calcium stearate into a high-speed mixer and mix at 1200 r / min for 8 minutes to obtain the premix. Step 3: Add hyperbranched polyester modified nano-titanium dioxide, surface hydroxylated carbon fiber and modified montmorillonite into a mixer and mix at 200℃ and 50rpm for 10 minutes to obtain inorganic filler premix. Step 4: Add the premix and inorganic filler premix together to a twin-screw extruder for melt blending and extrusion. The temperature of each section of the extruder is set to 190℃, the main machine speed is 500rpm, and the feeding speed is 30r / min. The melt is water-cooled, stretched, and pelletized to obtain a high-impact, weather-resistant, and toughened polypropylene composite material.

[0045] In step three, the rotor of the internal mixer is of the meshing type, and the filling factor is 0.8; In step four, the twin-screw extruder has a length-to-diameter ratio of 48:1, the screw assembly contains three sets of kneading blocks, the staggered angle of the kneading blocks is 90°, and the specific temperature settings for each section are as follows: Zone 1: 165℃, Zone 2: 175℃, Zone 3: 185℃, Zone 4: 190℃, Zone 5: 185℃, Head unit: 180℃.

[0046] In step two, the mixing temperature of the high-speed mixer is 60℃; In step four, after the melt passes through the extruder head, it first undergoes a first stage of cooling in a water bath at 80°C, and then a second stage of cooling in a water bath at 30°C. The total cooling time for the two stages is 20 seconds. Afterward, the surface moisture is dried by an air knife, and the melt is then pelletized. The particle size of the pelletized particles is 4mm.

[0047] It also includes a pretreatment step for surface-hydroxylated carbon fibers: Surface-hydroxylated carbon fibers were mixed with silane coupling agent KH-570 at a mass ratio of 100:2, placed in an acetone solution, and ultrasonically dispersed at 70°C for 40 minutes. Then, the acetone was removed by vacuum distillation, and the mixture was vacuum dried at 100°C to constant weight to obtain pretreated surface-hydroxylated carbon fibers. These pretreated surface-hydroxylated carbon fibers were used in step three.

[0048] In step four, the twin-screw extruder is equipped with a vacuum exhaust device with a vacuum degree of -0.06MPa, and the exhaust port is located between the fourth and fifth zones of the extruder.

[0049] Comparative Example 1: The difference between this comparative example and Example 1 is that this comparative example did not add hyperbranched polyester-modified nano-titanium dioxide when preparing the composite material.

[0050] Comparative Example 2 differs from Example 1 in that surface-hydroxylated carbon fibers were not added during the preparation of the composite material in this comparative example.

[0051] Comparative Example 3 differs from Example 1 in that no hindered amine light stabilizer compound was added during the preparation of the composite material in this comparative example.

[0052] Comparative Example 4 differs from Example 1 in that ethylene-octene block copolymer was not added during the preparation of the composite material in this comparative example.

[0053] The high-impact, weather-resistant, and toughened polypropylene composites prepared in Examples 1-3 and Comparative Examples 1-4 were subjected to performance tests. The test items and methods are as follows: Notched impact strength test of simply supported beam: The specimen size is 80mm×10mm×4mm, the notch depth is 2mm, and the test is carried out using a simply supported beam impact testing machine at 23℃. Xenon lamp aging and weather resistance test: The lamp was continuously irradiated under a xenon lamp light source for 500 hours, with a black panel temperature of 65℃ and a relative humidity of 50%. The tensile strength retention rate before and after aging was measured. Heat distortion temperature test: The sample size is 120mm×10mm×4mm, the load is 1.82MPa, the heating rate is 120℃ / h, and the temperature at which the sample deformation reaches 0.25mm is measured. Bending strength test: Specimen size 80mm×10mm×4mm, span 64mm, loading speed 2mm / min.

[0054] The test data of the high impact-resistant and weather-resistant toughened polypropylene composites prepared in Examples 1-3 and Comparative Examples 1-4 are recorded in the table below: By comparing and analyzing the data in the table, it can be seen that the high-impact, weather-resistant, and toughened polypropylene composite materials prepared using the processes in Examples 1-3 have significantly better performance than those prepared using the processes in Comparative Examples 1-4. This indicates that the present invention, by introducing hyperbranched polyester-modified nano-titanium dioxide, utilizes its abundant surface functional groups to form a strong interfacial interaction with the polypropylene matrix and surface hydroxylated carbon fibers, dispersing external impact stress, thereby improving the material's impact resistance, weather resistance, and service life. By adding a hindered amine light stabilizer compound, it synergistically captures free radicals generated during polypropylene oxidation, blocks the photo-oxidative degradation chain reaction, and improves the color stability and mechanical property retention rate of the composite material under long-term outdoor light exposure, solving the weather resistance problems of polypropylene materials such as easy yellowing and brittleness. By compounding ethylene-octene block copolymers with surface hydroxylated carbon fibers, it utilizes the toughening mechanism of the elastomer phase and the reinforcing effect of the fibers to absorb and dissipate impact energy while maintaining the rigidity and heat resistance of the polypropylene material, preventing crack propagation, thereby achieving a balance between high impact resistance and weather-resistant toughening effect.

[0055] By comparing and analyzing the relevant data in the table, it can be seen that the high-impact, weather-resistant, and toughened polypropylene composite material prepared by the molding process of this invention has excellent mechanical properties, weather resistance, and thermal stability.

[0056] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0057] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A high-impact, weather-resistant, toughened polypropylene composite material, characterized in that: Made from the following raw materials by weight: 40-60 parts of copolymer polypropylene matrix, 10-20 parts of acrylonitrile-styrene-acrylate copolymer grafted with glycidyl methacrylate, 5-15 parts of hyperbranched polyester modified nano titanium dioxide, 3-10 parts of surface hydroxylated carbon fiber, 2-8 parts of hindered amine light stabilizer compound, 1-5 parts of thioester antioxidant, 0.5-2 parts of calcium stearate, and 5-15 parts of ethylene-octene block copolymer; The preparation method of the hyperbranched polyester modified nano-titanium dioxide includes: dispersing nano-titanium dioxide in toluene, adding γ-methacryloxypropyltrimethoxysilane, refluxing at 75-85℃ for 4-6 hours under nitrogen protection, filtering, washing and drying to obtain silane coupling agent modified nano-titanium dioxide, then adding silane coupling agent modified nano-titanium dioxide and hyperbranched polyester to xylene, ultrasonically dispersing at 80-90℃ for 30-50 minutes, then heating to 120-130℃ and refluxing for 3-5 hours, cooling and centrifuging, and vacuum drying to constant weight to obtain hyperbranched polyester modified nano-titanium dioxide; The hindered amine light stabilizer compound is composed of bis(1-octoxy-2,2,6,6-tetramethyl-4-piperidinyl) sebacate and poly{[6-[(1,1,3,3-tetramethylbutyl)amino]-1,3,5-triazine-2,4-diyl][2-(2,2,6,6-tetramethylpiperidinyl)amino]hexylene[2,2,6,6-tetramethyl-4-piperidinyl]imino} in a mass ratio of 1:(0.5-2).

2. The high-impact, weather-resistant, and toughened polypropylene composite material according to claim 1, characterized in that: The melt flow rate of the copolymer polypropylene matrix is ​​0.5-5 g / 10 min. In the acrylonitrile-styrene-acrylate copolymer grafted with glycidyl methacrylate, the grafting rate of glycidyl methacrylate is 1.5%-3.5%, the rubber phase content of the acrylonitrile-styrene-acrylate copolymer is 40%-60%, and the glass transition temperature is -40℃ to -30℃.

3. The high-impact, weather-resistant, and toughened polypropylene composite material according to claim 1, characterized in that: The method for preparing the surface-hydroxylated carbon fibers includes: Carbon fibers are placed in a mixed solution of concentrated nitric acid and concentrated sulfuric acid, with a volume ratio of 1:(2-4). The solution is stirred in a water bath at 60-80℃ for 2-4 hours, then washed with deionized water until neutral, and dried in a vacuum drying oven at 80-100℃ for 12-24 hours to obtain surface-hydroxylated carbon fibers.

4. The high-impact, weather-resistant, and toughened polypropylene composite material according to claim 1, characterized in that: The thioester antioxidant is composed of pentaerythritol tetra(3-lauryl thiopropionate) and dioctadecyl thiodipropionate in a mass ratio of 1:(1-3), and the density of the ethylene-octene block copolymer is 0.85-0.89 g / cm³. 3 The melt flow index is 0.5-3 g / 10 min.

5. The high-impact, weather-resistant, and toughened polypropylene composite material according to claim 1, characterized in that: The material further includes 1-5 parts by weight of modified montmorillonite, and the preparation method of the modified montmorillonite includes: Sodium montmorillonite was dispersed in deionized water to prepare a suspension with a mass fraction of 1%-3%. Hexadecyltrimethylammonium bromide was added, with a mass ratio of hexadecyltrimethylammonium bromide to sodium montmorillonite of 1:(5-10). The mixture was stirred at 70-90℃ for 4-6 hours. After filtration, the mixture was washed with deionized water until no white precipitate was produced when tested with 0.1mol / L AgNO3 solution. After vacuum drying at 60-80℃, the mixture was ground through a 200-mesh sieve to obtain modified montmorillonite.

6. A method for preparing a high-impact, weather-resistant, and toughened polypropylene composite material, used to prepare the high-impact, weather-resistant, and toughened polypropylene composite material according to any one of claims 1-5, characterized in that: Includes the following steps: Step 1: Weigh out the following components according to the stated weight proportions: copolymer polypropylene matrix, acrylonitrile-styrene-acrylate copolymer grafted with glycidyl methacrylate, hyperbranched polyester modified nano titanium dioxide, surface hydroxylated carbon fiber, hindered amine light stabilizer compound, thioester antioxidant, calcium stearate, ethylene-octene block copolymer and modified montmorillonite. Step 2: Add the copolymer polypropylene matrix, acrylonitrile-styrene-acrylate copolymer grafted with glycidyl methacrylate, ethylene-octene block copolymer, hindered amine light stabilizer compound, thioester antioxidant and calcium stearate into a high-speed mixer and mix at 800-1200 r / min for 3-8 minutes to obtain the premix. Step 3: Add hyperbranched polyester modified nano-titanium dioxide, surface hydroxylated carbon fiber and modified montmorillonite into a mixer and mix at 180-200℃ and 30-50rpm for 5-10 minutes to obtain inorganic filler premix. Step 4: Add the premix and inorganic filler premix together to a twin-screw extruder for melt blending and extrusion. Set the temperature of each section of the extruder to 160-190℃, the main machine speed to 300-500rpm, and the feeding speed to 10-30r / min. After water cooling, the melt is stretched and pelletized to obtain a high-impact, weather-resistant, and toughened polypropylene composite material.

7. The method for preparing a high-impact, weather-resistant, and toughened polypropylene composite material according to claim 6, characterized in that: In step three, the rotor of the internal mixer is of the meshing type, and the filling coefficient is 0.6-0.8; In step four, the length-to-diameter ratio of the twin-screw extruder is (36-48):1, the screw assembly contains 2-3 sets of kneading blocks, the stagger angle of the kneading blocks is 45°-90°, and the specific temperature settings for each section are as follows: Zone 1: 160-165℃, Zone 2: 170-175℃, Zone 3: 180-185℃, Zone 4: 185-190℃, Zone 5: 180-185℃, Head unit: 175-180℃.

8. The method for preparing a high-impact, weather-resistant, toughened polypropylene composite material according to claim 6, characterized in that: In step two, the mixing temperature of the high-speed mixer is 40-60℃; In step four, after the melt passes through the extruder head, it first undergoes a first stage of cooling through a water tank with a water temperature of 60-80℃, and then undergoes a second stage of cooling through a water tank with a water temperature of 20-30℃. The total cooling time for the two stages is 10-20 seconds. Afterward, the surface moisture is dried by an air knife and then pelletized. The particle size of the pelletized particles is 2-4mm.

9. The method for preparing a high-impact, weather-resistant, and toughened polypropylene composite material according to claim 6, characterized in that: It also includes a pretreatment step for surface-hydroxylated carbon fibers: Surface-hydroxylated carbon fibers are mixed with silane coupling agent KH-570 at a mass ratio of 100:(0.5~2), placed in an acetone solution, and ultrasonically dispersed at 50-70℃ for 20-40 minutes. Then, the acetone is removed by vacuum distillation, and the carbon fibers are vacuum dried at 80-100℃ to constant weight to obtain pretreated surface-hydroxylated carbon fibers. These pretreated surface-hydroxylated carbon fibers are used in step three.

10. The method for preparing a high-impact, weather-resistant, and toughened polypropylene composite material according to claim 6, characterized in that: In step four, the twin-screw extruder is equipped with a vacuum exhaust device with a vacuum level of -0.09MPa to -0.06MPa, and the exhaust port is located between the fourth and fifth zones of the extruder.

Images