High-strength polypropylene engineering plastic composition for water squeezing vehicle and preparation method of high-strength polypropylene engineering plastic composition

Abstract

The invention discloses a high-strength polypropylene engineering plastic composition for a water squeezing vehicle and a preparation method of the high-strength polypropylene engineering plastic composition, and relates to the technical field of building materials. The high-strength polypropylene engineering plastic composition for the water squeezing vehicle at least comprises the following raw materials in parts by mass: 65-70 parts of polypropylene resin; 5 to 10 parts of polyamide resin; 20 to 25 parts of chopped glass fiber; 5 to 8 parts of ethylene-octylene copolymer; 3 to 8 parts of hydrophobic modified nano titanium dioxide coated sericite composite particles; 2 to 3 parts of maleic anhydride grafted polypropylene; 1 to 3 parts of hyperbranched polyamide modified graphene nanosheets; 0.3 to 0.5 part of an antioxidant; 0.2 to 0.4 part of a light stabilizer; and 0.5-1 part of a lubricant. According to the prepared high-strength polypropylene engineering plastic composition for the water squeezing vehicle, the strength, toughness and long-acting weather resistance of polypropylene engineering plastic are improved.

Description

Technical Field

[0001] This invention relates to the field of building materials technology, specifically to a high-strength polypropylene engineering plastic composition for water-pressing vehicles and its preparation method. Background Technology

[0002] As a key piece of equipment in municipal sanitation, sewage treatment and other fields, the core components of the water press truck (such as the pressing plate, load-bearing frame, feed hopper, etc.) need to withstand high pressure pressing loads and frequent mechanical impacts for a long time. At the same time, they are exposed to outdoor humid, ultraviolet radiation and weak acid / weak alkaline media environments. Therefore, the materials used are required to have high strength, high toughness, excellent weather resistance, media stability and good processability.

[0003] Polypropylene (PP) is the fastest-growing and most diverse of the five major general-purpose plastics in terms of production volume. As a widely used thermoplastic resin, PP possesses excellent mechanical properties, outstanding chemical resistance, good moisture resistance, and recyclability. Since its introduction, it has received widespread attention from various industries. Due to its advantages such as light weight, chemical resistance, ease of processing, and low cost, it is widely used in the manufacture of housings, covers, and structural components for sanitation equipment such as water-pressing carts.

[0004] However, standard polypropylene suffers from inherent defects such as insufficient mechanical strength, high low-temperature brittleness, poor weather resistance (susceptible to UV degradation), and easy staining and cleaning. Current technologies typically employ the addition of glass fiber (GF) for reinforcement and the introduction of elastomers to improve toughness. However, this simple physical blending modification method has significant bottlenecks: First, the weak interfacial bonding between GF and the PP matrix leads to low stress transfer efficiency, resulting in limited and unstable reinforcement; second, the introduction of GF often causes an imbalance between strength and toughness, i.e., a significant decrease in impact toughness; third, traditional weather-resistant additives are prone to migration and exudation, providing insufficient long-term protection; finally, the material surface lacks active protection, making it prone to aging, discoloration, and bacterial growth under complex outdoor conditions, and difficult to clean, severely affecting the aesthetics, hygiene, and service life of equipment. Therefore, developing a polypropylene engineering plastic with ultra-high strength, excellent toughness, and superior long-term weather resistance has become an urgent technical challenge to be solved in this field. Summary of the Invention

[0005] The purpose of this invention is to provide a high-strength polypropylene engineering plastic composition for water-pressing vehicles and its preparation method, thereby solving the following technical problems: Existing polypropylene engineering plastics used in the manufacture of water presses suffer from insufficient strength, poor impact toughness, and poor weather resistance.

[0006] The objective of this invention can be achieved through the following technical solutions: A high-strength polypropylene engineering plastic composition for a water-pressing vehicle, comprising at least the following parts by weight of raw materials: Polypropylene resin 65-70 parts; polyamide resin 5-10 parts; chopped glass fiber 20-25 parts; ethylene-octene copolymer 5-8 parts; hydrophobically modified nano-titanium dioxide coated sericite composite particles 3-8 parts; maleic anhydride grafted polypropylene 2-3 parts; hyperbranched polyamide modified graphene nanosheets 1-3 parts; antioxidant 0.3-0.5 parts; light stabilizer 0.2-0.4 parts; lubricant 0.5-1 parts.

[0007] As a further aspect of the present invention: the polypropylene resin is copolymer polypropylene, and the melt index of the copolymer polypropylene is 2-100 g / 10 min, and the polyamide resin is one or a mixture of nylon 1010, nylon 12 or nylon 6.

[0008] As a further aspect of the present invention, the preparation method of the hydrophobically modified nano-titanium dioxide coated sericite composite particles includes at least the following preparation steps: Sericite, tetrabutyl titanate, and pH adjuster were added to an ethanol / water mixture to adjust the pH to 4-5. The mixture was then stirred, aged, filtered, washed, dried, and dispersed to obtain nano-titanium dioxide-coated sericite composite particles. The nano-titanium dioxide-coated sericite composite particles were dispersed in an ethanol / water mixed solution, the pH was adjusted to 4-5, γ-methacryloyloxypropyltrimethoxysilane was added, and after the reaction, the particles were washed and dried to obtain hydrophobically modified nano-titanium dioxide-coated sericite composite particles.

[0009] As a further aspect of the present invention: the thickness of the nano-titanium dioxide coating in the nano-titanium dioxide-coated sericite composite particles is 20-100 nm, and the pH adjuster is a 10% NaOH solution and a 10% oxalic acid solution by mass fraction.

[0010] As a further aspect of the present invention: the mass ratio of sericite to tetrabutyl titanate is 1:0.5-2, and the addition ratio of nano-titanium dioxide-coated sericite composite particles to γ-methacryloyloxypropyltrimethoxysilane is 5-10:1.

[0011] As a further aspect of the present invention, the preparation method of the hyperbranched polyamide-modified graphene nanosheets includes at least the following preparation steps: Succinic anhydride was added to diethylenetriamine, and after reaction, hyperbranched polyamide was obtained. Graphene nanosheets were dispersed in distilled water, the pH was adjusted to 9-10, and an aqueous solution of the hyperbranched polyamide was added. After the reaction, the mixture was washed and freeze-dried to obtain hyperbranched polyamide-modified graphene nanosheets.

[0012] As a further aspect of the present invention, the mass ratio of the succinic anhydride to the diethylenetriamine is 10:7-10.

[0013] As a further aspect of the present invention, the mass ratio of the graphene nanosheets to the hyperbranched polyamide is 1:4-6.

[0014] As a further aspect of the present invention: the antioxidant is at least one of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, tris(2,4-di-tert-butylphenyl) phosphite, or bis(2,4-di-tert-butylphenol) pentaerythritol diphosphite; the light stabilizer is at least one of benzophenones, benzotriazoles, triazines, substituted acrylonitriles, or hindered amines; and the lubricant is at least one of zinc stearate, calcium stearate, stearic acid, oleamide, erucamide, stearamide, or ethylene bis-stearamide.

[0015] The method for preparing the high-strength polypropylene engineering plastic composition for water-pressing vehicles as described in any of the above claims includes at least the following preparation steps: Polypropylene resin, polyamide resin, ethylene-octene copolymer, hydrophobically modified nano-titanium dioxide coated sericite composite particles, maleic anhydride grafted polypropylene, hyperbranched polyamide modified graphene nanosheets, antioxidant, light stabilizer and lubricant are added to a high-speed mixer and mixed to obtain a premix. The premixed material is added from the main feed port of a twin-screw extruder, and chopped glass fibers are added from the side feed port. After melt extrusion, water cooling, and pelletizing, a high-strength polypropylene engineering plastic composition for water pressing vehicles is obtained.

[0016] The beneficial effects of this invention are: The high-strength polypropylene engineering plastic composition for water-pressing vehicles prepared in this invention uses polypropylene resin and polyamide resin as the matrix. Polypropylene resin provides good processability and basic mechanical properties. Low-hygroscopic polyamide resin is selected to improve the material's oil resistance and mechanical strength. Short-cut glass fibers and hyperbranched polyamide-modified graphene nanosheets are introduced as rigid reinforcing phases, significantly improving the material's tensile strength, flexural modulus, and heat distortion temperature, meeting the high-pressure load-bearing requirements of water-pressing vehicle components. Ethylene-octene copolymer is added as a flexible toughening phase to achieve a balance between rigidity and toughness, and maleic anhydride-grafted polypropylene is added as a compatibilizer to strengthen interfacial adhesion and improve stress transfer efficiency. This invention also adds hydrophobically modified nano-titanium dioxide-coated sericite composite particles, as well as processing aids such as antioxidants and light stabilizers to synergistically inhibit oxidative aging and photo-aging during processing and use, extending the material's service life. The high-strength polypropylene engineering plastic composition provided by this invention is mainly used in core components of water press trucks such as pressing plates, load-bearing frames, feeding hoppers, and boxes. It can also be extended to other outdoor high-pressure load-bearing engineering plastic components, such as structural parts of municipal sanitation equipment and sewage treatment equipment.

[0017] The hydrophobically modified nano-titanium dioxide-coated sericite composite particles prepared in this invention use sericite as the core and nano-titanium dioxide as the shell, achieving uniform coating through a sol-gel method. The coating thickness is controlled at 20-100 nm, providing both UV shielding and rigidity enhancement. Further hydrophobic modification significantly improves the interfacial compatibility between the composite particles and the polypropylene matrix, avoiding the agglomeration defects of traditional inorganic fillers. The layered structure of sericite also creates a "maze effect," delaying water vapor and gas penetration and improving the material's resistance to various media. The strong reflection and scattering of ultraviolet light by nano-titanium dioxide, combined with a light stabilizer, significantly improves the material's weather resistance. The composite particles and glass fiber synergistically reinforce the material, improving rigidity while avoiding the toughness loss caused by single glass fiber reinforcement, resulting in a more balanced mechanical property.

[0018] The hyperbranched polyamide-modified graphene nanosheets prepared in this invention are anchored to the graphene nanosheet surface through both covalent and non-covalent bonds. The branched structure inhibits graphene aggregation. By introducing hyperbranched polyamide-modified graphene nanosheets, the strength and fatigue resistance of the material are further improved, solving the multiphase interface compatibility problem of traditional systems. The hyperbranched polyamide segments are tightly anchored to the low-hygroscopic polyamide resin dispersion phase through hydrogen and amide bonds, and are also firmly bonded to the polypropylene resin matrix through physical entanglement and chemical coupling with maleic anhydride-grafted polypropylene, thus strongly connecting the polypropylene and polyamide phases. At the same time, the highly dispersed graphene sheets can effectively overlap with glass fibers, jointly constructing a stable three-dimensional interpenetrating reinforcement network, enabling efficient stress transfer and uniform dispersion. Ethylene-octene copolymer, as a traditional toughening phase, continues to play its elastomer function in this synergistic system, giving the prepared high-strength polypropylene engineering plastic composition excellent impact toughness while ensuring ultra-high strength. Detailed Implementation

[0019] The technical solutions in the embodiments of the present invention will be clearly and completely described below. 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 skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] Example 1: The preparation method of hydrophobically modified nano-titanium dioxide coated sericite composite particles includes the following steps: 20g of sericite (d50 and d90 are 1.59μm and 6.88μm, respectively) was added to an ethanol / water mixture with a volume ratio of 1:1 to prepare a 10% (w / w) suspension. The suspension was then placed in an 85℃ water bath and continuously stirred for 10 min. A 10% (w / w) oxalic acid solution was added dropwise to adjust the pH of the suspension to 4.5, and the suspension was continuously stirred for 20 min. 20g of tetrabutyl titanate and a pH adjuster were added simultaneously using a peristaltic pump to maintain a constant pH of 5. After the tetrabutyl titanate was completely added, the mixture was stirred for 1.5 h and then aged for 2 h. After filtration, washing, drying, and dispersing, nano-titanium dioxide-coated sericite composite particles were obtained. 20g of the above-mentioned nano-titanium dioxide coated sericite composite particles were added to an ethanol-water mixture with a volume ratio of 8:1. After ultrasonic dispersion for 30min, acetic acid was slowly added dropwise to adjust the pH of the solution to 4. Then, 3g of silane coupling agent γ-methacryloyloxypropyltrimethoxysilane was added. The mixture was stirred continuously at 60℃ using a magnetic stirrer for 12h. After the reaction was completed, the mixture was washed with alcohol and dried in an aging chamber to obtain hydrophobically modified nano-titanium dioxide coated sericite composite particles.

[0021] Example 2: The preparation method of hydrophobically modified nano-titanium dioxide coated sericite composite particles includes the following steps: 20g of sericite (d50 and d90 are 1.59μm and 6.88μm, respectively) was added to an ethanol / water mixture with a volume ratio of 1:1 to prepare a 10% (w / w) suspension. The suspension was then placed in an 85℃ water bath and continuously stirred for 10 min. A 10% (w / w) oxalic acid solution was added dropwise to adjust the pH of the suspension to 4.5, and the suspension was continuously stirred for 20 min. 30g of tetrabutyl titanate and a pH adjuster were added simultaneously using a peristaltic pump to maintain a constant pH of 5. After the tetrabutyl titanate was completely added, the mixture was stirred for 1.5 h and then aged for 2 h. The mixture was then filtered, washed, dried, and dispersed to obtain nano-titanium dioxide-coated sericite composite particles. 20g of the above-mentioned nano-titanium dioxide coated sericite composite particles were added to an ethanol-water mixture with a volume ratio of 8:1. After ultrasonic dispersion for 30min, acetic acid was slowly added dropwise to adjust the pH of the solution to 4. Then, 3g of silane coupling agent γ-methacryloyloxypropyltrimethoxysilane was added. The mixture was stirred continuously at 60℃ using a magnetic stirrer for 12h. After the reaction was completed, the mixture was washed with alcohol and dried in an aging chamber to obtain hydrophobically modified nano-titanium dioxide coated sericite composite particles.

[0022] Example 3: The preparation method of hyperbranched polyamide-modified graphene nanosheets includes the following steps: Add 82.4 g of diethylenetriamine to a 500 mL four-necked flask, then slowly add 100 g of succinic anhydride, heat at 50 °C for 2 h, then raise the temperature to 140 °C and hold for 4 h, and then quickly cool to room temperature to obtain hyperbranched polyamide. 1g of graphene nanosheets were dispersed in 250mL of distilled water and sonicated for 60min. The pH was adjusted to 9.0 by adding sodium hydroxide solution. 5g of the above hyperbranched polyamide was dissolved in 300mL of distilled water. Under vigorous stirring, the aqueous solution of hyperbranched polyamide was added dropwise to the dispersion of graphene nanosheets over 30min. After heating at 80℃ for 60min, the solution was rapidly cooled to 30℃. The nanosheets were washed repeatedly with distilled water 3-5 times and then freeze-dried to obtain hyperbranched polyamide-modified graphene nanosheets.

[0023] Example 4: The preparation method of the high-strength polypropylene engineering plastic composition for the water press truck includes the following steps: 65 parts by weight of polypropylene resin (4204), 6 parts by weight of polyamide resin (SG30), 5 parts by weight of ethylene-octene copolymer (8150), 4 parts by weight of hydrophobic modified nano-titanium dioxide coated sericite composite particles prepared in Example 1, 3 parts by weight of maleic anhydride grafted polypropylene (KF118), 2.5 parts by weight of hyperbranched polyamide modified graphene nanosheets prepared in Example 3, 0.2 parts by weight of antioxidant 1010, 0.2 parts by weight of antioxidant 168, 0.3 parts by weight of hindered amine light stabilizer (UV3529), and 0.8 parts by weight of lubricant calcium stearate were added to a high-speed mixer and mixed at 80°C for 8 min to obtain a premix. The above premixed material is added from the main feed port of the twin-screw extruder, and 25 parts by weight of chopped glass fiber (ERS300-14-T635B) is added from the side feed port. The temperature of each section of the twin-screw extruder is set as follows: Zone 1 200℃, Zone 2 220℃, Zone 3 230℃, Zone 4 235℃, and Die Head 225℃. The screw speed is 350-400 rpm. After melt extrusion, water cooling, and pelletizing, a high-strength polypropylene engineering plastic composition for water pressing vehicles is obtained.

[0024] Example 5: The preparation method of the high-strength polypropylene engineering plastic composition for a water press truck includes the following steps: 65 parts by weight of polypropylene resin (4204), 6 parts by weight of polyamide resin (SG30), 5 parts by weight of ethylene-octene copolymer (8150), 4 parts by weight of hydrophobic modified nano-titanium dioxide coated sericite composite particles prepared in Example 2, 3 parts by weight of maleic anhydride grafted polypropylene (KF118), 2.5 parts by weight of hyperbranched polyamide modified graphene nanosheets prepared in Example 3, 0.2 parts by weight of antioxidant 1010, 0.2 parts by weight of antioxidant 168, 0.3 parts by weight of hindered amine light stabilizer (UV3529), and 0.8 parts by weight of lubricant calcium stearate were added to a high-speed mixer and mixed at 80°C for 8 min to obtain a premix. The above premixed material is added from the main feed port of the twin-screw extruder, and 25 parts by weight of chopped glass fiber (ERS300-14-T635B) is added from the side feed port. The temperature of each section of the twin-screw extruder is set as follows: Zone 1 200℃, Zone 2 220℃, Zone 3 230℃, Zone 4 235℃, and Die Head 225℃. The screw speed is 350-400 rpm. After melt extrusion, water cooling, and pelletizing, a high-strength polypropylene engineering plastic composition for water pressing vehicles is obtained.

[0025] Example 6: The preparation method of the high-strength polypropylene engineering plastic composition for a water press truck includes the following steps: 70 parts by weight of polypropylene resin (4204), 10 parts by weight of polyamide resin (SG30), 8 parts by weight of ethylene-octene copolymer (8150), 7 parts by weight of hydrophobic modified nano-titanium dioxide coated sericite composite particles prepared in Example 1, 2 parts by weight of maleic anhydride grafted polypropylene (KF118), 1.5 parts by weight of hyperbranched polyamide modified graphene nanosheets prepared in Example 3, 0.1 parts by weight of antioxidant 1010, 0.1 parts by weight of antioxidant 168, 0.2 parts by weight of hindered amine light stabilizer (UV3529), and 0.5 parts by weight of lubricant calcium stearate were added to a high-speed mixer and mixed at 80°C for 8 min to obtain a premix. The premixed material was added from the main feed port of the twin-screw extruder, and 20 parts by weight of chopped glass fiber (ERS300-14-T635B) was added from the side feed port. The temperature of each section of the twin-screw extruder was set as follows: Zone 1 200℃, Zone 2 220℃, Zone 3 230℃, Zone 4 235℃, and Die Head 225℃. The screw speed was 350-400 rpm. After melt extrusion, water cooling, and pelletizing, a high-strength polypropylene engineering plastic composition for water pressing vehicles was obtained.

[0026] Example 7: The preparation method of the high-strength polypropylene engineering plastic composition for the water press truck includes the following steps: 70 parts by weight of polypropylene resin (4204), 10 parts by weight of polyamide resin (SG30), 8 parts by weight of ethylene-octene copolymer (8150), 7 parts by weight of hydrophobic modified nano-titanium dioxide coated sericite composite particles prepared in Example 2, 2 parts by weight of maleic anhydride grafted polypropylene (KF118), 1.5 parts by weight of hyperbranched polyamide modified graphene nanosheets prepared in Example 3, 0.1 parts by weight of antioxidant 1010, 0.1 parts by weight of antioxidant 168, 0.2 parts by weight of hindered amine light stabilizer (UV3529), and 0.5 parts by weight of lubricant calcium stearate were added to a high-speed mixer and mixed at 80°C for 8 min to obtain a premix. The premixed material was added from the main feed port of the twin-screw extruder, and 20 parts by weight of chopped glass fiber (ERS300-14-T635B) was added from the side feed port. The temperature of each section of the twin-screw extruder was set as follows: Zone 1 200℃, Zone 2 220℃, Zone 3 230℃, Zone 4 235℃, and Die Head 225℃. The screw speed was 350-400 rpm. After melt extrusion, water cooling, and pelletizing, a high-strength polypropylene engineering plastic composition for water pressing vehicles was obtained.

[0027] Comparative Example 1: The preparation method of hydrophobically modified sericite includes the following steps: 20g of sericite (d50 and d90 are 1.59μm and 6.88μm, respectively) was added to an ethanol / water mixture with a volume ratio of 8:1. After ultrasonic dispersion for 30min, acetic acid was slowly added dropwise to adjust the pH of the solution to 4. Then, 3g of silane coupling agent γ-methacryloyloxypropyltrimethoxysilane was added. The mixture was stirred continuously with a magnetic stirrer at 60℃ for 12h. After the reaction was completed, the mixture was washed with alcohol and dried in an aging chamber to obtain hydrophobically modified sericite.

[0028] Comparative Example 2: The preparation method of hydrophobically modified nano-titanium dioxide includes the following steps: 4g of nano-titanium dioxide was added to an ethanol-water mixture with a volume ratio of 8:1. After ultrasonic dispersion for 30 min, acetic acid was slowly added dropwise to adjust the pH of the solution to 4. Then, 0.6g of silane coupling agent γ-methacryloyloxypropyltrimethoxysilane was added. The mixture was stirred continuously at 60℃ with a magnetic stirrer for 12 h. After the reaction was completed, the mixture was washed with alcohol and dried in an aging chamber to obtain hydrophobically modified nano-titanium dioxide.

[0029] Compared with Example 4, Comparative Example 3 only replaced 4 parts by mass of the hydrophobic modified nano-titanium dioxide coated sericite composite particles prepared in Example 1 with 4 parts by mass of the hydrophobic modified sericite prepared in Comparative Example 1. The remaining components and preparation methods were completely the same as in Example 4.

[0030] Compared with Example 4, Comparative Example 4 only replaced 4 parts by mass of the hydrophobic modified nano-titanium dioxide coated sericite composite particles prepared in Example 1 with 4 parts by mass of the unhydrophobic modified nano-titanium dioxide coated sericite composite particles prepared in Example 1. The remaining components and preparation methods were completely the same as those in Example 4.

[0031] Compared with Example 4, Comparative Example 5 replaced 4 parts by mass of the hydrophobic modified nano-titanium dioxide coated sericite composite particles prepared in Example 1 with 4 parts by mass of the hydrophobic modified sericite prepared in Comparative Example 1 and the hydrophobic modified nano-titanium dioxide prepared in Comparative Example 2 (mass ratio 5:1). The remaining components and preparation methods were completely consistent with those of Example 4.

[0032] Compared with Example 4, Comparative Example 6 only replaced the hyperbranched polyamide-modified graphene nanosheets prepared in Example 3 with unmodified graphene nanosheets. The remaining components and preparation methods were completely the same as in Example 4.

[0033] Compared with Example 4, Comparative Example 7 only did not add the hydrophobic modified nano-titanium dioxide coated sericite composite particles prepared in Example 1. The other components and preparation methods were completely the same as in Example 4.

[0034] Compared with Example 4, Comparative Example 8 only did not add the hyperbranched polyamide-modified graphene nanosheets prepared in Example 3, while the other components and preparation methods were completely the same as in Example 4.

[0035] Performance testing Tensile strength: dumbbell-shaped specimens were tested according to ASTM D638:2014 at a tensile rate of 50 mm / min; the test results are shown in Table 1. Bending strength: Tested according to ASTM D790:2017, bending rate 2 mm / min, deflection 10 mm; test results are shown in Table 1; Notched impact strength of cantilever beam: tested according to ISO 180:2019; test results are shown in Table 1; Aging and yellowing resistance test: Accelerated aging test using a xenon lamp aging test chamber was conducted. The test samples were placed in the sample chamber according to GB / T16422.2-2014, and the samples were removed for testing after 1000 hours. The black panel temperature was 63℃±3℃, and the irradiance bandwidth (300nm-400nm) was 60W / m². 2 The narrowband (340nm) has a rate of 0.51 W / (m). 2 The test chamber temperature was 40℃, the relative humidity was 65%, and the water spraying cycle (spraying time / no spraying time) was 18min / 102min. Then, the color difference was calculated in the color difference tester according to GB / T7921. The observation conditions were: D65 light source. The test results are shown in Table 1. Heat and oxygen aging resistance test: The samples were subjected to heat and oxygen aging at 150℃ for 2000h in a high-temperature oven. The life end of the modified polypropylene was determined when the surface powdering area reached 10%. The test results are shown in Table 1. Table 1: Statistical Table of Performance Test Data of Specimens from Examples 4-7 and Comparative Examples 3-8

[0036] As shown in Table 1, the high-strength polypropylene engineering plastic composition for water-pressing vehicles provided in Examples 4-7 of the present invention has high strength, high toughness and long-lasting weather resistance. In Comparative Example 3, the sericite added was only hydrophobically modified without titanium dioxide coating, resulting in a significant decrease in the weather resistance of the polypropylene engineering plastic. In Comparative Example 4, the hydrophobically modified nano-titanium dioxide was used to coat the sericite, resulting in a decrease in the impact strength and a significant decrease in the thermo-oxidative aging time of the polypropylene engineering plastic. In Comparative Example 5, the sericite and nano-titanium dioxide were a physical mixture, resulting in a slight decrease in all aspects of the properties of the polypropylene engineering plastic and poor synergistic reinforcement. In Comparative Example 6, the graphene nanosheets were not modified, resulting in a significant decrease in the impact toughness of the polypropylene engineering plastic and limited improvement in mechanical properties. In Comparative Example 7, the sericite composite particles were not coated with hydrophobically modified nano-titanium dioxide, resulting in little change in the mechanical properties of the polypropylene engineering plastic, but a sharp deterioration in weather resistance. In Comparative Example 8, the graphene nanosheets were not modified with hyperbranched polyamide, resulting in a significant decrease in the tensile, flexural, and impact strength of the polypropylene engineering plastic.

[0037] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0038] The foregoing has provided a detailed description of one embodiment of the present invention, but this description is merely a preferred embodiment and should not be construed as limiting the scope of the invention. All equivalent variations and modifications made within the scope of the claims of this invention should still fall within the patent coverage of this invention.

Claims

1. A high-strength polypropylene engineering plastic composition for a water press truck, characterized in that, It shall include at least the following parts by weight of raw materials: Polypropylene resin 65-70 parts; polyamide resin 5-10 parts; chopped glass fiber 20-25 parts; ethylene-octene copolymer 5-8 parts; hydrophobically modified nano-titanium dioxide coated sericite composite particles 3-8 parts; maleic anhydride grafted polypropylene 2-3 parts; hyperbranched polyamide modified graphene nanosheets 1-3 parts; antioxidant 0.3-0.5 parts; light stabilizer 0.2-0.4 parts; lubricant 0.5-1 parts.

2. The high-strength polypropylene engineering plastic composition for a water-pressing vehicle according to claim 1, characterized in that, The polypropylene resin is a copolymer polypropylene, and the melt index of the copolymer polypropylene is 2-100 g / 10 min. The polyamide resin is one or a mixture of nylon 1010, nylon 12 or nylon 6.

3. The high-strength polypropylene engineering plastic composition for a water-pressing vehicle according to claim 1, characterized in that, The preparation method of the hydrophobically modified nano-titanium dioxide coated sericite composite particles includes at least the following preparation steps: Sericite, tetrabutyl titanate, and pH adjuster were added to an ethanol / water mixture to adjust the pH to 4-5. The mixture was then stirred, aged, filtered, washed, dried, and dispersed to obtain nano-titanium dioxide-coated sericite composite particles. The nano-titanium dioxide-coated sericite composite particles were dispersed in an ethanol / water mixed solution, the pH was adjusted to 4-5, γ-methacryloyloxypropyltrimethoxysilane was added, and after the reaction, the particles were washed and dried to obtain hydrophobically modified nano-titanium dioxide-coated sericite composite particles.

4. The high-strength polypropylene engineering plastic composition for a water-pressing vehicle according to claim 3, characterized in that, The thickness of the nano-titanium dioxide coating in the nano-titanium dioxide-coated sericite composite particles is 20-100 nm, and the pH adjuster is a 10% NaOH solution and a 10% oxalic acid solution.

5. The high-strength polypropylene engineering plastic composition for a water-pressing vehicle according to claim 3, characterized in that, The mass ratio of sericite to tetrabutyl titanate is 1:0.5-2, and the addition ratio of nano-titanium dioxide-coated sericite composite particles to γ-methacryloyloxypropyltrimethoxysilane is 5-10:

1.

6. The high-strength polypropylene engineering plastic composition for a water-pressing vehicle according to claim 1, characterized in that, The preparation method of the hyperbranched polyamide-modified graphene nanosheets includes at least the following preparation steps: Succinic anhydride was added to diethylenetriamine, and after reaction, hyperbranched polyamide was obtained. Graphene nanosheets were dispersed in distilled water, the pH was adjusted to 9-10, and an aqueous solution of the hyperbranched polyamide was added. After the reaction, the mixture was washed and freeze-dried to obtain hyperbranched polyamide-modified graphene nanosheets.

7. The high-strength polypropylene engineering plastic composition for a water-pressing vehicle according to claim 6, characterized in that, The mass ratio of the succinic anhydride to the diethylenetriamine is 10:7-10.

8. The high-strength polypropylene engineering plastic composition for a water-pressing vehicle according to claim 6, characterized in that, The mass ratio of the graphene nanosheets to the hyperbranched polyamide is 1:4-6.

9. The high-strength polypropylene engineering plastic composition for a water-pressing vehicle according to claim 1, characterized in that, The antioxidant is at least one of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, tris(2,4-di-tert-butylphenyl) phosphite, or bis(2,4-di-tert-butylphenol) pentaerythritol diphosphite; the light stabilizer is at least one of benzophenones, benzotriazoles, triazines, substituted acrylonitriles, or hindered amines; and the lubricant is at least one of zinc stearate, calcium stearate, stearic acid, oleamide, erucamide, stearamide, or ethylene bis-stearamide.

10. The method for preparing the high-strength polypropylene engineering plastic composition for a water-pressing vehicle according to any one of claims 1-9, characterized in that, It includes at least the following preparation steps: Polypropylene resin, polyamide resin, ethylene-octene copolymer, hydrophobically modified nano-titanium dioxide coated sericite composite particles, maleic anhydride grafted polypropylene, hyperbranched polyamide modified graphene nanosheets, antioxidant, light stabilizer and lubricant are added to a high-speed mixer and mixed to obtain a premix. The premixed material is added from the main feed port of a twin-screw extruder, and chopped glass fibers are added from the side feed port. After melt extrusion, water cooling, and pelletizing, a high-strength polypropylene engineering plastic composition for water pressing vehicles is obtained.

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