PCR ABS (Polymerase Chain Reaction Acrylonitrile Butadiene Styrene) modified material for sweeper and preparation method thereof

Abstract

The invention relates to the technical field of recovery and regeneration of waste ABS (Acrylonitrile Butadiene Styrene), and discloses a PCR (Polymerase Chain Reaction) ABS modified material for a sweeper and a preparation method of the PCR ABS modified material. The PCR ABS modified material for the sweeper comprises the following raw material components: a PCR ABS material, a composite modifier, an antioxidant, a light stabilizer, a wear-resistant agent, an antistatic agent and a flame retardant, the composite modifier is a compound of maleic anhydride grafted polypropylene and a maleic anhydride grafted acrylonitrile-butadiene-styrene copolymer, and the mass ratio of the maleic anhydride grafted polypropylene to the maleic anhydride grafted acrylonitrile-butadiene-styrene copolymer is (2-4.5): 1. According to the preparation method disclosed by the invention, the prepared PCR ABS modified material has good mechanical property, wear resistance, impact resistance, antistatic property and aging resistance through the steps of pretreatment, segmented material mixing, melt blending and extrusion, post-treatment and curing.

Description

Technical Field

[0001] This application relates to the field of recycling and regeneration technology of waste ABS, and in particular to a PCR ABS modified material for sweepers and its preparation method. Background Technology

[0002] Currently, with increasing environmental awareness, recycling waste plastics has become an important way to reduce environmental pollution and conserve resources. ABS (acrylonitrile-butadiene-styrene copolymer) is widely used in the casings and structural components of household appliances due to its excellent comprehensive mechanical properties, processing fluidity, and surface gloss. Among them, PCR (Post-Consumer Recycled) ABS material, which is ABS material recycled after consumption, has become a research hotspot due to its strong recyclability and its significant role in resource conservation and environmental protection.

[0003] However, after one or more uses, recycling, and reprocessing, the polymer chains of PCR ABS materials are prone to breakage, cross-linking, or degradation, leading to a significant decline in their original properties. For example, mechanical properties such as impact toughness and tensile strength decrease drastically, and their resistance to heat-oxidative aging and UV aging is weak. Long-term use can result in embrittlement and discoloration. Currently, common modification methods mainly rely on blending with a high proportion of virgin ABS or adding expensive compatibilizers and reinforcing agents to restore some properties. However, this significantly sacrifices the material's environmental value and economic efficiency, and fails to fundamentally solve the performance instability problem of the PCR matrix caused by historical processing damage.

[0004] As a home appliance integrating precision mechanics, electronics, and aesthetic design, robotic vacuum cleaners require materials for their outer shell and internal structural components to possess sufficient strength, rigidity, and impact resistance to protect internal components. They also need to exhibit good toughness, wear resistance, and antistatic properties. Existing high-content PCR ABS modified materials often struggle to simultaneously meet these stringent performance requirements, particularly in terms of wear resistance and antistatic properties, thus failing to adequately satisfy the high-performance material requirements of robotic vacuum cleaners. Summary of the Invention

[0005] To at least overcome one of the problems existing in the prior art, one objective of this invention is to provide a PCR ABS modified material for sweeping machines. This PCR ABS modified material for sweeping machines uses PCR ABS material, a composite modifier, an antioxidant, a light stabilizer, an abrasion resistant agent, an antistatic agent, and a flame retardant as raw materials. The composite modifier is a compound of maleic anhydride-grafted polypropylene and maleic anhydride-grafted acrylonitrile-butadiene-styrene copolymer, with a mass ratio of maleic anhydride-grafted polypropylene to maleic anhydride-grafted acrylonitrile-butadiene-styrene copolymer of (2~4.5):1. The resulting PCR ABS modified material for sweeping machines possesses excellent rigidity and toughness, strong abrasion resistance, and also exhibits antistatic properties, flame retardancy, and aging resistance, meeting the stringent requirements of sweeping machines and other applications for PCR ABS modified materials. A second objective of this invention is to provide a method for preparing the aforementioned PCR ABS modified material for sweeping machines.

[0006] Therefore, the present invention adopts the following technical solution: The first aspect of the present invention provides a PCR ABS modified material for a sweeping machine, the raw material components of which include: PCR ABS material, a composite modifier, an antioxidant, a light stabilizer, an abrasion resistant agent, an antistatic agent, and a flame retardant; the composite modifier is a compound of maleic anhydride-grafted polypropylene and maleic anhydride-grafted acrylonitrile-butadiene-styrene copolymer, and the mass ratio of maleic anhydride-grafted polypropylene to maleic anhydride-grafted acrylonitrile-butadiene-styrene copolymer is (2~4.5):1.

[0007] In the raw material composition of the PCR ABS modified material for sweeping machines used in this application, PCR ABS material is used as the matrix, and it forms a functional complement with components such as composite modifier, antioxidant, light stabilizer, wear-resistant agent, and antistatic agent. This effectively realizes the recycling of waste plastics, and at the same time, it specifically solves the problems of poor mechanical properties, insufficient aging resistance, and lack of wear resistance and antistatic properties of traditional PCR ABS materials. In the raw material components of PCR ABS modified materials, the composite modifier adopts a compound of maleic anhydride-grafted polypropylene and maleic anhydride-grafted acrylonitrile-butadiene-styrene copolymer with a mass ratio of (2~4.5):1. Maleic anhydride-grafted polypropylene is beneficial to improve the rigidity and tensile strength of the material, but its compatibility with PCR ABS material is limited. On the other hand, maleic anhydride-grafted acrylonitrile-butadiene-styrene copolymer has good compatibility with PCR ABS material, which makes up for the defects of maleic anhydride-grafted polypropylene, improves the uniform dispersion of maleic anhydride-grafted polypropylene in PCR ABS material, and synergistically improves the mechanical properties of PCR ABS modified materials. This meets the comprehensive requirements of sweeper shells and parts for PCR ABS modified materials such as low cost, high rigidity, high toughness, and strong wear resistance.

[0008] Preferably, the maleic anhydride-grafted polypropylene has a grafting rate of 0.8% to 1.2%, a melt flow rate of 25 to 40 g / 10 min at 230°C / 2.16 kg, and a weight-average molecular weight of 150,000 to 280,000. More preferably, the maleic anhydride-grafted polypropylene has a grafting rate of 0.9% to 1.2%, a melt flow rate of 30 to 40 g / 10 min at 230°C / 2.16 kg, and a weight-average molecular weight of 200,000 to 280,000.

[0009] Preferably, the maleic anhydride-grafted acrylonitrile-butadiene-styrene copolymer has a grafting rate of 1%~1.8%, a melt flow rate of 8~20 g / 10 min at 230℃ / 2.16 kg, and a rubber phase content of 10%~25%. More preferably, the maleic anhydride-grafted acrylonitrile-butadiene-styrene copolymer has a grafting rate of 1.3%~1.8%, a melt flow rate of 10~20 g / 10 min at 230℃ / 2.16 kg, and a rubber phase content of 15%~25%.

[0010] Preferably, the wear-resistant agent is at least one of polytetrafluoroethylene (PTFE) micro powder and polyethylene micro powder, and the particle size of the wear-resistant agent is 10-50 μm. More preferably, the wear-resistant agent is at least one of polytetrafluoroethylene (PTFE) micro powder and polyethylene micro powder, and the particle size of the wear-resistant agent is 20-50 μm. Even more preferably, the wear-resistant agent is a compound of polytetrafluoroethylene (PTFE) micro powder and polyethylene micro powder in a mass ratio of (2-4):(2-3), and the particle size of the wear-resistant agent is 30-50 μm.

[0011] Among the aforementioned wear-resistant agents, polytetrafluoroethylene (PTFE) micropowder has a low coefficient of friction, effectively reducing the surface friction coefficient and frictional resistance. Polyethylene micropowder itself possesses certain toughness and impact resistance, and its low melting point facilitates more uniform dispersion within the PCR ABS material matrix during melt blending. Controlling the particle size of the wear-resistant agents within the range of 10–50 μm ensures both uniform dispersion of the particles in the matrix and prevents damage to the material's mechanical properties due to excessively large particle sizes, thus achieving optimal wear resistance in the PCR ABS modified material.

[0012] Preferably, the antistatic agent is selected from ethoxylated alkylamine quaternary ammonium salt or stearamide propyl quaternary ammonium salt. More preferably, the ethoxylated alkylamine quaternary ammonium salt is selected from at least one of ethoxylated coconut oil alkyl methyl sulfate ammonium and ethoxylated hydrogenated tallow alkyl methyl nitrate ammonium, and the stearamide propyl quaternary ammonium salt is selected from at least one of stearamide propyl hydroxyethyl phosphate and stearamide propyl dimethyl methyl sulfate ammonium. Even more preferably, the ethoxylated alkylamine quaternary ammonium salt is selected from ethoxylated coconut oil alkyl methyl sulfate ammonium, and the stearamide propyl quaternary ammonium salt is selected from stearamide propyl hydroxyethyl phosphate ammonium.

[0013] Preferably, the antioxidant is a compound of antioxidant 1010, antioxidant 3114, and antioxidant 168, and the mass ratio of antioxidant 1010, antioxidant 3114, and antioxidant 168 is (1~2):(0.3~0.6):(0.5~1). More preferably, the antioxidant is a compound of antioxidant 1010, antioxidant 3114, and antioxidant 168, and the mass ratio of antioxidant 1010, antioxidant 3114, and antioxidant 168 is (1.6~2):(0.4~0.6):(0.5~1).

[0014] Preferably, the light stabilizer is a hindered amine light stabilizer. More preferably, the hindered amine light stabilizer is selected from at least one of hindered amine light stabilizer 292, hindered amine light stabilizer 622, hindered amine light stabilizer 770, and hindered amine light stabilizer 944. Even more preferably, the hindered amine light stabilizer is selected from at least one of hindered amine light stabilizer 292, hindered amine light stabilizer 622, and hindered amine light stabilizer 944.

[0015] Preferably, the flame retardant is a compound of montmorillonite and aluminum hydroxide surface-modified with a titanate coupling agent, and the mass ratio of montmorillonite to aluminum hydroxide surface-modified with a titanate coupling agent is (6~10):(1~3). More preferably, the flame retardant is a compound of montmorillonite and aluminum hydroxide surface-modified with a titanate coupling agent, and the mass ratio of montmorillonite to aluminum hydroxide surface-modified with a titanate coupling agent is (7~10):(2~3).

[0016] Ethoxylated alkylamine quaternary ammonium salts or stearamidopropyl quaternary ammonium salts are antistatic agents with rapid migration speeds, enabling them to quickly form a conductive layer on the material surface. This effectively reduces the surface resistance of the material, preventing dust from being attracted by static electricity during sweeping operation and ensuring the cleanliness and heat dissipation of the equipment. Furthermore, these two antistatic agents exhibit good compatibility with the PCR ABS material matrix and other components in the formulation, and compatibility issues will not reduce the mechanical properties of the material.

[0017] Among the antioxidants, antioxidant 1010 is a hindered phenolic primary antioxidant that can efficiently capture free radicals generated during the preparation and use of PCR ABS modified materials; antioxidant 3114 is a high molecular weight hindered phenolic antioxidant with a high thermal decomposition temperature, which does not decompose under the high-temperature environment of melt extrusion during the preparation of PCR ABS modified materials, thus contributing to the long-term maintenance of the antioxidant effect; antioxidant 168 is a phosphite auxiliary antioxidant that can decompose hydroperoxides in the material, preventing them from further generating free radicals. The specific compound ratio of these three agents achieves good antioxidant effects and also helps to maintain the antioxidant effect during long-term use, meeting the aging resistance requirements of sweeping machines for long-term indoor and outdoor use.

[0018] Hindered amine light stabilizers effectively prevent embrittlement, yellowing, and performance degradation caused by ultraviolet radiation by inhibiting photo-oxidation, thus extending product lifespan. The flame retardant is a blend of montmorillonite and surface-modified aluminum hydroxide. During combustion, the surface-modified aluminum hydroxide decomposes endothermally and dehydrates, while the montmorillonite layers act as a physical barrier and provide insulation. Together, they enhance the flame retardant efficiency of PCR ABS modified materials.

[0019] Preferably, in the raw materials of the PCR ABS modified material for the sweeper, the weight ratio of PCR ABS material, composite modifier, antioxidant and light stabilizer is (65-90):(4.5-12):(1.1-2.8):(1-3).

[0020] Preferably, in the raw materials of the PCR ABS modified material for the sweeper, the weight ratio of PCR ABS material, composite modifier, antioxidant, light stabilizer and abrasion resistant agent is (65-90): (4.5-12): (1.1-2.8): (1-3): (3.7-5).

[0021] Preferably, in the raw materials of the PCR ABS modified material for the sweeper, the weight ratio of PCR ABS material, composite modifier, antioxidant, light stabilizer, abrasion resistant agent and antistatic agent is (65-90): (4.5-12): (1.1-2.8): (1-3): (3.7-5): (0.5-3).

[0022] Preferably, in the raw materials of the PCR ABS modified material for the sweeper, the weight ratio of PCR ABS material, composite modifier, antioxidant, light stabilizer, abrasion resistant agent, antistatic agent and flame retardant is (65-90):(4.5-12):(1.1-2.8):(1-3):(3.7-5):(0.5-3):(2-6).

[0023] In the above technical solution, 65-90 parts by weight of PCR ABS material constitutes the largest proportion of the raw material components, ensuring a high recycling rate of waste plastics. The addition of 4.5-12 parts by weight of composite modifier and 1.1-2.8 parts by weight of antioxidant allows each functional component to play its full role, avoiding insufficient performance improvement due to insufficient addition of a certain component or cost waste due to excessive addition. The 4.5-12 parts by weight of composite modifier and 3.7-5 parts by weight of wear-resistant agent work synergistically to greatly improve the rigidity and wear resistance of the material. 1.1-2.8 parts by weight of antioxidant and 1-3 parts by weight of light stabilizer help extend the aging resistance of the material. Antistatic agent and flame retardant respectively endow the material with good antistatic and flame retardant properties, ultimately achieving the best overall performance of the PCR ABS modified material.

[0024] A second aspect of the present invention provides a method for preparing a PCR ABS modified material for a sweeper according to the first aspect of the present invention, comprising the following steps: S1. Pretreatment: The PCR ABS material is ultrasonically cleaned, broken up, and dried; S2: Segmented mixing: The first stage of mixing is carried out by adding pretreated PCR ABS material, composite modifier, antioxidant, light stabilizer and flame retardant, and then the second stage of mixing is carried out by adding abrasion resistant agent and antistatic agent to obtain premix; S3: Melt blending and extrusion: The premixed material is melt blended and extruded to obtain melt strips; S4: Post-processing and curing: After cooling, pelletizing, screening and drying the melt strip, it is subjected to constant temperature curing to obtain PCR ABS modified material for sweeping machines.

[0025] Preferably, in step S1, the ultrasonic cleaning power is 150-350W and the time is 20-40 minutes; the crushing is performed by crushing the PCR ABS material with a crusher, and then screening for particles with a particle size of 1-6 mm; the drying temperature is 80-120℃ and the drying time is 2-6 hours. More preferably, in step S1, the ultrasonic cleaning power is 180-350W and the time is 25-40 minutes; the crushing is performed by crushing the PCR ABS material with a crusher, and then screening for particles with a particle size of 1-6 mm; the drying temperature is 90-120℃ and the drying time is 4-6 hours.

[0026] Preferably, in step S2, the temperature of the first mixing stage is 25~30℃ and the time is 3~6 min; the temperature of the second mixing stage is 40~60℃ and the time is 5~10 min. More preferably, in step S2, the temperature of the first mixing stage is 28~30℃ and the time is 3~6 min; the temperature of the second mixing stage is 45~60℃ and the time is 5~10 min.

[0027] Preferably, in step S3, the temperature gradient from the feed port to the die head in the extrusion process is 180℃, 200℃, 215℃, 225℃, 230℃, 225℃, the die head temperature is 220℃, and the rotation speed is 350~450 rpm. More preferably, in step S3, the temperature gradient from the feed port to the die head in the extrusion process is 180℃, 200℃, 215℃, 225℃, 230℃, 225℃, the die head temperature is 220℃, and the rotation speed is 400~450 rpm.

[0028] Preferably, in step S4, the temperature for constant temperature curing is 60~80℃, and the time is 6~12h. More preferably, in step S4, the temperature for constant temperature curing is 70~80℃, and the time is 8~12h.

[0029] In this preparation method, the process includes pretreatment, segmented mixing, melt blending and extrusion, post-treatment, and aging. Specifically, the pretreatment in step S1 yields clean and dry PCR particles with a particle size of 1-6 mm. ABS material; Step S2: The first stage of mixing is carried out at 25~30℃ for 3~6 minutes to achieve preliminary uniform mixing of some raw materials, while avoiding premature softening of low melting point or heat-sensitive components. The second stage of mixing is carried out at a slightly higher temperature of 40~60℃ for 5~10 minutes, which helps to moderately soften some additives, promote their coating and preliminary dispersion in the raw materials, and lay a good foundation for subsequent melt blending. Step S3: The gradient temperature from the feed port to the die head, and the die head temperature of 220℃, helps to avoid insufficient melting due to excessively low temperature, resulting in unmelted particles, or material degradation due to excessively high temperature, resulting in a decrease in mechanical properties. In addition, the rotation speed of 350~450rpm provides sufficient shear force for the premix, promotes further melt blending of each component, improves dispersion uniformity, and ensures continuous and stable extrusion of melt strips. Step S4: The curing process relaxes the stress to a certain extent, effectively reducing the adhesion between particles and ensuring the quality stability between batches.

[0030] Compared with the prior art, the present invention has at least the following beneficial effects: 1) The raw material components of the PCR ABS modified material for sweepers in this application include PCR ABS material, composite modifier, antioxidant, light stabilizer, wear-resistant agent, antistatic agent and flame retardant. Among them, the composite modifier is a compound of maleic anhydride grafted polypropylene and maleic anhydride grafted acrylonitrile-butadiene-styrene copolymer. Through the reasonable proportion of each raw material component, especially the specific composition of composite modifier, wear-resistant agent, antistatic agent, etc., the PCR ABS modified material for sweepers obtained has good mechanical properties, wear resistance, impact resistance, antistatic and aging resistance.

[0031] 2) In the preparation method of the PCR ABS modified material for sweeping machine of this application, the PCR ABS modified material of this application is obtained by pretreatment, segmented mixing, melt blending and extrusion, post-treatment and curing, and the preparation conditions of each step are strictly controlled. This preparation method effectively improves the toughness, wear resistance and other properties and overall stability of the PCR ABS modified material. Detailed Implementation

[0032] The present invention will be further described in detail below through specific embodiments, comparative examples and tables, but is not limited to all the discussions and data.

[0033] The raw material components of the PCR ABS modified material used in sweepers include: maleic anhydride-grafted polypropylene purchased from Shanghai Rizhisheng New Technology Development Co., Ltd., with a grafting rate of 1.0%, a melt flow rate of 30 g / 10 min at 230℃ / 2.16 kg, and a weight-average molecular weight of 200,000; maleic anhydride-grafted acrylonitrile-butadiene-styrene copolymer purchased from Guangdong Jushi Chemical Co., Ltd., with a grafting rate of 1.1%~1.4%, a melt flow rate of 16~20 g / 10 min at 230℃ / 2.16 kg, and a rubber phase content of 10%~13%; polytetrafluoroethylene micropowder purchased from Shanghai Tongshi Technology Co., Ltd., with an average particle size of 35~40 μm; and polyethylene micropowder purchased from Mitsui Chemicals Co., Ltd. of Japan, model Chemipearl W400, with a particle size of 40 μm.

[0034] The preparation method of aluminum hydroxide surface modified with titanate coupling agent is as follows: 100g of dried aluminum hydroxide powder with a particle size D50 of 8μm is preheated to 110℃, and a 45% mass concentration isopropyltris(dioctylpyrophosphoryloxy)titanate ethanol solution is sprayed onto the aluminum hydroxide powder under stirring. The amount of isopropyltris(dioctylpyrophosphoryloxy)titanate is 1.5% of the weight of aluminum hydroxide. The reaction is carried out at 110℃ for 30min, and then cooled to obtain aluminum hydroxide surface modified with titanate coupling agent.

[0035] It is particularly important to emphasize that, unless otherwise specified, the raw materials, reagents or devices used in this invention can be obtained from conventional commercial sources.

[0036] Examples of PCR-modified ABS materials for use in sweepers: A PCR-modified ABS material for use in sweeping machines is prepared through the following steps: S1. Pretreatment: 650-900g of PCR ABS material was ultrasonically cleaned for 20-40 minutes at a power of 150-350W, transferred to a crusher for crushing, and then screened for particles with a particle size of 1-6mm. The material was then dried at 80-120℃ for 2-6 hours.

[0037] S2: Segmented mixing: Add the pretreated PCR ABS material, 45-120g of composite modifier, 11-28g of antioxidant, 10-30g of light stabilizer, and 20-60g of flame retardant to a high-speed mixer and perform the first stage of mixing at 25-30℃ for 3-6 minutes; then add 37-50g of abrasion resistant agent and 5-30g of antistatic agent and perform the second stage of mixing at 40-60℃ for 5-10 minutes to obtain the premix. S3: Melt blending and extrusion: The premixed material is fed into a twin-screw extruder for melt blending and extrusion. The gradient temperature from the feed port to the die head is set to 180℃, 200℃, 215℃, 225℃, 230℃, and 225℃. The die head temperature is 220℃, and the screw speed is controlled at 350~450 rpm. After the melt is extruded through the die head, melt strips are obtained. S4: Post-processing and maturation: The melt strip is cooled and pelletized, then passed through a double-layer vibrating screen with an upper screen aperture of 4.5 mm and a lower screen aperture of 2.0 mm. The middle layer particles are collected and dried at 80~100℃ for 2~6 h. The dried particles are then transferred to a constant temperature maturation treatment at 60~80℃ for 6~12 h to obtain PCR ABS modified material for sweeping machines.

[0038] Regarding step S1, in some specific implementations, the amount of PCR ABS material used can be 650g, 700g, 750g, 810g, or 900g; the ultrasonic cleaning power can be 150W, 200W, 280W, or 350W; the ultrasonic cleaning time can be 20min, 30min, 35min, or 40min; after crushing, the particle size of the screened particles can be 1mm, 2mm, or 6mm; the drying temperature can be 80℃, 100℃, or 120℃; and the drying time can be 2h, 3h, or 6h.

[0039] Regarding step S2, in some specific embodiments, the composite modifier is a compound of maleic anhydride-grafted polypropylene and maleic anhydride-grafted acrylonitrile-butadiene-styrene copolymer, and the mass ratio of maleic anhydride-grafted polypropylene to maleic anhydride-grafted acrylonitrile-butadiene-styrene copolymer can be 2:1, 2.5:1, 3:1, 4:4, or 4.5:1. The grafting rate of maleic anhydride-grafted polypropylene can be 0.8%, 1%, 1.1%, or 1.2%, and the melt flow rate at 230℃ / 2.16kg can be 25g / L. The mass flow rate can be 0 min, 30 g / 10 min, or 40 g / 10 min, with a weight-average molecular weight of 150,000, 200,000, 230,000, or 280,000. The grafting rate of maleic anhydride-grafted acrylonitrile-butadiene-styrene copolymer can be 1%, 1.2%, 1.6%, or 1.8%, and the melt flow rate at 230℃ / 2.16 kg can be 8 g / 10 min, 15 g / 10 min, or 20 g / 10 min. The rubber phase content can be 10%, 15%, 20%, 22%, or 25%. The antioxidant is a compound of antioxidant 1010, antioxidant 3114, and antioxidant 168, and the mass ratio of antioxidant 1010, antioxidant 3114, and antioxidant 168 can be 1:0.3:0.5, 1.5:0.6:0.5, 2:0.5:0.8, or 2:0.6:1. The light stabilizer is a hindered amine light stabilizer, which may be selected from at least one of hindered amine light stabilizer 292, hindered amine light stabilizer 622, hindered amine light stabilizer 770, and hindered amine light stabilizer 944. The flame retardant is a compound of montmorillonite and aluminum hydroxide surface-modified with a titanate coupling agent, and the mass ratio of montmorillonite to aluminum hydroxide surface-modified with a titanate coupling agent may be 6:1, 7:1, 10:1, 7:2, or 10:3. The montmorillonite may be sodium montmorillonite, and the titanate coupling agent may be isopropyltris(dioctylpyrophosphate)titanate. The wear-resistant agent can be at least one of polytetrafluoroethylene (PTFE) micropowder and polyethylene (PE) micropowder, and the particle size of the wear-resistant agent can be 10 μm, 20 μm, 30 μm, 40 μm, or 50 μm. The mass ratio of PTFE micropowder to PE micropowder in the wear-resistant agent can be 2:2.1, 3:2, 4:2.7, or 4:3. The antistatic agent can be selected from ethoxylated alkylamine quaternary ammonium salt or stearamidopropyl quaternary ammonium salt. The ethoxylated alkylamine quaternary ammonium salt can be selected from at least one of ethoxylated coconut oil alkyl methyl sulfate ammonium or ethoxylated hydrogenated tallow alkyl methyl nitrate ammonium. The stearamidopropyl quaternary ammonium salt can be selected from at least one of stearamidopropyl hydroxyethyl phosphate ammonium or stearamidopropyl dimethyl methyl sulfate ammonium.

[0040] Regarding step S2, in some specific implementations, the amount of composite modifier can be 45g, 60g, 80g, 90g, or 120g; the amount of antioxidant can be 11g, 15g, 20g, or 28g; the amount of light stabilizer can be 10g, 16g, 23g, or 30g; the amount of flame retardant can be 20g, 30g, 50g, or 60g; the amount of abrasion resistant agent can be 37g, 40g, 45g, or 50g; and the amount of antistatic agent can be 5g, 12g, 18g, 25g, or 30g. The mixing time for the first stage can be 25℃, 28℃, or 30℃, and the mixing time can be 3min, 4min, or 6min; the mixing time for the second stage can be 40℃, 50℃, or 60℃, and the mixing time can be 5min, 7min, or 10min.

[0041] In some specific implementations, for step S3, the screw speed is controlled at 350 rpm, 370 rpm, 410 rpm, or 450 rpm.

[0042] Regarding step S4, in some specific implementations, the drying temperature can be 80℃, 85℃, 95℃ or 100℃, and the drying time can be 2h, 3h or 6h; the constant temperature curing temperature can be 60℃, 70℃ or 80℃, and the constant temperature curing time can be 6h, 9h, 10h or 12h. Example 1

[0043] A PCR-modified ABS material for use in sweeping machines is prepared through the following steps: S1. Pretreatment: 800g of PCR ABS material was ultrasonically cleaned for 25min at a power of 300W, transferred to a crusher for crushing, and then screened for particles with a particle size of 3mm. The material was then dried at 90℃ for 4h.

[0044] S2: Segmented Mixing: Based on the pretreated PCR ABS material, 90g of a maleic anhydride-grafted polypropylene and maleic anhydride-grafted acrylonitrile-butadiene-styrene copolymer compound in a mass ratio of 2:1, 18g of a compound of antioxidant 1010, antioxidant 3114 and antioxidant 168 in a mass ratio of 1:0.3:0.5, 20g of hindered amine light stabilizer 292, and 42g of a compound of sodium montmorillonite and aluminum hydroxide surface modified with titanate coupling agent in a mass ratio of 6:1 were added to a high-speed mixer. The first stage of mixing was carried out at 25°C for 6 minutes. Then, 45g of a compound of polytetrafluoroethylene micropowder and polyethylene micropowder in a mass ratio of 3:2 and 20g of ethoxylated coconut oil alkyl methyl sulfate ammonium were added. The second stage of mixing was carried out at 50°C for 8 minutes to obtain the premix. S3: Melt blending and extrusion: The premixed material is fed into a twin-screw extruder for melt blending and extrusion. The gradient temperature from the feed port to the die head is set to 180℃, 200℃, 215℃, 225℃, 230℃, and 225℃. The die head temperature is 220℃, and the screw speed is controlled at 400 rpm. After the melt is extruded through the die head, melt strips are obtained. S4: Post-processing and curing: The melt strip is cooled and pelletized, then passed through a double-layer vibrating screen with an upper screen mesh size of 4.5 mm and a lower screen mesh size of 2.0 mm. The middle layer particles are collected and dried at 90℃ for 5 hours. Then, they are transferred to a constant temperature curing treatment at 70℃ for 8 hours to obtain PCR ABS modified material for sweeping machines. Example 2

[0045] The preparation method of a PCR ABS modified material for a sweeper is the same as in Example 1, except that in Example 2, the mass ratio of maleic anhydride-grafted polypropylene and maleic anhydride-grafted acrylonitrile-butadiene-styrene copolymer is 3:1. Example 3

[0046] The preparation method of a PCR ABS modified material for a sweeper is the same as in Example 1, except that in Example 3, the mass ratio of maleic anhydride-grafted polypropylene and maleic anhydride-grafted acrylonitrile-butadiene-styrene copolymer is 4.5:1. Example 4

[0047] The preparation method of a PCR ABS modified material for a sweeper is the same as in Example 1, except that in Example 4, the mass ratio of polytetrafluoroethylene micro powder to polyethylene micro powder is 2:2.1. Example 5

[0048] The preparation method of a PCR ABS modified material for a sweeper is the same as in Example 1, except that in Example 5, the mass ratio of polytetrafluoroethylene micro powder to polyethylene micro powder is 4:3. Example 6

[0049] The preparation method of a PCR ABS modified material for a sweeping machine is the same as in Example 1, except that in Example 6, the mass of ethoxylated coconut oil alkyl methyl sulfate ammonium is changed to 25g. Example 7

[0050] The preparation method of a PCR ABS modified material for a sweeping machine is the same as in Example 1, except that in Example 7, ethoxylated coconut oil alkyl methyl sulfate ammonium is replaced by stearamide propyl hydroxyethyl phosphate in equal amounts.

[0051] Comparative Example 1: The preparation method of a PCR ABS modified material for a sweeper is the same as in Example 1, except that the mass ratio of maleic anhydride-grafted polypropylene and maleic anhydride-grafted acrylonitrile-butadiene-styrene copolymer in Comparative Example 1 is 1:1.

[0052] Comparative Example 2: The preparation method of a PCR ABS modified material for a sweeper is the same as in Example 1, except that the mass ratio of polytetrafluoroethylene micro powder to polyethylene micro powder in Comparative Example 2 is 3:4.

[0053] Comparative Example 3: The preparation method of a PCR ABS modified material for a sweeping machine is the same as in Example 1, except that in Comparative Example 3, the mass of ethoxylated coconut oil alkyl methyl sulfate ammonium is changed to 35g.

[0054] Comparative Example 4: The preparation method of a PCR ABS modified material for a sweeping machine is the same as in Example 7, except that in Comparative Example 4, the mass of stearamide propyl hydroxyethyl ammonium phosphate is changed to 35g.

[0055] Material performance testing: The PCR ABS modified materials for sweeping machines obtained in Examples 1-7 and Comparative Examples 1-4 were subjected to various performance tests, and the test methods are as follows: 1. Tensile strength: Tested according to ASTM D638.

[0056] 2. Bending strength: Tested according to ASTM D790.

[0057] 3. Notched impact strength of cantilever beam: Tested according to ASTM D256.

[0058] 4. Abrasion resistance (wear loss): Tested according to ASTM D4060.

[0059] 5. Surface resistivity: Tested in accordance with IEC 60093.

[0060] 6. Flame retardancy rating: Tested according to UL-94 (sample thickness 3mm).

[0061] 7. Aging resistance: According to ISO 4892-2, a standard impact specimen with a standard V-notch and an 80mm×10mm×4mm diameter is placed in a xenon lamp aging test chamber and aged for 500 hours. The notched impact strength of the cantilever beam after aging is tested, and the impact strength retention rate is calculated according to the following formula: Impact strength retention rate (%) = Impact strength value after 500 hours of aging / Impact strength value before aging × 100%.

[0062] The test properties of the PCR ABS modified materials used in sweepers in Examples 1-7 and Comparative Examples 1-4 are shown in Table 1 below:

[0063] Examples 1-7 describe PCR ABS modified materials for sweeping machines. These materials consist of PCR ABS material, composite modifiers, abrasion resistant agents, antistatic agents, antioxidants, and light stabilizers. Specifically, the composite modifiers, abrasion resistant agents, and antistatic agents with specific compositions or ratios result in PCR ABS modified materials that possess excellent mechanical properties, abrasion resistance, antistatic properties, flame retardancy, and aging resistance. Their tensile strength reaches 52-57 MPa, flexural strength reaches 84-89 MPa, and cantilever beam notched impact strength is 23-28 kJ / m. 2 The wear loss is only 40~48mg / 1000r, and the surface resistivity is 8.9×10. 8 ~2.1×10 10 With an Ω·sq range and a flame retardant rating of V-0, the impact strength retention rate after 500 hours of xenon lamp aging is in the range of 90.2%~92.4%, which can meet the stringent requirements of high rigidity, high toughness, wear resistance, antistatic properties, and aging resistance for the outer shell and structural components of sweeping machines.

[0064] Compared with Example 1, Comparative Example 1 differs in that the mass ratio of maleic anhydride-grafted polypropylene and maleic anhydride-grafted acrylonitrile-butadiene-styrene copolymer in Comparative Example 1 is 1:1, which is not within the scope defined in this application. The results show that the flexural strength of the PCR ABS modified material of Comparative Example 1 is 78 MPa, and the notched impact strength of the cantilever beam decreases to 20 kJ / m. 2 After 500 hours of xenon lamp aging, the impact strength retention rate was only 87.1%. This may be because the proportion of maleic anhydride-grafted acrylonitrile-butadiene-styrene copolymer in the composite modifier is too high. Although it has good compatibility with PCR ABS material, the maleic anhydride-grafted polypropylene is relatively insufficient, which leads to a significant weakening of the rigidity enhancement effect of the composite modifier on the PCR ABS modified material. Moreover, the synergistic effect of the two in improving material compatibility has decreased. The molecular chain defects caused by historical processing damage in the PCR ABS material have not been effectively repaired, resulting in insufficient mechanical structural support. The molecular chains are more prone to breakage during thermo-oxidative aging. Therefore, the mechanical properties of the PCR ABS modified material in Comparative Example 1 have decreased to varying degrees.

[0065] Compared to Example 1, Comparative Example 2 differs in that the mass ratio of polytetrafluoroethylene (PTFE) micropowder to polyethylene (PE) micropowder in the wear-resistant agent is 3:4, which is outside the range defined in this application. The results show that the wear resistance of the PCR ABS modified material in Comparative Example 2 is the worst among all samples, with an abrasion loss as high as 63 mg / 1000 r. Simultaneously, its tensile strength is 51 MPa and its flexural strength is 80 MPa, both lower than those of Example 1. This may be because the excessive proportion of PE micropowder disrupts the low-friction characteristics of PTFE micropowder, reducing the uniform dispersion of the wear-resistant agent in the PCR ABS material matrix and preventing the formation of a continuous, dense, lubricating, and wear-resistant interface. Furthermore, the excessive PE micropowder leads to poor interfacial compatibility with the PCR ABS material, potentially causing microscopic defects within the material and further reducing the mechanical structural stability of the PCR ABS modified material.

[0066] Compared with Example 1, Comparative Example 3 differed in that the amount of antistatic agent used was 35g. The results showed that although the surface resistivity of the PCR ABS modified material in Comparative Example 3 was significantly reduced and the antistatic effect was enhanced, its mechanical properties and aging resistance were significantly decreased, with a tensile strength of only 49MPa and an impact strength retention rate of only 85.2% after aging. This may be because the amount of antistatic agent was excessive. Excessive antistatic agent aggregated within the material, disrupting the tight packing of molecular chains and stress transmission in the PCR ABS matrix. It also interfered with the effective action of antioxidants and light stabilizers, leading to a decrease in free radical scavenging efficiency and accelerated molecular chain degradation during thermo-oxidative and UV aging processes, thus accelerating the decline in tensile strength and aging resistance.

[0067] Compared with Example 7, Comparative Example 4 used 35g of antistatic agent. The results showed that the surface resistivity of the PCR ABS modified material in Comparative Example 4 decreased to 5.5×10⁻⁶. 8 The tensile strength, notched impact strength, and aging resistance all decreased significantly, with the tensile strength at only 48 MPa and the impact strength retention rate after aging at 86.9%. This may be because the excessive stearamidopropyl hydroxyethyl ammonium phosphate antistatic agent reduces the compatibility with the PCR ABS material matrix, forming microscopic defects inside the material, resulting in insufficient mechanical structural stability. During aging, these defects further expand, accelerating the degradation rate of molecular chains, thus causing varying degrees of decline in its mechanical properties and aging resistance.

[0068] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. For those skilled in the art, other variations or modifications can be made based on the above description. Any obvious variations or modifications derived from the technical solutions of the present invention are still within the protection scope of the present invention.

Claims

1. A PCR-modified ABS material for use in sweeping machines, characterized in that, Its raw material components include: PCR ABS material, composite modifier, antioxidant, light stabilizer, abrasion resistant agent, antistatic agent and flame retardant; The composite modifier is a compound of maleic anhydride-grafted polypropylene and maleic anhydride-grafted acrylonitrile-butadiene-styrene copolymer, and the mass ratio of maleic anhydride-grafted polypropylene to maleic anhydride-grafted acrylonitrile-butadiene-styrene copolymer is (2~4.5):

1.

2. The PCR ABS modified material for a sweeper according to claim 1, characterized in that, The wear-resistant agent is at least one of polytetrafluoroethylene micro powder and polyethylene micro powder, and the particle size of the wear-resistant agent is 10~50μm.

3. The PCR ABS modified material for a sweeper according to claim 1, characterized in that, The antistatic agent is selected from ethoxylated alkylamine quaternary ammonium salt or stearamide propyl quaternary ammonium salt.

4. The PCR ABS modified material for a sweeper according to claim 1, characterized in that, The antioxidant is a compound of antioxidant 1010, antioxidant 3114 and antioxidant 168, and the mass ratio of antioxidant 1010, antioxidant 3114 and antioxidant 168 is (1~2):(0.3~0.6):(0.5~1).

5. The PCR ABS modified material for a sweeper according to claim 1, characterized in that, The light stabilizer is a hindered amine light stabilizer.

6. The PCR ABS modified material for a sweeper according to claim 1, characterized in that, The flame retardant is a compound of montmorillonite and aluminum hydroxide surface modified with titanate coupling agent, and the mass ratio of montmorillonite to aluminum hydroxide surface modified with titanate coupling agent is (6~10):(1~3).

7. The PCR ABS modified material for a sweeper according to any one of claims 1 to 6, characterized in that, Its raw materials include the following components in parts by weight: 65-90 PCR ABS materials; 4.5–12 parts of composite modifier; Antioxidant 1.1–2.8 parts; 1-3 parts light stabilizer; 3.7 to 5 parts of wear-resistant agent; Antistatic agent 0.5-3 parts; 2 to 6 parts flame retardant.

8. A method for preparing a PCR-modified ABS material for a sweeper as described in any one of claims 1 to 7, characterized in that, Includes the following steps: S1. Pretreatment: The PCR ABS material is ultrasonically cleaned, broken up, and dried; S2: Segmented mixing: The first stage of mixing is carried out by adding pretreated PCR ABS material, composite modifier, antioxidant, light stabilizer and flame retardant, and then the second stage of mixing is carried out by adding abrasion resistant agent and antistatic agent to obtain premix; S3: Melt blending and extrusion: The premixed material is melt blended and extruded to obtain melt strips; S4: Post-processing and curing: After cooling, pelletizing, screening and drying the melt strip, it is subjected to constant temperature curing to obtain PCR ABS modified material for sweeping machines.

9. The method for preparing PCR ABS modified material for a sweeping machine according to claim 8, characterized in that, In step S2, the temperature of the first mixing stage is 25~30℃ and the time is 3~6 min; the temperature of the second mixing stage is 40~60℃ and the time is 5~10 min.

10. The method for preparing PCR ABS modified material for a sweeping machine according to claim 8, characterized in that, In step S3, the temperature gradient from the feed port to the die head in the extrusion process is 180℃, 200℃, 215℃, 225℃, 230℃, 225℃, the die head temperature is 220℃, and the rotation speed is 350~450 rpm. In step S4, the constant temperature curing temperature is 60~80℃ and the time is 6~12h.

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