Impact-resistant nylon rubber-encased composite wheel and method of making same

Abstract

The present application relates to the technical field of nylon rubber-encased composite wheels, and proposes a shock-resistant nylon rubber-encased composite wheel and a preparation method thereof.The composite wheel comprises a wheel core and a rubber layer, and the wheel core comprises the following raw materials by weight: 70-80 parts of nylon 66, 10-15 parts of maleic anhydride grafted POE, 3-6 parts of a hydrophobic toughening agent, 1-2 parts of a nucleating agent, 0.5-1 part of an antioxidant, and 0.3-0.6 parts of a lubricant.Among them, the nylon 66 serves as a base resin, and the maleic anhydride grafted POE is added to improve the impact resistance of the wheel core;the self-made hydrophobic toughening agent significantly enhances the hydrophobicity and flexibility of the nylon base, reduces the performance decline of the nylon due to moisture absorption, and improves the impact resistance of the composite wheel;therefore, the present application successfully solves the technical bottleneck of the insufficient impact resistance and waterproof performance of the nylon wheel core in the traditional nylon rubber-encased composite wheel, and has important application value in the technical field of nylon rubber-encased composite wheels.

Description

Technical Field

[0001] This invention relates to the field of nylon-coated composite wheel technology, specifically to an impact-resistant nylon-coated composite wheel and its preparation method. Background Technology

[0002] In modern industrial logistics, automated production lines, heavy equipment transportation, and various mobile machinery, wheels are key load-bearing, transmission, and movement components, and their performance directly affects the working efficiency, stability, and service life of the entire equipment.

[0003] Currently, traditional wheel materials have performance issues: metal wheels, especially cast steel or cast iron wheels, while possessing extremely high rigidity and load-bearing capacity, have high hardness and extremely poor shock absorption performance. During movement, they not only generate a lot of noise but also easily scratch and damage the ground. Furthermore, due to their low coefficient of friction with the ground, they lack sufficient traction in wet, slippery, or oily environments, posing safety hazards. On the other hand, fully elastic wheels, such as polyurethane wheels or rubber wheels, while providing excellent shock absorption, noise reduction, and good ground grip, have limited structural strength. Especially when subjected to heavy loads or frequent impact loads, they are prone to permanent deformation, crushing, or even tearing. Their wear resistance is also relatively poor, failing to meet the needs of high-intensity industrial applications.

[0004] To balance high strength and good surface performance, rubber-coated composite wheels have become a common solution. The structure of a rubber-coated composite wheel typically uses a high-strength material such as metal or engineering plastic as the wheel core (also called the skeleton) to provide the necessary structural support and load-bearing strength. Then, a layer of elastomeric material with high elasticity, a high coefficient of friction, and good wear resistance (i.e., the rubber layer) is coated around the contact area of ​​the wheel core, thus achieving an ideal combination of rigidity and flexibility.

[0005] However, despite the theoretical advantages of rubber-coated wheels, numerous problems still arise in practical manufacturing and application, especially under extremely harsh working conditions. Among these, the choice of wheel core material is crucial. Currently widely used wheel core materials include cast iron, aluminum alloys, and engineering plastics such as polyoxymethylene (PCM) and ordinary nylon (PA6 or PA66). While cast iron and aluminum alloy wheel cores offer high strength, their heavy weight increases the inertia and energy consumption of the equipment. Furthermore, their bonding with the outer rubber layer relies primarily on mechanical interlocking methods such as physical drilling or grooving, which limits the strength of the interface. Under prolonged heavy loads or strong impacts, the rubber layer is prone to peeling and detachment from the wheel core. While ordinary nylon wheel cores are lighter and have better adhesion to certain rubber compounds than metals, their impact toughness remains insufficient. Nylon material has decent toughness when dry, but it is hygroscopic. After absorbing moisture, its rigidity and strength will decrease. When subjected to sudden and violent impact, it is more likely to cause the wheel core itself to crack or break. Once the wheel core is damaged, the entire rubber-coated wheel will fail.

[0006] Therefore, it is urgent to solve the problems of poor impact resistance and waterproof performance of nylon wheel cores in order to meet the higher requirements of the nylon-coated composite wheel technology field. Summary of the Invention

[0007] This invention proposes an impact-resistant nylon-coated composite wheel and its preparation method, which solves the problem of poor impact resistance and waterproof performance of the nylon wheel core in related technologies.

[0008] The technical solution of the present invention is as follows:

[0009] This invention proposes an impact-resistant nylon-coated composite wheel, comprising a wheel core and a rubber layer. The wheel core comprises the following raw materials in parts by weight: 70-80 parts nylon 66, 10-15 parts maleic anhydride-grafted POE, 3-6 parts hydrophobic toughening agent, 1-2 parts nucleating agent, 0.5-1 parts antioxidant, and 0.3-0.6 parts lubricant.

[0010] As a further technical solution, the nucleating agent is one of talc, calcium carbonate, and silica.

[0011] As a further technical solution, the antioxidant is obtained by compounding antioxidant 1010 and antioxidant 168 in a mass ratio of 4:1.

[0012] As a further technical solution, the lubricant is one of ethylene bis-stearamide, oleamide, and erucamide.

[0013] In this invention, the wheel core uses nylon 66 as the matrix resin. Nylon 66 has excellent mechanical strength and can provide the basic load-bearing capacity of the wheel core. Maleic anhydride-grafted POE is added, which can be dispersed in the nylon matrix. When subjected to impact, it can effectively initiate, terminate and shear silver streaks, absorb impact energy, and thus effectively prevent crack propagation and prevent brittle fracture of the wheel core.

[0014] As a further technical solution, the wheel core is manufactured through the following steps:

[0015] A1. After drying nylon 66, mix it evenly with maleic anhydride-grafted POE, hydrophobic toughening agent, nucleating agent, antioxidant and lubricant to obtain mixed raw material;

[0016] A2. The mixed raw materials are melt-blended, extruded, cooled, and pelletized to obtain nylon composite material particles;

[0017] A3. Nylon composite material particles are injection molded to obtain the wheel core.

[0018] As a further technical solution, the drying process described in step A1 is carried out at a temperature of 100-110℃ for 4-6 hours.

[0019] As a further technical solution, in step A1, when the mixing is uniform, the rotation speed is 1000-1200 r / min and the mixing time is 5-10 min.

[0020] As a further technical solution, in step A3, during injection molding, the mold temperature is 80-90℃ and the barrel temperature is 250-265℃.

[0021] As a further technical solution, the hydrophobic toughening agent is prepared through the following steps:

[0022] B1. In a four-necked flask equipped with a mechanical stirrer, thermometer, reflux condenser (with a water separator pre-added to toluene at the top) and nitrogen inlet tube, melamine, n-decanoic acid, anhydrous N,N-dimethylformamide and p-toluenesulfonic acid are added sequentially. The mechanical stirrer is turned on, and nitrogen (flow rate 50 mL / min) is introduced to replace the air in the flask three times. Then, anhydrous toluene is added to the water separator, and the heating mantle is turned on to raise the temperature to 130-135℃. At this time, toluene forms an azeotrope with the water produced in the reaction. The aqueous phase is separated by the water separator, and the toluene is refluxed into the reaction system to continue carrying water. The reaction is carried out for 8-10 hours. After the reaction is completed, the reaction product A is obtained through post-processing.

[0023] B2. In a four-necked flask equipped with a mechanical stirrer, thermometer, reflux condenser (connected to a water separator with toluene pre-added), and nitrogen inlet tube, add reaction product A, 3-(methylthio)propionic acid, anhydrous N,N-dimethylformamide, and p-toluenesulfonic acid in sequence. Turn on the mechanical stirrer and purge the air in the flask three times with nitrogen (flow rate 50 mL / min). Add anhydrous toluene to the water separator and turn on the heating mantle to raise the temperature to 135-140℃. At this time, toluene forms an azeotrope with the water produced in the reaction. The aqueous phase is separated by the water separator, and the toluene is refluxed back into the reaction system to continue carrying water. The reaction is carried out for 6-8 hours. After the reaction is completed, the reaction product B is obtained through post-processing.

[0024] B3. In a four-necked flask equipped with a mechanical stirrer, thermometer, reflux condenser (with a tail gas absorption device at the top) and constant pressure dropping funnel, add reaction product B and anhydrous pyridine in sequence, start stirring, and slowly heat to 80-90℃. Then, slowly add 1,7-dichloro-octylmethyltetrasiloxane dropwise to the flask through the constant pressure dropping funnel, controlling the dropping time to 30-60 min. After the dropping is completed, keep the mixture under reflux for 12-24 h. After the reaction is completed, the hydrophobic toughening agent is obtained through post-treatment.

[0025] As a further technical solution, the ratio of the amounts of melamine, n-decanoic acid, anhydrous N,N-dimethylformamide and p-toluenesulfonic acid in step B1 is 13.3-14.5g:17.2g:100mL:0.3g.

[0026] As a further technical solution, the ratio of the amount of reaction product A, the amount of 3-(methylthio)propionic acid, the amount of anhydrous N,N-dimethylformamide and the amount of p-toluenesulfonic acid in step B2 is 30.3-32.5g:12.0g:120mL:0.4g.

[0027] As a further technical solution, the ratio of the amount of reaction product B, the anhydrous pyridine, and the 1,7-dichloro-octylmethyltetrasiloxane in step B3 is 78.5-80.6g:200mL:35.1g.

[0028] The reaction formulas for the above preparation process are as follows:

[0029]

[0030] In the preparation of the hydrophobic toughening agent, the amount of raw materials used in each step of this invention needs to be carefully considered. In step B1, the molar ratio of melamine to decanoic acid should be close to 1:1, with the former in excess, and two amino groups should be reserved for subsequent reactions. In step B2, the molar ratio of reaction product A to 3-(methylthio)propionic acid should be close to 1:1, with the former in excess, and one amino group should be reserved for subsequent reactions. Finally, in step B3, anhydrous pyridine acts as both a solvent and an acid absorbent. The molar ratio of reaction product B to 1,7-dichloro-octylmethyltetrasiloxane should be close to 2:1, with the former in excess, to induce a di-substitution reaction.

[0031] In the self-made hydrophobic toughening agent molecule of this invention, a thioether group, a Si-O-Si skeleton and a straight-chain alkyl (nonyl) are introduced through a three-step reaction. The three functional groups introduced all possess hydrophobicity and flexibility. When integrated, the three functional groups can not only play a synergistic role and significantly improve the waterproof and impact resistance of the nylon matrix, but also make the nylon matrix have better homogeneity compared to adding each functional additive individually.

[0032] As a further technical solution, the adhesive layer comprises the following raw materials in parts by weight: 80-90 parts thermoplastic polyurethane elastomer, 5-10 parts plasticizer, 1-2 parts abrasion resistant agent and 0.5-1 part UV resistant agent.

[0033] In this invention, the adhesive layer is made of thermoplastic polyurethane elastomer, combined with plasticizer, wear-resistant agent and UV stabilizer, so that it can maintain high elasticity, wear resistance and tear resistance while having good low temperature toughness and weather resistance.

[0034] As a further technical solution, the plasticizer is a polyester plasticizer.

[0035] As a further technical solution, the wear-resistant agent is one of polyethylene wax and molybdenum disulfide.

[0036] As a further technical solution, the UV protectant is one of UV-531, UV-214, UV-326 and UV-1577.

[0037] In this invention, the adhesive matrix is ​​a thermoplastic polyurethane elastomer, which has excellent wear resistance, high elasticity and tear resistance, and its mechanical properties are far superior to those of ordinary rubber. Plasticizers are added to adjust the hardness and low-temperature toughness of the thermoplastic polyurethane elastomer, so that it can still maintain good elasticity in cold environments.

[0038] This invention also provides a method for preparing an impact-resistant nylon-coated composite wheel, comprising the following steps:

[0039] C1. The thermoplastic polyurethane elastomer, the plasticizer, the abrasion resistant agent and the UV resistant agent are mixed and dried to obtain an adhesive composite material;

[0040] C2. Place the wheel core into the cavity of the rubber coating mold, close the mold and preheat the mold, then put the rubber composite material into the injection molding machine. After the composite material melts, it is injected and fills the cavity, wrapping the wheel core. After holding the pressure, the rubber layer cools and solidifies in the mold. Open the mold and cure to obtain the impact-resistant nylon rubber-coated composite wheel.

[0041] As a further technical solution, in step C1, the drying temperature is 80-90℃ and the drying time is 3-5 hours.

[0042] As a further technical solution, in step C2, the temperature during preheating of the mold is 50-60℃.

[0043] As a further technical solution, in step C2, the temperature of the injection molding machine is 190-205℃.

[0044] As a further technical solution, in step C2, the ripening time is 24-48 hours.

[0045] The working principle and beneficial effects of this invention are as follows:

[0046] 1. This invention uses nylon 66 as the matrix resin and adds maleic anhydride-grafted POE as a toughening agent to effectively absorb impact energy, prevent crack propagation, and prevent the wheel core from brittle fracture under heavy load or impact.

[0047] 2. By introducing a self-made hydrophobic toughening agent, the hydrophobicity and flexibility of the nylon matrix are significantly enhanced, the performance degradation of nylon due to moisture absorption is reduced, and the impact resistance of the composite wheel is improved.

[0048] In summary, this invention, through the synergistic optimization of material formulation and process, successfully solves the technical bottlenecks of insufficient impact resistance and waterproof performance in traditional nylon-coated wheels, and has significant application value in the field of nylon-coated composite wheel technology. Detailed Implementation

[0049] 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.

[0050] In the following examples and comparative examples, nylon 66, model PA66 101F; maleic anhydride-grafted POE, model POE-g-MAH 8780; thermoplastic polyurethane elastomer, model TPU 1185A; talc with a particle size of 1250 mesh; calcium carbonate with a particle size of 2000 mesh; silica with a particle size of 1500 mesh; and polyester plasticizer, specifically polypropylene adipate (CAS No. 25101-03-5, molecular weight 1500).

[0051] Example 1

[0052] Preparation of hydrophobic toughening agents:

[0053] B1. In a four-necked flask equipped with a mechanical stirrer, thermometer, reflux condenser (with a water separator pre-filled in the separator), and nitrogen inlet tube, add 13.3 g melamine, 17.2 g n-decanoic acid, 100 mL anhydrous N,N-dimethylformamide, and 0.3 g p-toluenesulfonic acid sequentially. Turn on the mechanical stirrer and introduce nitrogen gas (flow rate 50). The air in the flask was replaced three times at a rate of mL / min to prevent amino oxidation. Then, 200 mL of anhydrous toluene was added to the water separator, and the heating mantle was turned on to raise the temperature to 130 °C. At this time, the toluene and the water produced in the reaction formed an azeotrope. The aqueous phase was separated by the water separator, and the toluene was refluxed into the reaction system to continue carrying water. The reaction was carried out for 8 hours. The reaction was then completed. Heating was stopped, nitrogen gas was turned off, and the mixture was allowed to cool naturally to room temperature. The reaction solution was distilled under reduced pressure, and the remaining concentrated solution was poured into ice water. The solid was stirred and collected by suction filtration. The filter cake was washed with sodium carbonate aqueous solution (mass fraction 5%), and then washed with deionized water until the filtrate was neutral. The solution was then filtered and dried to obtain reaction product A.

[0054] B2. In a four-necked flask equipped with a mechanical stirrer, thermometer, reflux condenser (with a water separator pre-filled in the separator), and nitrogen inlet tube, add 60.6 g of reaction product A, 24.0 g of 3-(methylthio)propionic acid, 240 mL of anhydrous N,N-dimethylformamide, and 0.8 g of p-toluenesulfonic acid in sequence. Turn on the mechanical stirrer and introduce nitrogen gas (flow rate 50). Replace the air in the flask three times at a rate of mL / min to avoid oxidation of the amino group. Add 300 mL of anhydrous toluene to the water separator and turn on the heating mantle to raise the temperature to 135 °C. At this point, the toluene forms an azeotrope with the water produced in the reaction. Separate the aqueous phase through the water separator. Reflux the toluene back into the reaction system to continue carrying water. After 6 hours of reaction, the reaction is complete. Distill the reaction solution under reduced pressure. Pour the remaining concentrated liquid into ice water and stir to precipitate the solid. Collect the filter cake by vacuum filtration. Wash the filter cake with sodium carbonate aqueous solution (5% by mass) and then wash with deionized water until the filtrate is neutral. Filter by vacuum filtration and recrystallize with ethanol-water (8:2 by volume) as solvent. Filter and dry to obtain reaction product B.

[0055] B3. In a four-necked flask equipped with a mechanical stirrer, thermometer, reflux condenser (with a tail gas absorption device at the top) and constant pressure dropping funnel, 78.5 g of reaction product B and 200 mL of anhydrous pyridine were added sequentially. Stirring was started, and the mixture was slowly heated to 80 °C. Then, 35.1 g of 1,7-dichloro-octylmethyltetrasiloxane was slowly added dropwise to the flask through the constant pressure dropping funnel, with the addition time controlled at 30 min. After the addition was completed, the mixture was kept at reflux for 12 h. After the reaction was completed, the reaction solution was cooled to room temperature, filtered using a Buchner funnel, and the filter cake was washed twice with anhydrous pyridine. The filtrates were combined and purified by column chromatography using petroleum ether / ethyl acetate (volume ratio of 2:1). The mixture was then dried under vacuum to obtain a hydrophobic toughening agent.

[0056] Preparation of wheel core:

[0057] A1. Dry 70 parts of nylon 66 in a forced-air oven at 100℃ for 6 hours. Then, add it together with 10 parts of maleic anhydride-grafted POE, 3 parts of hydrophobic toughening agent, 1 part of talc, 0.5 parts of antioxidant (antioxidant 1010 and antioxidant 168 are compounded in a mass ratio of 4:1) and 0.3 parts of ethylene bis-stearamide into a high-speed mixer (speed of 1000 r / min) and mix for 10 minutes to obtain the mixed raw material.

[0058] A2. The mixed raw materials are fed into a twin-screw extruder (the temperature of each section of the extruder is set as follows: Zone 1 230℃, Zone 2 245℃, Zone 3 255℃, Zone 4 255℃, and Die Head 250℃) for melt blending, extrusion, cooling, and pelletizing to obtain nylon composite material particles.

[0059] A3. Nylon composite material particles are fed into the hopper of an injection molding machine (mold temperature 80℃, barrel temperature 250℃) for injection molding to obtain a wheel core;

[0060] A method for preparing an impact-resistant nylon-coated composite wheel includes the following steps:

[0061] C1. Mix 80 parts of thermoplastic polyurethane elastomer, 5 parts of polypropylene adipate, 1 part of molybdenum disulfide and 0.5 parts of UV-214, and dry at 80°C for 3 hours to obtain the adhesive composite material.

[0062] C2. Place the wheel core into the cavity of the rubber coating mold, close the mold and preheat the mold to 50°C, then put the rubber composite material into the injection molding machine (temperature is 190°C). After the composite material melts, it is injected and fills the cavity, wrapping the wheel core. After holding the pressure, the rubber layer cools and solidifies in the mold. Open the mold and cure for 24 hours to obtain an impact-resistant nylon rubber-coated composite wheel.

[0063] Example 2

[0064] Preparation of hydrophobic toughening agents:

[0065] B1. In a four-necked flask equipped with a mechanical stirrer, thermometer, reflux condenser (with a water separator pre-filled in the water separator), and nitrogen inlet tube, add 14.5g melamine, 17.2g n-decanoic acid, 100mL anhydrous N,N-dimethylformamide, and 0.3g p-toluenesulfonic acid in sequence. Turn on the mechanical stirrer and introduce nitrogen gas (flow rate 50). The air in the flask was replaced three times at a rate of mL / min to prevent amino oxidation. Then, 200 mL of anhydrous toluene was added to the water separator, and the heating mantle was turned on to raise the temperature to 135 °C. At this time, the toluene and the water produced in the reaction formed an azeotrope. The aqueous phase was separated by the water separator, and the toluene was refluxed into the reaction system to continue carrying water. The reaction was carried out for 10 h. The reaction was then stopped, the nitrogen gas was turned off, and the mixture was allowed to cool naturally to room temperature. The reaction solution was distilled under reduced pressure, and the remaining concentrated solution was poured into ice water. The solid was stirred and collected by suction filtration. The filter cake was washed with sodium carbonate aqueous solution (mass fraction 5%), and then washed with deionized water until the filtrate was neutral. The solution was then filtered and dried to obtain reaction product A.

[0066] B2. In a four-necked flask equipped with a mechanical stirrer, thermometer, reflux condenser (with a water separator pre-filled in the water separator), and nitrogen inlet tube, add 65.0 g of reaction product A, 24.0 g of 3-(methylthio)propionic acid, 240 mL of anhydrous N,N-dimethylformamide, and 0.8 g of p-toluenesulfonic acid in sequence. Turn on the mechanical stirrer and introduce nitrogen gas (flow rate 50). Replace the air in the flask three times at a rate of mL / min to avoid oxidation of the amino group. Add 300 mL of anhydrous toluene to the water separator and turn on the heating mantle to raise the temperature to 140 °C. At this point, the toluene forms an azeotrope with the water produced in the reaction. Separate the aqueous phase through the water separator. Reflux the toluene back into the reaction system to continue carrying water. After 8 hours of reaction, the reaction solution is distilled under reduced pressure. Pour the remaining concentrated solution into ice water, stir to precipitate solid, and collect the filter cake by vacuum filtration. Wash the filter cake with sodium carbonate aqueous solution (5% by mass), and then wash with deionized water until the filtrate is neutral. Filter by vacuum filtration, recrystallize with ethanol-water (8:2 by volume) as solvent, filter, and dry to obtain reaction product B.

[0067] B3. In a four-necked flask equipped with a mechanical stirrer, thermometer, reflux condenser (with a tail gas absorption device at the top) and constant pressure dropping funnel, 80.6 g of reaction product B and 200 mL of anhydrous pyridine were added sequentially. Stirring was started, and the mixture was slowly heated to 90 °C. Then, 35.1 g of 1,7-dichloro-octylmethyltetrasiloxane was slowly added dropwise to the flask through the constant pressure dropping funnel, with the addition time controlled at 60 min. After the addition was completed, the mixture was kept at reflux for 24 h. After the reaction was completed, the reaction solution was cooled to room temperature, filtered with a Buchner funnel, and the filter cake was washed three times with anhydrous pyridine. The filtrates were combined and purified by column chromatography using petroleum ether / ethyl acetate (volume ratio of 2:1) as the mobile phase. The mixture was then dried under vacuum to obtain the hydrophobic toughening agent.

[0068] Preparation of wheel core:

[0069] A1. Dry 75 parts of nylon 66 in a forced-air oven at 110℃ for 6 hours. Then, add it together with 12.5 parts of maleic anhydride-grafted POE, 4.5 parts of hydrophobic toughening agent, 1.5 parts of calcium carbonate, 0.75 parts of antioxidant (antioxidant 1010 and antioxidant 168 are compounded in a mass ratio of 4:1) and 0.45 parts of oleamide into a high-speed mixer (speed of 1200 r / min) and mix for 5 minutes to obtain the mixed raw material.

[0070] A2. The mixed raw materials are fed into a twin-screw extruder (the temperature of each section of the extruder is set as follows: Zone 1 230℃, Zone 2 245℃, Zone 3 255℃, Zone 4 255℃, and Die Head 250℃) for melt blending, extrusion, cooling, and pelletizing to obtain nylon composite material particles.

[0071] A3. Nylon composite material particles are fed into the hopper of an injection molding machine (mold temperature 90℃, barrel temperature 265℃) for injection molding to obtain a wheel core;

[0072] A method for preparing an impact-resistant nylon-coated composite wheel includes the following steps:

[0073] C1. Mix 85 parts of thermoplastic polyurethane elastomer, 7.5 parts of polypropylene adipate, 1.5 parts of molybdenum disulfide and 0.75 parts of UV-326, and dry at 85°C for 4 hours to obtain the adhesive composite material.

[0074] C2. Place the wheel core into the cavity of the overmolding mold, close the mold and preheat the mold to 60°C, then put the composite material into the injection molding machine (temperature is 205°C). After the composite material melts, it is injected and fills the cavity, wrapping the wheel core. After holding the pressure, the rubber layer cools and solidifies in the mold. Open the mold and cure for 36 hours to obtain an impact-resistant nylon overmolding composite wheel.

[0075] Example 3

[0076] The only difference between this embodiment and Embodiment 2 is that, in this embodiment, the wheel core is obtained through the following steps:

[0077] A1. Dry 80 parts of nylon 66 in a forced-air oven at 110℃ for 6 hours. Then, add it together with 15 parts of maleic anhydride-grafted POE, 6 parts of hydrophobic toughening agent, 2 parts of silica, 1 part of antioxidant (antioxidant 1010 and antioxidant 168 are compounded in a mass ratio of 4:1) and 0.6 parts of erucamide into a high-speed mixer (speed of 1200 r / min) and mix for 5 minutes to obtain the mixed raw material.

[0078] A2. The mixed raw materials are fed into a twin-screw extruder (the temperature of each section of the extruder is set as follows: Zone 1 230℃, Zone 2 245℃, Zone 3 255℃, Zone 4 255℃, and Die Head 250℃) for melt blending, extrusion, cooling, and pelletizing to obtain nylon composite material particles.

[0079] A3. Nylon composite material particles are fed into the hopper of an injection molding machine (mold temperature 90℃, barrel temperature 265℃) for injection molding to obtain a wheel core;

[0080] A method for preparing an impact-resistant nylon-coated composite wheel includes the following steps:

[0081] C1. Mix 90 parts of thermoplastic polyurethane elastomer, 10 parts of polypropylene adipate, 2 parts of molybdenum disulfide and 1 part of UV-1577, and dry at 90°C for 5 hours to obtain the adhesive composite material.

[0082] C2. Place the wheel core into the cavity of the rubber coating mold, close the mold and preheat the mold to 60°C, then put the rubber composite material into the injection molding machine (temperature is 205°C). After the composite material melts, it is injected and fills the cavity, wrapping the wheel core. After holding the pressure, the rubber layer cools and solidifies in the mold. Open the mold and cure for 48 hours to obtain an impact-resistant nylon rubber-coated composite wheel.

[0083] Comparative Example 1

[0084] The only difference between this comparative example and Example 2 is that, in this comparative example, an equal amount of hexadecyltrimethoxysilane was used to replace the hydrophobic toughening agent to prepare the composite wheel.

[0085] Comparative Example 2

[0086] Uses commercially available impact-resistant nylon 66, model: ST801AHS.

[0087] The nylon composite particles obtained in Examples 1-3 and Comparative Example 1 were compared with those in Comparative Example 2 to determine their impact resistance and water resistance.

[0088] The notched impact strength was determined according to GB / T 1043.1-2018 "Determination of impact properties of simply supported plastic beams - Part 1: Non-instrumental impact test".

[0089] The water absorption rate was determined according to GB / T 1034-2008 "Determination of Water Absorption of Plastics" standard.

[0090] The measurement results are shown in Table 1:

[0091] Table 1

[0092]

[0093] As can be seen from the measurement results in Table 1, the nylon composite material prepared in the embodiment of the present invention has higher impact strength and water absorption rate than the comparative example. Therefore, the composite wheel prepared in the present invention has excellent impact resistance and waterproof performance, and has important application value in the field of nylon coated composite wheel technology.

[0094] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An impact-resistant nylon-coated composite wheel, comprising a wheel core and a rubber layer, characterized in that, The wheel core comprises the following raw materials in parts by weight: 70-80 parts nylon 66, 10-15 parts maleic anhydride-grafted POE, 3-6 parts hydrophobic toughening agent, 1-2 parts nucleating agent, 0.5-1 part antioxidant and 0.3-0.6 parts lubricant; The hydrophobic toughening agent is prepared through the following steps: B1. In a flask, add melamine, n-decanoic acid, anhydrous N,N-dimethylformamide and p-toluenesulfonic acid in sequence, stir, and purge with nitrogen gas. Then add anhydrous toluene into the water separator, heat to 130-135℃, and react for 8-10 hours. After the reaction is completed, product A is obtained. B2. In a flask, add the reaction product A, 3-(methylthio)propionic acid, anhydrous N,N-dimethylformamide and p-toluenesulfonic acid in sequence, stir, introduce nitrogen gas, add anhydrous toluene into the water separator, heat to 135-140℃, react for 6-8 hours, and the reaction is completed to obtain reaction product B. B3. In a flask, add the reaction product B and anhydrous pyridine in sequence, stir, heat to 80-90°C, add 1,7-dichloro-octylmethyltetrasiloxane dropwise into the flask, after the addition is complete, keep warm and reflux for 12-24 hours, the reaction is completed, and the hydrophobic toughening agent is obtained. In step B1, the ratio of melamine, n-decanoic acid, anhydrous N,N-dimethylformamide, and p-toluenesulfonic acid is 13.3-14.5 g: 17.2 g: 100 mL: 0.3 g; in step B2, the ratio of reaction product A, 3-(methylthio)propionic acid, anhydrous N,N-dimethylformamide, and p-toluenesulfonic acid is 30.3-32.5 g: 12.0 g: 120 mL: 0.4 g; and in step B3, the ratio of reaction product B, anhydrous pyridine, and 1,7-dichloro-octylmethyltetrasiloxane is 78.5-80.6 g: 200 mL: 35.1 g.

2. The impact-resistant nylon-coated composite wheel according to claim 1, characterized in that, The nucleating agent is one of talc, calcium carbonate, and silica.

3. The impact-resistant nylon-coated composite wheel according to claim 1, characterized in that, The antioxidant is obtained by compounding antioxidant 1010 and antioxidant 168 in a mass ratio of 4:

1.

4. The impact-resistant nylon-coated composite wheel according to claim 1, characterized in that, The lubricant is one of ethylene bis-stearamide, oleamide, and erucamide.

5. The impact-resistant nylon-coated composite wheel according to claim 1, characterized in that, The adhesive layer comprises the following raw materials in parts by weight: 80-90 parts thermoplastic polyurethane elastomer, 5-10 parts plasticizer, 1-2 parts abrasion resistant agent and 0.5-1 part UV resistant agent.

6. A method for preparing an impact-resistant nylon-coated composite wheel, used to prepare the impact-resistant nylon-coated composite wheel as described in claim 5, characterized in that, Includes the following steps: C1. The thermoplastic polyurethane elastomer, the plasticizer, the abrasion resistant agent and the UV resistant agent are mixed and dried to obtain an adhesive composite material; C2. Place the wheel core into the cavity of the rubber coating mold, close the mold and preheat the mold, then put the rubber composite material into the injection molding machine. After the composite material melts, it is injected and fills the cavity, wrapping the wheel core. After holding the pressure, the rubber layer cools and solidifies in the mold. Open the mold and cure to obtain the impact-resistant nylon rubber-coated composite wheel.

Images