Lightweight high-elasticity EVA / nanofiller composite foamed sole material and preparation method thereof

Abstract

The invention belongs to the technical field of macromolecular materials for shoes, and particularly relates to a lightweight high-elasticity EVA / nanofiller composite foamed sole material and a preparation method thereof, which optimize the mechanical properties of the material, simplify the production process and reduce the production cost. The preparation method comprises the following steps: treating coal gangue powder with a silane coupling agent, blending and curing the treated coal gangue powder with functionalized graphene and an organic silicon resin emulsion, and adding a catalyst for catalysis to obtain a silica gel coated composite nano filler; carrying out hydrophobic modification treatment on the nano cellulose aerogel in methyltrimethoxysilane steam, so as to obtain hydrophobic modified aerogel particles; mixing the components, banburying, extruding and granulating; carrying out supercritical carbon dioxide saturation treatment, and then carrying out compression molding and rapid cooling to obtain the target composite foaming sole material. According to the scheme, by cooperatively regulating and controlling the filler interface bonding degree, the components and the process, the lightweight and high-elasticity properties of the material can be remarkably improved, and meanwhile, the wear resistance and the tearing strength of the material can be enhanced.

Description

Technical Field

[0001] This application belongs to the field of polymer footwear materials technology, specifically a lightweight, high-elastic EVA / nanofiller composite foamed shoe sole material and its preparation method. Background Technology

[0002] With the increasing demand in the athletic shoe market, the research and development of functional foamed shoe sole materials that are lightweight, highly elastic, and abrasion-resistant has gradually become a focus of industry attention. EVA (ethylene-vinyl acetate copolymer) is widely used in shoe sole foaming materials due to its excellent lightweight properties and processing performance. However, existing EVA foamed shoe sole materials still have shortcomings in achieving a combination of lightweight, high elasticity, and abrasion resistance, which limits their further application in the field of high-performance footwear materials.

[0003] For example, patent CN114702750B significantly improves the density, resilience, and abrasion resistance of materials by introducing various elastomers (such as polyester elastomers, random copolymer polystyrene thermoplastic elastomers, and polyolefin thermoplastic elastomers) and modified internally mixed silicone rubber. However, this technical solution does not involve the application of nanofillers, resulting in limited improvement in the mechanical properties of the material, especially in tear strength and durability, where there is still room for improvement. In addition, the use of multifunctional crosslinking agents and additives increases the complexity of the process and puts some pressure on production costs.

[0004] On the other hand, patent CN116144065B describes a foamed material with excellent impact resistance and shock absorption properties prepared using supercritical fluid technology (carbon dioxide-nitrogen system) combined with a dual crosslinking agent system. However, this technology primarily focuses on optimizing the material's damping performance, while paying insufficient attention to its lightweight and wear resistance. Furthermore, supercritical fluid technology requires sophisticated equipment, increasing production costs and process complexity, making it difficult to promote in large-scale industrial production.

[0005] The aforementioned issues indicate that existing EVA foam shoe sole materials still have certain limitations in achieving composite functions such as lightweight, high elasticity, and wear resistance, especially in the application of nanofillers, comprehensive improvement of mechanical properties, and economic efficiency of production processes. Therefore, developing a lightweight, high-elasticity EVA / nanofiller composite foam shoe sole material that can optimize material mechanical properties by introducing nanofillers while simplifying the production process and reducing production costs has significant practical importance and application value. Summary of the Invention

[0006] To address the aforementioned issues, this application provides a lightweight, high-elasticity EVA / nanofiller composite foamed shoe sole material and its preparation method. This material not only significantly improves the material's lightweight and high-elasticity properties but also enhances its abrasion resistance and tear resistance, making it a promising candidate for applications in the field of high-performance footwear materials.

[0007] To achieve the above objectives, the technical solution of this application is: a lightweight, high-elastic EVA / nanofiller composite foamed shoe sole material, wherein the density of the composite foamed shoe sole material is less than 0.15 g / cm³. 3 Rebound rate ≥65%, tear strength ≥25 kN / m.

[0008] This application further discloses a method for preparing the above-mentioned lightweight, high-elasticity EVA / nanofiller composite foamed shoe sole material, including the following steps: Step (1): By weight, 100 parts of coal gangue powder are treated with 5-8 parts of silane coupling agent and then mixed with 30-50 parts of functionalized graphene to obtain a mixed filler. Then, 25-40 parts of organosilicon resin emulsion are added and blended and cured to form organosilicon-coated composite nanofiller. 0.15-0.2 parts of catalyst are further added for catalysis to obtain silica gel-coated composite nanofiller. Step (2): The nanocellulose aerogel is hydrophobically modified in methyltrimethoxysilane vapor to obtain hydrophobically modified aerogel particles. Step (3): Mix 40-50 parts EVA, 15-25 parts polyamide elastomer, 8-12 parts TPU and 8-12 parts SEBS by weight and knead. Then add 3-8 parts hydrophobic modified aerogel particles and 3-8 parts silicone gel coated composite nanofiller, knead again, and finally add 3.0-4.5 parts foaming agent and 1.2-1.8 parts crosslinking agent, knead again, and extrude and granulate. Step (4): The granulated material is subjected to supercritical carbon dioxide saturation treatment, followed by molding and rapid cooling at a rate of >20℃ / min to obtain the target composite foamed shoe sole material.

[0009] The lightweight, high-elastic EVA / nanofiller composite foamed shoe sole material disclosed in this application has significant differences compared to traditional EVA foamed shoe sole materials. Traditional EVA foamed shoe sole materials have a relatively simple microporous structure and uneven pore wall thickness, resulting in insufficient mechanical properties and abrasion resistance. In contrast, this application introduces hydrophobically modified nanocellulose aerogel and organosilicon resin to coat the composite nanofiller, creating a uniformly distributed honeycomb microporous structure within the material. These micropores not only possess excellent shock absorption performance but also effectively disperse external stress, thereby improving the material's tear resistance and abrasion resistance. Furthermore, this method employs supercritical carbon dioxide foaming technology in the preparation process, combined with the synergistic effect of a low-temperature foaming agent and an odorless crosslinking agent, further optimizing the morphology and distribution of the microporous structure, ensuring that the material is lightweight while maintaining high elasticity and durability. Therefore, the composite foamed shoe sole material described in this application possesses a uniform honeycomb microporous structure, excellent mechanical properties, and good surface stability, providing an ideal solution for high-performance shoe materials.

[0010] Preferably, in step (1), the functionalized graphene is modified by hydrogen bonding with tannins, with ≤10 layers and a particle size ≤5μm. This method is applicable to any nanofiller with high specific surface area and good dispersibility to ensure the uniformity of the microporous structure inside the material.

[0011] Preferably, in step (2), the hydrophobic modification treatment is performed at a temperature of 80-100℃ for 2-4 hours. The main purpose of the hydrophobic modification treatment is to improve the interfacial compatibility of the nanocellulose aerogel, so that it can be uniformly dispersed in the matrix resin during the mixing process, thereby avoiding the decline in mechanical properties caused by agglomeration.

[0012] Preferably, in step (3), the rotor speed of the internal mixer is 20-50 r / min, and the mixing temperature is 105-115℃. The mixing process requires control of temperature and time to ensure thorough mixing of all components without degradation. Furthermore, the order in which the foaming agent and crosslinking agent are added has a significant impact on the final material's properties, necessitating strict control of operating conditions.

[0013] Preferably, in step (4), the supercritical carbon dioxide saturation treatment is performed at a pressure of 40 MPa, a temperature of 150°C, and a time of 1 hour. The application of supercritical carbon dioxide technology can effectively reduce the decomposition temperature of the foaming agent and promote the formation of microporous structures, ensuring the lightweight and high elasticity of the material.

[0014] Preferably, in step (4), the cooling rate after molding is >20℃ / min, the cooling medium is an ice-water mixture, and the water temperature is ≤5℃. The rapid cooling process can effectively fix the microporous structure and avoid the collapse of the pore walls due to thermal expansion, thereby ensuring the mechanical properties and appearance quality of the material.

[0015] This application provides a lightweight, high-elastic EVA / nanofiller composite foamed shoe sole material and its preparation method. First, coal gangue powder is surface-modified with a silane coupling agent KH570. This step aims to improve the interfacial compatibility between the coal gangue powder and the organic matrix, thereby enhancing the overall mechanical properties of the composite material. Next, the modified coal gangue powder is mixed with functionalized graphene, wherein the functionalized graphene is modified by tannic acid hydrogen bonding, has 5 layers, and a particle size of 3 micrometers, ultimately forming an organosilicon-coated composite nanofiller. This not only effectively disperses in the matrix resin but also significantly improves the rigidity and toughness of the material.

[0016] The next step is to perform hydrophobic modification treatment on the nanocellulose aerogel. The nanocellulose aerogel is placed in a methyltrimethoxysilane vapor environment at a controlled temperature of 90°C for 3 hours. After this treatment, the contact angle of the nanocellulose aerogel reaches 125°, indicating that its surface has good hydrophobic properties. The main purpose of the hydrophobic modification treatment is to improve the interfacial compatibility between the nanocellulose aerogel and the matrix resin, and to avoid the decline in mechanical properties caused by agglomeration. Then, the mixing stage begins. EVA, polyamide elastomer, TPU (thermoplastic polyurethane elastomer), SEBS (styrene-ethylene-butene-styrene block copolymer), hydrophobic modified nanocellulose aerogel, and organosilicon-coated composite nanofiller are weighed and mixed according to the mass ratio and added to a mixer for mixing. During this process, temperature and time must be strictly controlled to ensure that the components are fully mixed and do not degrade. Subsequently, AC foaming agent (azodicarbonamide) and DCP crosslinking agent (dicumyl peroxide) are added sequentially to the mixing system, and mixing continues until granulation. The order in which the foaming agent and crosslinking agent are added is crucial. The crosslinking agent should be added first to promote the crosslinking reaction between molecular chains, and then the foaming agent should be added to avoid premature decomposition that would affect the foaming effect.

[0017] After granulation, the material is placed in a supercritical carbon dioxide reactor for saturation treatment. The application of supercritical carbon dioxide technology can significantly reduce the decomposition temperature of the foaming agent and promote the formation of microporous structures, ensuring that the material is lightweight while maintaining high elasticity. The saturated material is then rapidly transferred to a compression molding machine. After molding under controlled conditions, the molded material is rapidly cooled, which effectively fixes the microporous structure and prevents pore wall collapse due to thermal expansion, thereby ensuring the mechanical properties and appearance quality of the material.

[0018] The core of this application lies in achieving a uniformly distributed honeycomb microporous structure within the material by introducing hydrophobically modified nanocellulose aerogel and silicone resin-coated composite nanofillers, combined with supercritical carbon dioxide foaming technology. This structure not only possesses excellent shock absorption performance but also effectively disperses external stress, thereby improving the material's tear resistance and abrasion resistance. Furthermore, the synergistic effect of the low-temperature foaming agent and odorless crosslinking agent used in this application further optimizes the morphology and distribution of the microporous structure, ensuring that the material is lightweight while maintaining high elasticity and durability.

[0019] Compared with the prior art, this application has the following advantages: 1. The lightweight, high-elastic EVA / nanofiller composite foamed shoe sole material of this application has a uniform honeycomb microporous structure, excellent mechanical properties and good surface stability, which can significantly improve the material's lightweight, high elasticity and wear resistance, and meet the needs of the high-performance footwear material field.

[0020] 2. In actual production, the preparation process described in this application is simple and easy to implement, with low production costs, and can meet the needs of large-scale production. Furthermore, by utilizing industrial waste such as coal gangue powder as one of the raw materials, it provides a new approach to the resource utilization of industrial waste. This feature not only helps reduce production costs but also has significant environmental implications. Detailed Implementation

[0021] The technical solutions described below in conjunction with the embodiments of this application will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0022] Unless otherwise specified, the functionalized graphene powder used in this embodiment and the comparative example is prepared using the following specific process: Raw graphene with ≤10 layers and ≤5μm particle size was dispersed in deionized water to prepare a suspension with a concentration of 5 mg / mL. The suspension was then subjected to ultrasonic treatment at 500 W for 30 minutes to achieve initial depolymerization. Subsequently, an aqueous solution of tannic acid (concentration 5wt%) was added, and the mass ratio of graphene to tannic acid was controlled at 1:0.8. The mixture was stirred continuously in a 60℃ constant temperature water bath for 2 hours to allow the phenolic hydroxyl groups in the tannic acid molecules to form hydrogen bonds with the defect sites and oxygen-containing groups on the graphene surface. After the reaction, the mixture was centrifuged at 12000 r / min for 10 minutes to remove free tannic acid. After repeating the centrifugation and washing three times, the precipitate was placed in a vacuum drying oven at 60℃ for 12 hours to obtain tannic acid hydrogen bond modified functionalized graphene powder.

[0023] Unless otherwise specified, the preparation process of the nanocellulose aerogel used in this embodiment and the comparative example is as follows: A 2 wt% aqueous suspension of nanocellulose (CNF, filament length 1-2 μm) was mixed with a 0.8 wt% polyvinyl butyral (PVB) ethanol solution and ultrasonically emulsified at 40 °C (500 W, 20 min) to form an oil-in-water prepolymer. 0.5 wt% epichlorohydrin crosslinking agent was added, and the mixture was reacted at 60 °C for 1 h to construct a three-dimensional network framework. The mixture was then transferred to a high-pressure reactor and injected with supercritical carbon dioxide (10 MPa, 35 °C). Pressure was released at a rate of 20 °C / min to induce pores, resulting in a density of 0.025 g / cm³. 3 The aerogel matrix was prepared by immersing it in a hexane solution containing 5 wt% methyltrimethoxysilane (MTMS) and 2 wt% nano-silica (30 nm particle size) under vacuum (-0.1 MPa) for 2 hours. After removal, it was placed in a 120°C hot air oven for curing for 30 minutes, allowing MTMS to condense on the surface of the aerogel skeleton to form a 50-100 nm thick flexible organosilicon / silica composite armor layer (contact angle > 150°, compressive strength 1.2 MPa). Finally, the aerogel was cut into 0.5-1 mm particles using a roller granulator, and a 1 μm thick polyurethane elastomer coating (Shore A hardness 85) was sprayed onto the surface to obtain nanocellulose aerogel. General Embodiment: A method for preparing a lightweight, highly elastic EVA / nanofiller composite foamed shoe sole material, comprising the following steps:

[0024] Step (1): By weight, 100 parts of 200-mesh coal gangue powder are treated with 5-8 parts of silane coupling agent KH570 and then mixed with 30-50 parts of functionalized graphene to obtain a mixed filler. Then, 25-40 parts of organosilicon resin emulsion with a solid content of 30% are added and blended and cured. After dispersion, an organosilicon-coated composite nanofiller is formed. Then, 0.15-0.2 parts of a composition of stannous octoate and N,N-dimethylcyclohexylamine in a 1:1 mass ratio are further mixed in and catalyzed under conditions of 85-90% humidity and 60-70℃ to obtain a silica gel-coated composite nanofiller. Step (2): The nanocellulose aerogel is hydrophobically modified in methyltrimethoxysilane vapor at a temperature of 80-100℃ for 2-4 hours to obtain hydrophobically modified aerogel particles with a contact angle >120°. Step (3): By weight ratio, mix 40-50 parts EVA, 15-25 parts polyamide elastomer, 8-12 parts TPU, and 8-12 parts SEBS in a mixer. The rotor speed of the mixer is 20-50 r / min, the mixing temperature is 105-115℃, and the mixing time is 10-20 min. Then add 3-8 parts hydrophobic modified aerogel particles and 3-8 parts silicone gel-coated composite nanofiller. The mixing temperature is 85-95℃, and the mixing time is 3-5 min. Finally, add 3.0-4.5 parts foaming agent and 1.2-1.8 parts crosslinking agent. The mixing temperature is 85-95℃, and the mixing time is 3-5 min. Extrude and granulate. The foaming agent is AC foaming agent, and the crosslinking agent is DCP crosslinking agent. Step (4): The granulated material is placed in a supercritical carbon dioxide reactor for saturation treatment. The pressure of the supercritical carbon dioxide saturation treatment is 40 MPa, the temperature is 150℃, and the time is 1h. Then, it is molded and rapidly cooled. The molding temperature is 160℃, the pressure is 15 MPa, the holding time is 3 minutes, and the cooling rate after molding is >20℃ / min. The cooling medium is an ice-water mixture with a water temperature ≤5℃. The target composite foamed shoe sole material is obtained. Example 1

[0025] A method for preparing a lightweight, highly elastic EVA / nanofiller composite foamed shoe sole material includes the following steps: Step (1): By weight, 100 parts of 200-mesh coal gangue powder were treated with 5 parts of silane coupling agent KH570 and then mixed with 30 parts of functionalized graphene to obtain a mixed filler. Then, 25 parts of organosilicon resin emulsion with a solid content of 30% were added and mixed and cured. After dispersion, an organosilicon-coated composite nanofiller was formed. Then, 0.15 parts of a composition of stannous octoate and N,N-dimethylcyclohexylamine in a 1:1 mass ratio were further mixed in and catalyzed at 85% humidity and 60℃ for 2 hours to obtain a silica gel-coated composite nanofiller. Step (2): The nanocellulose aerogel was subjected to hydrophobic modification treatment in methyltrimethoxysilane vapor at a temperature of 80°C for 2 hours to obtain hydrophobic modified aerogel particles with a contact angle >120°. Step (3): According to the weight ratio, 40 parts of EVA, 15 parts of polyamide elastomer, 8 parts of TPU and 8 parts of SEBS are mixed in a mixer. The rotor speed of the mixer is 20 r / min, the mixing temperature is 105℃ and the mixing time is 10 minutes. Then, 3 parts of hydrophobic modified aerogel particles and 3 parts of silicone gel coated composite nanofiller are added. The mixing temperature is 85℃ and the mixing time is 3 minutes. Finally, 3.0 parts of foaming agent AC and 1.2 parts of crosslinking agent DCP are added. The mixing temperature is 85℃ and the mixing time is 3 minutes. Then, the mixture is extruded and granulated. Step (4): The granulated material is placed in a supercritical carbon dioxide reactor for saturation treatment. The pressure of the supercritical carbon dioxide saturation treatment is 40 MPa, the temperature is 150℃, and the time is 1h. Then, it is molded and rapidly cooled. The molding temperature is 160℃, the pressure is 15 MPa, the holding time is 3 minutes, the cooling rate after molding is 22℃ / min, the cooling medium is an ice-water mixture, and the water temperature is ≤5℃. The target composite foamed shoe sole material is obtained. Example 2

[0026] A method for preparing a lightweight, highly elastic EVA / nanofiller composite foamed shoe sole material includes the following steps: Step (1): By weight, 100 parts of 200-mesh coal gangue powder were treated with 6 parts of silane coupling agent KH570 and then mixed with 35 parts of functionalized graphene to obtain a mixed filler. Then, 28 parts of organosilicon resin emulsion with a solid content of 30% were added and mixed and cured. After dispersion, an organosilicon-coated composite nanofiller was formed. Then, 0.16 parts of a composition of stannous octoate and N,N-dimethylcyclohexylamine in a 1:1 mass ratio were further mixed in and catalyzed at 86% humidity and 62℃ for 2.2 h to obtain a silica gel-coated composite nanofiller. Step (2): The nanocellulose aerogel was subjected to hydrophobic modification treatment in methyltrimethoxysilane vapor at a temperature of 85°C for 2.5 h to obtain hydrophobic modified aerogel particles with a contact angle >120°. Step (3): According to the weight ratio, 42 parts of EVA, 18 parts of polyamide elastomer, 9 parts of TPU and 9 parts of SEBS are mixed in an internal mixer. The rotor speed of the internal mixer is 25 r / min, the mixing temperature is 108℃ and the mixing time is 12 minutes. Then, 4 parts of hydrophobic modified aerogel particles and 4 parts of silicone gel coated composite nanofiller are added. The mixing temperature is 87℃ and the mixing time is 3.5 minutes. Finally, 3.5 parts of foaming agent AC and 1.4 parts of crosslinking agent DCP are added. The mixing temperature is 87℃ and the mixing time is 3.5 minutes. Then, the mixture is extruded and granulated. Step (4): The granulated material is placed in a supercritical carbon dioxide reactor for saturation treatment. The pressure of the supercritical carbon dioxide saturation treatment is 40 MPa, the temperature is 150℃, and the time is 1h. Then, it is molded and rapidly cooled. The molding temperature is 160℃, the pressure is 15 MPa, the holding time is 3 minutes, the cooling rate after molding is 22℃ / min, the cooling medium is an ice-water mixture, and the water temperature is ≤5℃. The target composite foamed shoe sole material is obtained. Example 3

[0027] A method for preparing a lightweight, highly elastic EVA / nanofiller composite foamed shoe sole material includes the following steps: Step (1): By weight, 100 parts of 200-mesh coal gangue powder were treated with 6.5 parts of silane coupling agent KH570 and then mixed with 40 parts of functionalized graphene to obtain a mixed filler. Then, 32 parts of organosilicon resin emulsion with a solid content of 30% were added and mixed and cured. After dispersion, an organosilicon-coated composite nanofiller was formed. Then, 0.17 parts of a composition of stannous octoate and N,N-dimethylcyclohexylamine in a 1:1 mass ratio were added and catalytically reacted at 87% humidity and 65℃ for 2.8 h to obtain a silica gel-coated composite nanofiller. Step (2): The nanocellulose aerogel was subjected to hydrophobic modification treatment in methyltrimethoxysilane vapor at a temperature of 90°C for 3 hours to obtain hydrophobic modified aerogel particles with a contact angle >120°. Step (3): According to the weight ratio, 45 parts of EVA, 20 parts of polyamide elastomer, 10 parts of TPU and 10 parts of SEBS are mixed in an internal mixer. The rotor speed of the internal mixer is 30 r / min, the mixing temperature is 110℃ and the mixing time is 15 minutes. Then, 5 parts of hydrophobic modified aerogel particles and 5 parts of silicone gel coated composite nanofiller are added. The mixing temperature is 89℃ and the mixing time is 4 minutes. Finally, 3.8 parts of foaming agent AC and 1.5 parts of crosslinking agent DCP are added. The mixing temperature is 89℃ and the mixing time is 4 minutes. The mixture is then extruded and granulated. Step (4): The granulated material is placed in a supercritical carbon dioxide reactor for saturation treatment. The pressure of the supercritical carbon dioxide saturation treatment is 40 MPa, the temperature is 150℃, and the time is 1h. Then, it is molded and rapidly cooled. The molding temperature is 160℃, the pressure is 15 MPa, the holding time is 3 minutes, the cooling rate after molding is 22℃ / min, the cooling medium is an ice-water mixture, and the water temperature is ≤5℃. The target composite foamed shoe sole material is obtained. Example 4

[0028] A method for preparing a lightweight, highly elastic EVA / nanofiller composite foamed shoe sole material includes the following steps: Step (1): By weight, 100 parts of 200-mesh coal gangue powder were treated with 7 parts of silane coupling agent KH570 and then mixed with 45 parts of functionalized graphene to obtain a mixed filler. Then, 35 parts of organosilicon resin emulsion with a solid content of 30% were added and mixed and cured. After dispersion, an organosilicon-coated composite nanofiller was formed. Then, 0.18 parts of a composition of stannous octoate and N,N-dimethylcyclohexylamine in a 1:1 mass ratio were added and catalytically reacted at 88% humidity and 67℃ for 3.2 hours to obtain a silica gel-coated composite nanofiller. Step (2): The nanocellulose aerogel was subjected to hydrophobic modification treatment in methyltrimethoxysilane vapor at a temperature of 95°C for 3.5 h to obtain hydrophobic modified aerogel particles with a contact angle >120°. Step (3): According to the weight ratio, 47 parts of EVA, 22 parts of polyamide elastomer, 11 parts of TPU and 11 parts of SEBS are mixed in an internal mixer. The rotor speed of the internal mixer is 35 r / min, the mixing temperature is 112℃ and the mixing time is 17 minutes. Then, 6 parts of hydrophobic modified aerogel particles and 6 parts of silicone gel coated composite nanofiller are added. The mixing temperature is 92℃ and the mixing time is 4.5 minutes. Finally, 4.2 parts of foaming agent AC and 1.6 parts of crosslinking agent DCP are added. The mixing temperature is 92℃ and the mixing time is 4.5 minutes. Then, the mixture is extruded and granulated. Step (4): The granulated material is placed in a supercritical carbon dioxide reactor for saturation treatment. The pressure of the supercritical carbon dioxide saturation treatment is 40 MPa, the temperature is 150℃, and the time is 1h. Then, it is molded and rapidly cooled. The molding temperature is 160℃, the pressure is 15 MPa, the holding time is 3 minutes, the cooling rate after molding is 22℃ / min, the cooling medium is an ice-water mixture, and the water temperature is ≤5℃. The target composite foamed shoe sole material is obtained. Example 5

[0029] A method for preparing a lightweight, highly elastic EVA / nanofiller composite foamed shoe sole material includes the following steps: Step (1): By weight, 100 parts of 200-mesh coal gangue powder were treated with 7.5 parts of silane coupling agent KH570 and then mixed with 48 parts of functionalized graphene to obtain a mixed filler. Then, 38 parts of organosilicon resin emulsion with a solid content of 30% were added and mixed and cured. After dispersion, an organosilicon-coated composite nanofiller was formed. Then, 0.19 parts of a composition of stannous octoate and N,N-dimethylcyclohexylamine in a 1:1 mass ratio were added and catalytically reacted at 89% humidity and 69℃ for 3.6 hours to obtain a silica gel-coated composite nanofiller. Step (2): The nanocellulose aerogel was subjected to hydrophobic modification treatment in methyltrimethoxysilane vapor at a temperature of 98°C for 3.8h to obtain hydrophobic modified aerogel particles with a contact angle >120°. Step (3): According to the weight ratio, 49 parts of EVA, 24 parts of polyamide elastomer, 11.5 parts of TPU and 11.5 parts of SEBS are mixed in an internal mixer. The rotor speed of the internal mixer is 45 r / min, the mixing temperature is 114℃ and the mixing time is 18 minutes. Then, 7 parts of hydrophobic modified aerogel particles and 7 parts of silicone gel coated composite nanofiller are added. The mixing temperature is 94℃ and the mixing time is 4.8 minutes. Finally, 4.4 parts of foaming agent AC and 1.7 parts of crosslinking agent DCP are added. The mixing temperature is 94℃ and the mixing time is 4.8 minutes. The mixture is then extruded and granulated. Step (4): The granulated material is placed in a supercritical carbon dioxide reactor for saturation treatment. The pressure of the supercritical carbon dioxide saturation treatment is 40 MPa, the temperature is 150℃, and the time is 1h. Then, it is molded and rapidly cooled. The molding temperature is 160℃, the pressure is 15 MPa, the holding time is 3 minutes, the cooling rate after molding is 22℃ / min, the cooling medium is an ice-water mixture, and the water temperature is ≤5℃. The target composite foamed shoe sole material is obtained. Example 6

[0030] A method for preparing a lightweight, highly elastic EVA / nanofiller composite foamed shoe sole material includes the following steps: Step (1): By weight, 100 parts of 200-mesh coal gangue powder were treated with 8 parts of silane coupling agent KH570 and then mixed with 50 parts of functionalized graphene to obtain a mixed filler. Then, 40 parts of organosilicon resin emulsion with a solid content of 30% were added and mixed and cured. After dispersion, an organosilicon-coated composite nanofiller was formed. Then, 0.20 parts of a composition of stannous octoate and N,N-dimethylcyclohexylamine in a 1:1 mass ratio were further mixed in and catalyzed at 90% humidity and 70℃ for 4 hours to obtain a silica gel-coated composite nanofiller. Step (2): The nanocellulose aerogel was subjected to hydrophobic modification treatment in methyltrimethoxysilane vapor at a temperature of 100℃ for 4 hours to obtain hydrophobic modified aerogel particles with a contact angle >120°. Step (3): According to the weight ratio, 50 parts of EVA, 25 parts of polyamide elastomer, 12 parts of TPU and 12 parts of SEBS are mixed in an internal mixer. The rotor speed of the internal mixer is 50 r / min, the mixing temperature is 115℃ and the mixing time is 20 minutes. Then, 8 parts of hydrophobic modified aerogel particles and 8 parts of silicone gel coated composite nanofiller are added. The mixing temperature is 95℃ and the mixing time is 5 minutes. Finally, 4.5 parts of foaming agent AC and 1.8 parts of crosslinking agent DCP are added. The mixing temperature is 95℃ and the mixing time is 5 minutes. Then, the mixture is extruded and granulated. Step (4): The granulated material is placed in a supercritical carbon dioxide reactor for saturation treatment. The pressure of the supercritical carbon dioxide saturation treatment is 40 MPa, the temperature is 150℃, and the time is 1h. Then, it is molded and rapidly cooled. The molding temperature is 160℃, the pressure is 15 MPa, the holding time is 3 minutes, the cooling rate after molding is 22℃ / min, the cooling medium is an ice-water mixture, and the water temperature is ≤5℃. The target composite foamed shoe sole material is obtained.

[0031] Comparative Example 1 The difference from Example 1 is that no functionalized graphene was added: A method for preparing a lightweight, highly elastic EVA / nanofiller composite foamed shoe sole material includes the following steps: Step (1): By weight, 100 parts of 200-mesh coal gangue powder were treated with 5 parts of silane coupling agent KH570 to obtain a mixed filler. Then, 25 parts of organosilicon resin emulsion with a solid content of 30% were added and mixed and cured. After dispersion, organosilicon-coated composite nanofiller was formed. Then, 0.15 parts of a composition of stannous octoate and N,N-dimethylcyclohexylamine in a 1:1 mass ratio were added. The mixture was catalytically reacted at 85% humidity and 60℃ for 2 hours to obtain a silica gel-coated composite nanofiller. Step (2): The nanocellulose aerogel was subjected to hydrophobic modification treatment in methyltrimethoxysilane vapor at a temperature of 80°C for 2 hours to obtain hydrophobic modified aerogel particles with a contact angle >120°. Step (3): According to the weight ratio, 40 parts of EVA, 15 parts of polyamide elastomer, 8 parts of TPU and 8 parts of SEBS are mixed in a mixer. The rotor speed of the mixer is 20 r / min, the mixing temperature is 105℃ and the mixing time is 10 minutes. Then, 3 parts of hydrophobic modified aerogel particles and 3 parts of silicone gel coated composite nanofiller are added. The mixing temperature is 85℃ and the mixing time is 3 minutes. Finally, 3.0 parts of foaming agent AC and 1.2 parts of crosslinking agent DCP are added. The mixing temperature is 85℃ and the mixing time is 3 minutes. Then, the mixture is extruded and granulated. Step (4): The granulated material is placed in a supercritical carbon dioxide reactor for saturation treatment. The pressure of the supercritical carbon dioxide saturation treatment is 40 MPa, the temperature is 150℃, and the time is 1h. Then, it is molded and rapidly cooled. The molding temperature is 160℃, the pressure is 15 MPa, the holding time is 3 minutes, the cooling rate after molding is 22℃ / min, the cooling medium is an ice-water mixture, and the water temperature is ≤5℃. The target composite foamed shoe sole material is obtained.

[0032] Comparative Example 2 The difference from Example 1 is that the catalytic reaction was not carried out under conditions of 85% humidity and 60°C: A method for preparing a lightweight, highly elastic EVA / nanofiller composite foamed shoe sole material includes the following steps: Step (1): By weight, 100 parts of 200-mesh coal gangue powder were treated with 5 parts of silane coupling agent KH570 and then mixed with 30 parts of functionalized graphene to obtain a mixed filler. Then, 25 parts of organosilicon resin emulsion with a solid content of 30% were added and mixed and cured. After dispersion, organosilicon-coated composite nanofiller was formed to obtain composite nanofiller. Step (2): The nanocellulose aerogel was subjected to hydrophobic modification treatment in methyltrimethoxysilane vapor at a temperature of 80°C for 2 hours to obtain hydrophobic modified aerogel particles with a contact angle >120°. Step (3): According to the weight ratio, 40 parts of EVA, 15 parts of polyamide elastomer, 8 parts of TPU and 8 parts of SEBS are mixed in an internal mixer. The rotor speed of the internal mixer is 20 r / min, the mixing temperature is 105℃ and the mixing time is 10 minutes. Then, 3 parts of hydrophobic modified aerogel particles and 3 parts of composite nanofiller are added. The mixing temperature is 85℃ and the mixing time is 3 minutes. Finally, 3.0 parts of foaming agent AC and 1.2 parts of crosslinking agent DCP are added. The mixing temperature is 85℃ and the mixing time is 3 minutes. Then, the mixture is extruded and granulated. Step (4): The granulated material is placed in a supercritical carbon dioxide reactor for saturation treatment. The pressure of the supercritical carbon dioxide saturation treatment is 40 MPa, the temperature is 150℃, and the time is 1h. Then, it is molded and rapidly cooled. The molding temperature is 160℃, the pressure is 15 MPa, the holding time is 3 minutes, the cooling rate after molding is 22℃ / min, the cooling medium is an ice-water mixture, and the water temperature is ≤5℃. The target composite foamed shoe sole material is obtained.

[0033] Comparative Example 3 The difference from Example 1 is that no nanocellulose aerogel was added: A method for preparing a lightweight, highly elastic EVA / nanofiller composite foamed shoe sole material includes the following steps: Step (1): By weight, 100 parts of 200-mesh coal gangue powder were treated with 5 parts of silane coupling agent KH570 and then mixed with 30 parts of functionalized graphene to obtain a mixed filler. Then, 25 parts of organosilicon resin emulsion with a solid content of 30% were added and mixed and cured. After dispersion, an organosilicon-coated composite nanofiller was formed. Then, 0.15 parts of a composition of stannous octoate and N,N-dimethylcyclohexylamine in a 1:1 mass ratio were further mixed in and catalyzed at 85% humidity and 60℃ for 2 hours to obtain a silica gel-coated composite nanofiller. Step (2): According to the weight ratio, 40 parts of EVA, 15 parts of polyamide elastomer, 8 parts of TPU and 8 parts of SEBS are mixed in an internal mixer. The rotor speed of the internal mixer is 20 r / min, the mixing temperature is 105℃ and the mixing time is 10 minutes. Then, 3 parts of silicone gel coated composite nanofiller are added. The mixing temperature is 85℃ and the mixing time is 3 minutes. Finally, 3.0 parts of foaming agent AC and 1.2 parts of crosslinking agent DCP are added. The mixing temperature is 85℃ and the mixing time is 3 minutes. Then, the mixture is extruded and granulated. Step (3): The granulated material is placed in a supercritical carbon dioxide reactor for saturation treatment. The pressure of the supercritical carbon dioxide saturation treatment is 40 MPa, the temperature is 150℃, and the time is 1h. Then, it is molded and rapidly cooled. The molding temperature is 160℃, the pressure is 15 MPa, the holding time is 3 minutes, and the cooling rate after molding is 22℃ / min. The cooling medium is an ice-water mixture with a water temperature ≤5℃. The target composite foamed shoe sole material is obtained.

[0034] Comparative Example 4 The difference from Example 1 is that step (3) was not subjected to intensive mixing: A method for preparing a lightweight, highly elastic EVA / nanofiller composite foamed shoe sole material includes the following steps: Step (1): By weight, 100 parts of 200-mesh coal gangue powder were treated with 5 parts of silane coupling agent KH570 and then mixed with 30 parts of functionalized graphene to obtain a mixed filler. Then, 25 parts of organosilicon resin emulsion with a solid content of 30% were added and mixed and cured. After dispersion, an organosilicon-coated composite nanofiller was formed. Then, 0.15 parts of a composition of stannous octoate and N,N-dimethylcyclohexylamine in a 1:1 mass ratio were further mixed in and catalyzed at 85% humidity and 60℃ for 2 hours to obtain a silica gel-coated composite nanofiller. Step (2): The nanocellulose aerogel was subjected to hydrophobic modification treatment in methyltrimethoxysilane vapor at a temperature of 80°C for 2 hours to obtain hydrophobic modified aerogel particles with a contact angle >120°. Step (3): According to the weight ratio, 40 parts of EVA, 15 parts of polyamide elastomer, 8 parts of TPU and 8 parts of SEBS are melt-mixed and granulated. Then, 3 parts of hydrophobic modified aerogel particles and 3 parts of silicone gel coated composite nanofiller are added. The mixing temperature is 85℃ and the mixing time is 3 minutes. Finally, 3.0 parts of foaming agent AC and 1.2 parts of crosslinking agent DCP are added. The mixing temperature is 85℃ and the mixing time is 3 minutes. Then, the mixture is extruded and granulated. Step (4): The granulated material is placed in a supercritical carbon dioxide reactor for saturation treatment. The pressure of the supercritical carbon dioxide saturation treatment is 40 MPa, the temperature is 150℃, and the time is 1h. Then, it is molded and rapidly cooled. The molding temperature is 160℃, the pressure is 15 MPa, the holding time is 3 minutes, the cooling rate after molding is 22℃ / min, the cooling medium is an ice-water mixture, and the water temperature is ≤5℃. The target composite foamed shoe sole material is obtained.

[0035] Comparative Example 5 The difference from Example 1 is that the material addition order in step (3) is incorrect: A method for preparing a lightweight, highly elastic EVA / nanofiller composite foamed shoe sole material includes the following steps: Step (1): By weight, 100 parts of 200-mesh coal gangue powder were treated with 5 parts of silane coupling agent KH570 and then mixed with 30 parts of functionalized graphene to obtain a mixed filler. Then, 25 parts of organosilicon resin emulsion with a solid content of 30% were added and mixed and cured. After dispersion, an organosilicon-coated composite nanofiller was formed. Then, 0.15 parts of a composition of stannous octoate and N,N-dimethylcyclohexylamine in a 1:1 mass ratio were further mixed in and catalyzed at 85% humidity and 60℃ for 2 hours to obtain a silica gel-coated composite nanofiller. Step (2): The nanocellulose aerogel was subjected to hydrophobic modification treatment in methyltrimethoxysilane vapor at a temperature of 80°C for 2 hours to obtain hydrophobic modified aerogel particles with a contact angle >120°. Step (3): According to the weight ratio, 40 parts EVA, 15 parts polyamide elastomer, 8 parts TPU, 8 parts SEBS, 3 parts hydrophobic modified aerogel particles and 3 parts silicone gel coated composite nanofiller are mixed in an internal mixer. The rotor speed of the internal mixer is 20 r / min, the mixing temperature is 105℃, and the mixing time is 10 minutes. Finally, 3.0 parts foaming agent AC and 1.2 parts crosslinking agent DCP are added. The mixing temperature is 85℃ and the mixing time is 3 minutes. Then, the mixture is extruded and granulated. Step (4): The granulated material is placed in a supercritical carbon dioxide reactor for saturation treatment. The pressure of the supercritical carbon dioxide saturation treatment is 40 MPa, the temperature is 150℃, and the time is 1h. Then, it is molded and rapidly cooled. The molding temperature is 160℃, the pressure is 15 MPa, the holding time is 3 minutes, the cooling rate after molding is 22℃ / min, the cooling medium is an ice-water mixture, and the water temperature is ≤5℃. The target composite foamed shoe sole material is obtained.

[0036] Comparative Example 6 The difference from Example 1 is that the material addition order in step (3) is incorrect: A method for preparing a lightweight, highly elastic EVA / nanofiller composite foamed shoe sole material includes the following steps: Step (1): By weight, 100 parts of 200-mesh coal gangue powder were treated with 5 parts of silane coupling agent KH570 and then mixed with 30 parts of functionalized graphene to obtain a mixed filler. Then, 25 parts of organosilicon resin emulsion with a solid content of 30% were added and mixed and cured. After dispersion, an organosilicon-coated composite nanofiller was formed. Then, 0.15 parts of a composition of stannous octoate and N,N-dimethylcyclohexylamine in a 1:1 mass ratio were further mixed in and catalyzed at 85% humidity and 60℃ for 2 hours to obtain a silica gel-coated composite nanofiller. Step (2): The nanocellulose aerogel was subjected to hydrophobic modification treatment in methyltrimethoxysilane vapor at a temperature of 80°C for 2 hours to obtain hydrophobic modified aerogel particles with a contact angle >120°. Step (3): According to the weight ratio, 40 parts of EVA, 15 parts of polyamide elastomer, 8 parts of TPU and 8 parts of SEBS are mixed in a mixer. The rotor speed of the mixer is 20 r / min, the mixing temperature is 105℃ and the mixing time is 10 minutes. Then, 3 parts of hydrophobic modified aerogel particles, 3 parts of silicone gel coated composite nanofiller, 3.0 parts of foaming agent AC and 1.2 parts of crosslinking agent DCP are added. The mixing temperature is 85℃ and the mixing time is 3 minutes. Then, the mixture is extruded and granulated. Step (4): The granulated material is placed in a supercritical carbon dioxide reactor for saturation treatment. The pressure of the supercritical carbon dioxide saturation treatment is 40 MPa, the temperature is 150℃, and the time is 1h. Then, it is molded and rapidly cooled. The molding temperature is 160℃, the pressure is 15 MPa, the holding time is 3 minutes, the cooling rate after molding is 22℃ / min, the cooling medium is an ice-water mixture, and the water temperature is ≤5℃. The target composite foamed shoe sole material is obtained.

[0037] Comparative Example 7 The difference from Example 1 is that the cooling rate in step (4) is 18°C / min: A method for preparing a lightweight, highly elastic EVA / nanofiller composite foamed shoe sole material includes the following steps: Step (1): By weight, 100 parts of 200-mesh coal gangue powder were treated with 5 parts of silane coupling agent KH570 and then mixed with 30 parts of functionalized graphene to obtain a mixed filler. Then, 25 parts of organosilicon resin emulsion with a solid content of 30% were added and mixed and cured. After dispersion, an organosilicon-coated composite nanofiller was formed. Then, 0.15 parts of a composition of stannous octoate and N,N-dimethylcyclohexylamine in a 1:1 mass ratio were further mixed in and catalyzed at 85% humidity and 60℃ for 2 hours to obtain a silica gel-coated composite nanofiller. Step (2): The nanocellulose aerogel was subjected to hydrophobic modification treatment in methyltrimethoxysilane vapor at a temperature of 80°C for 2 hours to obtain hydrophobic modified aerogel particles with a contact angle >120°. Step (3): According to the weight ratio, 40 parts of EVA, 15 parts of polyamide elastomer, 8 parts of TPU and 8 parts of SEBS are mixed in a mixer. The rotor speed of the mixer is 20 r / min, the mixing temperature is 105℃ and the mixing time is 10 minutes. Then, 3 parts of hydrophobic modified aerogel particles and 3 parts of silicone gel coated composite nanofiller are added. The mixing temperature is 85℃ and the mixing time is 3 minutes. Finally, 3.0 parts of foaming agent AC and 1.2 parts of crosslinking agent DCP are added. The mixing temperature is 85℃ and the mixing time is 3 minutes. Then, the mixture is extruded and granulated. Step (4): The granulated material is placed in a supercritical carbon dioxide reactor for saturation treatment. The pressure of the supercritical carbon dioxide saturation treatment is 40 MPa, the temperature is 150℃, and the time is 1h. Then, it is molded and rapidly cooled. The molding temperature is 160℃, the pressure is 15 MPa, the holding time is 3 minutes, and the cooling rate after molding is 18℃ / min. The cooling medium is an ice-water mixture with a water temperature ≤5℃. The target composite foamed shoe sole material is obtained.

[0038] Comparative Example 8 The difference from Example 1 is that the nanocellulose aerogel was not modified: A method for preparing a lightweight, highly elastic EVA / nanofiller composite foamed shoe sole material includes the following steps: Step (1): By weight, 100 parts of 200-mesh coal gangue powder were treated with 5 parts of silane coupling agent KH570 and then mixed with 30 parts of functionalized graphene to obtain a mixed filler. Then, 25 parts of organosilicon resin emulsion with a solid content of 30% were added and mixed and cured. After dispersion, an organosilicon-coated composite nanofiller was formed. Then, 0.15 parts of a composition of stannous octoate and N,N-dimethylcyclohexylamine in a 1:1 mass ratio were further mixed in and catalyzed at 85% humidity and 60℃ for 2 hours to obtain a silica gel-coated composite nanofiller. Step (2): According to the weight ratio, 40 parts of EVA, 15 parts of polyamide elastomer, 8 parts of TPU and 8 parts of SEBS are mixed in an internal mixer. The rotor speed of the internal mixer is 20 r / min, the mixing temperature is 105℃ and the mixing time is 10 minutes. Then, 3 parts of nanocellulose aerogel particles and 3 parts of silicone gel coated composite nanofiller are added. The mixing temperature is 85℃ and the mixing time is 3 minutes. Finally, 3.0 parts of foaming agent AC and 1.2 parts of crosslinking agent DCP are added. The mixing temperature is 85℃ and the mixing time is 3 minutes. Then, the mixture is extruded and granulated. Step (4): The granulated material is placed in a supercritical carbon dioxide reactor for saturation treatment. The pressure of the supercritical carbon dioxide saturation treatment is 40 MPa, the temperature is 150℃, and the time is 1h. Then, it is molded and rapidly cooled. The molding temperature is 160℃, the pressure is 15 MPa, the holding time is 3 minutes, the cooling rate after molding is 22℃ / min, the cooling medium is an ice-water mixture, and the water temperature is ≤5℃. The target composite foamed shoe sole material is obtained.

[0039] Comparative Example 9 The difference from Example 1 is that 9 parts of hydrophobically modified aerogel particles and 9 parts of silica gel-coated composite nanofiller were added: A method for preparing a lightweight, highly elastic EVA / nanofiller composite foamed shoe sole material includes the following steps: Step (1): By weight, 100 parts of 200-mesh coal gangue powder were treated with 5 parts of silane coupling agent KH570 and then mixed with 30 parts of functionalized graphene to obtain a mixed filler. Then, 25 parts of organosilicon resin emulsion with a solid content of 30% were added and mixed and cured. After dispersion, an organosilicon-coated composite nanofiller was formed. Then, 0.15 parts of a composition of stannous octoate and N,N-dimethylcyclohexylamine in a 1:1 mass ratio were further mixed in and catalyzed at 85% humidity and 60℃ for 2 hours to obtain a silica gel-coated composite nanofiller. Step (2): The nanocellulose aerogel was subjected to hydrophobic modification treatment in methyltrimethoxysilane vapor at a temperature of 80°C for 2 hours to obtain hydrophobic modified aerogel particles with a contact angle >120°. Step (3): According to the weight ratio, 40 parts of EVA, 15 parts of polyamide elastomer, 8 parts of TPU and 8 parts of SEBS are mixed in a mixer. The rotor speed of the mixer is 20 r / min, the mixing temperature is 105℃ and the mixing time is 10 minutes. Then, 9 parts of hydrophobic modified aerogel particles and 9 parts of silicone gel coated composite nanofiller are added. The mixing temperature is 85℃ and the mixing time is 3 minutes. Finally, 3.0 parts of foaming agent AC and 1.2 parts of crosslinking agent DCP are added. The mixing temperature is 85℃ and the mixing time is 3 minutes. Then, the mixture is extruded and granulated. Step (4): The granulated material is placed in a supercritical carbon dioxide reactor for saturation treatment. The pressure of the supercritical carbon dioxide saturation treatment is 40 MPa, the temperature is 150℃, and the time is 1h. Then, it is molded and rapidly cooled. The molding temperature is 160℃, the pressure is 15 MPa, the holding time is 3 minutes, the cooling rate after molding is 22℃ / min, the cooling medium is an ice-water mixture, and the water temperature is ≤5℃. The target composite foamed shoe sole material is obtained.

[0040] Comparative Example 10 The difference from Example 1 is that step (3): by weight ratio, 60 parts EVA, 30 parts polyamide elastomer, 8 parts TPU, and 8 parts SEBS are mixed. A method for preparing a lightweight, highly elastic EVA / nanofiller composite foamed shoe sole material includes the following steps: Step (1): By weight, 100 parts of 200-mesh coal gangue powder were treated with 5 parts of silane coupling agent KH570 and then mixed with 30 parts of functionalized graphene to obtain a mixed filler. Then, 25 parts of organosilicon resin emulsion with a solid content of 30% were added and mixed and cured. After dispersion, an organosilicon-coated composite nanofiller was formed. Then, 0.15 parts of a composition of stannous octoate and N,N-dimethylcyclohexylamine in a 1:1 mass ratio were further mixed in and catalyzed at 85% humidity and 60℃ for 2 hours to obtain a silica gel-coated composite nanofiller. Step (2): The nanocellulose aerogel was subjected to hydrophobic modification treatment in methyltrimethoxysilane vapor at a temperature of 80°C for 2 hours to obtain hydrophobic modified aerogel particles with a contact angle >120°. Step (3): According to the weight ratio, 60 parts of EVA, 30 parts of polyamide elastomer, 8 parts of TPU and 8 parts of SEBS are mixed in a mixer. The rotor speed of the mixer is 20 r / min, the mixing temperature is 105℃ and the mixing time is 10 minutes. Then, 3 parts of hydrophobic modified aerogel particles and 3 parts of silicone gel coated composite nanofiller are added. The mixing temperature is 85℃ and the mixing time is 3 minutes. Finally, 3.0 parts of foaming agent AC and 1.2 parts of crosslinking agent DCP are added. The mixing temperature is 85℃ and the mixing time is 3 minutes. Then, the mixture is extruded and granulated. Step (4): The granulated material is placed in a supercritical carbon dioxide reactor for saturation treatment. The pressure of the supercritical carbon dioxide saturation treatment is 40 MPa, the temperature is 150℃, and the time is 1h. Then, it is molded and rapidly cooled. The molding temperature is 160℃, the pressure is 15 MPa, the holding time is 3 minutes, the cooling rate after molding is 22℃ / min, the cooling medium is an ice-water mixture, and the water temperature is ≤5℃. The target composite foamed shoe sole material is obtained.

[0041] Density testing: water displacement method.

[0042] The rebound rate was tested using the falling ball method: Foam material was cut into 100mm×100mm×50mm pieces, ensuring a smooth and undamaged surface. The sample was placed in an environment of 23±2℃ and 50±5%RH for 16 hours. A falling ball device was used, with a steel ball diameter of 16mm, a mass of 16.7g, and a drop height of 500±1mm. The steel ball was allowed to fall freely, and the highest rebound height was recorded. This test was repeated 5 times, and the average value was taken. The rebound rate is the percentage of the rebound height to the initial height.

[0043] Hardness testing: The hardness of the foam plastic is measured using a hardness tester.

[0044] Compression set test: Method B in "Determination of Compression Set of Flexible Foam Polymer Materials" (GB / T 6669-2008): Compression test is carried out under normal temperature conditions.

[0045] Abrasion resistance: Refer to GB / T 3903.2.

[0046] Tensile strength test: Tested according to standard ISO1798-2008; results are shown in Table 1.

[0047] Table 1. Performance test results of the examples and comparative examples:

[0048] This embodiment of the solution achieves performance improvement through synergistic regulation of filler interface bonding and component control. Filler dispersion is strengthened; coal gangue powder is modified with siloxane bonds, increasing the surface hydroxyl graft density and forming a cross-linked network with the tannic acid-modified layer of functionalized graphene. The interfacial bonding transitions from physical adsorption to chemical bonding, significantly enhancing stress transfer efficiency and improving wear resistance. Aerogel activity evolution and hydrophobic modification improve compatibility with the matrix resin, transforming the aerogel from a rigid filler into a flexible stress hub while reducing density. The designed component ratios are coordinated, resulting in good overall elasticity and mechanical properties.

[0049] Compared to Example 1, Comparative Example 1 lacked functionalized graphene: only coal gangue powder was combined with the matrix, resulting in low stress transfer efficiency and brittle fracture of the pore walls under frictional loads; Comparative Example 2 lacked catalytic crosslinking and silicone gel coating: the silicone resin was not fully cured, the coating layer had defects, and the nanofiller agglomerated during mixing, causing stress concentration points; the lack of silicone gel coating resulted in a slight increase in density. Comparative Example 3 lost the support of the nanocellulose skeleton, resulting in disordered microporous structure and inability to uniformly disperse stress; Comparative Example 4 was not mixed, and uneven dispersion of filler formed local high-density areas, hindering uniform permeation and foaming of supercritical carbon dioxide, causing closed pores and structural defects; Comparative Example 5 had an incorrect feeding sequence, resulting in the simultaneous addition of aerogel and nanofiller, causing the hydrophobic surface to be coated by resin, losing the function of pore structure regulation; Comparative Example 6 had an incorrect order of adding foaming agent, resulting in the decomposition of AC foaming agent in the early stage of mixing, premature gas escape, leading to uncontrolled foaming density and pore wall perforation; Comparative Example 7 was cooled. Insufficient cooling rate leads to molecular chain relaxation during slow cooling, causing thermal expansion and deformation of the pore walls and loss of skeleton resilience. In Comparative Example 8, the cellulose aerogel was unmodified, resulting in poor compatibility between the hydrophilic surface and the organic matrix, causing aerogel particles to de-adhere at the interface and form crack sources. In Comparative Example 9, excessive filler leads to excessive nanoparticles clogging the aerogel pores, inhibiting the supercritical carbon dioxide diffusion path, resulting in micropore collapse and increased density. In Comparative Example 10, excessive EVA reduces the content of the elastomer continuous phase, and insufficient molecular chain flexibility weakens the deformation recovery ability of the honeycomb structure.

Claims

1. A method for preparing a lightweight, highly elastic EVA / nanofiller composite foamed shoe sole material, characterized in that, Includes the following steps: Step (1): By weight, 100 parts of coal gangue powder are treated with 5-8 parts of silane coupling agent and then mixed with 30-50 parts of functionalized graphene to obtain a mixed filler. Then, 25-40 parts of organosilicon resin emulsion are added and blended and cured to form organosilicon-coated composite nanofiller. 0.15-0.2 parts of catalyst are further added for catalysis to obtain silica gel-coated composite nanofiller. Step (2): The nanocellulose aerogel is hydrophobically modified in methyltrimethoxysilane vapor to obtain hydrophobically modified aerogel particles. Step (3): Mix 40-50 parts EVA, 15-25 parts polyamide elastomer, 8-12 parts TPU and 8-12 parts SEBS by weight and knead. Then add 3-8 parts hydrophobic modified aerogel particles and 3-8 parts silicone gel coated composite nanofiller, knead again, and finally add 3.0-4.5 parts foaming agent and 1.2-1.8 parts crosslinking agent, knead again, and extrude and granulate. Step (4): The granulated material is subjected to supercritical carbon dioxide saturation treatment, followed by molding and rapid cooling at a rate of >20℃ / min to obtain the target composite foamed shoe sole material.

2. The preparation method of the lightweight, high-elastic EVA / nanofiller composite foamed shoe sole material as described in claim 1, characterized in that, The catalyst in step (1) is a combination of stannous octoate and N,N-dimethylcyclohexylamine in a 1:1 mass ratio.

3. The preparation method of the lightweight, high-elastic EVA / nanofiller composite foamed shoe sole material as described in claim 1, characterized in that, The conditions for catalysis by the catalyst in step (1) are 85-90% humidity and 60-70℃.

4. The preparation method of the lightweight, high-elastic EVA / nanofiller composite foamed shoe sole material as described in claim 1, characterized in that, The conditions for hydrophobic modification treatment in step (2) are: temperature 80-100℃ and time 2-4h.

5. The preparation method of the lightweight, high-elastic EVA / nanofiller composite foamed shoe sole material as described in claim 1, characterized in that, The mixing process described in step (3) is as follows: the rotor speed of the mixer is 20-50 r / min, the mixing temperature is 105-115℃, and the mixing time is 10-20 min; 3-8 parts of hydrophobic modified aerogel particles and 3-8 parts of silica gel-coated composite nanofiller are added, the mixing temperature is 85-95℃, and the mixing time is 3-5 min; finally, 3.0-4.5 parts of foaming agent and 1.2-1.8 parts of crosslinking agent are added, the mixing temperature is 85-95℃, and the mixing time is 3-5 min.

6. The preparation method of the lightweight, high-elastic EVA / nanofiller composite foamed shoe sole material as described in claim 1, characterized in that, The foaming agent in step (3) is AC foaming agent, and the crosslinking agent is DCP crosslinking agent.

7. The preparation method of the lightweight, high-elastic EVA / nanofiller composite foamed shoe sole material as described in claim 1, characterized in that, The supercritical carbon dioxide saturation treatment in step (4) is performed at a pressure of 40 MPa, a temperature of 150°C, and a time of 1 h.

8. The preparation method of the lightweight, high-elastic EVA / nanofiller composite foamed shoe sole material as described in claim 1, characterized in that, The molding conditions in step (4) are: temperature 160℃, pressure 15 MPa, and holding time 3 minutes.

9. A lightweight, highly elastic EVA / nanofiller composite foamed shoe sole material, characterized in that, The material is prepared using the method described in any one of claims 1-8 for the preparation of lightweight, high-elastic EVA / nanofiller composite foamed shoe sole material.

10. The high-elastic EVA / nanofiller composite foamed shoe sole material as described in claim 9, characterized in that, The density of the high-elastic EVA / nanofiller composite foamed shoe sole material is less than 0.15 g / cm³. 3 Rebound rate ≥65%, tear strength ≥25kN / m.

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