Shoe sole composite processing method

Abstract

The invention relates to the technical field of sole processing, in particular to a sole composite processing method, which comprises the following steps: according to the rigidity requirement of an arch support area, preparing high-density slurry in which silicon nitride ceramic powder accounts for 30-40%, forming # imgabs0 # crystal phase through microwave-assisted sintering, and controlling the porosity to be 10-20%; according to the energy rebound requirement of the forefoot buffer area, graphene oxide / carboxymethyl cellulose aerogel powder is added into the slurry until the concentration is 25%, and the porosity is increased to 40-60% by combining the honeycomb porous network design; a nano silicon dioxide reinforcing agent is introduced into a wear-resistant area of the heel to 15%, a diamond-like carbon coating is formed through plasma surface treatment, and the porosity is limited to be 5-15%. According to the invention, silane is encapsulated by adopting polyurea microcapsules, and is released only when the material is damaged, so that dynamic self-repairing is realized, the shoe sole is endowed with dynamic repairing capability, and the service life is prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of sole processing, and specifically relates to a sole composite processing method. Background Art

[0002] In modern shoe-making processes, as a key component of shoes, the sole not only needs to have good abrasion resistance, anti-slip performance, elasticity, and supportiveness, but also needs to meet the diverse requirements of comfort, aesthetics, and adaptation to different usage scenarios. With the continuous progress of technology and the increasing quality requirements of consumers for footwear products, the limitations of traditional sole processing methods have gradually emerged, prompting the industry to continuously explore and develop more advanced sole composite processing technologies. In the early days, soles were mostly made of single materials such as rubber, leather, polyurethane, etc. Although rubber soles have excellent abrasion resistance and anti-slip performance, they are relatively hard in texture and the foot feeling when wearing is not comfortable enough. A single traditional sole material is difficult to simultaneously possess multiple excellent characteristics such as high abrasion resistance and light-weight buffering, and traditional chemical foaming methods are difficult to precisely control the pore morphology, which may lead to problems such as uneven pore size and irregular shape, affecting the performance and quality of the sole. There are certain limitations in compressive strength, and it may not be able to withstand large pressures or is prone to deformation and collapse after long-term use, affecting the service life and comfort of the sole. Summary of the Invention

[0003] The present invention aims at the technical problems existing in the prior art and provides a sole composite processing method.

[0004] The technical solution of the present invention to solve the above technical problems is as follows: Obtain foot biomechanical data, divide the sole into an arch support area, a forefoot buffer area, and a heel wear-resistant area based on a three-dimensional pressure distribution model, and perform a gradient injection molding process of a porous ceramic-polymer composite slurry by calculating the required porosity range of each area through finite element analysis, and use a supercritical carbon dioxide directional foaming technology to generate a gradient pore structure with bionic characteristics, specifically including the following sub-steps:

[0005] S101. According to the rigidity requirements of the arch support area, configure a high-density slurry with a silicon nitride ceramic powder ratio of 30 - 40%, and form a crystalline phase through microwave-assisted sintering, with the porosity controlled within 10 - 20%;

[0006] S102. For the energy rebound requirements of the forefoot buffer area, add at least 25% of graphene oxide / carboxymethyl cellulose aerogel powder to the slurry, and combine with a honeycomb-like porous network design to increase the porosity to 40 - 60%;

[0007] S103. Introduce at least 15% of nano-silica reinforcing agent in the heel wear-resistant area, and form a diamond-like carbon coating through plasma surface treatment, with the porosity being 5 - 15%;

[0008] Based on the above partition design, a stepped heating sintering process is adopted. Under a nitrogen atmosphere, the temperature is raised to 1700 - 1750°C at a rate of 15 - 20°C / min, and held for 0.5 - 2 h to form a composite sole with wear resistance, flexible buffering and breathable functions.

[0009] Preferably, for the gradient pore structure with bionic characteristics of the three-dimensional pressure distribution model, the following steps are sequentially executed:

[0010] S1. Collect dynamic plantar pressure data through a flexible piezoelectric film sensor array. Synchronously, obtain the arch curvature radius and sagittal plane angle morphological parameters by three-dimensional laser scanning, construct a spatio-temporal correlated pressure database and label the motion mode parameters;

[0011] S2. Divide the sole of the foot into: an arch support area with high curvature and low transient pressure, a forefoot buffer area under high-frequency impact load, and a heel wear-resistant area under the combined action of static pressure and shear force;

[0012] S3. Establish a three-dimensional model of the sole of the foot based on non-uniform rational B-spline surfaces. Interpolate and fuse the dynamic pressure data with the arch ligament stiffness and fascia elastic modulus parameters through a Gaussian kernel function to generate a biomechanically corrected continuous pressure field;

[0013] S4. Define the target performance of the arch support area with an elastic modulus of 15 ± 2 MPa and an energy absorption rate ≥ 75%, a damping coefficient of the forefoot buffer area of 0.35 ± 0.05 and a shear strength of the heel area ≥ 8 MPa, and establish a mapping relationship between the porosity and the elastic modulus;

[0014] S5. Generate a pore gradient distribution. The arch support area forms a 5% - 15% increasing pore along the curvature path. The forefoot area is set with a three-layer gradient structure of 20% - 40% - 25% from the surface layer to the core layer. The heel area adopts a honeycomb fiber composite structure with a porosity of 10% ± 2%, and outputs a design parameter set including porosity, pore size and orientation angle.

[0015] A further improvement of the technical solution of the present invention lies in: dividing the sole into an arch support area, a forefoot buffer area and a heel wear-resistant area through a three-dimensional pressure distribution model.

[0016] Preferably, the porous ceramic-polymer composite slurry includes the following mass ratio components and preparation rules:

[0017] (a). Matrix material: thermoplastic polyurethane 30 - 50%, with a melt index of 20 - 30 g / 10 min and a glass transition temperature ≤ -30°C;

[0018] (b). Ceramic phase: silicon nitride ceramic powder 20 - 40%, with a particle size range of 0.5 - 5 , The relative proportion is ≥90%. The particle size distribution is verified by a laser particle size analyzer, and the crystal phase purity is analyzed by XRD.

[0019] (c), Aerogel reinforcing agent: 10 - 25% of graphene oxide aerogel powder, specific surface area ≥600 , pore size distribution is 10 - 500 nm. After the aerogel is freeze-dried, it is crushed to 200 - 400 mesh.

[0020] (d), Functional additives: 5 - 15% of nano-silica reinforcing agent, 2 - 5% of microencapsulated silane coupling agent, 1 - 3% of foaming agent;

[0021] The preparation process of the slurry includes: melting the thermoplastic polyurethane particles at 180 - 200 °C, then successively adding silicon nitride powder, aerogel and additives, and mixing evenly in a twin-screw extruder at a rotation speed of 300 - 400 rpm. Control the solid content of the slurry to be 45 - 60%, and the viscosity range to be 5000 - 8000 mPa s. After mixing, it is sealed and left standing for 12 h to eliminate air bubbles.

[0022] A further improvement in the technical solution of the present invention lies in: introducing graphene oxide / carboxymethyl cellulose aerogel as a reinforcing agent to form a ceramic-aerogel-polymer ternary composite system with silicon carbide and thermoplastic polyurethane matrix.

[0023] Preferably, the directional foaming process is carried out by injecting the composite slurry into a mold cavity preheated to 90 - 110 °C. The inner wall of the mold is pre-set with a micron-level groove structure to guide the foaming direction. Supercritical carbon dioxide fluid is injected into the mold, and the supercritical carbon dioxide fluid is used as a foaming agent. Control the critical temperature to be 31.1 °C, the pressure to be 8 - 12 MPa, and maintain for 15 min to make the aerogel powder fully expand. The directional growth of pores is achieved by controlling the mold temperature gradient. The mold temperature in the arch support area is controlled at 80 - 120 °C to limit the foaming rate to form a dense structure. The mold temperature in the forefoot buffer area is reduced to 80 °C to promote the rapid expansion of the aerogel to form open pores. After foaming, the pressure is quickly released to atmospheric pressure, and the pore morphology is fixed by the elastic memory effect of the aerogel skeleton, and finally a gradient pore structure is obtained.

[0024] Preferably, the distribution rules of the gradient pores include:

[0025] Wear-resistant base layer: porosity is 10 - 20%, pore diameter ≤ , and densification is achieved by restricting the foaming agent addition amount to 1 - 2% and increasing the sintering temperature to 1700 - 1750 °C. The silicon nitride content in this layer is increased to 35 - 40%, and a diamond-like carbon coating is formed on the surface by plasma treatment.

[0026] Buffer layer: porosity 40-60%, pore size 100-300 , using 25% graphene oxide aerogel powder and 45% thermoplastic polyurethane matrix to form a three-dimensional honeycomb structure through supercritical carbon dioxide foaming;

[0027] Breathable surface: porosity 70-85%, pore size 500-800 , the sacrificial template method is used to decompose during the sintering process to form through channels, and the surface is sprayed with fluorosilane-modified graphene oxide hydrophobic coating.

[0028] Preferably, the implementation of the functional partitioning includes:

[0029] (a) Data of arch support area: Based on the finite element analysis to determine the rigidity requirements, the silicon nitride content in the slurry was adjusted to 35-40%, and nano-silicon dioxide was added as a grain boundary strengthener. The sintering was carried out under microwave assisted sintering at 2.45 GHz and a power density of 8 Next promotion Towards Phase transformation, β phase accounts for ≥95%, forming an interwoven rod-shaped grain structure, and the porosity is controlled at 15-20%;

[0030] (b) Forefoot buffer data: According to the impact absorption rate requirement, the impact absorption rate is ≥70%. Graphene oxide aerogel powder is added to the slurry to 25%. Combined with the step-wise foaming process, a gradient pore size distribution is generated to form a honeycomb porous network. The wall thickness of the honeycomb pores is 20-50 ;

[0031] (c) Heel wear-resistant area: 15% nano-silicon dioxide and 5% silicon carbide whiskers are introduced to form a dual-phase reinforced structure through hot pressing and sintering.

[0032] Preferably, a sole composite processing method further includes surface functionalization treatment:

[0033] (a) Preparation of hydrophobic coating: Fluorosilane and graphene oxide were dispersed in an ethanol solution, ultrasonically treated for 30 min, and then blended with thermoplastic polyurethane particles. An electrostatic spraying process was used to form a 10-30 m3 hydrophobic coating on the breathable surface. coating;

[0034] (b) Antibacterial functionalization: Add nano zinc oxide to the hydrophobic coating and load it on the surface of graphene oxide through the melt-gel method;

[0035] (c) Wear-resistant strengthening: magnetron sputtering technology is used to deposit 2-5 Thick hard film.

[0036] Preferably, microwave assisted sintering is introduced into the sintering process, and 2.45 GHz microwave assisted heating is used in a nitrogen atmosphere with a microwave power density of 5-10 , accelerate ceramic phase transformation and reduce energy consumption.

[0037] Preferably, the preparation of the graphene oxide aerogel powder comprises:

[0038] S1. Preparation of dispersion: Graphene oxide was dispersed in deionized water at a concentration of 2 mg / mL. After ultrasonic treatment for 24 h, the graphene oxide dispersion was blended with carboxymethyl cellulose and stirred for 24 h to form a homogeneous mixture.

[0039] S2, freeze drying process: the mixed solution is injected into a polytetrafluoroethylene mold, pre-frozen to -80°C, then transferred to a freeze dryer with a vacuum degree of ≤0.1 mbar, heated to -20°C for 12 hours, and then heated to 25°C for 24 hours to obtain a block aerogel;

[0040] S3, crushing and screening: use a jet mill to crush the aerogel into 200-400 mesh, and then screen and take the particle size of 10-50 The powder has a specific surface area of ​​600-800 , the pore size distribution peak is located at 50nm;

[0041] S4. Surface modification: The aerogel powder was immersed in an ethanol solution of a silane coupling agent, refluxed at 60° C. for 2 h, and centrifugally dried to obtain a hydrophobically modified aerogel.

[0042] Preferably, a sole composite processing method also includes a dynamic pore repair mechanism, using interfacial polymerization to prepare microcapsules with polyurea as shell material and silane coupling agent as core material, with a shell wall thickness of 0.5-1 , particle size distribution 20-50 , the core material loading rate is ≥85%. When the sole is subjected to local pressure ≥5MPa, the microcapsules rupture to release the coupling agent, which reacts with the hydroxyl groups in the thermoplastic polyurethane matrix to form -Si-OC- bonds, and at the same time penetrates into the pores and combines with the hydroxyl groups on the surface of the ceramic phase to form a three-dimensional cross-linked network, automatically filling the pores and repairing the structure.

[0043] Preferably, the performance indicators of the composite sole include: compressive strength ≥ 15MPa, density 0.8 , air permeability ≥ 2000mL, abrasion resistance ≤ 50mg / 1000 turns.

[0044] The beneficial effects of the present invention are as follows: The present invention drives the pore distribution through foot biomechanical data to achieve optimized zoning functions. By combining the high wear resistance of silicon carbide and the lightweight buffering characteristics of aerogel, it breaks through the performance bottleneck of traditional sole materials. It precisely controls the pore morphology using the supercritical state of carbon dioxide, avoiding the residual pollution of traditional chemical foaming agents. Through the synergistic effect of supercritical foaming and microwave sintering of the gradient pore structure, the pore morphology is precisely matched with the functional requirements, enhancing the compressive strength. Polyurea microcapsules encapsulate silanes and are released only when the material is damaged, achieving dynamic self-repair, endowing the sole with dynamic repair ability, extending the service life, and fixing the pore morphology through the elastic recovery of aerogel, avoiding the collapse problem of traditional foamed materials after pressure relief, ensuring the stability of the gradient structure. The buffer layer adopts a honeycomb porous network to enhance the energy absorption rate of the sole. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 It is a flowchart of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0046] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative efforts fall within the scope of protection of the present application.

[0047] Embodiment 1

[0048] As Figure 1 , this embodiment provides a method for composite processing of a sole, which specifically includes the following steps: Obtain foot biomechanical data, divide the sole of the foot into an arch support area, a forefoot buffer area, and a heel wear-resistant area based on a three-dimensional pressure distribution model, and perform a gradient injection molding process of a porous ceramic-polymer composite slurry by calculating the required range of porosity in each area through finite element analysis. Use supercritical carbon dioxide directional foaming technology to generate a gradient pore structure with bionic characteristics, which specifically includes the following sub-steps:

[0049] S101. According to the rigidity requirements of the arch support area, configure a high-density slurry with a silicon nitride ceramic powder content of 30-40%, and form crystalline phase through microwave-assisted sintering, and control the porosity within 10-20%;

[0050] S102. For the energy rebound requirements of the forefoot buffer area, add at least 25% of graphene oxide / carboxymethyl cellulose aerogel powder to the slurry, and combine with the design of a honeycomb porous network to increase the porosity to 40-60%;

[0051] S103. Introduce at least 15% of nano-silica reinforcing agent into the rear heel wear-resistant area, and form a diamond-like carbon coating with a porosity of 5 - 15% through plasma surface treatment;

[0052] Based on the above partition design, adopt a stepwise heating and sintering process, heat up to 1700 - 1750 °C at a rate of 15 - 20 °C / min in a nitrogen atmosphere, and hold for 0.5 - 2 h to form a composite sole with wear resistance, flexible buffering and breathable functions.

[0053] Preferably, for the gradient pore structure with bionic characteristics of the three-dimensional pressure distribution model, the following steps are sequentially executed:

[0054] S1. Collect plantar dynamic pressure data through a flexible piezoelectric film sensor array, synchronously obtain the arch curvature radius and sagittal plane angle morphology parameters by three-dimensional laser scanning, construct a spatio-temporal correlated pressure database and label the motion mode parameters;

[0055] S2. Divide the plantar surface into: an arch support area with high curvature and low transient pressure, a forefoot buffer area subjected to high-frequency impact loads, and a rear heel wear-resistant area subjected to the combined action of static pressure and shear force;

[0056] S3. Establish a three-dimensional model of the plantar surface based on non-uniform rational B-spline surfaces, interpolate and fuse the dynamic pressure data with the arch ligament stiffness and fascia elastic modulus parameters through a Gaussian kernel function to generate a biomechanically corrected continuous pressure field;

[0057] S4. Define the target performance of the arch support area with an elastic modulus of 15 ± 2 MPa and an energy absorption rate ≥ 75%, a damping coefficient of 0.35 ± 0.05 for the forefoot buffer area and a shear strength ≥ 8 MPa for the rear heel area, and establish a mapping relationship between the porosity and the elastic modulus;

[0058] S5. Generate a pore gradient distribution, form a 5% - 15% increasing pore along the curvature path in the arch support area, set a three-layer gradient structure of 20% - 40% - 25% from the surface layer to the core layer in the forefoot area, and adopt a honeycomb fiber composite structure with a porosity of 10% ± 2% in the rear heel area, and output a design parameter set including porosity, pore size and orientation angle.

[0059] Preferably, the porous ceramic-polymer composite slurry includes the following mass ratio components and preparation rules:

[0060] (e). Matrix material: 30 - 50% of thermoplastic polyurethane, with a melt index of 20 - 30 g / 10 min and a glass transition temperature ≤ -30 °C. Medical-grade thermoplastic polyurethane is selected to ensure biocompatibility and low-temperature toughness;

[0061] (f). Ceramic phase: 20 - 40% of silicon nitride ceramic powder, with a particle size range of 0.5 - 5 , The relative proportion is ≥90%. The particle size distribution is verified by a laser particle size analyzer, and the crystal phase purity is analyzed by XRD.

[0062] (g), Aerogel reinforcing agent: 10 - 25% graphene oxide aerogel powder, specific surface area ≥600 , pore size distribution is 10 - 500 nm. The aerogel is freeze-dried and then crushed to 200 - 400 mesh to ensure its uniform dispersion in the slurry.

[0063] (h), Functional additives: 5 - 15% nano-silica reinforcing agent, 2 - 5% microencapsulated silane coupling agent, 1 - 3% foaming agent.

[0064] The preparation process of the slurry includes: melting thermoplastic polyurethane particles at 180 - 200 °C, then successively adding silicon nitride powder, aerogel and additives, and mixing evenly in a twin-screw extruder at a rotation speed of 300 - 400 rpm. Control the solid content of the slurry to be 45 - 60%, and the viscosity range to be 5000 - 8000 mPa s. After mixing, seal and let stand for 12 h to eliminate air bubbles.

[0065] Preferably, the directional foaming process is carried out by injecting the composite slurry into a mold cavity preheated to 90 - 110 °C. The inner wall of the mold is pre-set with a micron-level groove structure to guide the foaming direction. Supercritical carbon dioxide fluid is injected into the mold, and the supercritical carbon dioxide fluid is used as the foaming agent. Control the critical temperature to be 31.1 °C and the pressure to be 8 - 12 MPa, and maintain for 15 min to make the aerogel powder fully expand. The directional growth of pores is achieved by controlling the mold temperature gradient. Control the mold temperature in the arch support area to be 80 - 120 °C to limit the foaming rate to form a dense structure. The mold temperature in the forefoot buffer area is reduced to 80 °C to promote the rapid expansion of the aerogel to form open pores. After foaming, quickly release the pressure to atmospheric pressure, and use the elastic memory effect of the aerogel skeleton to fix the pore morphology, and finally obtain a gradient pore structure.

[0066] Preferably, the distribution rules of the gradient pores include:

[0067] Wear-resistant base layer: The porosity is 10 - 20%, and the pore diameter ≤ , and densification is achieved by restricting the foaming agent addition amount to 1 - 2% and increasing the sintering temperature to 1700 - 1750 °C. The silicon nitride content in this layer is increased to 35 - 40%, and the surface is treated by plasma to generate a diamond-like carbon coating, with a hardness ≥1800 HV and a friction coefficient ≤0.15.

[0068] Buffer layer: The porosity is 40 - 60%, and the pore diameter is 100 - 300 , 25% of graphene oxide aerogel powder is compounded with 45% of thermoplastic polyurethane matrix, and a three-dimensional honeycomb structure is formed by supercritical carbon dioxide foaming, with an energy resilience rate ≥ 85% and a compression set ≤ 5%;

[0069] Breathable surface layer: The porosity is 70 - 85%, and the pore diameter is 500 - 800 , Using the sacrificial template method, the PLA fiber diameter is 500 , with a volume ratio of 30%, decomposes during the sintering process to form through channels, and a fluorosilane-modified graphene oxide hydrophobic coating is sprayed on the surface layer, with a contact angle of the hydrophobic coating ≥ 150° and a sliding angle ≤ 5°, and a gas permeability ≥ 2500 mL / ( ).

[0070] Preferably, the realization of the functional zones includes:

[0071] (d), Arch support area data: Based on finite element analysis, the rigidity requirement is determined, with an elastic modulus ≥ 1.5 GPa. The silicon nitride content in the slurry is adjusted to 35 - 40%, and nano-silica is added as a grain boundary strengthening agent. Microwave-assisted sintering at 2.45 GHz and a power density of 8 promotes phase transformation to phase, with a β-phase proportion ≥ 95%, forming an interwoven rod-like grain structure, and the porosity is controlled to 15 - 20%;

[0072] (e), Forefoot buffer area data: According to the impact absorption rate requirement, the impact absorption rate ≥ 70%. Graphene oxide aerogel powder is added to the slurry up to 25%, combined with a stepped foaming process. The first-stage pressure is 8 MPa / 90°, and the second-stage pressure is relieved to 5 MPa / 60° to generate a gradient pore size distribution. The surface layer is 500 100 , forming a honeycomb-like porous network, and the wall thickness of the honeycomb pores is 20 - 50 ;

[0073] (f), Rearfoot wear-resistant area: 15% of nano-silica and 5% of silicon carbide whiskers are introduced, and a dual-phase reinforced structure is formed by hot pressing sintering at a pressure of 500 MPa and a temperature of 1650°.

[0074] Preferably, a sole composite processing method further includes surface functionalization treatment:

[0075] (d), Preparation of hydrophobic coating: Fluorosilane and graphene oxide are dispersed in an ethanol solution, ultrasonicated for 30 min, and then blended with thermoplastic polyurethane particles. An electrostatic spraying process is used to form a 10 - 30 coating on the breathable surface layer;

[0076] (e) Antibacterial functionalization: 5wt% nano zinc oxide with a particle size of 30nm was added to the hydrophobic coating and loaded on the surface of graphene oxide by the sol-gel method. After activation by ultraviolet light, the 24h antibacterial rate against Escherichia coli and Staphylococcus aureus was ≥99.9%;

[0077] (f) Wear-resistant strengthening: magnetron sputtering technology is used to deposit 2-5 Thick hard film, fiber hardness ≥ 2200HV, friction coefficient reduced to 0.12.

[0078] Preferably, microwave assisted sintering is introduced into the sintering process, and 2.45 GHz microwave assisted heating is used in a nitrogen atmosphere with a microwave power density of 5-10 , accelerate ceramic phase transformation and reduce energy consumption.

[0079] Preferably, the preparation of the graphene oxide aerogel powder comprises:

[0080] S1. Preparation of dispersion: Graphene oxide was dispersed in deionized water at a concentration of 2 mg / mL. After ultrasonic treatment for 24 h, the graphene oxide dispersion was blended with carboxymethyl cellulose and stirred for 24 h to form a homogeneous mixture.

[0081] S2, freeze drying process: the mixed solution is injected into a polytetrafluoroethylene mold, pre-frozen to -80°C, then transferred to a freeze dryer with a vacuum degree of ≤0.1 mbar, heated to -20°C for 12 hours, and then heated to 25°C for 24 hours to obtain a block aerogel;

[0082] S3, crushing and screening: use a jet mill to crush the aerogel into 200-400 mesh, and then screen and take the particle size of 10-50 The powder has a specific surface area of ​​600-800 , the pore size distribution peak is located at 50nm;

[0083] S4. Surface modification: The aerogel powder was immersed in an ethanol solution of a silane coupling agent, refluxed at 60°C for 2 hours, and centrifugally dried to obtain a hydrophobically modified aerogel, the dispersion uniformity of which in the thermoplastic polyurethane matrix was improved by 40% compared with the unmodified powder.

[0084] Preferably, a sole composite processing method also includes a dynamic pore repair mechanism, using interfacial polymerization to prepare microcapsules with polyurea as shell material and silane coupling agent as core material, with a shell wall thickness of 0.5-1 , particle size distribution 20-50 , the core material loading rate is ≥ 85%. When the sole is subjected to a local pressure ≥ 5 MPa, the microcapsules rupture to release the coupling agent, which reacts with the hydroxyl groups in the thermoplastic polyurethane matrix to form -Si-O-C- bonds. At the same time, it penetrates into the pores and binds to the hydroxyl groups on the surface of the ceramic phase to form a three-dimensional cross-linked network, automatically filling the pores and repairing the structure.

[0085] Preferably, the performance indicators of the composite sole include: compressive strength ≥ 15 MPa, density 0.8 , air permeability ≥ 2000 mL, abrasion resistance ≤ 50 mg / 1000 revolutions.

[0086] Example 2

[0087] The present invention provides a technical solution: a sole composite processing method, including the following steps:

[0088] S1. Based on the peak pressure data in the arch area, set the arch support area as the high wear-resistant area;

[0089] S2. Take 20% silicon nitride ceramic powder, 50% thermoplastic polyurethane matrix, 20% graphene oxide aerogel powder, and 10% nano-silica reinforcing agent, and adjust the slurry to make its solid content 45%;

[0090] S3. Inject the composite slurry into a preheated mold, use carbon dioxide supercritical fluid as the foaming agent, control the temperature at 80 °C and the pressure at 8 MPa, so that the aerogel powder expands directionally to form gradient pores. After foaming, sinter by stepwise heating, with a heating rate of 10 °C / min, and the final sintering temperature is 1600 °C, and keep warm for 1 h;

[0091] S4. Based on the data of the arch support area, adjust the silicon nitride content in the slurry to 35%, and generate crystalline phase. Based on the data of the forefoot buffer area, add flexible aerogel powder to 20% to form a honeycomb-like porous network;

[0092] S5. Spray a hydrophobic coating formed by blending fluorosilane-modified graphene oxide and thermoplastic polyurethane on the breathable surface layer, and the coating thickness is 10 ;

[0093] S6. Under a nitrogen atmosphere, heat by 2.45 GHz microwave radiation, and the microwave power density is 5 , accelerate the transformation of the ceramic phase and reduce energy consumption;

[0094] S7. Add microencapsulated silane coupling agent to the slurry. When the sole is damaged under pressure, the microcapsules rupture to release the coupling agent, automatically filling the pores and repairing the structure.

[0095] Example 3

[0096] The present invention provides a technical solution: a sole composite processing method, comprising the following steps:

[0097] S1. According to the peak pressure data of the arch area, the arch support area is set as a high wear-resistant area;

[0098] S2, take 30% silicon nitride ceramic powder, 40% thermoplastic polyurethane matrix, 25% graphene oxide aerogel powder, and 5% nano-silicon dioxide reinforcing agent, and prepare a slurry so that its solid content is 50%;

[0099] S3, injecting the composite slurry into the preheated mold, using carbon dioxide supercritical fluid as the foaming agent, controlling the temperature at 100°C and the pressure at 12MPa, so that the aerogel powder can be directionally expanded to form gradient pores, and then sintering by step-wise heating at a heating rate of 15°C / min, the final sintering temperature is 1700°C, and the temperature is kept for 1.5h;

[0100] S4. Based on the arch support area data, the silicon nitride content in the slurry is adjusted to 38%, and the sintering is performed to generate Crystal phase, based on the forefoot buffer data, adding flexible aerogel powder to 25% to form a honeycomb porous network;

[0101] S5, spraying a hydrophobic coating formed by blending fluorosilane-modified graphene oxide and thermoplastic polyurethane on the breathable surface, the coating thickness is 20 ;

[0102] S6, 2.45 GHz microwave radiation heating was used in a nitrogen atmosphere, and the microwave power density was 7 , accelerate ceramic phase transformation and reduce energy consumption;

[0103] S7. Add microencapsulated silane coupling agent to the slurry. When the sole is damaged by pressure, the microcapsules rupture and release the coupling agent, automatically filling the pores and repairing the structure.

[0104] Example 4

[0105] The present invention provides a technical solution: a sole composite processing method, comprising the following steps:

[0106] S1. According to the peak pressure data of the arch area, the arch support area is set as a high wear-resistant area;

[0107] S2, take 40% silicon nitride ceramic powder, 30% thermoplastic polyurethane matrix, 15% graphene oxide aerogel powder, and 15% nano-silicon dioxide reinforcing agent, and prepare a slurry so that the solid content is 60%;

[0108] S3. Inject the composite slurry into a preheated mold, use carbon dioxide supercritical fluid as the foaming agent, control the temperature at 120 °C and the pressure at 15 MPa, so that the aerogel powder expands directionally to form gradient pores. After foaming, sinter by stepwise heating, with a heating rate of 20 °C / min, and the final sintering temperature is 1750 °C, keep the temperature for 2 h;

[0109] S4. Based on the data of the arch support area, adjust the silicon nitride content in the slurry to 40%, and generate crystalline phase after sintering. Based on the data of the forefoot buffer area, add flexible aerogel powder to 20% to form a honeycomb-like porous network;

[0110] S5. Spray a hydrophobic coating formed by blending fluorosilane-modified graphene oxide and thermoplastic polyurethane on the breathable surface layer, and the coating thickness is 30 ;

[0111] S6. Under a nitrogen atmosphere, heat by 2.45 GHz microwave radiation, and the microwave power density is 10 , accelerate the ceramic phase transformation and reduce energy consumption;

[0112] S7. Add microencapsulated silane coupling agent to the slurry. When the sole is damaged under pressure, the microcapsules break to release the coupling agent, automatically filling the pores and repairing the structure.

[0113] Experimental Examples

[0114] 1. Verify the light weight, mechanical strength, functional characteristics and environmental adaptability of the composite sole provided by the present invention through experiments. The density is measured by the Archimedes method, and the strength is tested by a universal mechanical testing machine, and the following table is obtained:

[0115] 2. Description of Comparative Examples:

[0116] Comparative Example 1: Traditional EVA sole, without ceramic composite and gradient pore structure;

[0117] Comparative Example 2: Use the slurry formula of Example 3, but sinter with a traditional resistance furnace.

[0118] Conclusion:

[0119] The silicon nitride content is positively correlated with the compressive strength: the compressive strength of Example 4 reaches 24 MPa, which is 50% higher than that of Example 2;

[0120] Microwave sintering significantly improves the β-phase transformation: the β-phase content in Example 3 is 93%, and in Comparative Example 2 with the same formula without microwave is only 75%;

[0121] Supercritical pressure gradient optimizes air permeability: In Example 4, the air permeability rate is 2600 mL at a pressure of 15 MPa, which is 160% higher than that of Comparative Example 2.

[0122] The energy resilience rate is related to the aerogel content: In Example 3, the resilience rate reaches 90% when the aerogel content is 25%, and in Example 2 it is 85%.

[0123] 2. Response relationship between dynamic repair and gradient pores

[0124] Synergistic mechanism:

[0125] The high-porosity buffer layer (40%-45%) provides a diffusion channel for the silane released after the microcapsules rupture, and the low-porosity support area (15%-20%) restricts the crack propagation path.

[0126] In Example 4, when the microcapsule addition amount is 10%, the repair agent can cover more than 90% of the crack area.

[0127] 3. Negative impacts of the lack of technical synergy

[0128] It can be seen from the table that the lightweight, mechanical strength, functional characteristics, and environmental adaptability of the composite sole provided by the present invention meet the expected design, and the performance of each example is stable and meets the requirements of functional zoning.

[0129] Although the preferred embodiments of the present invention have been described, those skilled in the art can make additional changes and modifications to these embodiments once they learn the basic creative concept. Therefore, the appended claims are intended to be construed as including the preferred embodiments and all changes and modifications falling within the scope of the present invention.

[0130] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention is also intended to include these modifications and variations.

Claims

1. A sole composite processing method, characterized in that, It includes the following steps: Obtain foot biomechanical data, divide the sole of the foot into an arch support area, a forefoot buffer area, and a heel wear-resistant area based on a three-dimensional pressure distribution model, perform a gradient casting process of a porous ceramic-polymer composite slurry by finite element analysis to calculate the porosity requirement range of each area, and use a supercritical carbon dioxide directional foaming technology to generate a gradient pore structure with bionic characteristics, which specifically includes the following sub-steps: S101. According to the rigidity requirement of the arch support area, a high-density slurry with a silicon nitride ceramic powder proportion of 30 - 40% is configured and sintered by microwave assistance to form crystalline phase, and the porosity is controlled within 10 - 20%; S102. For the energy rebound requirement of the forefoot buffer area, add at least 25% of graphene oxide / carboxymethyl cellulose aerogel powder to the slurry, and combine with a honeycomb porous network design to increase the porosity to 40-60%; S103. Introduce at least 15% of nano-silica reinforcing agent in the heel wear-resistant area, form a diamond-like carbon coating by plasma surface treatment, and the porosity is 5-15%; Based on the above partition design, adopt a stepped heating and sintering process, heat up to 1700-1750°C at a rate of 15-20°C / min in a nitrogen atmosphere, and keep it warm for 0.5-2h to form a composite sole with wear resistance, flexible buffering and breathable functions.

2. The sole composite processing method according to claim 1, characterized in that, The porous ceramic-polymer composite slurry includes the following components by mass ratio: 20-40% of silicon nitride ceramic powder, 30-50% of thermoplastic polyurethane matrix, 10-25% of graphene oxide aerogel powder, 5-15% of nano-silica reinforcing agent, and the solid content of the slurry is 45-60%; The preparation process of the slurry includes: melting thermoplastic polyurethane particles at 180 - 200 °C, then successively adding silicon nitride powder, aerogel and additives, and mixing uniformly in a twin-screw extruder at a rotation speed of 300 - 400 rpm, controlling the solid content of the slurry to be 45 - 60%, and the viscosity range to be 5000 - 8000 mPa s. After mixing is completed, seal and let stand for 12 h to eliminate air bubbles.

3. A sole composite processing method according to claim 1, characterized in that, The directional foaming process is to inject the composite slurry into a mold cavity preheated to 90-110°C. The inner wall of the mold is pre-set with a micron-level groove structure to guide the foaming direction. Inject supercritical carbon dioxide fluid into the mold, use the supercritical carbon dioxide fluid as a foaming agent, control the critical temperature at 31.1°C, the pressure at 8-12MPa, and maintain it for 15min to make the aerogel powder fully expand. Through the control of the mold temperature gradient, the pore is realized to grow directionally. In the arch support area, control the mold temperature at 80-120°C to limit the foaming rate to form a dense structure. The mold temperature in the forefoot buffer area is reduced to 80°C to promote the rapid expansion of the aerogel to form open pores. After the foaming is completed, quickly release the pressure to normal pressure, and use the elastic memory effect of the aerogel skeleton to fix the pore morphology, and finally obtain a gradient pore structure.

4. A sole composite processing method according to claim 3, characterized in that, The distribution rules of the gradient pores include: The porosity of the wear-resistant base layer is 10-20%, and the pore diameter ≤ ; The porosity of the buffer layer is 40 - 60%, and the pore diameter is 100 - 300 ; The porosity of the breathable surface layer is 70 - 85%, and the pore diameter is 500 - 800 .

5. A sole composite processing method according to claim 1, characterized in that, The implementation of the functional partition includes: based on the data of the arch support area, adjusting the silicon nitride content in the slurry to 35-40%, and adding nano-silica as a grain boundary strengthener, and forming crystalline phases. Based on the data of the forefoot buffer area, adding graphene aerogel powder to the slurry up to 25% to form a honeycomb-like porous network. In the heel wear-resistant area, 15% nano-silica and 5% silicon carbide whiskers are introduced, and a dual-phase reinforced structure is formed by hot press sintering.

6. A method for composite processing of a sole according to claim 1, characterized in that, It also includes surface functionalization treatment. A hydrophobic coating is sprayed on the breathable surface layer. The coating is made by blending fluorosilane-modified graphene oxide and thermoplastic polyurethane, and the thickness of the coating is 10 - 30 , nano-zinc oxide is added to the hydrophobic coating and loaded on the surface of graphene oxide by the sol-gel method. A hard film with a thickness of 2 - 5 is deposited on the surface of the base layer by magnetron sputtering technology.

7. A method for composite processing of a sole according to claim 1, characterized in that Microwave-assisted sintering is introduced in the sintering process. Under a nitrogen atmosphere, microwave-assisted heating at 2.45 GHz is used, and the microwave power density is 5-10 , accelerating the ceramic phase transformation and reducing energy consumption.

8. A sole composite processing method according to claim 2, characterized in that, The graphene oxide aerogel powder is prepared by blending a graphene oxide dispersion with carboxymethyl cellulose, stirring for 24 hours to form a homogeneous mixture, injecting the mixture into a polytetrafluoroethylene mold, pre-freezing to -80°C, and then transferring it to a freeze dryer with a vacuum degree of ≤0.1 mbar, heating to -20°C for 12 hours, and then heating to 25°C for 24 hours to obtain a block aerogel, crushing the aerogel to 200-400 mesh, and sieving to obtain a particle size of 10-50 The powder has a specific surface area of ​​600-800 The aerogel powder was immersed in an ethanol solution of a silane coupling agent, refluxed at 60 °C for 2 h, and centrifugally dried to obtain a hydrophobically modified aerogel.

9. A sole composite processing method according to claim 1, characterized in that, It also includes a dynamic pore repair mechanism. Microcapsules with polyurea as the shell material and silane coupling agent as the core material are prepared by interfacial polymerization. The shell wall thickness is 0.5 - 1 , and the particle size distribution is 20 - 50 . The core material loading rate is ≥85%. When the sole is subjected to a local pressure ≥5 MPa, the microcapsules rupture to release the coupling agent, which reacts with the hydroxyl groups in the thermoplastic polyurethane matrix to form -Si-O-C- bonds. At the same time, it penetrates into the pores and binds to the hydroxyl groups on the surface of the ceramic phase to form a three-dimensional cross-linked network, automatically filling the pores and repairing the structure.

10. A sole composite processing method according to claim 1, characterized in that, For the gradient pore structure with bionic characteristics of the three-dimensional pressure distribution model, the following steps are sequentially executed: S1. Collect the dynamic pressure data of the sole of the foot through a flexible piezoelectric film sensor array, synchronously obtain the arch curvature radius and sagittal plane angle morphology parameters by three-dimensional laser scanning, construct a spatio-temporal correlated pressure database and mark the motion mode parameters; S2. Divide the sole of the foot into: an arch support area with high curvature and low transient pressure, a forefoot buffer area under high-frequency impact load, and a heel wear-resistant area under the combined action of static pressure and shear force; S3. Establish a three-dimensional model of the sole of the foot based on non-uniform rational B-spline surface, interpolate and fuse the dynamic pressure data with the arch ligament stiffness and fascia elastic modulus parameters through a Gaussian kernel function to generate a continuously corrected pressure field of biomechanics; S4. Define the target performance of the arch support area with an elastic modulus of 15 ± 2 MPa and an energy absorption rate of ≥ 75%, and a damping coefficient of 0.35 ± 0.05 in the forefoot buffer area , and a shear strength of ≥ 8 MPa in the heel area, and establish the mapping relationship between porosity and elastic modulus; S5. Generate a pore gradient distribution, with a 5%-15% increasing pore along the curvature path in the arch support area, a three-layer gradient structure of 20%-40%-25% from the surface layer to the core layer in the forefoot area, and a honeycomb fiber composite structure with a porosity of 10%±2% in the heel area, and output a set of design parameters including porosity, pore size, and orientation angle.

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