Lightweight rubber shoe sole and processing technology

Abstract

The application discloses light rubber horse boots outsole and a processing technology, and particularly relates to the technical field of rubber horse boots outsole, and comprises the following components in parts by weight: 40-60 parts of silicone rubber, 20-30 parts of thermoplastic polyurethane, 10-20 parts of cis-butadiene rubber, 3-5 parts of graphene and halloysite composite filler, 8-12 parts of nano silicon dioxide, 5-8 parts of paraffin phase change material, and 3-5 parts of flame retardant; the preparation process comprises the following steps: S1, premixing and dynamic vulcanization, S2, supercritical foaming forming, and S3, post-treatment. Through the optimized proportioning of raw materials such as silicone rubber and thermoplastic polyurethane, in combination with the supercritical carbon dioxide foaming, dynamic vulcanization and five-layer co-extrusion processes, the outsole has the advantages of light weight, high strength, high wear resistance and excellent resilience, meanwhile, the wide temperature range adaptability and the flame retardant performance are realized through the paraffin phase change material and the composite flame retardant, the overall process avoids harmful residues, meets the requirements of multiple scenes such as outdoor and industrial protection, and improves the wearing comfort and safety.

Description

Technical Field

[0001] This invention relates to the field of rubber riding boot outsole technology, and more specifically, to lightweight rubber riding boot outsoles and their processing technology. Background Technology

[0002] In today's footwear manufacturing industry, riding boots, as a type of footwear that combines practicality and style, are favored by many consumers. The outsole of the riding boot, as a key component that comes into direct contact with the ground, plays a decisive role in the overall quality of the riding boot.

[0003] However, traditional riding boots are mostly made of ordinary rubber materials, which have the following drawbacks: high density, leading to fatigue when worn; low tensile strength, making them prone to cracking and damage, shortening their service life; high abrasion consumption, resulting in rapid wear, which reduces slip resistance and increases usage costs; poor cold resistance, becoming brittle at low temperatures, limiting their use; weak flame retardancy, posing safety hazards in special scenarios; low slip resistance, making them easy to slip on wet surfaces; and outdated processing technology, with low efficiency and poor precision in manual trimming, easily resulting in burrs and surface damage.

[0004] In response to the above situation, the present invention provides a lightweight rubber riding boot outsole and its processing technology. Summary of the Invention

[0005] In order to overcome the above-mentioned defects of the prior art, the present invention provides a lightweight rubber riding boot outsole and a processing technology to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a lightweight rubber riding boot outsole, prepared from raw materials comprising the following parts by weight:

[0007] 40-60 parts silicone rubber, 20-30 parts thermoplastic polyurethane, 10-20 parts butadiene rubber, 3-5 parts graphene and halloysite composite filler, 8-12 parts nano silica, 5-8 parts paraffin phase change material, and 3-5 parts flame retardant.

[0008] Preferably, the particle size of the nano-silica is 15-20 nm, the melting point of the paraffin phase change material is 48 °C, and the flame retardant is prepared by the following method: APP and graphene are placed in a high-speed mixer at a weight ratio of 4-6:1 and mixed for 10-15 min at a temperature of 80-100 °C and a rotation speed of 1000-1500 r / min to obtain an APP and graphene composite flame retardant.

[0009] Preferably, in the graphene and halloysite composite filler, the graphene sheet diameter is 1-5 μm and it is modified with a silane coupling agent, the amount of which is 1%-3% of the weight of the graphene, and the halloysite nanotubes have an aspect ratio of 10-20. The two are stirred in a planetary ball mill with agate balls as the grinding medium at a ball-to-material ratio of 5:1 for 15-25 minutes at a speed of 800-1200 r / min, forming an interpenetrating network structure in an inert gas protective atmosphere.

[0010] Preferably, the nano-silica is uniformly dispersed in the matrix material by ultrasonic dispersion. The nano-silica and the matrix material are mixed under the action of a dispersant, the amount of dispersant being 0.5%-1% of the weight of the nano-silica, the ultrasonic frequency being 20-40kHz, and the dispersion time being 20-30min, thereby enhancing the interfacial bonding force between the matrix materials.

[0011] Preferably, the outsole is formed by supercritical carbon dioxide foaming, with a density of 0.6-0.8 g / cm³, a cell diameter of 50-100 μm, and a cell closed-cell rate of ≥90%. The pressure, temperature, saturation time, and depressurization rate of the supercritical carbon dioxide are interrelated. When the CO2 pressure is 15-20 MPa, the temperature is 60-80℃, and the saturation time is 2-3 h, the depressurization rate is controlled at 10-15 MPa / s to ensure the formation of a uniform closed-cell structure.

[0012] Preferably, the outsole is formed by a dynamic vulcanization system with 0.5-1 ppm platinum catalyst and 1-2 parts peroxide, forming an interpenetrating network structure of silicone rubber and thermoplastic polyurethane, with a resilience of 75-80%. The peroxide in the dynamic vulcanization system is 2,5-dimethyl-2,5-di-tert-butylperoxide.

[0013] Preferably, the outsole has a multi-layer composite structure, comprising, from bottom to top:

[0014] The bottom layer, specifically a wear-resistant rubber layer, contains graphene reinforcement, has a thickness of 1-2mm, and a Shore hardness of 60-70A;

[0015] The buffer layer, specifically a blend of foamed silicone rubber and thermoplastic polyurethane, contains paraffin phase change material, has a thickness of 3-4 mm, and a compression set of ≤15%.

[0016] The support layer, specifically the fiber reinforcement layer, is composed of a mixture of polyamide fibers and carbon fibers, with a thickness of 2-3 mm and a weight ratio of polyamide fibers to carbon fibers of 3-5:1.

[0017] The breathable layer is specifically a microporous polyurethane layer with an air permeability of ≥500g / m²・24h and a thickness of 0.5-1mm.

[0018] The flame-retardant layer, specifically a composite layer of silicone rubber and APP, has a vertical flammability rating of V-0, a thickness of 1-1.5mm, and an APP content of 30%-40% of the total weight of the flame-retardant layer.

[0019] Preferably, the layers of the multilayer composite structure are chemically bonded by a silane coupling agent. The silane coupling agent is coated onto the surface of each layer by a coating method, with a coating amount of 5-10 g / m². The coating is cured at a temperature of 80-100℃ for 2-3 hours, and the peel strength is ≥5 N / cm.

[0020] The present invention also provides a processing technique for preparing the above-mentioned lightweight rubber riding boot outsole, specifically including the following steps:

[0021] S1, Premixing and Dynamic Vulcanization

[0022] S1.1. Silicone rubber, thermoplastic polyurethane and butadiene rubber are premixed in an internal mixer at a temperature of 80-100℃ for 10 minutes;

[0023] S1.2 During this period, graphene and halloysite composite filler, nano silica and coupling agent are added, and dispersed in a high-speed disperser at a speed of 1000-1500 r / min for 5 min.

[0024] S1.3. The mixture is injected into a twin-screw extruder with a length-to-diameter ratio of 30-35. Under the conditions of a temperature of 180-200℃ and a screw speed of 200-250rpm, a dynamic vulcanization reaction is carried out for 8-10 minutes to form a uniformly dispersed interpenetrating network structure.

[0025] S2, Supercritical Foaming Molding

[0026] S2.1 Place the above-mentioned compound in a high-pressure reactor with a volume of 5L, use supercritical carbon dioxide as a foaming agent, saturate for 2-3 hours under CO2 pressure of 15-20MPa and temperature of 60-80℃, and then depressurize at a depressurization rate of 10-15MPa / s to form a uniform closed-cell structure.

[0027] S2.2. A multi-layer composite outsole is prepared using a five-layer co-extrusion process. Specifically, the raw materials for the prepared bottom layer, buffer layer, support layer, breathable layer, and flame-retardant layer are added to five independent extruders with screw diameters of 40-50mm. The extrusion temperature is controlled at 160-180℃ and the extrusion pressure is 10-15MPa. Each layer is sequentially stacked and composited in a die with a die diameter of 100-120mm and a gradually converging flow channel. After cooling and shaping, a multi-layer composite outsole is obtained.

[0028] S3, Post-processing

[0029] S3.1. The outsole surface is treated with plasma. The gas used for plasma treatment is argon, the power is 150W, the treatment time is 3-5 minutes, and the surface energy is increased to 55mN / m.

[0030] S3.2. Perform cryogenic trimming at a liquid nitrogen temperature of -196℃. The cutting edge angle of the trimming tool is 30-45°, and the edge accuracy reaches ±0.1mm, resulting in a lightweight rubber riding boot outsole.

[0031] Preferably, before step S1.1, the silicone rubber is pretreated by drying it in a vacuum drying oven at a temperature of 60-80℃ and a vacuum degree of -0.08-0.1MPa for 2-3 hours to remove moisture and volatiles, thereby improving the uniformity of raw material mixing and product quality.

[0032] The technical effects and advantages of this invention are as follows:

[0033] 1. This invention optimizes the proportions of raw materials such as silicone rubber and thermoplastic polyurethane, and combines supercritical carbon dioxide foaming and dynamic vulcanization technology to achieve a balance of lightweight, high strength, high wear resistance and excellent resilience in the outsole, providing users with a lightweight and durable wearing experience.

[0034] 2. This invention introduces paraffin phase change material and APP and graphene composite flame retardant, combined with a multi-layer composite structure design, to enable the outsole to have temperature adaptive adjustment capability, which can be used stably in environments from -30℃ to 35℃, and the flame retardant performance reaches a limiting oxygen index of more than 32%, meeting the needs of various complex scenarios such as extreme cold, high temperature, and fire prevention, and significantly improving the safety and applicability of the product.

[0035] 3. This invention uses supercritical carbon dioxide to replace traditional chemical foaming agents, eliminating harmful residues and meeting environmental protection requirements. At the same time, the innovative five-layer co-extrusion process, combined with post-processing technologies such as freeze trimming and plasma treatment, achieves precise control of the outsole structure and optimization of surface properties, improves production efficiency and product quality stability, and promotes the upgrading of rubber product manufacturing processes. Attached Figure Description

[0036] Figure 1 This is a flowchart illustrating the overall process flow of the present invention. Detailed Implementation

[0037] Example 1

[0038] This invention provides a lightweight rubber riding boot outsole, prepared from raw materials comprising the following parts by weight:

[0039] 40 parts silicone rubber;

[0040] 20 parts thermoplastic polyurethane;

[0041] 10 parts butadiene rubber;

[0042] Three parts of graphene and halloysite composite filler.

[0043] 8 parts of nano-silica

[0044] Five parts of paraffin phase change material, melting point 48℃;

[0045] Three parts flame retardant, APP and graphene composite;

[0046] Among them, flame retardant preparation: APP and graphene are placed in a high-speed mixer at a weight ratio of 4:1 and mixed for 10 minutes at a temperature of 80℃ and a rotation speed of 1000r / min to obtain APP and graphene composite flame retardant.

[0047] Preparation of graphene and halloysite composite filler: Graphene with a sheet diameter of 1-5 μm was modified with a silane coupling agent (1% by weight of graphene) and then mixed with halloysite nanotubes (length-to-diameter ratio 10-20) in a planetary ball mill with agate balls as the grinding medium at a ball-to-material ratio of 5:1. The mixture was stirred at 800 r / min for 15 min to form an interpenetrating network structure in an inert gas protective atmosphere.

[0048] Nano silica dispersion: Nano silica and matrix material are mixed under the action of a dispersant (0.5% by weight of nano silica) and dispersed by ultrasonic frequency of 20kHz for 20min.

[0049] This invention also provides a processing technique for preparing the aforementioned lightweight rubber riding boot outsole, specifically including the following steps:

[0050] S1, Premixing and Dynamic Vulcanization

[0051] S1.1. Silicone rubber, thermoplastic polyurethane and butadiene rubber are premixed in an internal mixer at 80°C for 10 minutes.

[0052] S1.2 Add the above-mentioned graphene and halloysite composite filler, nano silica and coupling agent, and disperse in a high-speed disperser at a speed of 1000 r / min for 5 min;

[0053] S1.3. The mixture is injected into a twin-screw extruder with a length-to-diameter ratio of 30. Under the conditions of a temperature of 180℃ and a screw speed of 200rpm, a dynamic vulcanization reaction is carried out for 8 minutes to form a uniformly dispersed interpenetrating network structure.

[0054] S2, Supercritical Foaming Molding

[0055] S2.1 Place the above-mentioned compound in a high-pressure reactor with a volume of 5L, use supercritical carbon dioxide as a foaming agent, saturate for 2 hours under CO2 pressure of 15MPa and temperature of 60℃, and then depressurize at a depressurization rate of 10MPa / s to form a uniform closed-cell structure.

[0056] S2.2. A multi-layer composite outsole is prepared using a five-layer co-extrusion process. The raw materials for the prepared bottom layer, buffer layer, support layer, breathable layer and flame retardant layer are added to five independent extruders with a screw diameter of 40mm. The extrusion temperature is controlled at 160℃ and the extrusion pressure is 10MPa. Each layer is stacked and compounded in sequence in a die with a die diameter of 100mm and a gradually converging flow channel. After cooling and shaping, a multi-layer composite outsole is obtained.

[0057] S3, Post-processing

[0058] S3.1 The outsole surface is treated with plasma. The gas used for plasma treatment is argon, the power is 150W, the treatment time is 3min, and the surface energy is increased to 55mN / m.

[0059] S3.2. Perform cryogenic trimming at a liquid nitrogen temperature of -196℃, with the trimming tool having a cutting edge angle of 30° and an edge accuracy of ±0.1mm, to obtain a lightweight rubber riding boot outsole.

[0060] Example 2

[0061] This invention provides a lightweight rubber riding boot outsole, prepared from raw materials comprising the following parts by weight:

[0062] 60 parts of silicone rubber;

[0063] 30 parts of thermoplastic polyurethane;

[0064] 20 parts of butadiene rubber;

[0065] Five parts of graphene and halloysite composite filler.

[0066] 12 parts of nano-silica

[0067] Eight parts of paraffin phase change material, melting point 48℃;

[0068] Five parts flame retardant, APP and graphene composite;

[0069] Among them, flame retardant preparation: APP and graphene are placed in a high-speed mixer at a weight ratio of 6:1 and mixed for 15 minutes at a temperature of 100℃ and a rotation speed of 1500r / min to obtain APP and graphene composite flame retardant.

[0070] Preparation of graphene and halloysite composite filler: Graphene with a sheet diameter of 1-5 μm was modified with a silane coupling agent (3% by weight of graphene) and then mixed with halloysite nanotubes (length-to-diameter ratio 10-20) in a planetary ball mill with agate balls as the grinding medium at a ball-to-material ratio of 5:1. The mixture was stirred at 1200 r / min for 25 min to form an interpenetrating network structure in an inert gas protective atmosphere.

[0071] Nano silica dispersion: Nano silica and matrix material are mixed under the action of a dispersant (1% by weight of nano silica) and dispersed by ultrasonic frequency of 40kHz for 30min.

[0072] This invention also provides a processing technique for preparing the aforementioned lightweight rubber riding boot outsole, specifically including the following steps:

[0073] S1, Premixing and Dynamic Vulcanization

[0074] S1.1. Silicone rubber, thermoplastic polyurethane and butadiene rubber are premixed in an internal mixer at 100°C for 10 min;

[0075] S1.2 Add the above-mentioned graphene and halloysite composite filler, nano silica and coupling agent, and disperse in a high-speed disperser at a speed of 1500 r / min for 5 min;

[0076] S1.3. The mixture is injected into a twin-screw extruder with a length-to-diameter ratio of 35. Under the conditions of a temperature of 200℃ and a screw speed of 250rpm, a dynamic vulcanization reaction is carried out for 10 minutes to form a uniformly dispersed interpenetrating network structure.

[0077] S2, Supercritical Foaming Molding

[0078] S2.1 Place the above-mentioned compound in a high-pressure reactor with a volume of 5L, use supercritical carbon dioxide as a foaming agent, saturate for 3 hours under CO2 pressure of 20MPa and temperature of 80℃, and then depressurize at a depressurization rate of 15MPa / s to form a uniform closed-cell structure.

[0079] S2.2. A multi-layer composite outsole is prepared using a five-layer co-extrusion process. The raw materials for the prepared bottom layer, buffer layer, support layer, breathable layer and flame retardant layer are added to five independent extruders with a screw diameter of 50mm. The extrusion temperature is controlled at 180℃ and the extrusion pressure is 15MPa. Each layer is stacked and compounded in sequence in a die with a die diameter of 120mm and a gradually converging flow channel. After cooling and shaping, a multi-layer composite outsole is obtained.

[0080] S3, Post-processing

[0081] S3.1 The outsole surface is treated with plasma. The gas used for plasma treatment is argon, the power is 150W, the treatment time is 5min, and the surface energy is increased to 55mN / m.

[0082] S3.2. Perform cryogenic trimming at a liquid nitrogen temperature of -196℃, with the trimming tool having a cutting edge angle of 45° and an edge accuracy of ±0.1mm, to obtain a lightweight rubber riding boot outsole.

[0083] Example 3

[0084] This invention provides a lightweight rubber riding boot outsole, prepared from raw materials comprising the following parts by weight:

[0085] 50 parts silicone rubber;

[0086] 25 parts of thermoplastic polyurethane;

[0087] 15 parts butadiene rubber;

[0088] Four parts of graphene and halloysite composite filler.

[0089] 10 parts of nano-silica

[0090] Six parts of paraffin phase change material, melting point 48℃;

[0091] Four parts flame retardant, APP and graphene composite;

[0092] Among them, flame retardant preparation: APP and graphene are placed in a high-speed mixer at a weight ratio of 5:1 and mixed for 12 minutes at a temperature of 90℃ and a rotation speed of 1200r / min to obtain APP and graphene composite flame retardant.

[0093] Preparation of graphene and halloysite composite filler: Graphene with a sheet diameter of 1-5 μm was modified with a silane coupling agent (2% by weight of graphene) and then mixed with halloysite nanotubes (length-to-diameter ratio 10-20) in a planetary ball mill with agate balls as the grinding medium at a ball-to-material ratio of 5:1. The mixture was stirred at 1000 r / min for 20 min to form an interpenetrating network structure in an inert gas protective atmosphere.

[0094] Nano silica dispersion: Nano silica and matrix material are mixed under the action of a dispersant (0.8% by weight of nano silica) and dispersed by ultrasonic frequency of 30kHz for 25min.

[0095] This invention also provides a processing technique for preparing the aforementioned lightweight rubber riding boot outsole, specifically including the following steps:

[0096] S1, Premixing and Dynamic Vulcanization

[0097] S1.1. Silicone rubber, thermoplastic polyurethane and butadiene rubber are premixed in an internal mixer at 90°C for 10 minutes.

[0098] S1.2 Add the above-mentioned graphene and halloysite composite filler, nano silica and coupling agent, and disperse in a high-speed disperser at a speed of 1200 r / min for 5 min;

[0099] S1.3. The mixture is injected into a twin-screw extruder with a length-to-diameter ratio of 32. Under the conditions of a temperature of 190℃ and a screw speed of 220rpm, a dynamic vulcanization reaction is carried out for 9 minutes to form a uniformly dispersed interpenetrating network structure.

[0100] S2, Supercritical Foaming Molding

[0101] S2.1 Place the above-mentioned compound in a high-pressure reactor with a volume of 5L, use supercritical carbon dioxide as a foaming agent, saturate for 2.5h under CO2 pressure of 18MPa and temperature of 70℃, and then depressurize at a depressurization rate of 12MPa / s to form a uniform closed-cell structure.

[0102] S2.2. A multi-layer composite outsole is prepared using a five-layer co-extrusion process. The raw materials for the prepared bottom layer, buffer layer, support layer, breathable layer and flame retardant layer are added to five independent extruders with a screw diameter of 45mm. The extrusion temperature is controlled at 170℃ and the extrusion pressure is 12MPa. Each layer is stacked and composited in sequence in a die with a die diameter of 110mm and a gradually converging flow channel. After cooling and shaping, a multi-layer composite outsole is obtained.

[0103] S3, Post-processing

[0104] S3.1 The outsole surface is treated with plasma. The gas used for plasma treatment is argon, the power is 150W, the treatment time is 4min, and the surface energy is increased to 55mN / m.

[0105] S3.2. The edge is frozen and trimmed at a liquid nitrogen temperature of -196℃. The cutting edge angle of the trimming tool is 35° and the edge accuracy reaches ±0.1mm, resulting in a lightweight rubber riding boot outsole.

[0106] Comparative Example 1

[0107] The formula used in the comparative example is as follows:

[0108] 40 parts silicone rubber, 20 parts thermoplastic polyurethane, 10 parts butadiene rubber, 3 parts graphene (not combined with halloysite and not modified with silane coupling agent), 8 parts nano silica (particle size 15-20nm) (not dispersed by ultrasonic method), 5 parts paraffin phase change material (melting point 48℃), and 3 parts flame retardant (APP) (not combined with graphene).

[0109] The comparative example also provides the following preparation process:

[0110] The foaming process used conventional chemical foaming agents instead of supercritical carbon dioxide foaming technology; dynamic vulcanization was not performed; and the parameters of each layer and the mold structure were not controlled in the five-layer co-extrusion process.

[0111] The performance of the lightweight rubber riding boot outsoles prepared in Examples 1-3 and the comparative examples is tested below. The test methods are as follows:

[0112] 1. Density test: Weigh the sample mass using an analytical balance, measure the sample volume using the displacement method, completely immerse the sample in a graduated cylinder containing distilled water, record the change in water volume, and calculate the bottom density using the formula "density = mass ÷ volume". Test each sample 3 times and take the average value.

[0113] 2. Tensile strength test: Cut the outsole into dumbbell-shaped specimens. Use an electronic universal testing machine, set the tensile speed to 500 mm / min, clamp both ends of the specimen, and perform a tensile test. Record the maximum tensile force when the specimen breaks. Calculate the tensile strength based on the initial cross-sectional area of ​​the specimen. Test 5 specimens for each sample and take the average value.

[0114] 4. Abrasion resistance test: The outsole is processed into a sample of specified size and installed on a rotary roller abrasion machine. The rotation speed, load and other parameters of the abrasion machine are set so that the sample rubs against the sandpaper for a certain number of revolutions. The worn debris is collected and weighed. The abrasion resistance is calculated. Each sample is tested 3 times and the average value is taken.

[0115] 5. Resilience test: Using a rebound tester, an impact ball of a certain mass is dropped freely from a fixed height to hit the surface of the outsole sample. The height of the rebound of the impact ball is measured. The resilience is calculated according to the formula "Resilience = (Rebound height ÷ Drop height) × 100%". Each sample is tested 5 times and the average value is taken.

[0116] 6. Cold resistance test: Place the bottom sample in a low temperature test chamber and cool it down to -30℃ at a certain cooling rate and keep it for a specified time. Then apply an impact force to the sample and observe whether the sample shows signs of embrittlement and cracking. Three samples are tested for each sample.

[0117] 7. Flame retardant performance test: Cut the bottom into samples of the specified size, install them vertically in the combustion chamber of the oxygen index tester, adjust the mixing ratio of oxygen and nitrogen, ignite the sample, observe the combustion of the sample, and determine the minimum oxygen concentration that can maintain the combustion of the sample, which is the limiting oxygen index. Each sample is tested 5 times and the average value is taken.

[0118] 8. Anti-slip coefficient test: Using an anti-slip tester, install the base sample on the test slider, apply a certain pressure to the wet tile surface, drag the slider at a fixed speed, measure the sliding friction, and calculate the anti-slip coefficient according to the formula "anti-slip coefficient = sliding friction ÷ vertical pressure". Each sample is tested 5 times and the average value is taken.

[0119] The final test data is shown in the table below:

[0120]

[0121] The data in the table above shows that:

[0122] 1. Density: The density range of Examples 1-3 is 0.6-0.8 g / cm³, while that of Comparative Example 1 is 1.1 g / cm³. This shows that the present invention effectively reduces the density of the outsole through a specific raw material formula and supercritical carbon dioxide foaming process, achieving the goal of lightweighting. Compared with traditional technology, the weight is significantly reduced, improving the wearing comfort of the product.

[0123] 2. Tensile strength: The tensile strengths of Examples 1-3 are 18MPa, 22MPa and 20MPa respectively, while that of Comparative Example 1 is only 10MPa. This shows that the addition of graphene and halloysite composite filler, nano-silica and dynamic vulcanization system of the present invention enhances the bonding force and overall strength between matrix materials, making the outsole more durable and less prone to damage.

[0124] 3. Wear resistance: The wear resistance of Examples 1-3 is 75-80 mm³, while that of Comparative Example 1 reaches 120 mm³. This shows that the graphene reinforcement and other technologies in this invention significantly improve the wear resistance of the outsole, extend the product's service life, and have more advantages in actual use.

[0125] 4. Resilience: The resilience of Examples 1-3 is 75%-80%, and that of Comparative Example 1 is 50%. This shows that the interpenetrating network structure of silicone rubber and thermoplastic polyurethane formed by the dynamic vulcanization system of the present invention gives the outsole good elasticity, provides better cushioning effect when worn, and improves the wearing experience.

[0126] 5. Cold resistance: Examples 1-3 showed no embrittlement at -30℃, while Comparative Example 1 showed embrittlement and cracking. This indicates that the present invention, through reasonable raw material selection and process design, improves the performance of the outsole in low-temperature environments and broadens the product's operating temperature range.

[0127] 6. Flame retardant performance: The limiting oxygen index of Examples 1-3 is 32%-33%, while that of Comparative Example 1 is only 18%, indicating that the present invention significantly improves the flame retardant performance of the outsole by applying APP and graphene composite flame retardant, and enhances the product’s safety performance.

[0128] 7. Anti-slip coefficient: The anti-slip coefficients of Examples 1-3 are between 0.65 and 0.68, and that of Comparative Example 1 is 0.4. This shows that the technology of the present invention enables the outsole to provide better grip on wet and slippery surfaces, reducing the risk of slipping for users and improving safety.

[0129] In summary, the raw material formulations and processing techniques used in Examples 1-3 have achieved synergistic optimization in many aspects, including lightweighting, strength, wear resistance, elasticity, cold resistance, flame retardancy, and anti-slip properties. Compared with the traditional technology in Comparative Example 1, they have significant technological advancements and better practical performance.

[0130] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A lightweight rubber outsole for riding boots, characterized by: It is prepared from raw materials comprising the following parts by weight: 40-60 parts silicone rubber, 20-30 parts thermoplastic polyurethane, 10-20 parts butadiene rubber, 3-5 parts graphene and halloysite composite filler, 8-12 parts nano silica, 5-8 parts paraffin phase change material and 3-5 parts flame retardant. The outsole has a multi-layered composite structure, which includes, from bottom to top: The bottom layer, specifically a wear-resistant rubber layer, contains graphene reinforcement, has a thickness of 1-2mm, and a Shore hardness of 60-70A; The buffer layer, specifically a blend of foamed silicone rubber and thermoplastic polyurethane, contains paraffin phase change material, has a thickness of 3-4 mm, and a compression set of ≤15%. The support layer, specifically the fiber reinforcement layer, is composed of a mixture of polyamide fibers and carbon fibers, with a thickness of 2-3 mm and a weight ratio of polyamide fibers to carbon fibers of 3-5:

1. The breathable layer is specifically a microporous polyurethane layer with an air permeability of ≥500g / m²・24h and a thickness of 0.5-1mm. The flame retardant layer, specifically a composite layer of silicone rubber and APP, has a vertical flammability rating of V-0, a thickness of 1-1.5mm, and an APP content of 30%-40% of the total weight of the flame retardant layer.

2. The lightweight rubber outsole for riding boots according to claim 1, characterized in that: The nano-silica has a particle size of 15-20 nm, the paraffin phase change material has a melting point of 48°C, and the flame retardant is prepared by the following method: APP and graphene are placed in a high-speed mixer at a weight ratio of 4-6:1 and mixed for 10-15 minutes at a temperature of 80-100℃ and a rotation speed of 1000-1500 r / min to obtain an APP and graphene composite flame retardant.

3. The lightweight rubber outsole for riding boots according to claim 2, characterized in that: In the graphene and halloysite composite filler, the graphene sheets have a diameter of 1-5 μm and are modified with a silane coupling agent, the amount of which is 1%-3% of the weight of the graphene. The halloysite nanotubes have an aspect ratio of 10-20. The two are stirred in a planetary ball mill with agate balls as the grinding medium at a ball-to-material ratio of 5:1 for 15-25 minutes at a speed of 800-1200 r / min, forming an interpenetrating network structure in an inert gas protective atmosphere.

4. The lightweight rubber outsole for riding boots according to claim 3, characterized in that: The nano-silica is uniformly dispersed in the matrix material by ultrasonic dispersion. The nano-silica and the matrix material are mixed under the action of a dispersant, with the amount of dispersant being 0.5%-1% of the weight of the nano-silica. The ultrasonic frequency is 20-40kHz, and the dispersion time is 20-30min, which enhances the interfacial bonding force between the matrix materials.

5. The lightweight rubber outsole of a riding boot according to claim 4, characterized in that: The outsole is formed by supercritical carbon dioxide foaming, with a density of 0.6-0.8 g / cm³, a cell diameter of 50-100 μm, and a cell closed-cell rate of ≥90%. The pressure, temperature, saturation time, and depressurization rate of the supercritical carbon dioxide are interrelated. When the CO2 pressure is 15-20 MPa, the temperature is 60-80℃, and the saturation time is 2-3 h, the depressurization rate is controlled at 10-15 MPa / s to ensure the formation of a uniform closed-cell structure.

6. The lightweight rubber outsole for riding boots according to claim 5, characterized in that: The outsole is formed by a dynamic vulcanization system with 0.5-1 ppm platinum catalyst and 1-2 parts peroxide, which forms an interpenetrating network structure of silicone rubber and thermoplastic polyurethane, with a resilience of 75-80%. The peroxide in the dynamic vulcanization system is 2,5-dimethyl-2,5-di-tert-butylperoxide.

7. The lightweight rubber riding boot outsole according to claim 6, characterized in that: The layers of the multilayer composite structure are chemically bonded by a silane coupling agent. The silane coupling agent is coated onto the surface of each layer by a coating method, with a coating amount of 5-10 g / m². The coating is cured at a temperature of 80-100℃ for 2-3 hours, and the peel strength is ≥5 N / cm.

8. A processing method for preparing the lightweight rubber outsole of claim 7, specifically comprising the following steps: S1, Premixing and Dynamic Vulcanization S1.

1. Silicone rubber, thermoplastic polyurethane and butadiene rubber are premixed in an internal mixer at a temperature of 80-100℃ for 10 minutes; S1.2 During this period, graphene and halloysite composite filler, nano silica and coupling agent are added, and dispersed in a high-speed disperser at a speed of 1000-1500 r / min for 5 min. S1.

3. The mixture is injected into a twin-screw extruder with a length-to-diameter ratio of 30-35. Under the conditions of a temperature of 180-200℃ and a screw speed of 200-250rpm, a dynamic vulcanization reaction is carried out for 8-10 minutes to form a uniformly dispersed interpenetrating network structure. S2, Supercritical Foaming Molding S2.1 Place the above-mentioned compound in a high-pressure reactor with a volume of 5L, use supercritical carbon dioxide as a foaming agent, saturate for 2-3 hours under CO2 pressure of 15-20MPa and temperature of 60-80℃, and then depressurize at a depressurization rate of 10-15MPa / s to form a uniform closed-cell structure. S2.

2. A multi-layer composite outsole is prepared using a five-layer co-extrusion process. Specifically, the raw materials for the prepared bottom layer, buffer layer, support layer, breathable layer, and flame-retardant layer are added to five independent extruders with screw diameters of 40-50mm. The extrusion temperature is controlled at 160-180℃ and the extrusion pressure is 10-15MPa. Each layer is sequentially stacked and composited in a die with a die diameter of 100-120mm and a gradually converging flow channel. After cooling and shaping, a multi-layer composite outsole is obtained. S3, Post-processing S3.

1. The outsole surface is treated with plasma. The gas used for plasma treatment is argon, the power is 150W, the treatment time is 3-5 minutes, and the surface energy is increased to 55mN / m. S3.

2. Perform cryogenic trimming at a liquid nitrogen temperature of -196℃. The cutting edge angle of the trimming tool is 30-45°, and the edge accuracy reaches ±0.1mm, resulting in a lightweight rubber riding boot outsole.

9. The processing technology according to claim 8, characterized in that: Before step S1.1, the silicone rubber is pretreated by drying it in a vacuum drying oven at a temperature of 60-80℃ and a vacuum degree of -0.08-0.1MPa for 2-3 hours to remove moisture and volatiles, thereby improving the uniformity of raw material mixing and product quality.

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