Rubber product formula and preparation method thereof
Through the blending of bio-based rubber, natural rubber and specific fillers and the use of epoxy soybean oil, the problem of insufficient environmental protection and mechanical properties of sole materials is solved, and a broadsol material suitable for mid-to-high-end footwear products is prepared, achieving improvements in environmental protection and performance.
Patent Information
- Application Number
- CN202510639378.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-19
- Publication Date
- 2025-07-25
AI Technical Summary
The existing sole rubber materials have poor environmental protection and poor mechanical properties, making it difficult to meet the high performance requirements and the development trend of green manufacturing.
Bio-based butadiene rubber is blended with natural rubber and styrene butadiene rubber, combined with reinforcement fillers such as carbon black, white carbon black, wollastonite, and epoxy soybean oil and ACTmix RA-70 as plasticizers and additives to prepare rubber materials through specific kneading and vulcanization processes.
Prepare high rebound, wear-resistant, fatigue-resistant and environmentally friendly rubber materials, suitable for outsoles of mid-to-high-end footwear products, meet comfort and durability needs, while reducing carbon emissions and resource consumption.
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Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of sole preparation, and more particularly, to a rubber product formula and a preparation method thereof. Background Art
[0002] With the continuous improvement of comfort, environmental protection and functionality in the consumer market, the sole materials of footwear products, especially sports shoes, casual shoes, etc., are developing towards the direction of lightweight, high elasticity, wear resistance and green environmental protection. As the part of the shoe body structure that directly contacts the ground, the sole needs to balance multiple key performance such as wear resistance, anti-slip, shock absorption and support, so the performance requirements for its materials are very high.
[0003] Traditional soles mostly use synthetic rubbers (such as styrene-butadiene rubber SBR, cis-butadiene rubber BR) or petroleum-based materials such as foamed EVA. Although the performance of such materials is relatively stable, there are environmental pollution problems that cannot be ignored in their production processes, such as high energy consumption, high carbon emissions, and difficulty in degradation, which are not conducive to the promotion of the sustainable development strategy. At the same time, as an important part of the daily consumer goods field, the footwear industry has put forward higher requirements for green manufacturing, material safety and resource recycling.
[0004] In this context, bio-based rubber materials have gradually been applied to sole preparation. Bio-based rubbers made from renewable resources such as vegetable oil or natural rubber have good elasticity and flexibility, and can replace traditional petroleum-based rubbers to a certain extent, which helps to reduce carbon emissions and petrochemical resource consumption. However, currently commercially available bio-based rubbers still have certain shortcomings in terms of mechanical strength, wear resistance and processing adaptability, and are difficult to be directly applied to the preparation of soles with high performance requirements.
[0005] In addition, in order to improve the wear resistance and mechanical properties of the sole, traditional reinforcing fillers such as carbon black or silica are often added. However, these fillers have poor compatibility and dispersibility with bio-based rubbers, which affect the processing performance and service life of the final composite material. At the same time, traditional plasticizers such as paraffin oil and petroleum-based softeners have safety and environmental protection hazards and are not suitable for use in wearable products that are in long-term contact with the human body.
[0006] Therefore, there is an urgent need to develop a new type of rubber material system with both environmental protection, mechanical properties and process adaptability, especially suitable for the sole preparation scenario, which not only meets the performance requirements of footwear products but also conforms to the industry development trend of green manufacturing. Summary of the Invention
[0007] In view of this, the present invention proposes a rubber product formula and a preparation method thereof, aiming to solve the problems of poor environmental protection and poor mechanical properties of the sole rubber material in the current technology.
[0008] On the one hand, a rubber product formula proposed by the present invention includes: Base rubber, reinforcing filler, softening plasticizer, vulcanizing agent and functional additive; The base rubber includes: 40-70 parts of natural rubber, 15-45 parts of bio-based cis-1,4-polybutadiene rubber and 10-30 parts of styrene-butadiene rubber; The reinforcing filler includes: 15-35 parts of carbon black, 1-10 parts of wollastonite, 5-15 parts of precipitated silica and 1-1.5 parts of TESPT; The softening plasticizer is 3-10 parts of epoxidized soybean oil; The vulcanizing agent includes: 1-4 parts of sulfur, 0.1-2 parts of N-tert-butyl-2-benzothiazole sulfenamide, 2-4 parts of zinc oxide, 0.5-1.5 parts of stearic acid and 0.5-1.5 parts of zinc metaphosphate; The functional additive is 1-2 parts of ACTmix RA-70.
[0009] Further, it includes: base rubber, reinforcing filler, softening plasticizer, vulcanizing agent and functional additive; The base rubber includes: 50-60 parts of natural rubber, 20-40 parts of bio-based cis-1,4-polybutadiene rubber and 15-25 parts of styrene-butadiene rubber; The reinforcing filler includes: 20-30 parts of carbon black, 3-6 parts of wollastonite, 8-12 parts of precipitated silica and 1-1.5 parts of TESPT; The softening plasticizer is 5-8 parts of epoxidized soybean oil; The vulcanizing agent includes: 2-3 parts of sulfur, 0.6-1 part of N-tert-butyl-2-benzothiazole sulfenamide, 2.5-3.5 parts of zinc oxide, 0.8-1.2 parts of stearic acid and 0.8-1.2 parts of zinc metaphosphate; The functional additive is 1.2-1.8 parts of ACTmix RA-70.
[0010] Further, the bio-based cis-1,4-polybutadiene rubber is prepared by the following method: using corn straw, sugarcane bagasse, rice husk or lignin as raw materials, using 0.5%-1.5% dilute sulfuric acid, and performing steam explosion at 180-200 °C for 15-30 min to destroy the cellulose structure; Adding cellulase and hemicellulase, controlling the pH to 4.8, the temperature to 50 °C, and enzymatically hydrolyzing for 48-72 h to obtain a C5 / C6 sugar mixture; Using the strain Escherichia coli or Clostridium acetobutylicum to ferment the C5 / C6 sugar mixture to obtain 1,3-butanediol; HZSM-5 or SAPO-34 is selected as the solid acid molecular sieve catalyst and calcined in air at 550 °C for 4 h for activation; taking the 1,3-butanediol as the reaction substrate, a feed mixture is prepared according to the mass ratio of 1,3-butanediol to water being 1:5, and when preheated to 100-120 °C, the feed mixture is pumped into a fixed-bed tubular reactor, the reaction temperature of the fixed-bed tubular reactor is set to 380-430 °C, and the space velocity is 1-3 h -1 , the aspect ratio of the bed of the solid acid molecular sieve catalyst is controlled at 10:1, dehydration is carried out in an inert environment, and after the reaction ends, 1,3-butadiene is obtained; A composite catalyst is prepared with NdCl3:Al(i-Bu)3:THF being (0.1-1) mol:(1-10) mod:(10-20) mL, and 12-18 wt% of the 1,3-butadiene and the composite catalyst are polymerized in a reaction kettle, the temperature is controlled at 40-60 °C, and the reaction is carried out for 2-4 h to obtain a precursor; Maleic anhydride is introduced into the molecular chain of the precursor by graft copolymerization to obtain the bio-based cis-1,4-polybutadiene rubber.
[0011] Further, the addition amount of the cellulase is 15-25 FPU / g of the raw material, and the addition amount of the hemicellulase is 100-150 FPU / g of the raw material.
[0012] Further, when fermenting the C5 / C6 sugar mixture, the concentration of the C5 / C6 sugar mixture is controlled at 80-120 g / L, the pH is maintained at 6.5±0.2, and it is cultured under anaerobic conditions for 48 h, and 1,3-butanediol with a purity ≥95% is separated by a membrane separation or vacuum distillation method; When Escherichia coli is selected as the fermentation strain, the temperature is controlled at 37 °C; when Clostridium is selected, the temperature is controlled at 30 °C.
[0013] Further, the carbon black is N660 carbon black.
[0014] Further, the epoxy value of the epoxy soybean oil ≥6%, and the viscosity at 25 °C is 300-600 MPa·s.
[0015] On the other hand, the present invention also provides a method for preparing a rubber product, including: Pre-drying carbon black, white carbon black and wollastonite to remove moisture; Adding natural rubber into a mixer, and controlling the temperature at 40-60 °C; Successively adding bio-based cis-1,4-polybutadiene rubber and styrene-butadiene rubber, and mixing and plasticizing for 2-5 min to obtain a basic rubber compound; Add carbon black, precipitated silica, wollastonite, TESPT, zinc oxide, stearic acid and zinc metaphosphate in sequence, mix evenly. After adding, knead for 5 - 8 min with the temperature controlled at 90 - 110 °C; Cool down to 60 - 70 °C, add epoxidized soybean oil, continue to knead for 2 - 4 min, add ACTmix RA - 70, and mix evenly; Naturally cool to room temperature. Open mill and add sulfur and N - tert - butyl - 2 - benzothiazole sulfenamide, knead for 1 - 2 min to obtain the final kneaded rubber.
[0016] Furthermore, store the final kneaded rubber sealed in a cool place at room temperature for 12 - 24 h; Use a molding press to inject into the mold cavity for shaping, and conduct hot - press vulcanization. Control the temperature at 145 - 155 °C, the time at 8 - 15 min, and the pressure at 8 - 12 MPa.
[0017] Furthermore, add antioxidant TBHQ accounting for 0.5% - 1.5% of the mass of the final kneaded rubber during the hot - press vulcanization process.
[0018] Compared with the prior art, the beneficial effects of the present invention are as follows: Bio - based cis - 1,4 - polybutadiene rubber synthesized from plant cellulose resources is introduced into the basic rubber compound, significantly reducing the dependence on petrochemical resources and carbon emissions. This bio - based rubber is prepared through a multi - step process of C5 / C6 sugar fermentation - catalytic dehydration - directional polymerization. It is not only renewable in source and clean in process, but also the graft modification with maleic anhydride improves its compatibility with inorganic fillers, which is beneficial to improving the overall mechanical properties and processing properties of the rubber.
[0019] Natural rubber, bio - based cis - 1,4 - polybutadiene rubber and styrene - butadiene rubber are blended in a specific proportion, synergistically achieving high elasticity, good low - temperature resistance and recovery properties, as well as excellent wear - resistance and crack - resistance properties. In the reinforcement system, three different - structured fillers of carbon black, precipitated silica and wollastonite are compounded, taking into account the reinforcement, dispersion and weight - reduction goals. The introduction of precipitated silica and wollastonite helps to improve the wear - resistance and compression set properties of the material.
[0020] The introduction of TESPT as a coupling agent enhances the interfacial bonding force between precipitated silica and wollastonite and the organic rubber, improving the filler dispersion and the mechanical strength of the composite rubber compound; ACTmix RA - 70 as a multifunctional pre - dispersed synergistic additive can synergistically promote the vulcanization efficiency and cross - linking uniformity, improving the dynamic properties of the product.
[0021] Epoxidized soybean oil is used to replace the traditional petroleum - based softener. Its high epoxy value can react with the double bonds in the rubber, not only playing a plasticizing role, but also improving the vulcanization cross - linking efficiency. At the same time, it avoids the problem of the release of volatile organic compounds that may be brought by paraffin oil, which is beneficial to the safety of wearable products.
[0022] During the preparation process, a process design combining staged internal mixing and subsequent open milling is adopted to effectively control the temperature window, ensure the full dispersion and reaction of each component, and avoid premature cross-linking. At the same time, in the final vulcanization stage, by precisely controlling the pressure, temperature and time, and optionally adding antioxidant TBHQ, the thermal stability and anti-aging performance of the product are improved to ensure the molding quality.
[0023] The prepared rubber material has both high resilience, good abrasion resistance, fatigue resistance and environmental friendliness, and is particularly suitable for the manufacturing requirements of the soles of mid- to high-end shoe products such as sports shoes and casual shoes, and can respond to the market trend of sustainable manufacturing on the basis of meeting comfort and durability. Detailed implementation mode
[0024] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.
[0025] The preparation method of the rubber product in the embodiment of the present invention is as follows: Pre-dry N660 carbon black, white carbon black and wollastonite to remove moisture; Add natural rubber into an internal mixer, and control the temperature at 40 - 60°C; Add bio-based cis-1,4-polybutadiene rubber and styrene-butadiene rubber in sequence, and mix and plasticate for 2 - 5 min to obtain a basic rubber compound; Add carbon black, white carbon black, wollastonite, TESPT, zinc oxide, stearic acid and zinc metaphosphate in sequence, mix evenly, and after adding, knead for 5 - 8 min, and control the temperature at 90 - 110°C; Cool down to 60 - 70°C, add epoxidized soybean oil with an epoxy value ≥ 6% and a viscosity of 300 - 600 MPa·s at 25°C, continue to knead for 2 - 4 min, and add ACTmix RA-70 and mix evenly; Naturally cool to room temperature, add sulfur and N-tert-butyl-2-benzothiazolesulfenamide during open milling, and knead for 1 - 2 min to obtain the final kneaded rubber compound.
[0026] Seal and store the final kneaded rubber compound in a cool place at room temperature for 12 - 24 h; Use a mold press to inject into the mold cavity for shaping, and carry out hot press vulcanization, control the temperature at 145 - 155°C, the time at 8 - 15 min, and the pressure at: 8 - 12 MPa.
[0027] Add antioxidant TBHQ with a mass of 0.5% - 1.5% of the final kneaded rubber compound during the hot press vulcanization process.
[0028] The preparation method of bio-based cis-1,4-polybutadiene rubber is as follows: Using corn stover, bagasse, rice husk or lignin as raw materials, 0.5%-1.5% dilute sulfuric acid is used, and steam explosion is carried out at 180-200 °C for 15-30 min to destroy the cellulose structure; Cellulase and hemicellulase are added, the pH is controlled at 4.8, the temperature is 50 °C, and enzymatic hydrolysis is carried out for 48-72 h to obtain a C5 / C6 sugar mixture; the addition amount of cellulase is 15-25 FPU / g of raw materials, and the addition amount of hemicellulase is 100-150 FPU / g of raw materials.
[0029] Using the strain Escherichia coli or Clostridium acetobutylicum to ferment the C5 / C6 sugar mixture to obtain 1,3-butanediol; During fermentation: control the concentration of the C5 / C6 sugar mixture to be 80-120 g / L, maintain the pH at 6.5 ± 0.2, culture under anaerobic conditions for 48 h, and use membrane separation or vacuum distillation methods to separate and obtain 1,3-butanediol with a purity ≥ 95%; When selecting Escherichia coli as the fermentation strain, the temperature is controlled at 37 °C; when selecting Clostridium, the temperature is controlled at 30 °C.
[0030] Select HZSM-5 or SAPO-34 as the solid acid molecular sieve catalyst, and calcine it in air at 550 °C for 4 h for activation; use 1,3-butanediol as the reaction substrate, configure the feed mixture according to the mass ratio of 1,3-butanediol to water of 1:5, start pumping the feed mixture to the fixed-bed tubular reactor when preheated to 100-120 °C, set the reaction temperature of the fixed-bed tubular reactor to 380-430 °C, the space velocity to 1-3 h-1, control the bed aspect ratio of the solid acid molecular sieve catalyst at 10:1, dehydrate under an inert environment, and after the reaction, obtain 1,3-butadiene; Prepare a composite catalyst with NdCl3:Al(i-Bu)3:THF as (0.1-1) mol:(1-10) mod:(10-20) mL, polymerize 12-18 wt% of 1,3-butadiene and the composite catalyst in a reaction kettle, control the temperature at 40-60 °C, and react for 2-4 h to obtain a precursor; Introduce maleic anhydride into the molecular chain of the precursor by graft copolymerization to obtain bio-based cis-1,4-polybutadiene rubber.
[0031] According to the above preparation method, Examples 1-3 and comparative examples are obtained, and the ingredient addition amounts of each example and comparative example are shown in Table 1.
[0032] Table 1
[0033] Among them, the addition amount of antioxidant TBHQ is % based on the mass of the mixed rubber in the group, and the rest of the units are all parts by weight.
[0034] The performance of Examples 1-3 and the comparative examples was detected, and the experimental results are shown in Table 2.
[0035] Table 2
[0036] As can be seen from the table: the tensile strength of Example 2 was increased to 15.6 MPa (a 25.8% increase compared to the comparative example); the tear strength was increased to 32.0 kN / m, improving the damage resistance of the material; the modulus at a specified elongation and the elongation at break increased synchronously, indicating that the material has good rigidity-flexibility coordination.
[0037] The heat aging strength retention rate of the comparative example was only 69.5%, while that of Example 2 was increased to 84.5%; epoxidized soybean oil and zinc metaphosphate synergistically provided excellent antioxidant and thermal stability effects.
[0038] In addition, replacing traditional BR with bio-based cis-butadiene rubber can reduce the carbon footprint and environmental burden; using plant-derived epoxidized soybean oil as a plasticizer is safe and environmentally friendly.
[0039] The Mooney viscosities of Examples 1-3 were moderate, being 71–74 MU, which is suitable for conventional rubber processing equipment.
[0040] The hot pressing and vulcanization time is short, being 8-15 min, and the temperature is low (145–155 °C), saving energy and reducing consumption.
[0041] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to the above examples, those of ordinary skill in the art should understand that: the specific implementation manners of the present invention can still be modified or equivalently replaced, and any modification or equivalent replacement without departing from the spirit and scope of the present invention should be covered by the protection scope of the claims of the present invention.
Claims
1. A rubber product formula, characterized in that, Comprising: Base rubber compound, reinforcing filler, softening plasticizer, vulcanizing agent and functional additive; The base rubber compound comprises: 40 - 70 parts of natural rubber, 15 - 45 parts of bio-based cis-1,4-polybutadiene rubber and 10 - 30 parts of styrene-butadiene rubber; The reinforcing filler comprises: 15 - 35 parts of carbon black, 1 - 10 parts of wollastonite, 5 - 15 parts of precipitated silica and 1 - 1.5 parts of TESPT; The softening plasticizer is 3 - 10 parts of epoxidized soybean oil; The vulcanizing agent comprises: 1 - 4 parts of sulfur, 0.1 - 2 parts of N-tert-butyl-2-benzothiazole sulfenamide, 2 - 4 parts of zinc oxide, 0.5 - 1.5 parts of stearic acid and 0.5 - 1.5 parts of zinc metaphosphate; The functional additive is 1 - 2 parts of ACTmix RA-70.
2. The rubber product formulation according to claim 1, characterized in that, Comprising: Base rubber compound, reinforcing filler, softening plasticizer, vulcanizing agent and functional additive; The base rubber compound comprises: 50 - 60 parts of natural rubber, 20 - 40 parts of bio-based cis-1,4-polybutadiene rubber and 15 - 25 parts of styrene-butadiene rubber; The reinforcing filler comprises: 20 - 30 parts of carbon black, 3 - 6 parts of wollastonite, 8 - 12 parts of precipitated silica and 1 - 1.5 parts of TESPT; The softening plasticizer is 5 - 8 parts of epoxidized soybean oil; The vulcanizing agent comprises: 2 - 3 parts of sulfur, 0.6 - 1 part of N-tert-butyl-2-benzothiazole sulfenamide, 2.5 - 3.5 parts of zinc oxide, 0.8 - 1.2 parts of stearic acid and 0.8 - 1.2 parts of zinc metaphosphate; The functional additive is 1.2 - 1.8 parts of ACTmix RA-70.
3. A rubber product formulation according to claim 1, characterized in that, The bio-based cis-1,4-polybutadiene rubber is prepared by the following method: using corn straw, bagasse, rice husk or lignin as raw materials, using 0.5% - 1.5% dilute sulfuric acid, and performing steam explosion at 180 - 200 °C for 15 - 30 min to destroy the cellulose structure; Adding cellulase and hemicellulase, controlling the pH to be 4.8 and the temperature to be 50 °C, and performing enzymatic hydrolysis for 48 - 72 h to obtain a C5 / C6 sugar mixture; Using the strain Escherichia coli or Clostridium acetobutylicum to ferment the C5 / C6 sugar mixture to obtain 1,3-butanediol; HZSM-5 or SAPO-34 is selected as the solid acid molecular sieve catalyst and calcined in air at 550 °C for 4 h for activation; the 1,3-butanediol is used as the reaction substrate, and a feed mixture is prepared according to the mass ratio of 1,3-butanediol to water of 1:5, and when preheated to 100-120 °C, the feed mixture is pumped into a fixed-bed tubular reactor, the reaction temperature of the fixed-bed tubular reactor is set at 380-430 °C, and the space velocity is 1-3 h -1 , the aspect ratio of the bed layer of the solid acid molecular sieve catalyst is controlled at 10:1, and dehydration is carried out in an inert environment. After the reaction, 1,3-butadiene is obtained; Preparing a composite catalyst with NdCl3:Al(i-Bu)3:THF being (0.1 - 1) mol:(1 - 10) mod:(10 - 20) mL, polymerizing 12 - 18 wt% of the 1,3-butanediol and the composite catalyst in a reaction kettle, controlling the temperature to be 40 - 60 °C, and reacting for 2 - 4 h to obtain a precursor; Introducing maleic anhydride into the molecular chain of the precursor by graft copolymerization to obtain the bio-based cis-1,4-polybutadiene rubber.
4. A rubber product formulation according to claim 3, characterized in that The addition amount of the cellulase is 15 - 25 FPU / g of raw materials, and the addition amount of the hemicellulase is 100 - 150 FPU / g of raw materials.
5. A rubber product formulation according to claim 3, characterized in that, When fermenting the C5 / C6 sugar mixture, controlling the concentration of the C5 / C6 sugar mixture to be 80 - 120 g / L, maintaining the pH at 6.5 ± 0.2, culturing under anaerobic conditions for 48 h, and separating by membrane separation or vacuum distillation to obtain 1,3-butanediol with a purity ≥ 95%; When Escherichia coli is selected as the fermentation strain, the temperature is controlled at 37 °C; when Clostridium is selected, the temperature is controlled at 30 °C.
6. A rubber product formulation according to claim 1, characterized in that, The carbon black is N660 carbon black.
7. A rubber product formulation according to claim 1, characterized in that, The epoxy value of the epoxidized soybean oil is ≥6%, and the viscosity at 25 °C is 300 - 600 MPa·s.
8. A method for preparing a rubber product, characterized in that, It is made by using the rubber product formula described in Claim 1, including: Pre-dry carbon black, precipitated silica and wollastonite to remove moisture; Add natural rubber into the internal mixer, and control the temperature at 40 - 60 °C; Add bio-based cis-butadiene rubber and styrene-butadiene rubber in sequence, and mix and plasticate for 2 - 5 min to obtain the basic rubber compound; Add carbon black, precipitated silica, wollastonite, TESPT, zinc oxide, stearic acid and zinc metaphosphate in sequence, mix evenly, and after adding, mix and knead for 5 - 8 min, and control the temperature at 90 - 110 °C; Cool down to 60 - 70 °C, add epoxidized soybean oil, continue to mix and knead for 2 - 4 min, and add ACTmix RA-70 and mix evenly; Naturally cool to room temperature, open mill and add sulfur and N-tert-butyl-2-benzothiazole sulfenamide, and mix and knead for 1 - 2 min to obtain the final mixed rubber.
9. The preparation method of the rubber product according to claim 8, characterized in that, Seal and store the final mixed rubber in a cool place at room temperature for 12 - 24 h; Use a mold press to inject into the mold cavity for shaping, and carry out hot press vulcanization, control the temperature at 145 - 155 °C, the time at 8 - 15 min, and the pressure at: 8 - 12 MPa.
10. The preparation method of the rubber product according to claim 9, characterized in that, Add 0.5% - 1.5% of the antioxidant TBHQ based on the mass of the final mixed rubber during the hot press vulcanization process.