Environment-friendly modified rubber material as well as preparation method and application thereof

Abstract

The invention relates to an environment-friendly modified rubber material, which is prepared from the following ingredients in parts by weight: 30 to 40 parts of natural rubber, 35 to 50 parts of bio-based ethylene propylene diene terpolymers, 15 to 25 parts of bio-based elastomers, 10 to 20 parts of straw powder, 5 to 10 parts of reed fibers, 3 to 5 parts of vulcanization systems and 2 to 4 parts of environment-friendly plasticizers. The environment-friendly modified rubber material disclosed by the invention has high elasticity, high strength, environment friendliness and recyclability, provides a suitable sports effect, and is suitable for outdoor sports floors.

Description

Technical Field

[0001] The invention relates to an environmentally friendly modified rubber material and a preparation method and application thereof. Background Art

[0002] Traditional sports flooring materials mostly rely on rolls or assembled floors made primarily of petroleum-based synthetic rubber (such as styrene-butadiene rubber (SBR) and petroleum-based EPDM), which are non-renewable and difficult to degrade. Existing bio-based elastomers (such as bio-based POE and bio-based EPDM) are environmentally friendly, but when used alone in sports flooring, they struggle to achieve the synergistic optimization of multiple performance dimensions, including high elasticity, high strength, wear resistance, environmental friendliness, and recyclability, while meeting mechanical performance requirements. Furthermore, agricultural waste such as straw and reeds are often incinerated, causing environmental pollution. Although they have recently been used as rubber fillings to improve rubber's environmental friendliness, the significant difference in surface formulation between straw and rubber can lead to poor interfacial compatibility, resulting in reduced tensile strength. Summary of the Invention

[0003] The purpose of the present invention is to provide an environmentally friendly modified rubber material that has both strength and environmental friendliness and can be recycled, as well as a preparation method and application thereof.

[0004] The present invention adopts the following technical solutions: An environmentally friendly modified rubber material comprises the following components in parts by weight: 30-40 parts of natural rubber, 35-50 parts of bio-based ethylene propylene diene terpolymer, 15-25 parts of bio-based elastomer, 10-20 parts of straw powder, 5-10 parts of reed fiber, 3-5 parts of vulcanization system, and 2-4 parts of environmentally friendly plasticizer.

[0005] Wherein, the bio-based elastomer is a bio-based polyolefin elastomer.

[0006] The straw powder has a particle size of 80-100 meshes, and the aspect ratio of the reed fiber is greater than 25.

[0007] The straw powder and reed fiber were pretreated with 5wt% NaOH solution for 24 hours and then washed and dried before use.

[0008] The vulcanization system comprises 1.2 parts by weight of sulfur, 2 parts by weight of ZnO, and 0.8 parts by weight of accelerator CZ.

[0009] Wherein, the environmentally friendly plasticizer is 1.5 parts by weight of acetyl tributyl citrate and 1.5 parts by weight of epoxidized soybean oil.

[0010] A method for preparing the above-mentioned environmentally friendly modified rubber material comprises the following steps: (1) Natural rubber and acetyl tributyl citrate are masticated at 60-65°C for 3-4 minutes; (2) Add bio-based ethylene propylene diene terpolymer and epoxidized soybean oil, and mix at 115°C to 125°C for 4 to 5 minutes; (3) Add bio-based elastomer, straw powder and reed fiber and disperse at 130℃~140℃ for 5~6 minutes; (4) Inject the vulcanization system and dynamically vulcanize at 175℃~180℃ and 45~60rpm for 8~12min.

[0011] An application of the above-mentioned environmentally friendly modified rubber material in the preparation of sports floors.

[0012] The beneficial effects of the present invention are: through the synergistic effect of the bio-based POE / EPDM compound system and the modified straw fiber, the present invention improves the tensile strength and impact absorption rate of the material. At the same time, the high rebound rate can significantly improve the energy feedback efficiency. At the same time, it has extremely low vertical deformation to provide protection for athletes' joints, can withstand harsh environments, and increase service life.

[0013] The present invention uses bio-based materials and agricultural waste straw, which reduces carbon emissions while having excellent biodegradability, eliminating microplastic pollution from the source, and has excellent environmental protection performance.

[0014] This invention also uses plasticizer molecular anchoring technology, enabling the material to retain up to 92% of its tensile strength and 94% of its ball rebound after three cycles. The 30% recycled material blend with new material system reduces raw material costs by 22%, demonstrating excellent recyclability. DETAILED DESCRIPTION

[0015] The present invention will be further described in detail below through examples.

[0016] Example 1 (1) Pretreatment of straw powder: crush the straw into 80-100 mesh, soak it in 5 wt% sodium hydroxide solution with a liquid-to-solid ratio of 5:1; stir it at room temperature for 24 hours, filter it, and wash it with deionized water until the filtrate pH is 7.0 ± 0.5; dry it in an 80 °C forced air drying oven until the moisture content is ≤ 0.5%.

[0017] Reed fiber pretreatment: Reed stems are cut into fiber bundles (length 3-5 mm) with an aspect ratio greater than 25. Other treatments are the same as the pretreatment process of straw powder.

[0018] (2) The initial temperature of the internal mixer is 60°C. 350 g of natural rubber NR and 15 g of acetyl tributyl citrate ATBC are added and the mixer is plasticized at 30 rpm for 3 min.

[0019] (3) Adding bio-based ethylene propylene diene terpolymer EPDM (Dow ENGAGE TMREN EPDM) 400g, epoxidized soybean oil ESO 15g, 120℃, 40rpm, mixing for 4min.

[0020] (4) Invest in bio-based polyolefin elastomer POE (Dow ENGAGE TM REN 7467) 200g, straw powder 150g, reed fiber 80g, 135℃, 40rpm, disperse for 6min.

[0021] (5) Inject 12g of sulfur, 20g of ZnO, and 8g of accelerator CZ, and seal the mixing chamber.

[0022] (6) 180°C, 50 rpm, dynamic vulcanization for 10 min; torque platform value 42 N·m.

[0023] Example 2 (1) Pretreatment of straw powder: crush the straw into 80-100 mesh, soak it in 5 wt% sodium hydroxide solution with a liquid-to-solid ratio of 5:1; stir it at room temperature for 24 hours, filter it, and wash it with deionized water until the filtrate pH is 7.0 ± 0.5; dry it in an 80 °C forced air drying oven until the moisture content is ≤ 0.5%.

[0024] Reed fiber pretreatment: Reed stems are cut into fiber bundles (length 3-5 mm) with an aspect ratio greater than 25. Other treatments are the same as the pretreatment process of straw powder.

[0025] (2) The initial temperature of the internal mixer is 60°C. 350 g of natural rubber NR and 10 g of acetyl tributyl citrate ATBC are added and the mixer is plasticized at 30 rpm for 3 min.

[0026] (3) Adding bio-based ethylene propylene diene terpolymer EPDM (Dow ENGAGE TM REN EPDM) 350g, epoxidized soybean oil ESO 10g, 120℃, 40rpm, mix for 5min.

[0027] (4) Invest in bio-based polyolefin elastomer POE (Dow ENGAGE TM REN 7467) 250g, straw powder 220g, reed fiber 130g, 135℃, 40rpm, disperse for 5min.

[0028] (5) Inject 12g of sulfur, 20g of ZnO, and 8g of accelerator CZ, and seal the mixing chamber.

[0029] (6) 182°C, 50 rpm, dynamic vulcanization for 12 min; torque platform value 38 N·m.

[0030] Example 3 (1) Pretreatment of straw powder: crush the straw into 80-100 mesh, soak it in 5 wt% sodium hydroxide solution with a liquid-to-solid ratio of 5:1; stir it at room temperature for 24 hours, filter it, and wash it with deionized water until the filtrate pH is 7.0 ± 0.5; dry it in an 80 °C forced air drying oven until the moisture content is ≤ 0.5%.

[0031] (2) The initial temperature of the internal mixer is 60°C. Add 500 g of natural rubber NR and 20 g of acetyl tributyl citrate ATBC, and plasticize at 30 rpm for 4 min.

[0032] (3) Adding bio-based ethylene propylene diene terpolymer EPDM (Dow ENGAGE TM REN EPDM) 400g, epoxidized soybean oil ESO 10g, 120℃, 40rpm, mixing for 6min.

[0033] (4) Invest in bio-based polyolefin elastomer POE (Dow ENGAGE TM REN 7467) 150g, straw powder 200g, 135℃, 40rpm, disperse for 5min.

[0034] (5) Inject 12g of sulfur, 20g of ZnO, and 8g of accelerator CZ, and seal the mixing chamber.

[0035] (6) 180°C, 55 rpm, dynamic vulcanization for 8 min; torque platform value 45 N·m.

[0036] Comparative Example (1) The initial temperature of the internal mixer is 60°C. 400 g of natural rubber NR and 30 g of dioctyl phthalate are added to the mixer at 30 rpm and plasticized for 4 min.

[0037] (2) Add petroleum-based EPDM (ExxonMobil Vistalon TM 7500) 200g, 120℃, 40rpm, mixing for 4min.

[0038] (3) Add 250g of calcium carbonate, 120°C, 40rpm, and disperse for 5 minutes.

[0039] (4) Inject 12g of sulfur, 20g of ZnO, and 8g of accelerator CZ, and seal the mixing chamber.

[0040] (5) 180°C, 50 rpm, dynamic vulcanization for 10 min; torque platform value 42 N·m.

[0041] Effect Examples Performance testing was conducted on the modified rubber products prepared in Examples 1-3 and the comparative example. Sports flooring performance was measured in accordance with GB / T 14833-2020 and EN 14904 standards, environmental performance was measured in accordance with ISO 14040 and ASTM D6866, and recyclability was measured as the performance retention after three cycles of recycling. The results are shown in Tables 1-3.

[0042] Ball rebound rate test conditions: The test ball is a Dunlop Fort tennis ball (mass 56.7g); the drop height is 1m; the temperature is 23±2°C; the calculation formula is rebound height / drop height×100%.

[0043] The specific recycling method of the material is: crush the waste material to a particle size of ≤0.5mm, add 80~60wt% of new material according to 20~40wt% of recycled material, and dynamically vulcanize at 170℃~175℃ and 45~60rpm for 7~9min.

[0044] Table 1 Test results of mechanical properties of materials .

[0045] Table 2 Material environmental protection test results .

[0046] Table 3 Material recycling performance test .

Claims

1. An environmentally friendly modified rubber material, characterized in that: The invention comprises the following components in parts by weight: 30-40 parts of natural rubber, 35-50 parts of bio-based ethylene propylene diene terpolymer, 15-25 parts of bio-based elastomer, 10-20 parts of straw powder, 5-10 parts of reed fiber, 3-5 parts of vulcanization system, and 2-4 parts of environmentally friendly plasticizer.

2. The environmentally friendly modified rubber material according to claim 1, characterized in that: The bio-based elastomer is a bio-based polyolefin elastomer.

3. The environmentally friendly modified rubber material according to claim 1, characterized in that: The particle size of the straw powder is 80-100 meshes, and the aspect ratio of the reed fiber is greater than 25.

4. The environmentally friendly modified rubber material according to claim 3, characterized in that: The straw powder and reed fiber were pretreated with 5 wt % NaOH solution for 24 h, washed with water and dried before use.

5. The environmentally friendly modified rubber material according to claim 1, characterized in that: The vulcanization system comprises 1.2 parts by weight of sulfur, 2 parts by weight of ZnO, and 0.8 parts by weight of accelerator CZ.

6. The environmentally friendly modified rubber material according to claim 1, characterized in that: The environmentally friendly plasticizer is 1.5 parts by weight of acetyl tributyl citrate and 1.5 parts by weight of epoxidized soybean oil.

7. A method for preparing the environmentally friendly modified rubber material according to any one of claims 1 to 6, characterized in that: It includes the following steps: (1) Natural rubber and acetyl tributyl citrate are masticated at 60-65°C for 3-4 minutes; (2) Add bio-based ethylene propylene diene terpolymer and epoxidized soybean oil, and mix at 115°C to 125°C for 4 to 5 minutes; (3) Add bio-based elastomer, straw powder and reed fiber and disperse at 130℃~140℃ for 5~6 minutes; (4) Inject the vulcanization system and dynamically vulcanize at 175℃~180℃ and 45~60rpm for 8~12min.

8. Use of the environmentally friendly modified rubber material according to claims 1 to 6 in the preparation of sports flooring.