Modified polyethylene anaerobic biodegradable material as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of sports equipment, and particularly relates to a modified polyethylene anaerobic biodegradable material as well as a preparation method and application thereof. Comprising the following components in parts by weight: 70-100 parts of polyethylene, 0-5 parts of probiotic anaerobic degradable plastic master batch, 0-5 parts of anaerobic enzyme accelerant, 5-15 parts of ethylene-vinyl acetate copolymer, 1-15 parts of corn starch, 0.1-5 parts of compatibilizer, 0.01-0.06 part of fluoroelastomer, 2-8 parts of coupling agent and 1-5 parts of dispersing agent. According to the invention, polyethylene is used as a matrix, and through directional modification of a degradation trigger and synergistic enhancement of a trace of functional aids, the controllable anaerobic biodegradation capability is given to polyethylene for the first time on the premise of retaining excellent processability and mechanical properties of polyethylene, and the long-standing technical bottleneck that performance and environmental protection cannot be achieved at the same time in the field of sports equipment is broken through; and an industrialization feasible path is provided for green upgrading of sports equipment.

Description

Technical Field

[0001] This invention belongs to the technical field of sports equipment, specifically relating to a modified polyethylene anaerobic biodegradable material, its preparation method, and its application. Background Technology

[0002] With the popularization and development of sports, pickleball, as an emerging sport combining the characteristics of tennis, badminton, and table tennis, is gaining increasing popularity. The user experience and durability of pickleballs largely depend on the performance of their manufacturing materials. Currently, pickleballs are mainly made of plastic materials such as polyethylene. While these materials have good processing properties and durability, their degradation rate in the natural environment is extremely slow, requiring decades or even longer to completely decompose. With the increasing popularity of pickleball, the number of discarded pickleballs has increased dramatically, placing enormous pressure on the environment. Furthermore, the impact resistance of pickleballs is currently limited; they typically deform and crack after less than 2000 hits, affecting the gaming experience and the ball's lifespan.

[0003] Existing technologies have addressed the problems of pickballs made from plastic materials such as polyethylene. For example, patent CN116603221A – a highly elastic and biodegradable pickball – uses biodegradable materials such as polylactic acid to manufacture the pickball. Although it can be decomposed into water and carbon dioxide by microorganisms in the natural environment and is harmless to the environment, the use of biodegradable materials alone still has shortcomings in terms of elasticity and impact resistance, making it difficult to meet the needs of sports. In order to improve the overall performance of pickballs, new pickball materials with excellent performance have been developed, such as patent CN109734983A – a pickball rotational molding polyethylene-polyolefin elastomer composite material and its preparation method. It uses polyethylene and polyolefin elastomer composite to improve the elasticity and impact resistance of pickballs, but discarded pickballs cannot be naturally degraded.

[0004] In conclusion, existing materials used in making pickles struggle to simultaneously possess both biodegradability and athletic performance, which is detrimental to the sport's development and hinders the green and sustainable development of the sports equipment industry. Therefore, a new technological solution is needed to address these issues. Summary of the Invention

[0005] The purpose of this invention is to provide a modified polyethylene anaerobic biodegradable material, its preparation method, and its application, in order to solve the problems mentioned in the background art, such as the difficulty in combining degradation performance and sports performance in the materials used to make pickles, which is not conducive to the development needs of this sport and makes it difficult to promote the green and sustainable development of the sports equipment industry.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a modified polyethylene anaerobic biodegradable material, comprising the following components in parts by weight: 70-100 parts polyethylene, 0-5 parts probiotic anaerobic biodegradable plastic masterbatch, 0-5 parts anaerobic enzyme promoter, 5-15 parts ethylene-vinyl acetate copolymer, 1-15 parts corn starch, 0.1-5 parts compatibilizer, 0.01-0.06 parts fluoroelastomer, 2-8 parts coupling agent, and 1-5 parts dispersant, wherein the polyethylene comprises the following components in parts by weight: 30-50 parts mixed... The mixture comprises 40-50 parts of low-density polyethylene and linear low-density polyethylene; the probiotic anaerobic degradable plastic masterbatch is one of plant-based starch, polybutylene succinate, and ethylene carbonate oxide; the anaerobic enzyme promoter is a mixture of ferrous sulfate, sodium citrate, and Tween-80; the compatibilizer is one of maleic anhydride-grafted polyethylene, ethylene-acrylic acid copolymer, and ethylene-methyl acrylate copolymer; the coupling agent is silane coupling agent KH570; and the dispersant is a mixture of several of polyethylene wax, zinc stearate, and calcium stearate.

[0007] The specific steps for preparing modified polyethylene anaerobic biodegradable materials according to the above formula are as follows: S1. Dry the formulated amounts of polyethylene, ethylene-vinyl acetate copolymer, and corn starch at 75–85°C for 3–5 hours, controlling the moisture content to ≤0.5%; S2. Grind the compatibilizer, coupling agent and dispersant separately and pass them through a 150-250 mesh sieve for later use; S3. Add the dried polyethylene, ethylene-vinyl acetate copolymer and corn starch to a high-speed mixer, heat to 50-70°C, add compatibilizer, coupling agent and dispersant in sequence, mix for 3-7 minutes, add probiotic anaerobic degradable plastic masterbatch, anaerobic enzyme promoter and fluoroelastomer, and continue to mix at 700-900 rpm for 8-12 minutes to obtain the mixture. S4. Transfer the mixture to a twin-screw extruder, control the temperature in stages, melt extrude at a screw speed of 200-300 rpm, and then cut into pellets by water cooling or air cooling to obtain modified granules with a particle size of 3-5 mm, which are modified polyethylene anaerobic biodegradable materials; wherein, the temperature of the stages is controlled as follows: the temperature of the first zone is 150-160℃; the temperature of the second zone is 160-170℃; the temperature of the third zone is 170-180℃; and the die temperature is 175-185℃.

[0008] In addition to the above technical solutions, the modified polyethylene anaerobic biodegradable material prepared above can also be applied to rotomolded pickles.

[0009] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention, through the introduction of biodegradable components and optimized formulation design, successfully developed a modified polyethylene material that can degrade rapidly in anaerobic environments while possessing excellent athletic performance. This solves the problem that existing pickle ball materials cannot simultaneously meet the requirements of degradation and athletic performance, thus promoting the green and sustainable development of the sports equipment industry. By introducing anaerobic enzyme promoters and probiotic-type anaerobic degradable plastic masterbatches, the degradation rate of the material is effectively controlled, providing targets for anaerobic microorganisms and accelerating the destruction process of the plastic molecular structure. This ensures the material's performance while achieving rapid degradation in anaerobic environments, effectively solving the problem of slow degradation of traditional plastic materials. By adding specific proportions of compatibilizers, coupling agents, dispersants, and other auxiliary components, the compatibility and mechanical properties of the material are effectively improved. This allows the modified polyethylene material to maintain good degradation performance while significantly improving impact resistance and durability, helping to extend the service life of sports equipment such as pickles and reducing resource waste and environmental pollution caused by frequent replacements. 2. This invention employs a design that blends mixed low-density polyethylene (LDPE) and linear LDPE, retaining the high toughness and impact resistance of polyethylene. By adding a dual-engine system of "beneficial bacteria-type anaerobic degradation masterbatch + anaerobic enzyme promoter," microorganisms are activated to target and attack the polyethylene molecular chains in landfill or anaerobic environments, thereby accelerating the biodegradation of traditional polyethylene. The introduction of ethylene-vinyl acetate copolymer and corn starch not only enhances the low-temperature flexibility but also provides a carbon source for microorganisms, synergistically promoting degradation without sacrificing mechanical strength. The addition of trace amounts of fluoroelastomer significantly improves weather resistance and corrosion resistance, solving the problem of easy aging of biodegradable materials. Furthermore, with the synergistic effect of compatibilizers and coupling agents, the interfacial bonding between polyethylene and corn starch and ethylene-vinyl acetate copolymer is strengthened, preventing phase separation and ensuring the uniformity and processing stability of the material. The dispersant ensures that each component is uniformly dispersed in the system, preventing performance defects caused by agglomeration. 3. By precisely controlling process parameters such as drying temperature, drying time, mixing temperature, mixing time, screw speed, and segmented temperature control, this invention achieves fine regulation of material properties, ensuring the stability and consistency of product quality and providing strong support for large-scale industrial production. 4. This invention uses polyethylene (PE) as the matrix and, through directional modification with degradation triggers and synergistic enhancement with trace functional additives, for the first time endows polyethylene with controllable anaerobic biodegradability while retaining its excellent processability and mechanical properties. This breaks through the long-standing technical bottleneck in the field of sports equipment where performance and environmental protection cannot be achieved simultaneously, and provides an industrially feasible path for the green upgrading of sports equipment. Attached Figure Description

[0010] Figure 1 Microscopic images of pickle samples tested before and after incubation conditions according to the present invention; Figure 2 This is a comparison graph showing the biogas production of the positive control and the inoculum in this invention; Figure 3 This is a comparative diagram showing the production of biogas from pickle samples and the control of inoculum in this invention; Figure 4 This is a percentage biodegradation graph of the positive control, determined by the carbon conversion rate of cellulose to carbon in the gas phase in this invention. Figure 5 This is a graph showing the percentage of carbon in the pickle ball sample material converted into carbon in the gas phase, based on the biodegradation rate of this invention. Detailed Implementation

[0011] The following examples are used to further illustrate the content of the present invention and do not limit the application of the present invention (all numbers below are parts by weight). Example 1:

[0012] First, 40 parts of mixed low-density polyethylene, 50 parts of linear low-density polyethylene, 5 parts of ethylene-vinyl acetate copolymer, and 5 parts of corn starch were dried at 75-85℃ for 3-5 hours, controlling the moisture content to ≤0.5%. Next, grind 0.1 parts of maleic anhydride-grafted polyethylene, 2 parts of silane coupling agent KH570, 2 parts of zinc stearate and calcium stearate mixture through a 150-250 mesh sieve for later use. Next, the dried mixed low-density polyethylene, linear low-density polyethylene, ethylene-vinyl acetate copolymer and corn starch are added to a high-speed mixer and heated to 50-70°C. Then, the prepared maleic anhydride grafted polyethylene, silane coupling agent KH570, zinc stearate and calcium stearate mixture are added in sequence and mixed for 3-7 minutes. Then, 1 part of ferrous sulfate, sodium citrate and Tween-80 mixture, 2 parts of polybutylene succinate and 0.01 parts of fluoroelastomer are added and the mixture is continued to be mixed at 700-900 rpm for 8-12 minutes to obtain the mixture. Then, the mixture is transferred to a twin-screw extruder with segmented temperature control: zone 1 temperature is 150-160℃; zone 2 temperature is 160-170℃; zone 3 temperature is 170-180℃; and the die temperature is 175-185℃. After melt extrusion at a screw speed of 200-300 rpm, the mixture is water-cooled or air-cooled and pelletized to obtain modified granules with a particle size of 3 mm, which are modified polyethylene anaerobic biodegradable materials. Finally, the modified particles are ground into a fine powder of 60-80 mesh, and the colorant (pigment) is added and stirred for 3-8 minutes to obtain a mixed color powder. The obtained mixed color powder is then added in portions of 29 grams to a single rotational molding die on a rotational molding machine (to improve production efficiency, the rotational molding machine should have at least 20-40 rotational molding dies). The rotational molding is carried out at 320-340°C for 15-25 minutes under nitrogen protection. Then, the rotational molding die is cooled with tap water at a frequency of 3 times every 10 seconds. After cooling to room temperature, the die is opened to obtain a sphere. After the sphere has been stationary for 24 hours, 35-45 holes with a diameter of 6-8 mm are evenly punched on its surface. After punching, a peak ball is obtained.

[0013] Pickball samples were extracted and tested using the ASTM D5511-18 standard test method (for determining the anaerobic biodegradability of plastic materials under solid anaerobic digestion conditions), which aims to determine the percentage of carbon in the sample converted into gaseous carbon under conditions similar to those of anaerobic digesters treating municipal solid waste with high solids content.

[0014] The testing method for picket ball samples involves removing a sufficient amount of inoculum (approximately 15 kg) from the post-fermentation container and carefully and uniformly mixing it by hand to obtain a homogeneous culture medium. Three blanks (inoculum only), a positive control (thin-layer chromatography cellulose), a negative control (optional), and the test substance being evaluated are tested.

[0015] Manually mix 1000 g of wet weight (at least 20% solids) of inoculum in a small container for 2 to 3 minutes, then add 15 to 100 g of the test substance or control with volatile solids. For three blanks containing only inoculum, mix 1000 g of the same inoculum in a small container for 2 to 3 minutes with the same intensity as the other containers containing the test substance or control. Accurately determine the weight of the inoculum and test substance added to each individual Ellenmore flask. Add the mixture to a 2-liter wide-mouth Ellenmore flask, gently and evenly spreading and compacting the material to achieve a uniform density. After placing the Erlenmore flask in the incubator, connect the gas collection device. Incubate the Erlenmore flask at 52°C in darkness or diffused light to establish thermophilic conditions, and continue incubation until no net gas is produced from the positive control (reference substance) and test substance reactors for at least five days. Control the pH of the water used to measure biogas production to be below 2 by adding HCl (hydrogen chloride).

[0016] The presence of gas in the positive control and gas collector indicates that the inoculum is viable, and gas displacement was observed in both the positive control and the test samples. ASTM D5511 specifies that for a test to be considered valid, the positive control must reach 70% within 30 days, and the deviation between repeated tests must be less than 20% of the mean. The biogas volume was measured in the gas sampling bag, and the gas displacement observed after 45 days is shown in the table below: ; As shown in the table above, the positive control showed 84.76% within 15 days, and the average difference between repeated experiments was less than 20%.

[0017] like Figure 1 As shown, Figures A and B represent the anaerobic biodegradation process of unexposed test sample pickles, while Figures C and D represent the anaerobic biodegradation process of exposed test sample pickles (Note: Due to lighting and different monitors, the sample color may differ slightly from the image).

[0018] The percentage biodegradation rates for the positive control and test samples were calculated by measuring the cumulative carbon dioxide and methane production from each flask, which was obtained by subtracting the carbon dioxide and methane release from the blank sample at the end of the 45-day test. The calculations were based on the total organic carbon content obtained from the positive control and test samples, and the percentage of cellulose biodegradation rate for the test samples compared to the positive control is shown in the table below: ; As shown in the table above and the gas displacement table observed after 45 days, biodegradation occurred in the pickle ball samples. After 45 days of cultivation, the biodegradation level of the positive control was 96.57%, while that of the pickle ball samples was 7.50%.

[0019] The biodegradation of pickle ball samples is based on the determination of the conversion of carbon in the test material into gaseous carbon (CH4 and CO), and can also be performed in... Figure 2 , Figure 3 , Figure 4 and Figure 5 This was observed in [the context]. Example 2:

[0020] The modified polyethylene anaerobic biodegradable material prepared in this embodiment and the pickles made from the modified polyethylene anaerobic biodegradable material are the same as those in Example 1, except for the selection of raw materials and the amount of formulation. Specifically, 40 parts of mixed low-density polyethylene, 50 parts of linear low-density polyethylene, 10 parts of ethylene-vinyl acetate copolymer, 10 parts of corn starch, 4 parts of plant-based starch, 1.5 parts of ferrous sulfate, a mixture of sodium citrate and Tween-80, 0.4 parts of ethylene-acrylic acid copolymer, 0.02 parts of fluoroelastomer, 6 parts of silane coupling agent KH570, and 2 parts of a mixture of polyethylene wax and zinc stearate are used as the components for making the modified polyethylene anaerobic biodegradable material. Example 3:

[0021] The modified polyethylene anaerobic biodegradable material prepared in this embodiment and the pickles made from the modified polyethylene anaerobic biodegradable material are the same as those in Example 1, except for the selection of raw materials and the amount of formulation. Specifically, 40 parts of mixed low-density polyethylene, 50 parts of linear low-density polyethylene, 12 parts of ethylene-vinyl acetate copolymer, 12 parts of corn starch, 5 parts of ethylene carbonate oxide, 2 parts of ferrous sulfate, a mixture of sodium citrate and Tween-80, 0.5 parts of ethylene-methyl acrylate copolymer, 0.03 parts of fluoroelastomer, 5 parts of silane coupling agent KH570, 2 parts of polyethylene wax, and a mixture of zinc stearate and calcium stearate are used as components for making the modified polyethylene anaerobic biodegradable material.

[0022] The pickles prepared in Examples 1-3 were tested using an impact tester. The test duration was set to 48 hours, with 2500 impacts and a ball speed of 80 km / h. After more than 2500 impacts, the surface of the pickles showed no damage, cracking, or stringing. The bounce consistency test showed a bounce of 76.2–86.4 cm after a free fall of 198 cm. The mass loss rate of the pickles prepared by this invention was 35–45% after 180 days of landfill. Therefore, the pickles prepared using modified polyethylene anaerobic biodegradable material of this invention not only ensure the material's performance but also achieve rapid degradation in an anaerobic environment; significantly improving impact resistance and durability, helping to extend the service life of sports equipment such as pickles, and reducing resource waste and environmental pollution caused by frequent replacements.

Claims

1. A modified polyethylene anaerobic biodegradable material, characterized in that, It comprises the following components in parts by weight: 70-100 parts polyethylene, 0-5 parts probiotic anaerobic degradable plastic masterbatch, 0-5 parts anaerobic enzyme promoter, 5-15 parts ethylene-vinyl acetate copolymer, 1-15 parts corn starch, 0.1-5 parts compatibilizer, 0.01-0.06 parts fluoroelastomer, 2-8 parts coupling agent, and 1-5 parts dispersant.

2. The modified polyethylene anaerobic biodegradable material according to claim 1, characterized in that, The polyethylene comprises the following components in parts by weight: 30 to 50 parts of blended low-density polyethylene and 40 to 50 parts of linear low-density polyethylene.

3. The modified polyethylene anaerobic biodegradable material according to claim 1, characterized in that, The probiotic-type anaerobic degradable plastic masterbatch is one of plant-based starch, polybutylene succinate, and ethylene carbonate oxide.

4. The modified polyethylene anaerobic biodegradable material according to claim 1, characterized in that, The anaerobic enzyme promoter is a mixture of ferrous sulfate, sodium citrate, and Tween-80.

5. The modified polyethylene anaerobic biodegradable material according to claim 1, characterized in that, The compatibilizer is one of maleic anhydride-grafted polyethylene, ethylene-acrylic acid copolymer, and ethylene-methyl acrylate copolymer.

6. The modified polyethylene anaerobic biodegradable material according to claim 1, characterized in that, The coupling agent is a silane coupling agent, KH570.

7. The modified polyethylene anaerobic biodegradable material according to claim 1, characterized in that, The dispersant is a mixture of several of the following: polyethylene wax, zinc stearate, and calcium stearate.

8. A method for preparing a modified polyethylene anaerobic biodegradable material, characterized in that, The specific steps are as follows: S1. Dry the formulated amounts of polyethylene, ethylene-vinyl acetate copolymer, and corn starch at 75–85°C for 3–5 hours, controlling the moisture content to ≤0.5%; S2. Grind the compatibilizer, coupling agent and dispersant separately and pass them through a 150-250 mesh sieve for later use; S3. Add the dried polyethylene, ethylene-vinyl acetate copolymer and corn starch to a high-speed mixer, heat to 50-70°C, add compatibilizer, coupling agent and dispersant in sequence, mix for 3-7 minutes, add probiotic anaerobic degradable plastic masterbatch, anaerobic enzyme promoter and fluoroelastomer, and continue to mix at 700-900 rpm for 8-12 minutes to obtain the mixture. S4. Transfer the mixture into a twin-screw extruder, control the temperature in stages, melt and extrude at a screw speed of 200-300 rpm, and then cut into pellets by water cooling or air cooling to obtain modified granules with a particle size of 3-5 mm, which are modified polyethylene anaerobic biodegradable materials.

9. The method for preparing a modified polyethylene anaerobic biodegradable material according to claim 8, characterized in that, In S4, the temperature is controlled in sections: Zone 1 temperature is 150-160℃; Zone 2 temperature is 160-170℃; Zone 3 temperature is 170-180℃; and the die head temperature is 175-185℃.

10. The application of a modified polyethylene anaerobic biodegradable material as described in any one of claims 1-7 in rotomolded pickles.

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