A winding film recycling linear polyethylene modified material and its lawn and preparation method

Abstract

The application discloses a winding film recycling linear polyethylene modified material and a lawn and a preparation method thereof, and relates to the technical fields of regenerated plastic modification and artificial lawn production. The winding film recycling linear polyethylene modified material is prepared from the following raw materials in parts by weight: 80-95 parts of waste linear polyethylene winding film, 5-20 parts of metallocene polyethylene and 0.5-1 part of an antioxidant. The metallocene polyethylene has excellent toughening, compatibility and weather resistance modification effects, so that the mechanical strength, the anti-aging performance and the forming processability of the recycled linear polyethylene material are greatly improved, the prepared artificial lawn has high tensile strength, good resilience, good ultraviolet aging resistance and long service life, meanwhile, the resource-efficient utilization of the waste winding film is realized, the production cost of the artificial lawn is reduced, the application is green and environment-friendly, and has a good industrial application prospect.

Description

Technical Field

[0001] This invention relates to the field of recycled plastic modification and artificial turf production technology, specifically to a modified linear polyethylene material made from recycled stretch film, its turf, and a preparation method thereof. Background Technology

[0002] With increasingly stringent low-carbon regulations governing the entire lifecycle of polymer materials, artificial turf, a widely used outdoor rubber and plastic product in municipal, sports, and school settings, faces core development directions in low-carbon transformation, formula reduction, and solid waste resource utilization. Currently, most artificial turf fibers on the market are made from virgin polyethylene raw materials. Virgin polyethylene relies on energy-intensive processes such as crude oil cracking and polymerization, resulting in carbon emissions of 2.5-3.2 tons of CO2 per ton. The carbon footprint of raw materials accounts for over 70% of the overall carbon emissions of turf, highlighting the problems of high fossil resource consumption and high carbon emissions. Simultaneously, traditional turf formulations heavily rely on virgin resins and high-content weather-resistant additives, leading to significant material redundancy, high production costs, and a lack of core low-carbon reduction technologies. This makes it difficult to meet the market's urgent needs for green building material certification, carbon footprint traceability, and large-scale low-carbon production.

[0003] The volume of industrial waste polyethylene stretch film is enormous. Traditional landfilling, incineration, and low-end recycling methods easily lead to environmental problems such as white pollution and greenhouse gas emissions. Particularly noteworthy is that during conventional high-temperature granulation processing of waste stretch film, the polyethylene molecular chains are prone to secondary breakage and thermo-oxidative degradation, resulting in severe damage to the molecular structure. This leads to disordered melt flow, poor processing stability, and problems such as carbon buildup in equipment, die scaling, and high defect rates in finished products. The industry can only use it in low proportions, resulting in extremely low resource utilization. Compared to virgin polyethylene, recycled stretch film can achieve 60%-75% carbon emission reduction and save a significant amount of crude oil resources, demonstrating significant low-carbon circular value. However, recycled materials generally suffer from defects such as high brittleness, insufficient mechanical properties, poor weather resistance, and weak interfacial adhesion. When used in large proportions in artificial turf production, the finished product performance fails to meet standards, greatly limiting its large-scale promotion and application.

[0004] Existing artificial turf modification technologies mostly focus on optimizing new material formulations, with limited research on low-carbon adaptation modification technologies for GRS wrapping film recycled materials. They lack core processes such as molecular chain repair, low-temperature chain protection, and precise toughening, making it impossible to meet the industry's demands for high performance, low carbon emissions, and low cost.

[0005] Therefore, how to develop a method for recycling linear polyethylene modified material using a stretch film, as well as its turf and preparation method, is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0006] In view of this, the present invention provides a modified linear polyethylene filament for recycling using a stretch film, the turf thereof, and a method for its preparation.

[0007] A modified linear polyethylene stretch film material made from recycled materials is prepared by comprising the following parts by weight of raw materials:

[0008] 80-95 parts of waste linear polyethylene stretch film, 5-20 parts of metallocene polyethylene, and 0.5-1 part of antioxidant; The density of the metallocene polyethylene is 0.910-0.927 g / cm³. 3 The test conditions were 190℃, 2.16kg, and melt flow rate of 0.5-5g / 10min; The antioxidants include hindered phenolic antioxidants and / or phosphite antioxidants.

[0009] Furthermore, the density of the metallocene polyethylene is 0.912-0.915 g / cm³. 3 The test conditions were 190℃, 2.16kg, and melt flow rate of 1-2g / 10min.

[0010] The beneficial effects of adopting the above-mentioned further technical solutions are as follows: the 1-2 g / 10 min melt flow rate is close to that of virgin polyethylene 7042, exhibiting the best compatibility. Simultaneously, when the melt flow rate exceeds 2, the relative molecular weight distribution widens, and the overall tensile strength and impact strength of the material decrease significantly. Metallocene polyethylene within this parameter range can be precisely adapted to recycled linear polyethylene matrices, achieving excellent toughening, compatibility, and molecular chain repair effects.

[0011] Furthermore, the antioxidant is one or more of antioxidant 1010, antioxidant 168, antioxidant 618 or antioxidant 1098.

[0012] The beneficial effects of adopting the above-mentioned further technical solutions are: it can effectively inhibit the thermo-oxidative degradation of recycled materials during secondary processing, and avoid molecular chain breakage and carbon buildup in equipment.

[0013] This invention also provides a method for preparing recycled linear polyethylene modified material from stretch film, comprising the following steps: (1) Weigh each raw material according to the described method for recycling linear polyethylene modified material from stretch film; (2) Pretreatment: The waste linear polyethylene wrapping film is crushed, washed, dried, melt-granulated, and filtered to remove impurities; (3) Modified granulation: The pretreated waste linear polyethylene wrapping film, metallocene polyethylene and antioxidant are first melt-premixed by a single screw, then fed into a twin screw for secondary low-temperature plasticization, water-cooled and granulated, and then sealed and dried at constant temperature to remove odor, to obtain the modified linear polyethylene material of the wrapping film.

[0014] Furthermore, in step (2), the purity of the waste linear polyethylene wrapping film is controlled to be ≥98%.

[0015] Furthermore, in step (3), the single-screw melt premixing temperature is 180-220℃, the twin-screw secondary low-temperature plasticizing temperature is 150-180℃, the constant temperature drying temperature is 70-80℃, the constant temperature drying time is 4-8h, and the preferred constant temperature drying time is 7-8h.

[0016] This invention also provides an artificial turf prepared using recycled linear polyethylene modified material through a stretch film, comprising the following raw materials in parts by weight: The stretch film contains 30-52 parts of recycled linear polyethylene modified material, 40-60 parts of virgin polyethylene material, 8-10 parts of color masterbatch, and 0.5-2 parts of processing stabilizing agent. The processing stabilizing agent includes one or more of hindered amine high molecular weight light stabilizers, PPA additives, or erucamide.

[0017] The beneficial effects of this invention are that the processing stabilizing agents achieve the functions of weather resistance and anti-aging, improve processing fluidity, and reduce carbon buildup at the die opening, thus meeting the molding and production needs of recycled straw.

[0018] This invention also provides a method for preparing artificial turf using recycled linear polyethylene modified material through stretch film, comprising the following steps: 1) Weigh each raw material according to the method described above for preparing artificial turf using recycled linear polyethylene modified material through stretch film; 2) Fiber drawing: The wrapped film is drawn into fibers using a single screw extruder by recycling modified linear polyethylene material, virgin polyethylene material, masterbatch and processing stabilizer. 3) Finishing: Twisting the grass fibers, tufting, and applying adhesive backing to create the finished lawn.

[0019] Furthermore, in step 2), the single screw wire drawing controls the stretching to 5-6, the retraction to 10%-20%, and the water bath to 90-95℃.

[0020] Compared with the prior art, the present invention has the following outstanding advantages: This invention uses recycled industrial waste PE stretch film as the main modified material to achieve high-value utilization of solid waste resources, avoiding white pollution and carbon emission problems caused by landfilling and incineration of the stretch film after it is discarded; the recycled material can achieve carbon emission reduction compared with virgin PE, and the finished product meets the requirements of GRS recycled product traceability, green building material certification, etc., which significantly reduces the carbon footprint of artificial turf throughout its entire life cycle and reduces the consumption of fossil raw materials such as crude oil; By using metallocene polyethylene with specific density and melt flow rate, the broken molecular chains of waste PE are precisely repaired, the matrix is ​​toughened, and the interface is compatible. Combined with a compounded antioxidant system, the thermo-oxidative aging of recycled materials during secondary processing is inhibited. The resulting modified material has significantly improved tensile and impact properties. Ultimately, the tensile strength and elongation at break of the artificial grass fibers are comparable to those of virgin PE raw materials. The LISPORT turf has significantly better wear resistance, tufting force of grass fibers, and single-fiber pull-out force than ordinary unmodified recycled materials. The grass fibers also have improved resistance to ultraviolet aging, resulting in a significantly extended service life in outdoor applications.

[0021] Optimizing processing stability and significantly improving continuous production efficiency: The hindered phenol combined with phosphite in an antioxidant system effectively increases the thermal weight loss temperature of the modified material, inhibits the small molecule cracking and carbonization during extrusion, and reduces secondary molecular chain breakage by combining it with a two-stage segmented low-temperature melting process. The measured cleaning interval of the wire drawing machine die head has been extended from more than ten hours to more than 40 hours, which greatly reduces the frequency of downtime for die cleaning, reduces production losses and product defect rate; the addition of hindered amine light stabilizer, PPA, and erucamide compound processing aids further improves melt flowability and eliminates die head fouling.

[0022] To address the odor defect of recycled materials and improve the user experience: The modified granules are dried at a closed, constant temperature of 70-80℃ for a long time to remove odors, thus removing low-molecular-weight volatile impurities from the recycled materials. Odor rating verification shows that the odor level of the modified raw materials is significantly reduced after drying, solving the industry-wide problem of pungent odor in traditional stretch film recycled granules.

[0023] The addition of metallocene polyethylene increases the pull-out force of the entire turf by 5-10N and the pull-out force of a single blade by 2-3N, and improves the abrasion resistance of the grass fibers by 5000-10000 revolutions.

[0024] Addressing the technological gaps and pain points in this industry, this invention uses GRS-certified recycled stretch film as the core material, introduces precise modification with metallocene polyethylene, and combines it with a low-temperature granulation chain-protecting system, a dedicated gradient-curing backing adhesive, and an additive formulation system to effectively repair molecular chain damage in the recycled material and solve problems such as carbon buildup during processing and performance degradation. This invention enables a high proportion of recycled materials to replace virgin plastics, establishes a fully traceable low-carbon production system, significantly reduces the carbon footprint of the product throughout its entire life cycle, and achieves GRS compliance, low-carbon reduction, superior performance, and controllable cost control for industrialization while ensuring the mechanical properties and weather resistance stability of the turf, aligning with the green and circular development trend of artificial turf.

[0025] This invention aims to solve the technical problems of molecular chain degradation, poor processing performance, easy carbon accumulation, and low blending ratio in the secondary processing of existing recycled waste polyethylene stretch film. It overcomes the industry pain points of traditional recycled artificial turf, such as weak mechanical properties, insufficient weather resistance, redundant additives, high carbon footprint, and inability to meet GRS green certification requirements. This invention optimizes the modified material formulation system, introduces metallocene polyethylene with specific parameters for toughening and compatibility modification, and combines it with a two-stage low-temperature granulation chain-protecting process and a precise fiber drawing and forming process. This achieves a high proportion of recycled stretch film material replacing virgin polyethylene raw materials. While simplifying additives, reducing production costs and carbon emissions, it also ensures that the performance of artificial turf fibers and finished turf reaches the level of virgin materials, realizing high-value utilization of solid waste resources and industrialized low-carbon turf production.

[0026] This invention relates to a modified linear polyethylene material from recycled waste polyethylene stretch film. Using recycled polyethylene resin from waste polyethylene stretch film as the base material, and combining it with metallocene polyethylene with specific parameters as the core modifying agent, along with a suitable antioxidant system, the material is melt-blended and modified for use in artificial turf production, achieving a high proportion of recycled materials. This effectively solves the defects of traditional recycled polyethylene materials, such as high aging brittleness, poor weather resistance, insufficient processing stability, and weak mechanical properties of the turf fibers. This invention utilizes the excellent toughening, compatibility, and weather-resistant modification effects of metallocene polyethylene to significantly improve the mechanical strength, anti-aging properties, and molding processability of recycled linear polyethylene materials. The resulting artificial turf fibers have high tensile strength, good resilience, resistance to UV aging, and a long service life. Simultaneously, it achieves efficient resource utilization of waste stretch film, reduces the production cost of artificial turf, is environmentally friendly, and has good prospects for industrial application. Detailed Implementation

[0027] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] The virgin polyethylene used in the embodiments and comparative examples of this invention meets the following standard: density of 0.918 g / cm³. 3 Notched impact strength of cantilever beam: 45.2 kJ / m 2 Tensile strength 15.4 MPa, elongation at break 646%.

[0029] The performance parameters of the waste linear polyethylene stretch film of this invention are not limited. The preparation steps and parameters of the modified linear polyethylene material from the recycled stretch film in the embodiments of this invention are determined according to the following polyethylene virgin material standards, and must meet the following range: density of 0.916-0.922 g / cm³. 3Notched impact strength of cantilever beam: 47.2-59.7 kJ / m 2 Tensile strength 15.4-20.2 MPa, elongation at break 524%-646%.

[0030] Example 1 A method for preparing recycled linear polyethylene modified material from stretch film includes the following steps: (1) Weigh the raw materials: 80 kg of waste linear polyethylene stretch film, 20 kg of metallocene polyethylene, and 0.5 kg of antioxidant; The density of metallocene polyethylene is 0.912 g / cm³. 3 The test conditions were 190℃, 2.16kg, and melt flow rate of 2g / 10min.

[0031] The antioxidants are antioxidant 1010 and antioxidant 168 in a mass ratio of 2:1; (2) Pretreatment: The waste linear polyethylene wrapping film is crushed, washed, dried, melt-granulated and filtered to remove impurities. The purity of the waste linear polyethylene wrapping film is 98%. (3) Modified granulation: The pretreated waste linear polyethylene wrapping film, metallocene polyethylene and antioxidant are first melt-premixed by a 180 single screw, then fed into a twin screw for secondary low-temperature plasticization at 150℃, water-cooled and granulated, and then sealed and dried at 80℃ for 4 hours to remove odor, to obtain modified linear polyethylene recycled wrapping film.

[0032] Example 2 A method for preparing recycled linear polyethylene modified material from stretch film includes the following steps: (1) Weigh the raw materials: 85 kg of waste linear polyethylene stretch film, 15 kg of metallocene polyethylene, and 0.7 kg of antioxidant; The density of metallocene polyethylene is 0.912 g / cm³. 3 The test conditions were 190℃, 2.16kg, and melt flow rate of 5g / 10min.

[0033] The antioxidant is antioxidant 618; (2) Pretreatment: The waste linear polyethylene wrapping film is crushed, washed, dried, melt-granulated, filtered and impurities removed. The purity of the waste linear polyethylene wrapping film is 98%. (3) Modified granulation: The pretreated waste linear polyethylene wrapping film, metallocene polyethylene and antioxidant are first melt-premixed at 200℃ by a single screw, and then sent to a twin screw for secondary low-temperature plasticization at 170℃. After water cooling and pelletizing, the mixture is sealed and dried at 80℃ for 6 hours to remove odor, thus obtaining modified linear polyethylene recycled wrapping film.

[0034] Example 3 A method for preparing recycled linear polyethylene modified material from stretch film includes the following steps: (1) Weigh the raw materials: 90 kg of waste linear polyethylene stretch film, 10 kg of metallocene polyethylene, and 0.8 kg of antioxidant; The density of metallocene polyethylene is 0.912 g / cm³. 3 The test conditions were 190℃, 2.16kg, and melt flow rate of 1g / 10min.

[0035] The antioxidant is antioxidant 1098; (2) Pretreatment: The waste linear polyethylene wrapping film is crushed, washed, dried, melt-granulated, filtered and impurities removed. The purity of the waste linear polyethylene wrapping film is 99%. (3) Modified granulation: The pretreated waste linear polyethylene wrapping film, metallocene polyethylene and antioxidant are first melt-premixed at 220℃ by a single screw, and then sent to a twin screw for secondary low-temperature plasticization at 180℃. After water cooling and pelletizing, the mixture is sealed and dried at a constant temperature of 70-℃ for 8 hours to remove odor, thus obtaining modified linear polyethylene recycled wrapping film.

[0036] Example 4 A method for preparing recycled linear polyethylene modified material from stretch film includes the following steps: (1) Weigh the raw materials: 92 kg of waste linear polyethylene stretch film, 8 kg of metallocene polyethylene, and 0.9 kg of antioxidant; The density of metallocene polyethylene is 0.912 g / cm³. 3 The test conditions were 190℃, 2.16kg, and melt flow rate of 2g / 10min.

[0037] The antioxidants are antioxidant 1010 and antioxidant 618 in a mass ratio of 1:1; (2) Pretreatment: The waste linear polyethylene wrapping film is crushed, washed, dried, melt-granulated, filtered and impurities removed. The purity of the waste linear polyethylene wrapping film is 98%. (3) Modified granulation: The pretreated waste linear polyethylene wrapping film, metallocene polyethylene and antioxidant are first melt-premixed at 200℃ by a single screw, and then sent to a twin screw for secondary low-temperature plasticization at 160℃. After water cooling and pelletizing, the mixture is sealed and dried at 70℃ for 6 hours to remove odor, thus obtaining modified linear polyethylene recycled wrapping film.

[0038] Example 5 A method for preparing recycled linear polyethylene modified material from stretch film includes the following steps: (1) Weigh the raw materials: 95 kg of waste linear polyethylene stretch film, 5 kg of metallocene polyethylene, and 1 kg of antioxidant; The density of metallocene polyethylene is 0.912 g / cm³. 3The test conditions were 190℃, 2.16kg, and melt flow rate of 2g / 10min.

[0039] The antioxidants are antioxidant 168 and antioxidant 1098 in a mass ratio of 2:1; (2) Pretreatment: The waste linear polyethylene wrapping film is crushed, washed, dried, melt-granulated, filtered and impurities removed. The purity of the waste linear polyethylene wrapping film is 98%. (3) Modified granulation: The pretreated waste linear polyethylene wrapping film, metallocene polyethylene and antioxidant are first melt-premixed at 220℃ by a single screw, and then sent to a twin screw for secondary low-temperature plasticization at 180℃. After water cooling and pelletizing, the mixture is sealed and dried at 80℃ for 8 hours to remove odor, thus obtaining modified linear polyethylene recycled wrapping film.

[0040] Example 6 A method for preparing recycled linear polyethylene modified material from stretch film includes the following steps: (1) Weigh the raw materials: 95 kg of waste linear polyethylene stretch film, 5 kg of metallocene polyethylene, and 1 kg of antioxidant; The density of metallocene polyethylene is 0.910 g / cm³. 3 The test conditions were 190℃, 2.16kg, and melt flow rate of 2g / 10min.

[0041] The antioxidants are antioxidant 168 and antioxidant 1098 in a mass ratio of 1:1; (2) Pretreatment: The waste linear polyethylene wrapping film is crushed, washed, dried, melt-granulated, filtered and impurities removed. The purity of the waste linear polyethylene wrapping film is 98%. (3) Modified granulation: The pretreated waste linear polyethylene wrapping film, metallocene polyethylene and antioxidant are first melt-premixed at 200℃ by a single screw, and then sent to a twin screw for secondary low-temperature plasticization at 160℃. After water cooling and pelletizing, the mixture is sealed and dried at 70℃ for 6 hours to remove odor, thus obtaining modified linear polyethylene recycled wrapping film.

[0042] Example 7 A method for preparing recycled linear polyethylene modified material from stretch film includes the following steps: (1) Weigh the raw materials: 95 kg of waste linear polyethylene stretch film, 5 kg of metallocene polyethylene, and 1 kg of antioxidant; The density of metallocene polyethylene is 0.915 g / cm³. 3 The test conditions were 190℃, 2.16kg, and melt flow rate of 2g / 10min.

[0043] The antioxidants are antioxidant 168 and antioxidant 1098 in a mass ratio of 2:1; (2) Pretreatment: The waste linear polyethylene wrapping film is crushed, washed, dried, melt-granulated, filtered and impurities removed. The purity of the waste linear polyethylene wrapping film is 98%. (3) Modified granulation: The pretreated waste linear polyethylene wrapping film, metallocene polyethylene and antioxidant are first melt-premixed at 200℃ by a single screw, and then sent to a twin screw for secondary low-temperature plasticization at 160℃. After water cooling and pelletizing, the mixture is sealed and dried at 70℃ for 6 hours to remove odor, thus obtaining modified linear polyethylene recycled wrapping film.

[0044] Example 8 A method for preparing recycled linear polyethylene modified material from stretch film includes the following steps: (1) Weigh the raw materials: 95 kg of waste linear polyethylene stretch film, 5 kg of metallocene polyethylene, and 1 kg of antioxidant; The density of metallocene polyethylene is 0.915 g / cm³. 3 The test conditions were 190℃, 2.16kg, and melt flow rate of 2g / 10min.

[0045] The antioxidants are antioxidant 168 and antioxidant 1098 in a mass ratio of 2:1; (2) Pretreatment: The waste linear polyethylene wrapping film is crushed, washed, dried, melt-granulated, filtered and impurities removed. The purity of the waste linear polyethylene wrapping film is 98%. (3) Modified granulation: The pretreated waste linear polyethylene wrapping film, metallocene polyethylene and antioxidant are first melt-premixed at 200℃ by a single screw, and then sent to a twin screw for secondary low-temperature plasticization at 160℃. After water cooling and pelletizing, the mixture is sealed and dried at 70℃ for 6 hours to remove odor, thus obtaining modified linear polyethylene recycled wrapping film.

[0046] Example 9 A method for preparing recycled linear polyethylene modified material from stretch film includes the following steps: (1) Weigh the raw materials: 95 kg of waste linear polyethylene stretch film, 5 kg of metallocene polyethylene, and 1 kg of antioxidant; The density of metallocene polyethylene is 0.927 g / cm³. 3 The test conditions were 190℃, 2.16kg, and melt flow rate of 2g / 10min.

[0047] The antioxidants are antioxidant 168 and antioxidant 1098 in a mass ratio of 2:1; (2) Pretreatment: The waste linear polyethylene wrapping film is crushed, washed, dried, melt-granulated, filtered and impurities removed. The purity of the waste linear polyethylene wrapping film is 98%. (3) Modified granulation: The pretreated waste linear polyethylene wrapping film, metallocene polyethylene and antioxidant are first melt-premixed at 200℃ by a single screw, and then sent to a twin screw for secondary low-temperature plasticization at 160℃. After water cooling and pelletizing, the mixture is sealed and dried at 70℃ for 6 hours to remove odor, thus obtaining modified linear polyethylene recycled wrapping film.

[0048] Example 10 A method for preparing recycled linear polyethylene modified material from stretch film includes the following steps: (1) Weigh the raw materials: 88 kg of waste linear polyethylene stretch film, 12 kg of metallocene polyethylene, and 0.8 kg of antioxidant; The density of metallocene polyethylene is 0.915 g / cm³. 3 The test conditions were 190℃, 2.16kg, and melt flow rate of 2g / 10min.

[0049] The antioxidant is antioxidant 618; (2) Pretreatment: The waste linear polyethylene wrapping film is crushed, washed, dried, melt-granulated, filtered and impurities removed. The purity of the waste linear polyethylene wrapping film is 98%. (3) Modified granulation: The pretreated waste linear polyethylene wrapping film, metallocene polyethylene and antioxidant are first melt-premixed at 200℃ by a single screw, and then sent to a twin screw for secondary low-temperature plasticization at 160℃. After water cooling and pelletizing, the mixture is sealed and dried at 70℃ for 6 hours to remove odor, thus obtaining modified linear polyethylene recycled wrapping film.

[0050] Example 11 A method for preparing recycled linear polyethylene modified material from stretch film includes the following steps: (1) Weigh the raw materials: 91 kg of waste linear polyethylene stretch film, 9 kg of metallocene polyethylene, and 0.9 kg of antioxidant; The density of metallocene polyethylene is 0.915 g / cm³. 3 The test conditions were 190℃, 2.16kg, and melt flow rate of 2g / 10min.

[0051] The antioxidant is antioxidant 1098; (2) Pretreatment: The waste linear polyethylene wrapping film is crushed, washed, dried, melt-granulated, filtered and impurities removed. The purity of the waste linear polyethylene wrapping film is 98%. (3) Modified granulation: The pretreated waste linear polyethylene wrapping film, metallocene polyethylene and antioxidant are first melt-premixed at 200℃ by a single screw, and then sent to a twin screw for secondary low-temperature plasticization at 160℃. After water cooling and pelletizing, the mixture is sealed and dried at 70℃ for 6 hours to remove odor, thus obtaining modified linear polyethylene recycled wrapping film.

[0052] Example 12 A method for preparing recycled linear polyethylene modified material from stretch film includes the following steps: (1) Weigh the raw materials: 86 kg of waste linear polyethylene stretch film, 14 kg of metallocene polyethylene, and 0.7 kg of antioxidant; The density of metallocene polyethylene is 0.915 g / cm³. 3 The test conditions were 190℃, 2.16kg, and melt flow rate of 2g / 10min.

[0053] The antioxidants are antioxidant 1010 and antioxidant 618 in a mass ratio of 2:1; (2) Pretreatment: The waste linear polyethylene wrapping film is crushed, washed, dried, melt-granulated, filtered and impurities removed. The purity of the waste linear polyethylene wrapping film is 98%. (3) Modified granulation: The pretreated waste linear polyethylene wrapping film, metallocene polyethylene and antioxidant are first melt-premixed at 200℃ by a single screw, and then sent to a twin screw for secondary low-temperature plasticization at 160℃. After water cooling and pelletizing, the mixture is sealed and dried at 70℃ for 1 hour to remove odor, thus obtaining modified linear polyethylene recycled wrapping film.

[0054] Comparative Example 1 A method for preparing recycled linear polyethylene modified material from stretch film includes the following steps: (1) Weigh out the raw materials: 100 kg of waste linear polyethylene stretch film and 0.7 kg of antioxidant; (2) Pretreatment: The waste linear polyethylene wrapping film is crushed, washed, dried, melt-granulated, filtered and impurities removed. The purity of the waste linear polyethylene wrapping film is 98%. (3) Modified granulation: The pretreated waste linear polyethylene wrapping film and antioxidant are first melt-premixed at 200℃ by a single screw, and then sent to a twin screw for secondary low-temperature plasticization at 160℃. After water cooling and pelletizing, the film is sealed and dried at 70℃ for 1 hour to remove odor, thus obtaining modified linear polyethylene recycled wrapping film.

[0055] Comparative Example 2 A method for preparing recycled linear polyethylene modified material from stretch film includes the following steps: (1) Weigh the raw materials: 60 kg of waste linear polyethylene stretch film, 40 kg of polyethylene, and 0.7 kg of antioxidant; The density of polyethylene is 0.918 g / cm³. 3 The test conditions were 190℃, 2.16kg, and melt flow rate of 2g / 10min.

[0056] The antioxidants are antioxidant 1010 and antioxidant 618 in a mass ratio of 2:1; (2) Pretreatment: The waste linear polyethylene wrapping film is crushed, washed, dried, melt-granulated, filtered and impurities removed. The purity of the waste linear polyethylene wrapping film is 98%. (3) Modified granulation: The pretreated waste linear polyethylene wrapping film, polyethylene and antioxidant are first melt-premixed at 200℃ by a single screw, and then sent to a twin screw for secondary low-temperature plasticization at 160℃. After water cooling and pelletizing, the mixture is sealed and dried at 70℃ for 1 hour to remove odor, thus obtaining modified linear polyethylene material recycled from the wrapping film.

[0057] Comparative Example 3 A method for preparing recycled linear polyethylene modified material from stretch film includes the following steps: (1) Weigh the raw materials: 100 kg of recycled linear polyethylene stretch film (containing a small amount of flat film and HDPE) and 0.7 kg of antioxidant; The antioxidants are antioxidant 1010 and antioxidant 618 in a mass ratio of 2:1; (2) Pretreatment: The waste linear polyethylene wrapping film is crushed, washed, dried, melt-granulated, filtered and impurities removed. The purity of the waste linear polyethylene wrapping film is 98%. (3) Modified granulation: The recycled linear polyethylene wrapping film (containing a small amount of flat film and HDPE) and antioxidant are first premixed by a single screw at 200℃, then fed into a twin screw for secondary low-temperature plasticization at 160℃, water-cooled and granulated, and then sealed and dried at 70℃ for 1 hour to remove odor, thus obtaining the modified recycled linear polyethylene wrapping film.

[0058] Performance test items and test standards (mechanical performance testing): Test conditions: All tests were conducted in accordance with the national standard for rubber and plastic testing, and the thermal decomposition temperature, density and core mechanical properties of the modified materials in each example and comparative example were tested respectively.

[0059] Test item description: 1. Thermal decomposition temperature: Tested using a thermogravimetric analyzer (TGA) under nitrogen atmosphere, with a heating rate of 10℃ / min; 2. Density: Tested according to GB / T 1033.1-2008; 3. Mechanical properties: Tensile strength and elongation at break are tested according to GB / T1040.2-2018.

[0060] Table 1 Mechanical properties of modified materials

[0061] By comparing the performance test data of each embodiment and comparative example, it is clear that the present invention, by modifying waste PE stretch film recycled material with specific physical properties of metallocene polyethylene and compound antioxidant system, can significantly repair the molecular chain damage of recycled material, comprehensively improve the mechanical properties of the material, and completely solve the defects of low mechanical strength, poor toughness and unstable performance of traditional recycled material, thus possessing significant technical advantages.

[0062] The metallocene modification of the core material demonstrates significant synergistic effects: Compared to Comparative Examples 1, 2, and 3 without added metallocene polyethylene, the notched impact strength and tensile strength of the cantilever beams in all embodiments of this invention are significantly improved. The impact strength increase ranges from 20% to 55%, and the tensile strength increase ranges from 15% to 50%, proving that metallocene polyethylene with defined parameters can effectively repair broken molecular chains in recycled waste stretch film, improve matrix compatibility and structural stability, and fundamentally improve the inherent defects of high brittleness and low strength in recycled materials. Even under conditions of high-proportion blending of recycled materials, the mechanical properties of the modified material still far exceed those of conventional unmodified recycled material systems.

[0063] Within the defined range of physical properties, the overall rigidity and toughness of the material are simultaneously optimized with the increase of the metallocene polyethylene content. Example 1, with a metallocene content of 20 kg, exhibits the best overall performance, achieving a tensile strength of 20.2 MPa and an impact strength of 59.7 kJ / m². 2 It provides high-performance support for high-load and high-weather-resistance artificial turf scenarios; the various embodiments with low addition of 5 parts metallocene still achieve significantly better performance than the comparative ratio, taking into account both low cost and high performance, adapting to the needs of large-scale general-purpose turf mass production, and having a wider range of formulation compatibility.

[0064] The density of metallocene polyethylene is controlled between 0.910 and 0.915 g / cm³. 3 When the melt flow index is 1-2 g / 10 min, it exhibits high compatibility with PE turf virgin material 7042, with optimal matrix-interface compatibility, significantly improved elongation at break, and substantial enhancement of grass fiber toughness and crack resistance; when the metallocene density increases to 0.927 g / cm³... 3 At that time, the material toughness decreased slightly, which verified the scientific validity and necessity of limiting the range of metallocene parameters in this invention and avoided the problem of unstable performance of general metallocene modification.

[0065] Evaluation of turf abrasion resistance and pull-out strength: Example 13 A method for preparing artificial turf using recycled linear polyethylene modified material through stretch film includes the following steps: 1) Weigh the raw materials: 60 kg of virgin polyethylene 7042, 40 kg of modified linear polyethylene recycled from the stretch film in Example 2, 10 kg of color masterbatch, and 2 kg of processing stabilizer (the mass ratio of virgin polyethylene 7042, erucamide, UV944 and polyethylene wax is 50:20:27:3, and virgin polyethylene 7042 is used as the carrier of the processing stabilizer). 2) Fiber drawing: The recycled linear polyethylene modified material, polyethylene virgin material, color masterbatch and processing stabilizer of the stretch film are drawn into fibers by a single screw. The single screw drawing is controlled with a draw length of 5.5, a heat setting shrinkage ratio of 80%, and a water bath temperature of 90 ℃. 3) Finishing: Twisting the grass fibers, tufting, and applying adhesive backing to create the finished lawn.

[0066] Lawn specifications: Grass fiber specifications: DTEX 10000 / 6F, row spacing: 5 / 8, stitch length: 15 stitches / 10cm, backing fabric: single layer + mesh, latex: carboxylated styrene-butadiene latex.

[0067] Example 14 A method for preparing artificial turf using recycled linear polyethylene modified material through stretch film includes the following steps: 1) Weigh the raw materials: 80 kg of virgin polyethylene 7042, 20 kg of modified linear polyethylene recycled from the stretch film in Example 2, 9 kg of color masterbatch, and 1 kg of processing stabilizing agent (the mass ratio of virgin polyethylene 7042, erucamide, UV944 and polyethylene wax is 50:20:27:3). 2) Fiber drawing: The recycled linear polyethylene modified material, polyethylene virgin material, color masterbatch and processing stabilizer of the stretch film are drawn into fibers by a single screw. The single screw drawing is controlled with a draw length of 5.5, a heat setting shrinkage ratio of 80%, and a water bath temperature of 95℃. 3) Finishing: Twisting the grass fibers, tufting, and applying adhesive backing to create the finished lawn.

[0068] Lawn specifications: Grass fiber specifications: DTEX 10000 / 6F, row spacing: 5 / 8, stitch length: 15 stitches / 10cm, backing fabric: single layer + mesh, latex: carboxylated styrene-butadiene latex.

[0069] Example 15 A method for preparing artificial turf using recycled linear polyethylene modified material through stretch film includes the following steps: 1) Weigh the raw materials: 80 kg of virgin polyethylene 7042, 40 kg of modified linear polyethylene recycled from stretch film in Example 7, 10 kg of color masterbatch, and 2 kg of processing stabilizer (the mass ratio of virgin polyethylene 7042, erucamide, UV944 and polyethylene wax is 50:20:27:3). 2) Fiber drawing: The recycled linear polyethylene modified material, polyethylene virgin material, color masterbatch and processing stabilizer of the stretch film are drawn into fibers by a single screw. The single screw drawing is controlled with a draw length of 5.5, a heat setting shrinkage ratio of 80%, and a water bath temperature of 95℃. 3) Finishing: Twisting the grass fibers, tufting, and applying adhesive backing to create the finished lawn.

[0070] Lawn specifications: Grass fiber specifications: DTEX 10000 / 6F, row spacing: 5 / 8, stitch length: 15 stitches / 10cm, backing fabric: single layer + mesh, latex: carboxylated styrene-butadiene latex.

[0071] Example 16 A method for preparing artificial turf using recycled linear polyethylene modified material through stretch film includes the following steps: 1) Weigh the raw materials: 80 kg of virgin polyethylene 7042, 20 kg of modified linear polyethylene recycled from the stretch film in Example 7, 9 kg of color masterbatch, and 1 kg of processing stabilizing agent (the mass ratio of virgin polyethylene 7042, erucamide, UV944 and polyethylene wax is 50:20:27:3). 2) Fiber drawing: The recycled linear polyethylene modified material, polyethylene virgin material, color masterbatch and processing stabilizer of the stretch film are drawn into fibers by a single screw. The single screw drawing is controlled with a draw length of 5.5, a heat setting shrinkage ratio of 80%, and a water bath temperature of 95℃. 3) Finishing: Twisting the grass fibers, tufting, and applying adhesive backing to create the finished lawn.

[0072] Grass fiber specifications: DTEX 10000 / 6F, row spacing: 5 / 8, stitch length: 15 stitches / 10cm, base fabric: single layer + mesh, latex: carboxylated styrene-butadiene latex.

[0073] Example 17 A method for preparing artificial turf using recycled linear polyethylene modified material through stretch film includes the following steps: 1) Weigh the raw materials: 80 kg of virgin polyethylene 7042, 30 kg of modified linear polyethylene recycled from stretch film in Example 9, 9 kg of color masterbatch, and 1 kg of processing stabilizing agent (the mass ratio of virgin polyethylene 7042, UV944 and polyethylene wax is 70:27:3). 2) Fiber drawing: The recycled linear polyethylene modified material, polyethylene virgin material, color masterbatch and processing stabilizer of the stretch film are drawn into fibers by a single screw. The single screw drawing is controlled with a draw length of 5.5, a heat setting shrinkage ratio of 80%, and a water bath temperature of 92℃. 3) Finishing: Twisting the grass fibers, tufting, and applying adhesive backing to create the finished lawn.

[0074] Lawn specifications: Grass fiber specifications: DTEX 10000 / 6F, row spacing: 5 / 8, stitch length: 15 stitches / 10cm, backing fabric: single layer + mesh, latex: carboxylated styrene-butadiene latex.

[0075] Comparative Example 4 A method for preparing artificial turf using recycled linear polyethylene modified material through stretch film includes the following steps: 1) Weigh the raw materials: 80 kg of virgin polyethylene 7042, 40 kg of modified linear polyethylene recycled from the stretch film of Comparative Example 1, 10 kg of color masterbatch, and 2 kg of processing stabilizing agent (the mass ratio of virgin polyethylene 7042, erucamide, UV944 and polyethylene wax is 50:20:27:3). 2) Fiber drawing: The recycled linear polyethylene modified material, polyethylene virgin material, color masterbatch and processing stabilizer of the stretch film are drawn into fibers by a single screw. The single screw drawing is controlled with a draw length of 5.5, a heat setting shrinkage ratio of 80%, and a water bath temperature of 95℃. 3) Finishing: Twisting the grass fibers, tufting, and applying adhesive backing to create the finished lawn.

[0076] Lawn specifications: Grass fiber specifications: DTEX 10000 / 6F, row spacing: 5 / 8, stitch length: 15 stitches / 10cm, backing fabric: single layer + mesh, latex: carboxylated styrene-butadiene latex.

[0077] Comparative Example 5 A method for preparing artificial turf using recycled linear polyethylene modified material through stretch film includes the following steps: 1) Weigh the raw materials: 80 kg of virgin polyethylene 7042, 20 kg of modified linear polyethylene recycled from the wrapping film of Comparative Example 2, 9 kg of color masterbatch, and 1 kg of processing stabilizing agent (the mass ratio of virgin polyethylene 7042, erucamide, UV944 and polyethylene wax is 50:20:27:3). 2) Fiber drawing: The recycled linear polyethylene modified material, polyethylene virgin material, color masterbatch and processing stabilizer of the stretch film are drawn into fibers by a single screw. The single screw drawing is controlled with a draw length of 5.5, a heat setting shrinkage ratio of 80%, and a water bath temperature of 95℃. 3) Finishing: Twisting the grass fibers, tufting, and applying adhesive backing to create the finished lawn.

[0078] Lawn specifications: Grass fiber specifications: DTEX 10000 / 6F, row spacing: 5 / 8, stitch length: 15 stitches / 10cm, backing fabric: single layer + mesh, latex: carboxylated styrene-butadiene latex.

[0079] Comparative Example 6 A method for preparing artificial turf using recycled linear polyethylene modified material through stretch film includes the following steps: 1) Weigh the raw materials: 80 kg of virgin polyethylene 7042, 20 kg of modified linear polyethylene recycled from the wrapping film of Comparative Example 3, 9 kg of color masterbatch, and 1 kg of processing stabilizing agent (the mass ratio of virgin polyethylene 7042, erucamide, UV944 and polyethylene wax is 50:20:27:3). 2) Fiber drawing: The recycled linear polyethylene modified material, polyethylene virgin material, color masterbatch and processing stabilizer of the stretch film are drawn into fibers by a single screw. The single screw drawing is controlled with a draw length of 5.5, a heat setting shrinkage ratio of 80%, and a water bath temperature of 95℃. 3) Finishing: Twisting the grass fibers, tufting, and applying adhesive backing to create the finished lawn.

[0080] Lawn specifications: Grass fiber specifications: DTEX 10000 / 6F, row spacing: 5 / 8, stitch length: 15 stitches / 10cm, backing fabric: single layer + mesh, latex: carboxylated styrene-butadiene latex.

[0081] Comparative Example 7 A method for preparing artificial turf using recycled linear polyethylene modified material through stretch film includes the following steps: 1) Weigh out the following raw materials: 100 kg of virgin polyethylene 7042, 9 kg of color masterbatch, and 1 kg of processing stabilizer (the mass ratio of virgin polyethylene 7042, erucamide, UV944, and polyethylene wax is 50:20:27:3). 2) Fiber drawing: Polyethylene virgin material, color masterbatch and processing stabilizer are drawn into fibers by a single screw. The single screw drawing is controlled with a draw length of 5.5, a heat setting shrinkage ratio of 80%, and a water bath temperature of 95℃. 3) Finishing: Twisting the grass fibers, tufting, and applying adhesive backing to create the finished lawn.

[0082] Lawn specifications: Grass fiber specifications: DTEX 10000 / 6F, row spacing: 5 / 8, stitch length: 15 stitches / 10cm, backing fabric: single layer + mesh, latex: carboxylated styrene-butadiene latex.

[0083] Abrasion resistance test method: Sample specifications: 41 80cm / block, 2 sets of parallel samples, avoiding roll joints and defects; fill with quartz sand + EPDM rubber granules in layers according to the actual site ratio, and compact with a roller to the filling height. Environmental pretreatment: 23±2℃, RH 50%±5%, constant temperature and humidity, stand for 24 hours to reach equilibrium moisture content. Testing instrument: Lisport Testing process: Take photos at 5000 RPM to assess the branching of the grass fibers.

[0084] Pull-out force test method: The test was performed using an electronic universal testing machine according to the method in standard ISO 4919, specifically by taking a 20 mm section. A freshly prepared 20cm sample block was placed in an environment with a relative humidity of (65±4)% and a temperature of (20±2)℃ for 24 hours. The sample block was placed on an electronic universal testing machine and a half-clump of grass fibers was clamped with clamps perpendicular to the sample block direction. The machine was turned on, and the maximum force value was recorded as the pull-out force value of the grass fibers after the grass fibers were completely pulled out. The pull-out force value of each sample block was based on the average value of 10 sample data.

[0085] Table 2 Abrasion resistance and lawn pull-out force data

[0086] Note: Performance comparison test, lawn models and specifications are the same.

[0087] Table 2 shows that metallocene-modified turf exhibits improved abrasion resistance and pull-out force. Furthermore, lower metallocene densities generally result in better abrasion resistance, and higher metallocene content leads to a more significant improvement in pull-out force. This is primarily due to the narrow molecular weight distribution and high impact strength of metallocene materials. Additionally, metallocene materials have significantly higher thermal stability than ordinary linear polyethylene, resulting in stable grass fiber morphology and stronger surface adhesion between the latex and grass fibers in the adhesive drying oven. Comparative examples show that conventional virgin turf exhibits severe abrasion at 10,000 revolutions, while the abrasion resistance of unmodified recycled stretch film significantly decreases. This is mainly because the molecular chains of the stretch film material break down into smaller molecules during processing, significantly impacting the overall strength of the material.

[0088] Continuous production performance evaluation: Example 18 A method for preparing artificial turf using recycled linear polyethylene modified material through stretch film includes the following steps: (1) Weigh the raw materials: 80 kg of waste linear polyethylene stretch film, 20 kg of metallocene polyethylene, and 0.5 kg of antioxidant; The density of metallocene polyethylene is 0.912 g / cm³. 3 The test conditions were 190℃, 2.16kg, and melt flow rate of 2g / 10min.

[0089] The antioxidants are antioxidant 1010 and antioxidant 168 in a mass ratio of 2:1; (2) Pretreatment: The waste linear polyethylene wrapping film is crushed, washed, dried, melt-granulated, filtered and impurities removed. The purity of the waste linear polyethylene wrapping film is 98%. (3) Modified granulation: The pretreated waste linear polyethylene wrapping film, metallocene polyethylene and antioxidant are first melt-premixed at 180 ℃ by a single screw, and then sent to a twin screw for secondary low-temperature plasticization at 160 ℃. After water cooling and pelletizing, the mixture is sealed and dried at 75 ℃ for 8 hours to remove odor, thus obtaining modified linear polyethylene recycled wrapping film.

[0090] (4) Weigh the raw materials: 50 kg of virgin polyethylene 7042, 42 kg of modified linear polyethylene recycled for stretch film, 8 kg of color masterbatch, and 1 kg of processing stabilizer (the mass ratio of virgin polyethylene 7042, erucamide, UV944 and polyethylene wax is 50:20:27:3). (5) Wire drawing: The linear polyethylene modified material, polyethylene virgin material, color masterbatch and processing stabilizer of the stretch film are drawn by a single screw. The single screw drawing is controlled with a stretch of 5.5 and a shrinkage of 15%, and the water bath is 92℃. (6) Finishing: Twisting grass fibers, tufting, and backing adhesive to make finished lawn.

[0091] Grass fiber specifications: DTEX 10000 / 6F, row spacing: 5 / 8, stitch length: 15 stitches / 10cm, base fabric: single layer + mesh, latex: carboxylated styrene-butadiene latex.

[0092] Example 19 A method for preparing artificial turf using recycled linear polyethylene modified material through stretch film includes the following steps: (1) Weigh the raw materials: 80 kg of waste linear polyethylene stretch film, 20 kg of metallocene polyethylene, and 0.5 kg of antioxidant; The density of metallocene polyethylene is 0.912 g / cm³. 3 The test conditions were 190℃, 2.16kg, and melt flow rate of 2g / 10min.

[0093] The antioxidants are antioxidant 1010 and antioxidant 168 in a mass ratio of 2:1; (2) Pretreatment: The waste linear polyethylene wrapping film is crushed, washed, dried, melt-granulated, filtered and impurities removed. The purity of the waste linear polyethylene wrapping film is 98%. (3) Modified granulation: The pretreated waste linear polyethylene wrapping film, metallocene polyethylene and antioxidant are first melt-premixed at 180 ℃ by a single screw, and then sent to a twin screw for secondary low-temperature plasticization at 160 ℃. After water cooling and pelletizing, the mixture is sealed and dried at 75 ℃ for 8 hours to remove odor, thus obtaining modified linear polyethylene recycled wrapping film.

[0094] (4) Weigh the raw materials: 50 kg of virgin polyethylene 7042, 22 kg of modified linear polyethylene recycled for stretch film, 8 kg of color masterbatch, and 1 kg of processing stabilizer (the mass ratio of virgin polyethylene 7042, erucamide, UV944 and polyethylene wax is 50:20:27:3). (5) Wire drawing: The linear polyethylene modified material, polyethylene virgin material, color masterbatch and processing stabilizer of the stretch film are drawn by a single screw. The single screw drawing is controlled with a stretch of 5.5 and a shrinkage of 15%, and the water bath is 92℃. (6) Finishing: Twisting grass fibers, tufting, and backing adhesive to make finished lawn.

[0095] Grass fiber specifications: DTEX 10000 / 6F, row spacing: 5 / 8, stitch length: 15 stitches / 10cm, base fabric: single layer + mesh, latex: carboxylated styrene-butadiene latex.

[0096] Example 20 A method for preparing artificial turf using recycled linear polyethylene modified material through stretch film includes the following steps: (1) Weigh the raw materials: 80 kg of waste linear polyethylene stretch film, 20 kg of metallocene polyethylene, and 0.5 kg of antioxidant; The density of metallocene polyethylene is 0.912 g / cm³. 3 The test conditions were 190℃, 2.16kg, and melt flow rate of 2g / 10min.

[0097] The antioxidants are antioxidant 1010 and antioxidant 168 in a mass ratio of 2:1; (2) Pretreatment: The waste linear polyethylene wrapping film, metallocene polyethylene and antioxidant are crushed, washed, dried, melt-granulated and filtered to remove impurities. The purity of the waste linear polyethylene wrapping film is 98%. (3) Modified granulation: The pretreated waste linear polyethylene wrapping film is first melt-premixed at 180 ℃ by a single screw, then sent to a twin screw for secondary low-temperature plasticization at 160 ℃, water-cooled and granulated, and then sealed and dried at 75 ℃ for 8 hours to remove odor, thus obtaining modified linear polyethylene recycled wrapping film.

[0098] (4) Weigh the raw materials: 50 kg of virgin polyethylene 7042, 42 kg of modified linear polyethylene recycled for stretch film, 8 kg of color masterbatch, and 1 kg of processing stabilizer (the mass ratio of virgin polyethylene 7042, erucamide, UV944 and polyethylene wax is 50:20:27:3). (5) Wire drawing: The linear polyethylene modified material, polyethylene virgin material, color masterbatch and processing stabilizer of the stretch film are drawn by a single screw. The single screw drawing is controlled with a stretch of 5.5 and a shrinkage of 15%, and the water bath is 92℃. (6) Finishing: Twisting grass fibers, tufting, and backing adhesive to make finished lawn.

[0099] Grass fiber specifications: DTEX 10000 / 6F, row spacing: 5 / 8, stitch length: 15 stitches / 10cm, base fabric: single layer + mesh, latex: carboxylated styrene-butadiene latex.

[0100] Comparative Example 8: A method for preparing artificial turf using recycled linear polyethylene modified material through stretch film includes the following steps: (1) Weigh the raw materials: 80 kg of waste linear polyethylene stretch film, 20 kg of metallocene polyethylene, and 0.5 kg of antioxidant; The density of metallocene polyethylene is 0.912 g / cm³. 3 The test conditions were 190℃, 2.16kg, and melt flow rate of 2g / 10min.

[0101] The antioxidants are antioxidant 1010 and antioxidant 168 in a mass ratio of 2:1; (2) Pretreatment: The waste linear polyethylene wrapping film is crushed, washed, dried, melt-granulated, filtered and impurities removed. The purity of the waste linear polyethylene wrapping film is 98%. (3) Modified granulation: The pretreated waste linear polyethylene wrapping film, metallocene polyethylene and antioxidant are first melt-premixed at 180 ℃ by a single screw, and then sent to a twin screw for secondary low-temperature plasticization at 160 ℃. After water cooling and pelletizing, the mixture is sealed and dried at 75 ℃ for 8 hours to remove odor, thus obtaining modified linear polyethylene recycled wrapping film.

[0102] (4) Weigh the raw materials: 50 kg of virgin polyethylene 7042, 42 kg of modified linear polyethylene recycled for stretch film, 8 kg of color masterbatch, and 1 kg of processing stabilizer (the mass ratio of virgin polyethylene 7042, erucamide, UV944 and polyethylene wax is 50:20:27:3). (5) Wire drawing: The linear polyethylene modified material, polyethylene virgin material, color masterbatch and processing stabilizer of the stretch film are drawn by a single screw. The single screw drawing is controlled with a stretch of 5.5 and a shrinkage of 15%, and the water bath is 92℃. (6) Finishing: Twisting grass fibers, tufting, and backing adhesive to make finished lawn.

[0103] Grass fiber specifications: DTEX 10000 / 6F, row spacing: 5 / 8, stitch length: 15 stitches / 10cm, base fabric: single layer + mesh, latex: carboxylated styrene-butadiene latex.

[0104] Comparative Example 9: A method for preparing artificial turf using recycled linear polyethylene modified material through stretch film includes the following steps: (1) Weigh the raw materials: 80 kg of waste linear polyethylene stretch film and 20 kg of metallocene polyethylene; The density of metallocene polyethylene is 0.912 g / cm³. 3 The test conditions were 190℃, 2.16kg, and melt flow rate of 2g / 10min.

[0105] (2) Pretreatment: The waste linear polyethylene wrapping film is crushed, washed, dried, melt-granulated, filtered and impurities removed. The purity of the waste linear polyethylene wrapping film is 98%. (3) Modified granulation: The pretreated waste linear polyethylene wrapping film, metallocene polyethylene and antioxidant are first melt-premixed at 180 ℃ by a single screw, and then sent to a twin screw for secondary low-temperature plasticization at 160 ℃. After water cooling and pelletizing, the mixture is sealed and dried at 75 ℃ for 8 hours to remove odor, thus obtaining modified linear polyethylene recycled wrapping film.

[0106] (4) Weigh the raw materials: 70 kg of new polyethylene 7042, 22 kg of modified linear polyethylene recycled for stretch film, 8 kg of color masterbatch, and 1 kg of processing stabilizer (the mass ratio of new polyethylene 7042, erucamide, UV944 and polyethylene wax is 50:20:27:3). (5) Wire drawing: The linear polyethylene modified material, polyethylene virgin material, color masterbatch and processing stabilizer of the stretch film are drawn by a single screw. The single screw drawing is controlled with a stretch of 5.5 and a shrinkage of 15%, and the water bath is 92℃. (6) Finishing: Twisting grass fibers, tufting, and backing adhesive to make finished lawn.

[0107] Grass fiber specifications: DTEX 10000 / 6F, row spacing: 5 / 8, stitch count: 15 stitches / 10cm, base fabric: single layer + mesh, latex: carboxylated styrene-butadiene latex. Thermogravimetric analysis (TGA) test procedure: using DSC in a nitrogen atmosphere, the temperature is programmed to rise to 300℃ and held for 5 minutes to find the decomposition endothermic initiation temperature.

[0108] Cleaning time for the die head: Table 3 Schedule for Cleaning Die Heads on Machines

[0109] Table 4. Thermogravimetric Temperature of Modified Materials

[0110] As can be seen from the data in Tables 2 and 3 above, adding antioxidants can significantly increase the thermal decomposition temperature of the material during the modification of recycled linear polyethylene wrapping film. Since the straw screw extrusion temperature is set in the range of 240-250℃, it can significantly improve the small molecule decomposition and carbonization during the processing, reduce carbon deposits, and thus reduce the time for cleaning the die head spinneret.

[0111] Odor evaluation criteria: Example 21 Example 18: Recycled linear polyethylene modified material from stretch film was heated in a 70°C mixing oven for 4 hours, cooled for 24 hours, and then the odor was evaluated.

[0112] Example 22 Example 20: Recycled linear polyethylene modified material from stretch film was heated in a 70°C mixing oven for 4 hours, cooled for 24 hours, and then the odor was evaluated.

[0113] Example 23 Example 18: Recycled linear polyethylene modified material from stretch film was heated in a 70°C mixing oven for 8 hours and cooled for 24 hours before odor was evaluated.

[0114] Comparative Example 10 Example 18: Odor was evaluated after pelleting recycled linear polyethylene modified material from stretch film and cooling for 24 hours.

[0115] Table 5. Level 6 Evaluation Criteria

[0116] Table 6 Odor Rating Table

[0117] Based on the results of the basic control group, the modified recycled film material of Comparative Example 10, which adopted the formulation of Example 18, was directly evaluated after only being pelletized and cooled at room temperature for 24 hours. The odor level reached level 5, which means it had a strong and bothersome odor. It was the group with the worst odor performance among all the test samples. This indicates that the modified recycled film material that has not undergone high-temperature drying treatment has more residual volatile impurities and a prominent odor defect.

[0118] Under the same drying process conditions, the difference in formulation had a slight impact on the odor of the material. Both Examples 21 and 22 used a unified process of heating and drying in a 70℃ oven for 4 hours followed by cooling for 24 hours. Example 21 used the formulation from Example 18, and Example 22 used the formulation from Example 20. Both groups of samples had an odor level of 3, indicating a noticeable but not unpleasant odor. Compared to the undried Comparative Example 10, the odor levels of both dried samples were significantly reduced, demonstrating a significant improvement in odor. This proves that the 70℃ drying process for 4 hours can effectively remove volatile odor substances from the modified stretch film recovery material and effectively weaken the pungent and unpleasant odor of the material.

[0119] Under the same formulation system, drying time is a key factor affecting the odor quality of the material. Examples 21 (drying at 70℃ for 4 hours) and 23 (drying at 70℃ for 8 hours) both used the same formulation as Example 18, differing only in drying time. The sample dried for 4 hours had an odor level of 3, while the sample from Example 23, dried for 8 hours, had an odor level reduced to 2, indicating a pleasant but not unpleasant odor, further optimizing the sensory experience. This demonstrates that under constant temperature drying conditions of 70℃, appropriately extending the drying time can more effectively remove residual volatile odor components from the material, further improving the odor quality of the modified recycled stretch film.

[0120] The core conclusions drawn from the combined results of the various experiments are as follows: High-temperature drying is an effective means of improving the odor of modified recycled stretch film, significantly solving the problem of unpleasant odor from the recycled material; extending the drying time at a process temperature of 70℃ can continuously optimize the odor performance of the material; while different modification formulas have a certain fine-tuning effect on the odor of the recycled material, the optimization effect is far less significant than the improvement effect of the drying heat treatment process and the adjustment of the drying time. This experiment can provide effective data support for optimizing the deodorization process and adapting the formula for production of modified recycled stretch film.

[0121] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A type of reclaimed linear polyethylene modified material for stretch film, characterized in that, It is made from the following raw materials in parts by weight: 80-95 parts of waste linear polyethylene stretch film, 5-20 parts of metallocene polyethylene, and 0.5-1 part of antioxidant; The density of the metallocene polyethylene is 0.910-0.927 g / cm³. 3 The test conditions were 190℃, 2.16kg, and melt flow rate of 0.5-5g / 10min; The antioxidants include hindered phenolic antioxidants and / or phosphite antioxidants.

2. The recyclable linear polyethylene modified material using a stretch film according to claim 1, characterized in that, The density of the metallocene polyethylene is 0.912-0.915 g / cm³. 3 The test conditions were 190℃, 2.16kg, and melt flow rate of 1-2g / 10min.

3. The recyclable linear polyethylene modified material for stretch film according to claim 1, characterized in that, The antioxidant is one or more of antioxidant 1010, antioxidant 168, antioxidant 618 or antioxidant 1098.

4. A method for preparing recycled linear polyethylene modified material using stretch film, characterized in that, Includes the following steps: (1) Weigh each raw material according to any one of claims 1-3 for the recycled linear polyethylene modified material of the stretch film; (2) Pretreatment: The waste linear polyethylene wrapping film is crushed, washed, dried, melt-granulated, and filtered to remove impurities; (3) Modified granulation: The pretreated waste linear polyethylene wrapping film, metallocene polyethylene and antioxidant are first melt-premixed by a single screw, then fed into a twin screw for secondary low-temperature plasticization, water-cooled and granulated, and then sealed and dried at constant temperature to remove odor, to obtain the modified linear polyethylene material of the wrapping film.

5. The method for preparing a modified linear polyethylene film for recycling according to claim 4, characterized in that, In step (2), the purity of the waste linear polyethylene wrapping film is controlled to be ≥98%.

6. The method for preparing a modified linear polyethylene film for recycling according to claim 4, characterized in that, In step (3), the single-screw melt premixing temperature is 180-220℃, the twin-screw secondary low-temperature plasticizing temperature is 150-180℃, the constant temperature drying temperature is 70-80℃, and the constant temperature drying time is 4-8h.

7. An artificial turf prepared using recycled linear polyethylene modified material through a stretch film, characterized in that, It is made from the following raw materials in parts by weight: The stretch film according to any one of claims 1-3 contains 30-52 parts of recycled linear polyethylene modified material, 0-60 parts of virgin polyethylene material, 8-10 parts of color masterbatch, and 0.5-2 parts of processing stabilizing agent, wherein the processing stabilizing agent includes one or more of hindered amine high molecular weight light stabilizers, PPA additives, or erucamide.

8. A method for preparing artificial turf using recycled linear polyethylene modified material through stretch film, characterized in that, Includes the following steps: 1) Weigh each raw material according to claim 7 for the artificial turf prepared by using recycled linear polyethylene modified material with stretch film; 2) Fiber drawing: The wrapped film is drawn into fibers using a single screw extruder by recycling modified linear polyethylene material, virgin polyethylene material, color masterbatch, and processing stabilizer. 3) Finishing: Twisting the grass fibers, tufting, and applying adhesive backing to create the finished lawn.

9. The method for preparing artificial turf using recycled linear polyethylene modified material through stretch film according to claim 8, characterized in that, In step 2), the single screw wire drawing control stretch is 5-6, the shrinkage is 10%-20%, and the water bath is 90-95℃.

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