Recycling type nylon-based artificial grass yarn formula and low-carbon manufacturing process

Abstract

The invention discloses a cyclic regeneration type nylon-based artificial grass yarn formula and a low-carbon manufacturing process, the cyclic regeneration type nylon-based artificial grass yarn formula comprises regenerated PA6, POE, an antioxidant system and a lubricant, the proportion range of the regenerated PA6 is 50-65% and the optimal proportion is 60%, the proportion range of the POE is 20-30% and the optimal proportion is 25%, the proportion range of the antioxidant system is 0.5-1.5% and the optimal proportion is 1%, and the proportion range of the lubricant is 0.5-1.5% and the optimal proportion is 1%. The proportion range of the lubricant is 0.3-0.8%, and the optimal proportion is 0.5%.

Description

Technical Field

[0001] The present invention belongs to the technical field of artificial grass filaments. More specifically, it particularly relates to a formula for recycled nylon-based artificial grass filaments and a low-carbon manufacturing process. Background Art

[0002] In recent years, with the industrialization and commercialization development of sports such as football, tennis, and golf, the development of artificial turf has also been very rapid. Artificial turf can be applied not only in the field of sports but also in various leisure and decoration fields.

[0003] The artificial turf used in existing sports fields generally consists of a base layer and artificial grass filaments. However, the current artificial grass filaments have the following defects:

[0004] 1. High material cost: The price of virgin PA6 fluctuates greatly (> 25,000 yuan / ton), and the cost of grass filament raw materials accounts for more than 60%; the traditional LLDPE toughening scheme results in insufficient hardness of the grass filaments (Shore D hardness ≤ 55);

[0005] 2. Insufficient environmental protection: Petroleum-based nylon cannot pass the GRS (Global Recycled Standard) certification, restricting exports to the EU market; the recovery rate of waste fishing nets and textiles < 10%, resulting in serious resource waste.

[0006] 3. Performance defects: The falling weight impact strength ≤ 25 kJ / m 2 (FIFA standard ≥ 30 kJ / m 2 );Poor resistance to heat and humidity aging: After 30 days in an environment of 70°C / 95% RH, the tensile strength decreases by 40%. Summary of the Invention

[0007] In view of the deficiencies of the prior art, the present invention provides a formula for recycled nylon-based artificial grass filaments and a low-carbon manufacturing process to solve the problems raised in the above background art.

[0008] To achieve the above objectives, the present invention is realized through the following technical solutions: A formula for recycled nylon-based artificial grass filaments includes recycled PA6, POE, an antioxidant system, and a lubricant. The proportion range of the recycled PA6 is 50 - 65% and the optimal proportion is 60%. The proportion range of the POE is 20 - 30% and the optimal proportion is 25%. The proportion range of the antioxidant system is 0.5 - 1.5% and the optimal proportion is 1%. The proportion range of the lubricant is 0.3 - 0.8% and the optimal proportion is 0.5%.

[0009] Furthermore, the recycled PA6 is regenerated through alkali washing and solid-phase polycondensation, with its intrinsic viscosity decreasing from 1.2 dL / g of the virgin PA6 to 0.9 - 1.1 dL / g; the molecular weight distribution (PDI) of the recycled PA6 is narrowed from 3.5 to 2.2.

[0010] Furthermore, the POE is an ethylene-octene copolymer with an octene content of 28% and a glass transition temperature of -55°C, endowing the grass filaments with high elasticity and a rebound rate of ≥90%; the POE and the compatibilizer SEBS-g-MAH can synergistically toughen, with the impact strength increased by 40%; the grafting rate of the compatibilizer SEBS-g-MAH is 1.2%, and 8% of the MAH groups react with the terminal amino groups of the recycled PA6 to form a PA-g-SEBS graft, with the interfacial peel strength increased from 10 N / mm to 18 N / mm.

[0011] Furthermore, the antioxidant system is used to synergistically inhibit thermal-oxidative aging. Using the elastomer test of ASTM D3895, the oxidation induction time (OIT) is ≥30 min, extending the life of the grass filaments to 10 years.

[0012] Furthermore, the lubricant is ethylene bisstearamide, which is used to reduce the melt viscosity (the melt index is increased from 4 g / 10 min to 6 g / 10 min) and prevent die swell at the extrusion die.

[0013] A low-carbon manufacturing process for a recycled nylon-based artificial grass filament includes the following steps:

[0014] S1, Pretreatment of recycled PA6: The recycled PA6 is crushed and sorted through a vortex separator to remove metal impurities with a purity of ≥99.9%; then it is purified by alkali washing with a 5% NaOH solution under stirring at 80°C for 2 hours to remove surface oil stains and coatings; solid-phase polycondensation is carried out at 200°C under nitrogen protection for 6 hours, so that the intrinsic viscosity is restored from 0.7 dL / g to 1.0 dL / g.

[0015] S2, Blending modification: Obtain a mixed material through a co-rotating twin-screw extruder;

[0016] S3, Grass filament forming: The mixed material is melt-spun through a melt spinning machine and then cooled in a water bath to obtain a grass filament with a filament crystallinity of 35 - 40%; it is pre-drawn 3 times at 70°C through a hot roll with a diameter of 300 mm, then main-drawn 5 times at 90°C through a hot box with a length of 6 m, and finally relaxation heat-treated at 120°C for 10 seconds through a shaping machine.

[0017] Further, in S2, the temperature zones of the parallel twin-screw extruder are 200°C in zone 1, 210°C in zone 2, 220°C in zone 3, 230°C in zone 4, and 220°C at the die head (zone 5); the screw combination of the parallel twin-screw extruder adopts an alternating arrangement of high-shear blocks (KB45) and reverse threads, the dispersed phase particle size is ≤1 μm, the pressure of vacuum devolatilization is -0.09 MPa, and the volatile content is ≤0.05%.

[0018] Further, in S3, the die head temperature of the melt spinning machine is 220°C, the orifice diameter of the spinneret plate is 0.25 mm, and the number of holes is 200 holes / m; the water temperature for water bath cooling is 25°C and the flow rate is 2 m / s.

[0019] The present invention provides a formula for recycled nylon-based artificial grass filaments and a low-carbon manufacturing process, having the following beneficial effects:

[0020] 1. Circular economy value: The recycling rate of waste fishing nets is increased to 70%, reducing marine plastic pollution; through GRS certification, the product can enjoy tariff reduction when exported to the EU (the tax rate is reduced from 6.5% to 2%).

[0021] 2. High performance and low cost: The impact strength is increased by 40% and the service life is ≥10 years; the raw material cost is reduced by 30% and the gross profit margin is increased to 30%.

[0022] 3. Low-carbon competitiveness: In the existing technology, the carbon footprint of virgin PA6 is 3.0 kg CO2 / kg (data source: ULProspector database), while in the present invention, through the modification of recycled materials, the carbon footprint is reduced to 1.5 kg CO2 / kg, meeting the FIFA "Sustainable Development Goals 2030"; it is applicable to the replacement needs of 50,000 standard football fields globally (the potential market scale is 12 billion yuan). Description of the Drawings

[0023] Figure 1 It is a process flow schematic diagram of the present invention; Specific Embodiments

[0024] The following further describes in detail the embodiments of the present invention in conjunction with the drawings and examples. The following examples are used to illustrate the present invention, but cannot be used to limit the scope of the present invention.

[0025] In the description of the present invention, unless otherwise specified, "a plurality of" means two or more; the orientation or positional relationship indicated by terms such as "upper", "lower", "left", "right", "inner", "outer", "front end", "rear end", "head", "tail", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be construed as a limitation on the present invention. In addition, terms such as "first", "second", "third", etc. are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0026] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "connected" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0027] The present invention provides a technical solution: a formula for a recycled nylon-based artificial grass fiber, including recycled PA6, POE, an antioxidant system, and a lubricant. The proportion range of recycled PA6 is 50 - 65% and the optimal proportion is 60%. The proportion range of POE is 20 - 30% and the optimal proportion is 25%. The proportion range of the antioxidant system is 0.5 - 1.5% and the optimal proportion is 1%. The proportion range of the lubricant is 0.3 - 0.8% and the optimal proportion is 0.5%.

[0028] Among them, the recycled PA6 is regenerated by alkali washing and solid-phase polycondensation. The intrinsic viscosity is reduced from 1.2 dL / g of the virgin PA6 to 0.9 - 1.1 dL / g; the molecular weight distribution (PDI) of the recycled PA6 is narrowed from 3.5 to 2.2.

[0029] Among them, POE is an ethylene-octene copolymer. The octene content of the POE is 28%, and the glass transition temperature is -55°C, giving the grass fiber high elasticity and a rebound rate of ≥90%; POE and the compatibilizer SEBS-g-MAH can synergistically toughen, and the impact strength is increased by 40%; it can also be blended with 5% EVA through LLDPE (MI = 2.0 g / 10 min). Although the cost is reduced by 5% again, the impact strength drops to 30 kJ / m 2 , the second solution is dynamically vulcanized TPV (PA / EPDM), and a vulcanizing agent needs to be added additionally, but the process complexity increases. The grafting rate of the compatibilizer SEBS-g-MAH is 1.2%, and 8% of the MAH groups react with the terminal amino groups of the recycled PA6 to form a PA-g-SEBS graft, and the interfacial peel strength is increased from 10 N / mm to 18 N / mm.

[0030] Among them, the antioxidant system is used to synergistically inhibit thermal-oxidative aging. Using the elastomer test of ASTM D3895, the oxidation induction time (OIT) ≥ 30 min, and the life of the grass filaments is extended to 10 years.

[0031] Among them, the lubricant is ethylene bisstearamide, which is used to reduce the melt viscosity (the melt index is increased from 4 g / 10 min to 6 g / 10 min) and prevent die swell during extrusion.

[0032] Examples, such as Figure 1 , a low-carbon manufacturing process for recycled nylon-based artificial grass filaments, comprising the following steps:

[0033] S1, Pretreatment of recycled PA6: The recycled PA6 is crushed and sorted by a vortex separator to remove metal impurities, with a purity ≥ 99.9%; then it is stirred with 5% NaOH solution at 80 °C for 2 hours for alkali washing and purification to remove surface oil stains and coatings; solid-phase polycondensation is carried out at 200 °C under nitrogen protection for 6 hours, so that the intrinsic viscosity is restored from 0.7 dL / g to 1.0 dL / g.

[0034] S2, Blending and modification: Obtain a mixed material through a parallel twin-screw extruder; the temperature zones of the parallel twin-screw extruder are 200 °C in zone 1, 210 °C in zone 2, 220 °C in zone 3, 230 °C in zone 4, and 220 °C at the die head (zone 5); the screw combination of the parallel twin-screw extruder adopts an alternating arrangement of high-shear blocks (KB45) and reverse threads, the dispersed phase particle size ≤ 1 μm, the pressure of vacuum devolatilization is -0.09 MPa, and the volatile content ≤ 0.05%.

[0035] S3, Grass filament forming: Melt-spin the mixed material through a melt spinning machine, and then carry out water bath cooling to obtain a grass filament with a filament crystallinity of 35 - 40%; perform 3-fold pre-drawing through a hot roll with a diameter of 300 mm at 70 °C, then perform 5-fold main drawing through a hot box with a length of 6 m at 90 °C, and finally perform relaxation heat treatment at 120 °C for 10 seconds through a shaping machine; the die head temperature of the melt spinning machine is 220 °C, the orifice diameter of the spinneret is 0.25 mm, and the number of holes is 200 holes / m; the water temperature of the water bath cooling is 25 °C, and the flow rate is 2 m / s.

[0036] In its performance tests,

[0037] 1. Mechanical properties:

[0038] (1) Tensile strength: 38 MPa (ISO 527-2);

[0039] (2) Izod impact strength: 36 kJ / m 2 (FIFA standard test: impact with a 5 kg hammer head from a height of 1.2 m);

[0040] (3) Flexural modulus: 1.2 GPa (ASTM D790).

[0041] 2. Weather resistance:

[0042] (1) Xenon lamp aging (ISO 4892-2, 1000 hours): Tensile strength retention rate is 92%, color difference ΔE ≤ 2.5;

[0043] (2) Damp heat cycle (-30°C to 70°C, 50 cycles): No delamination or cracking (GB / T 2423.34).

[0044] The present invention can recycle waste fishing nets with an efficiency as high as 70%. It has passed the GRS certification. When the product is exported to the EU, it can enjoy tariff reduction (the tax rate is reduced from 6.5% to 2%). It has good circular economy value; the overall impact strength is increased by 40%, the service life is ≥ 10 years, the raw material cost is reduced by 30%, and the gross profit margin is increased to 30%. It has the characteristics of high performance and low cost. In the prior art, the carbon footprint of virgin PA6 is 3.0 kg CO2 / kg (data source: UL Prospector database). However, through the modification of recycled materials in the present invention, the carbon footprint is reduced to 1.5 kg CO2 / kg, meeting the FIFA "Sustainable Development Goals 2030" and applicable to the replacement needs of 50,000 standard football fields globally (the potential market scale is 12 billion yuan), having broad market prospects.

[0045] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separated. The components shown as units may or may not be physical units, that is, they may be located in one place or distributed to multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment. Those of ordinary skill in the art can understand and implement it without creative efforts.

[0046] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A recycled nylon-based artificial turf yarn formula, characterized in that: The invention comprises recycled PA6, POE, an antioxidant system and a lubricant, wherein the proportion of the recycled PA6 is in the range of 50-65% and the optimal proportion is 60%, the proportion of the POE is in the range of 20-30% and the optimal proportion is 25%, the proportion of the antioxidant system is in the range of 0.5-1.5% and the optimal proportion is 1%, and the proportion of the lubricant is in the range of 0.3-0.8% and the optimal proportion is 0.5%.

2. A recycled nylon-based artificial turf yarn formula according to claim 1, characterized in that: After alkali washing and solid phase polycondensation regeneration, the intrinsic viscosity of the regenerated PA6 is reduced from 1.2 dL / g of the original PA6 to 0.9-1.1 dL / g; the molecular weight distribution (PDI) of the regenerated PA6 is narrowed from 3.5 to 2.

2.

3. The formula of the recycled nylon-based artificial turf yarn according to claim 1, characterized in that: The POE is an ethylene-octene copolymer, the octene content of the POE is 28%, the glass transition temperature is -55°C, and the grass silk has high elasticity and a rebound rate of ≥90%; the POE and the compatibilizer SEBS-g-MAH can synergistically enhance toughness, and the impact strength is increased by 40%; the grafting rate of the compatibilizer SEBS-g-MAH is 1.2%, and 8% of the MAH groups react with the terminal amine groups of the regenerated PA6 to form a PA-g-SEBS graft, and the interface peeling strength is increased from 10N / mm to 18N / mm.

4. The recycled nylon-based artificial turf yarn formula according to claim 1, characterized in that: The antioxidant system is used to synergistically inhibit thermal oxidative aging, and adopts the elastomer test of ASTM D3895, with an oxidation induction time (OIT) of ≥30 minutes, thereby extending the life of the grass yarn to 10 years.

5. The formula and low-carbon manufacturing process of a recyclable nylon-based artificial turf yarn according to claim 1, characterized in that: The lubricant is ethylene bis stearamide, which is used to reduce melt viscosity (melt index increases from 4 g / 10 min to 6 g / 10 min) and prevent extrusion die expansion.

6. The low-carbon manufacturing process of recycled nylon-based artificial turf yarn according to claim 1 comprises the following steps: S1, regenerated PA6 pretreatment: the regenerated PA6 is crushed and sorted by an eddy current separator to remove metal impurities, with a purity of ≥99.9%; Then, 5% NaOH solution was stirred at 80°C for 2 hours for alkaline washing and purification to remove surface oil and coating; The solid phase polycondensation was carried out at 200° C. under nitrogen protection for 6 hours, so that the intrinsic viscosity was restored from 0.7 dL / g to 1.0 dL / g. S2, blending modification: the mixed material is obtained by parallel twin-screw extruder; S3, grass yarn forming: the mixed material is melt-spun through a melt spinning machine, and then cooled in a water bath to obtain grass yarns with a crystallinity of 35-40%; it is pre-stretched 3 times at 70°C by a hot roller with a diameter of 300mm, and then mainly stretched 5 times at 90°C by a hot box with a length of 6m, and finally relaxed and heat treated at 120°C for 10 seconds by a setting machine.

7. A low-carbon manufacturing process for recycled nylon-based artificial turf yarn according to claim 6, characterized in that: In the S2, the temperature zones of the parallel twin-screw extruder are 200°C for zone 1, 210°C for zone 2, 220°C for zone 3, 230°C for zone 4, and 220°C for the die head (zone 5); the screw combination of the parallel twin-screw extruder adopts high shear blocks (KB45) and reverse threads arranged alternately, the dispersed phase particle size is ≤1μm, the vacuum devolatilization pressure is -0.09MPa, and the volatile content is ≤0.05%.

8. The low-carbon manufacturing process of recycled nylon-based artificial turf yarn according to claim 6, characterized in that: In S3, the die head temperature of the melt spinning machine is 220° C., the spinneret aperture is 0.25 mm, and the number of holes is 200 holes / meter; the water temperature of the water bath cooling is 25° C., and the flow rate is 2 m / s.

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