EP-4739479-A1 - METHOD FOR PRODUCING RAW MATERIAL FOR USE IN MANUFACTURING ARTIFICIAL TURF FIBERS, AND METHOD FOR PRODUCING FIBER OF SAID RAW MATERIAL AND FIBERS OBTAINED THEREBY

EP4739479A1EP 4739479 A1EP4739479 A1EP 4739479A1EP-4739479-A1

Abstract

Methods for producing a raw material for use in the manufacturing of artificial turf fiber, which raw material comprises reclaimed artificial turf fiber, which methods comprise separating a fiber fraction from an artificial turf and cleaning it by whirling the fiber fraction inside a flow chamber having an outer screen at a periphery of the flow chamber to obtain a purified fiber fraction, and filtrating the purified fiber fraction in a melt filter to provide a filtrate which is recovered as said raw material. The disclosure further relates to artificial fiber comprising reclaimed turf fiber and methods for producing such artificial fiber.

Inventors

ANDERSEN, DENNIS
HEITKÖNIG, René

Assignees

Re-Match Holding A/S

Dates

Publication Date: 20260513
Application Date: 20240705

Claims (1)

C L A I M S 1. A method for producing a raw material (506) for use in the manufacturing of artificial turf fiber, which raw material (506) comprises reclaimed artificial turf fiber, preferably polyolefin turf fiber, said method comprising the following steps: (a) separating a fiber fraction (33, 35) from an artificial turf (1), (b) cleaning the fiber fraction (33, 35) by whirling the fiber fraction (2) inside a flow chamber (511) to form a vortex flow while keeping a material outlet (514) of the flow chamber closed, which flow chamber has an outer screen (512) arranged along at least a portion of a periphery of the flow chamber (511), the material outlet (514) being connected to the flow chamber (511, to provide a heavy fraction (501) at a bottom (511b) of the flow chamber, a purified fiber fraction (503) inside the flow chamber, and a fines fraction (502) on a side (512s) of the screen (512) which side faces away from the flow chamber (511), (c) filtering the purified fiber fraction (503) in a melt filter to provide a filtrate (505), and (d) recovering the filtrate (505) as the raw material (506) for producing artificial turf fibers, said raw material is optionally in granular form. 2. The method according to claim 1, wherein step (b) is implemented in a cleaning unit (510) comprising the flow chamber (511) with the outer screen (512), a bladed rotor (513) arranged at the bottom (211b) of the flow chamber, and an inlet (515) connected to the flow chamber (511), and step (b) comprises the steps of (bl) feeding the fiber fraction (33, 35) to the flow chamber (511) through the inlet (515), (b2) whirling the fiber fraction (33, 35) in the flow chamber (511) by way of rotation of the bladed rotor (513) while keeping the material outlet closed (514), (b3) collecting the fines fraction (501) from the side (512s) of the screen (512) faces away from the flow chamber (511), (b4) collecting the heavy fraction (502) at the bottom (511b) of the flow chamber, and (b5) opening the material outlet (514) to collect the purified fiber fraction (503). 3. The method according to claim 1 or 2, wherein the outer screen (512) has a screen size in the range of 0.5 to 10 mm, preferably 0.55 to 6 mm or 1 to 5 mm, more preferably 2 to 3 mm. 4. The method according to claim 2 and optionally claim 3, wherein the bladed rotor (513) of the cleaning unit (510) has a rotational speed in the range of 10 till 1500 RPM. 5. The method according to any one of the preceding claims, wherein step (b) further comprises adding an air flow to the flow chamber, preferably at a rate in the range 10 to 10000 Nm 3 /hr. 6. The method according to any one of the preceding claims, comprising further cleaning the purified fiber fraction (503) by repeating step (b) in a second flow chamber to provide a second heavy fraction, a further purified fiber fraction, and a second fines fraction, wherein step (c) comprises filtrating the further purified fiber fraction to provide the filtrate (505), optionally wherein the further cleaning of the purified fiber fraction (505) is implemented in a second cleaning unit, which second cleaning unit is of the same type as the cleaning unit (510). 7. The method according to claim 6, wherein at least a portion of the second heavy fraction is recycled to the step of cleaning the fiber fraction. 8. The method according to claim 7, wherein step (b) is repeated in the second cleaning unit wherein one or more of a rotational speed of a bladed rotor of the second cleaning unit, and an air flow to the second flow chamber is selected to provide a predetermined amount of the second heavy fraction, such as a second heavy fraction which constitutes 1 to 50 w/w % of the purified fiber fraction (35). 9. The method according to any one of the preceding claims, wherein step (c) comprises filtrating in a laser filter and/or a screen melt filter, preferably a laser filter and a screen melt filter and more preferably filtration step (c) comprises two filtration steps. 10. The method according to any one of the preceding claims, wherein the melt filter comprises a filter having a size in the range 5 pm to 450 pm, preferably 10 to 300 pm, more preferably 50 to 200 pm. 11. The method according to any one of the preceding claims, wherein step (c) comprises controlling a pressure drop in the melt filter to a pressure set-point, which pressure set-point is constant, or controlling the pressure drop in the melt filter to be at or below an upper pressure threshold. 12. The method according to claim 11, wherein the pressure set-point is 30 bar or less or the upper pressure threshold is 30 bar. 13. The method according to any one of the preceding claims, wherein step (c) further comprises controlling a pressure on an inlet side of the melt filter to be 80 bar(a) or less. 14. The method according to any one of the preceding claims, wherein step (a) comprises separating the artificial turf (1) into the fiber fraction (33, 35), into an infill portion (23, 29a-c) and a backing material portion (34). 15. The method according to claim 14, wherein step (a) comprises a feeding and a downsizing section (100) an infill separation section (200) and a turf and backing separation section (300), wherein said feeding and downsizing section (100) is in fluid communication with the infill separation section (200) and the turf and backing separation section (300), and wherein the feeding and downsizing section (100) comprises the following steps: (al) feeding a moist artificial turf product (1) to the feeding and downsizing section (100), (a2) downsizing the moist artificial synthetic turf product (1) into a downsized turf material (2), preferably to no more than 120 by 120 mm, and feeding the downsized turf material to a drying unit (102), (a3) drying the downsized turf material (2) in the drying unit (102), for example in a drum drier, to a moisture content of no more than 5% w/w, preferably no more than 3% w/w, most preferably no more than 1% w/w, to a dried material (3) (a4) separating the dried material (3) by screening in a first sieving unit (103) into at least a first fraction (4a) substantially comprising an infill material which is fed to the infill separation section (200) and a second fraction (4b) substantially comprising turf fiber and backing components, (a5) downsizing the second fraction (4b) substantially comprising turf fiber and backing components to at most 50 mm in the largest dimension in a downsizing unit (104) and optionally feeding the further downsized fraction (5) to a first screening unit (105), such as a drum screen having openings of 4 to 8 mm, preferably, 6 mm, to provide a small fraction (6a) and a large fraction (6b), (a 6) feeding the further downsized fraction (5) or if present, the large fraction (6b), obtained in step (a5) to a material hopper continuously supplying the fraction, optionally downsized further to at most 35 mm in the largest dimension, to the turf and backing separation section (300); and (a7) further processing the first fraction (4a) obtained in step (a4) and the small fraction (6a), if present, obtained in step (a5) in the infill separation section (200), wherein the turf and backing separation section (300) comprises the steps of (a8) separating the downsized fraction (5) or large fraction (7) obtained in step (a5) downsized further to at most 35 mm in the largest dimension, by specific gravity and size by providing an airflow directed upwards in a second separator (301) configured to cause a swirling motion whereby a second lighter fraction (33) is entrained upwards in the air flow and a second heavy fraction (34) is allowed to fall downwards; where the second lighter fraction (33) substantially comprises turf fiber components, and second heavy fraction substantially comprises a mixture of backing material and turf fiber component, and a9) recovering the second lighter fraction (33) as the fiber fraction (35). 16. A method for producing a fiber (607), preferably a turf fiber for an artificial turf, from reclaimed artificial turf fiber, comprising the steps of (e) providing a fiber raw material (603) comprising reclaimed artificial turf fiber (506), optionally further comprising virgin polymer (601) and/or one or more additives (602) selected from antioxidants, and processing aids, and (g) extruding the fiber raw material (603) to form the fiber (607) or to form a film (607') which film is then processed to form a slit-film fiber. 17. A method according to claim 16, wherein the fiber is a bicomponent fiber. 18. The method according to claim 17, wherein the fiber (607) is a core-shell type fiber, further comprising the step of (f) providing a shell material (606), which shell material comprises polymer material (604) and additives (605), wherein the polymer material (604) is selected from virgin polymer, Post-Industrial polymer material, post-consumer polymer material or mixtures thereof, and the additives (605) are selected from one or more of colorants, UV-stabilizers, and anti-oxidants, and wherein step (g) comprises co-extruding the fiber raw material (603) and the shell material (606) to form the core-shell type fiber (607), the fiber raw material forming a core of the core-shell type fiber (607) and the shell material forming a shell of the core-shell type fiber. 19. The method according to claim 17, wherein the fiber (607) is a slit-film fiber, further comprising the step of (f') providing a cover material (606), which cover material comprises polymer material (604) and additives (605), wherein the polymer material (604) is selected from virgin polymer, Post-Industrial polymer material, post-consumer polymer material or mixtures thereof, and the additives (605) are selected from one or more of colorants, UV-stabilizers, and anti-oxidants, and wherein step (g) comprises co-extruding the fiber raw material (603) and the cover material (606) to form a multi-layer film (607'), the fiber raw material forming a first layer (603') and the cover material forming a cover layer (606') of the multilayer film (607'), which multilayer film (607') is then processed into the slit-film fiber. 20. The method according to any one of claims 16 to 19, wherein the reclaimed artificial turf fiber is obtained using mechanical separation of artificial turf. 21. The method according to claim 20, wherein the mechanical separation is a method according to any one of claims 1 to 15. 22. A method for producing a fiber according any one of claims 16 to 21, wherein reclaimed artificial turf fiber constitutes 25 w/w% or more of a total polymer content of the fiber, preferably 35 w/w% or more, more preferably 50 w/w% or more, most preferably 70 w/w% or more of the total polymer content, wherein the total polymer content is the mass sum of reclaimed artificial turf fiber, virgin polymer, and Post-Industrial polymer material in the fiber. 23. A fiber comprising reclaimed artificial turf fiber, preferably wherein the fiber is a turf fiber for an artificial turf. 24. The fiber according to claim 23 obtained by a method according to any one of claims 16 to 21.

Description

Method for producing raw material for use in manufacturing artificial turf fibers, and method for producing fiber of said raw material and fibers obtained thereby Field of Technology The present invention relates to a method for producing raw material for producing artificial turf fibers which raw material comprises reclaimed artificial turf fibers. The invention further relates to a method for producing artificial fibers using reclaimed artificial turf fiber. Background Synthetic turf (artificial turf) has been used for many years as surfaces for football, baseball and soccer fields. In the recent years it has been used in other applications where an alternative to natural grass is desired. These applications include at least playgrounds, residential and commercial lawns and other landscaping, paths, paintball fields, tennis courts, putting greens, dog runs etc. Typically, synthetic turf includes a grass-like fabric having a backing and a plurality of upstanding ribbons, also called face fibers, resembling grass. Many synthetic turf products also include an infill material dispersed among the upstanding ribbons, which may consist of sand, tire rubber crumb, or other particulates, either singularly or in combination with each other. The infill material simulates the soil in natural turf, acts as a ballast, and/or contributes to the physical properties of the turf, such as resiliency, that makes the turf suitable for a particular use. The face fibers, or turf fiber, is often made from polyethylene or polypropylene. Synthetic turf typically has a coating to attach the turf fiber to the backing, which coating is often polyurethane. Synthetic turf has a limited life span, depending on the construction of the turf, the application for which it is used, weathering and how the turf is maintained. As an example, a typical synthetic turf for use as an athletic field may have a useful life of from about 8 to 15 years. A large amount of synthetic turf is currently being used in hundreds of athletic fields and in other applications. Disposing of the turf is very expensive due to the composition of materials ranging from recycled rubber, sand to plastic. To avoid sending the turf to landfills at a substantial cost, recycling and reusing all or portions of the synthetic turf has been an explored option over recent years. Recycling and reusing synthetic turf involve separating the components of the synthetic turf in order to reclaim the components at a degree of purity sufficient for the intended use of the reclaimed component. One separation process is described in W02010/075098 in which infill is separated from the backing and the grass like fibers followed by downsizing and further removal of infill followed by agglomeration. The granules of agglomerated turf fragments are placed into an extruder. The granules are extruded to form an extrudate, for example in the shape of a strand or ribbon. As only the infill is removed the granules obtained is a mixed material composed of multiple synthetic turf components, and thus of limited purity, which restricts the options for reusing the material. A similar process is described in US2014/312526A1 disclosing separating the filler (infill) from the base (backing) and fiber of the artificial turf, crushing the base and fiber and forming a solid reproduction material therefrom by injection or extrusion. The solid reproduction material thus comprises both fiber and backing and is a mixed material of limited purity. EP2096211B1 describes another method for disposing of synthetic grass in which grass fiber and backing are first separated from infill and additional components and then subsequently separated in a large number of steps. A grass fiber ("grass filament") portion is thus reclaimed and it is suggested that it may be recycled to produce new synthetic grass filaments however with no disclosure of such method. EP2862688 deals with a dry separation process where the individual components are provided essentially pure. The method comprises three specific separation steps in a specific order hence the separation is based on size, specific gravity and specific gravity, size and shape. The process yields a grass fiber portion (turf fiber), sand portions, rubber portions and backing portions. Hence, existing process can separate the components of synthetic turf thereby providing materials which in terms of recycling have a higher quality than mixed materials. When recycling materials it is desirable to achieve closed-loop recycling where the product at the end of its lifetime is recycled to make the same product. Having once already made a material to meet the requirements of a specific product, recycling the material into the same product re-captures the value of the material. However, recycled materials generally have less than acceptable physical properties at least in part due to wear and contamination arising during the life time. Hence, the extent to which such Post-Consu