Classifications

• • D—TEXTILES; PAPER
  • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
  • D06N—WALL, FLOOR, OR LIKE COVERING MATERIALS, e.g. LINOLEUM, OILCLOTH, ARTIFICIAL LEATHER, ROOFING FELT, CONSISTING OF A FIBROUS WEB COATED WITH A LAYER OF MACROMOLECULAR MATERIAL; FLEXIBLE SHEET MATERIAL NOT OTHERWISE PROVIDED FOR
  • D06N7/00—Flexible sheet materials not otherwise provided for, e.g. textile threads, filaments, yarns or tow, glued on macromolecular material
  • D06N7/0063—Floor covering on textile basis comprising a fibrous top layer being coated at the back with at least one polymer layer, e.g. carpets, rugs, synthetic turf
  • D06N7/0065—Floor covering on textile basis comprising a fibrous top layer being coated at the back with at least one polymer layer, e.g. carpets, rugs, synthetic turf characterised by the pile
• • D—TEXTILES; PAPER
  • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
  • D01D—MECHANICAL METHODS OR APPARATUS IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS
  • D01D4/00—Spinnerette packs; Cleaning thereof
  • D01D4/02—Spinnerettes
• • D—TEXTILES; PAPER
  • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
  • D01D—MECHANICAL METHODS OR APPARATUS IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS
  • D01D5/00—Formation of filaments, threads, or the like
  • D01D5/08—Melt spinning methods
  • D01D5/088—Cooling filaments, threads or the like, leaving the spinnerettes
  • D01D5/0885—Cooling filaments, threads or the like, leaving the spinnerettes by means of a liquid
• • D—TEXTILES; PAPER
  • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
  • D01D—MECHANICAL METHODS OR APPARATUS IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS
  • D01D5/00—Formation of filaments, threads, or the like
  • D01D5/253—Formation of filaments, threads, or the like with a non-circular cross section; Spinnerette packs therefor
• • D—TEXTILES; PAPER
  • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
  • D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
  • D01F1/00—General methods for the manufacture of artificial filaments or the like
  • D01F1/02—Addition of substances to the spinning solution or to the melt
  • D01F1/06—Dyes
• • D—TEXTILES; PAPER
  • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
  • D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
  • D01F6/00—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof
  • D01F6/02—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from homopolymers obtained by reactions only involving carbon-to-carbon unsaturated bonds
  • D01F6/04—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from homopolymers obtained by reactions only involving carbon-to-carbon unsaturated bonds from polyolefins
• • D—TEXTILES; PAPER
  • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
  • D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
  • D01F6/00—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof
  • D01F6/44—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from mixtures of polymers obtained by reactions only involving carbon-to-carbon unsaturated bonds as major constituent with other polymers or low-molecular-weight compounds
  • D01F6/46—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from mixtures of polymers obtained by reactions only involving carbon-to-carbon unsaturated bonds as major constituent with other polymers or low-molecular-weight compounds of polyolefins
• • D—TEXTILES; PAPER
  • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
  • D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
  • D01F6/00—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof
  • D01F6/58—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from homopolycondensation products
  • D01F6/60—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from homopolycondensation products from polyamides
• • D—TEXTILES; PAPER
  • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
  • D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
  • D01F6/00—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof
  • D01F6/88—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from mixtures of polycondensation products as major constituent with other polymers or low-molecular-weight compounds
  • D01F6/90—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from mixtures of polycondensation products as major constituent with other polymers or low-molecular-weight compounds of polyamides
• • E—FIXED CONSTRUCTIONS
  • E01—CONSTRUCTION OF ROADS, RAILWAYS, OR BRIDGES
  • E01C—CONSTRUCTION OF, OR SURFACES FOR, ROADS, SPORTS GROUNDS, OR THE LIKE; MACHINES OR AUXILIARY TOOLS FOR CONSTRUCTION OR REPAIR
  • E01C13/00—Pavings or foundations specially adapted for playgrounds or sports grounds; Drainage, irrigation or heating of sports grounds
  • E01C13/08—Surfaces simulating grass ; Grass-grown sports grounds
• • D—TEXTILES; PAPER
  • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
  • D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
  • D01F1/00—General methods for the manufacture of artificial filaments or the like
  • D01F1/02—Addition of substances to the spinning solution or to the melt
  • D01F1/04—Pigments
• • D—TEXTILES; PAPER
  • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
  • D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
  • D01F6/00—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof
  • D01F6/44—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from mixtures of polymers obtained by reactions only involving carbon-to-carbon unsaturated bonds as major constituent with other polymers or low-molecular-weight compounds
• • D—TEXTILES; PAPER
  • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
  • D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
  • D01F6/00—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof
  • D01F6/88—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from mixtures of polycondensation products as major constituent with other polymers or low-molecular-weight compounds
• • D—TEXTILES; PAPER
  • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
  • D06N—WALL, FLOOR, OR LIKE COVERING MATERIALS, e.g. LINOLEUM, OILCLOTH, ARTIFICIAL LEATHER, ROOFING FELT, CONSISTING OF A FIBROUS WEB COATED WITH A LAYER OF MACROMOLECULAR MATERIAL; FLEXIBLE SHEET MATERIAL NOT OTHERWISE PROVIDED FOR
  • D06N2201/00—Chemical constitution of the fibres, threads or yarns
  • D06N2201/02—Synthetic macromolecular fibres
  • D06N2201/0254—Polyolefin fibres
• • D—TEXTILES; PAPER
  • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
  • D06N—WALL, FLOOR, OR LIKE COVERING MATERIALS, e.g. LINOLEUM, OILCLOTH, ARTIFICIAL LEATHER, ROOFING FELT, CONSISTING OF A FIBROUS WEB COATED WITH A LAYER OF MACROMOLECULAR MATERIAL; FLEXIBLE SHEET MATERIAL NOT OTHERWISE PROVIDED FOR
  • D06N2201/00—Chemical constitution of the fibres, threads or yarns
  • D06N2201/02—Synthetic macromolecular fibres
  • D06N2201/0263—Polyamide fibres
• • D—TEXTILES; PAPER
  • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
  • D06N—WALL, FLOOR, OR LIKE COVERING MATERIALS, e.g. LINOLEUM, OILCLOTH, ARTIFICIAL LEATHER, ROOFING FELT, CONSISTING OF A FIBROUS WEB COATED WITH A LAYER OF MACROMOLECULAR MATERIAL; FLEXIBLE SHEET MATERIAL NOT OTHERWISE PROVIDED FOR
  • D06N2211/00—Specially adapted uses
• • D—TEXTILES; PAPER
  • D10—INDEXING SCHEME ASSOCIATED WITH SUBLASSES OF SECTION D, RELATING TO TEXTILES
  • D10B—INDEXING SCHEME ASSOCIATED WITH SUBLASSES OF SECTION D, RELATING TO TEXTILES
  • D10B2321/00—Fibres made from polymers obtained by reactions only involving carbon-to-carbon unsaturated bonds
  • D10B2321/02—Fibres made from polymers obtained by reactions only involving carbon-to-carbon unsaturated bonds polyolefins
  • D10B2321/021—Fibres made from polymers obtained by reactions only involving carbon-to-carbon unsaturated bonds polyolefins polyethylene
• • D—TEXTILES; PAPER
  • D10—INDEXING SCHEME ASSOCIATED WITH SUBLASSES OF SECTION D, RELATING TO TEXTILES
  • D10B—INDEXING SCHEME ASSOCIATED WITH SUBLASSES OF SECTION D, RELATING TO TEXTILES
  • D10B2331/00—Fibres made from polymers obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds, e.g. polycondensation products
  • D10B2331/02—Fibres made from polymers obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds, e.g. polycondensation products polyamides
• • D—TEXTILES; PAPER
  • D10—INDEXING SCHEME ASSOCIATED WITH SUBLASSES OF SECTION D, RELATING TO TEXTILES
  • D10B—INDEXING SCHEME ASSOCIATED WITH SUBLASSES OF SECTION D, RELATING TO TEXTILES
  • D10B2505/00—Industrial
  • D10B2505/20—Industrial for civil engineering, e.g. geotextiles
  • D10B2505/202—Artificial grass

Definitions

• the invention relates to the field of artificial turf, and more particular to artificial turf fibers and the manufacture thereof.
• Synthetic grass fields have been used for years to provide a surface that simulates natural grass. These synthetic grass fields have many benefits over natural grass and, in addition, can be installed and used in places that do not allow for natural grass fields, for example, in regions where it is particularly hot and dry.
• US patent US 10,793,973 B2 relates to a synthetic monofilament fiber for use in an artificial lawn which has multiple tapered elevations which are believed be associated with increased risk of skin abrasion, and an increased proneness to wear and tear and the associated generation of microplastic waste.
• EP 1950 350 A1 discloses various fibers, some of which have large bulbs at the center and on the ends. These fibers have stress points at the point the bulbs are connected to the fiber. As a result, these types of fibers have a tendency to fray or split along these stress points.
• a further fiber is disclosed in US006491991B2 which has a curved cross section with a series of flat, planar sections which may lead to decreased mechanical stiffness and other undesired properties.
• Korean patent KR 10-1989-0002109 discloses a spinneret for manufacturing monofilaments for artificial turf.
• the spinneret has an outer periphery formed of continuously repeated triangles of the same size, and an inner periphery formed of continuously repeated curved parts of the same size, for forming a monofilament that by definition has a cross-section that is the same as the cross-section of the spinneret. Since the triangles and the curved parts are connected to neighboring triangles and curved parts for forming the outer periphery and inner periphery, respectively, then a slope (which may also be referred to as tangent line) is indeterminate at each connection point on each respective periphery.
• the slope at each connection point between neighboring triangles and curved parts on each respective periphery is indeterminate, or in other words, the slope as measured at each point along the respective peripheries has a discontinuity at each connection point. If each point on each respective periphery is defined with respect to a cartesian coordinate system x-y to have coordinate (x,y), then the slope at each point is dy/dx.
• a method of manufacturing an artificial turf fiber includes extruding a polymer mixture through at least one fiber profile opening of an extrusion plate to form an artificial turf fiber, the fiber profile opening including: first and second end portion openings, and a curved middle portion opening connected with the first and second end portion openings, the curved middle portion having at least a first spine opening proximate to the first end portion opening and a second spine opening proximate to the second end portion opening; allowing the extruded polymer mixture to travel along a distance between the at least one fiber profile opening of the extrusion plate to a quenching unit, where the first and second spine openings are sized and positioned such that a net polymer mass flow in the extruded polymer mixture from a position of the first spine opening to a first end portion of the fiber and from a position of the second spine opening to a second end portion of the fiber occurs before the fiber is quenched; and quenching the extruded polymer mixture in the quenching unit to form the artificial turf
• an artificial turf fiber by extruding a polymer mixture through at least one fiber profile opening of an extrusion plate including at least a first spine opening proximate to the first end portion opening and a second spine opening proximate to the second end portion opening results in a fiber that has less thinning of the fiber end portions, more resistance to curling of the end of the fiber, and hence more mechanical stability and/or strength.
• the fiber end portions are defined as the end portions in a cross-section of the fiber, whereas the end of the fiber refers to the end of the length of the fiber (i.e. the tip of the fiber).
• the one or more spine openings of the extrusion plate result in a net polymer mass flow, which occurs between extrusion of a polymer mass from the extrusion plate (in the form of an unquenched polymer fiber) and quenching of the fiber via, for example, a quenching unit.
• the extruded fiber may travel a specified distance before entering the quenching unit.
• the net polymer mass flow which is in the direction from a region of the extruded fiber (corresponding to the spine opening of the extrusion plate) to the closest end portion of the fiber, mitigates or prevents a reduction in width of the first and second end portions of the quenched fiber in comparison to a width of the end portion openings of the extrusion plate, thereby increasing dimensional stability and/or mitigating or preventing curling of the end of the quenched fiber.
• the first spine opening is positioned in the middle portion opening on a first arc length defined by a first angle of less than or equal to 60°, or between 35°- 55°, or between 40°- 50°, or at 45°, where the first arc length is measured along the curved middle portion opening from the first end portion opening
• the second spine opening is positioned in the middle portion opening on a second arc length defined by a second angle of less than or equal to 60°, or between 35°- 55°, or between 40°- 50°, or at 45°, where the second arc length is measured along curved middle portion opening from the second end portion opening.
• the quenched fiber includes a first spine created by extruding the polymer mass through the first spine opening and a second spine created by extruding the polymer mass through the second spine opening.
• the quenched fiber even though formed by extruding a polymer mass through an extrusion dye having one or more spine openings, has no visible spines, although the fiber retains the benefits of being extruded through an extrusion dye having one or more spine openings (i.e., mitigation of thinning of the width (or no thinning of the width) of the end portions of the fibers in comparison to a width of the end portion openings of the extrusion dye).
• the ratio of an area of the first spine opening to an area of the first end portion opening is larger than the ratio of a cross-sectional area of the first spine of the quenched fiber to a cross-sectional area of the first end portion of the quenched fiber, the first end portion of the fiber being created by extruding the polymer mass through the first end portion opening, and/or the ratio of an area of the second spine opening to an area of the second end portion opening is larger than the ratio of a cross-sectional area of the second spine of the quenched fiber to a cross-sectional area of the second end portion of the quenched fiber, the second end portion of the fiber being created by extruding the polymer mass through the second end portion opening.
• this feature has the benefit that the spines on the fiber are smaller than the spine openings of the extrusion plate, meaning that the spines may in some instances be barely visible, or in some cases, even invisible.
• an amplitude of the first spine of the quenched fiber is less than an amplitude of the first spine opening, and an amplitude of the second spine of the quenched fiber is less than an amplitude of the second spine opening.
• a width of the first end portion opening is larger than a width of a first section of the middle portion opening adjacent to the first end portion opening
• a width of the second end portion opening is larger than a width of a second section of the middle portion opening adjacent to the second end portion opening
• a width of the first end portion of the quenched fiber is larger than a width of a first section of a middle portion of the quenched fiber adjacent to the first end portion of the quenched fiber
• a width of the second end portion of the quenched fiber is larger than a width of a second section of the middle portion of the quenched fiber adjacent to the second end portion of the quenched fiber.
• the width of the first and second end portion openings are respectively larger than a maximum width of the middle portion opening, and the width of the first and second end portions are respectively larger than a maximum width of a middle portion of the quenched fiber.
• a center of the curved middle portion opening includes a bulge opening, and a maximum width of the middle portion opening including the bulge opening is greater than a maximum width of the first and second end portion openings.
• This feature may also advantageously result in a fiber that is more resilient to forces, and may further result in a fiber that is less likely to flatten through use (i.e., the fiber, including the curved middle portion, retains its curvature), particularly when combined with other features, such as the width of the first and second end portions being respectively larger than a maximum width of a middle portion of the quenched fiber.
• the bulge opening may further provide a fiber with increased mechanical strength that increase the ability of the fiber to quickly straighten up again after a temporary load-induced buckling.
• the curved middle portion opening has two opposing longitudinal contours (i.e., boundary lines), where at least one of the contours includes, or includes exclusively of, uninterrupted undulations.
• the effect of a boundary line consisting completely of uninterrupted undulations may be beneficial because the entire boundary line of the fiber is free of planar areas, pointed elevations and pointed depressions.
• Some prior art artificial turf fibers have a boundary line comprising a series of elevations or depressions to scatter incident light and provide a matt surface impression which is similar to the look of a natural grass fiber surface.
• some prior art fibers have fiber profile contours with multiple successive concave depressions or multiple successive convex elevations.
• Such an outline has several disadvantages: series of concave depressions result in thin, pointed protrusions. These can lead to a very rough surface, especially when using relatively hard, mechanically robust polymer material, which in turn can lead to skin damage.
• these pointed protrusions are subject to high mechanical stress, resulting in a large amount of material being abraded in a short period of time. This abrasion can end up in the environment as unwanted microplastic waste.
• a shape with a contour consisting of uninterrupted undulations has the advantage that the incident light is diffusely scattered, so that a matt, natural surface impression is created, without having to accept problems regarding the risk of injury, microplastics, hygiene or mechanical integrity of the fibers.
• all depressions and indentations of the fiber surface are rounded, or in other words, a tangent line may be formed or defined (i.e., a tangent line is determinate) at each point on boundary lines that define the fiber in cross section, thereby minimizing the risk of splicing, the risk of skin burns, the generation of microplastic and the accumulation of dirt and debris.
• each point on the boundary lines is defined with respect to a cartesian coordinate system x-y to have coordinate (x,y), then the slope at each point is dy/dx, and according to an embodiment of the present invention, the boundary lines have a continuous slope as measured at each point along the boundary lines. In other words, the boundary lines have no discontinuities in slope.
• a further benefit may be that the extrusion process can run true to shape. This means that the shape of the fiber cross section essentially matches the shape of the extrusion die profile opening. As the boundary line of the fiber profile is free of pointed protrusions or indentations, the extrusion die profile is also free of such pointed protrusions or elevations. As a consequence, the formation of speed differences of the extruded polymer mass during extrusion which may result in deformed fibers may be prevented.
• the curved middle portion opening has a shape of one or more sinusoidal waves, or the curved middle portion opening has a shape of an arc, such as an arc of a segment of a circle, an arc of a segment of an ellipse, an arc of a segment of a horseshoe, an arc of a segment of a U, or an arc of a segment of a ⁇ .
• a radius of curvature of the middle portion opening decreases from a center of the middle portion opening towards the end portion openings.
• a cross-section of the fiber being shaped like an arc of a segment of an ellipse, an arc of a segment of a horseshoe, an arc of a segment of a U, or an arc of a segment of a ⁇ may have the advantage of providing fibers which are particularly robust against the flattening of the fiber during production or use. It has been observed that small curvatures do not always recover their original shape (as produced during the extrusion process) after being compressed or flattened during transport through rollers and spinnerets or when subjected to a weight, e.g. the weight of a player or a ball.
• a strong curvature as observed in a segment of a horseshoe, a segment of a U, or a segment of a ⁇ provides an intrinsic elasticity and ability to recover the original shape.
• the use of fiber profiles with a boundary line that is curved like a circular segment arc can have the advantage that light falling from different directions is scattered homogeneously because the curvature of the fiber profile is the same when viewed from all directions. This also means that the light reflected by the artificial turf looks the same when viewed from different angles. As a result, even a synthetic turf that has a too uniform orientation of the fibers due to the manufacturing process does not have any artificial dependence of the optical impression on the viewing angle.
• an artificial turf fiber extruded from an extrusion dye having at least one spine opening in combination with one or more of: (1) an average cross-sectional width of a middle portion opening that increases (preferably monotonically) from the end portion openings to the center of the middle portion; (2) thickened end portion openings (preferably having a thickness that is greater than a maximum thickness of the middle portion opening (between the two end portion openings), excluding the thickness of the center of the middle portion opening when the center may include a rounded bulge opening; and (3) a thickened center opening of the middle portion opening (i.e. a rounded bulge opening), where the thickness is preferably thicker that the thicknesses of the end portion openings, has the synergistic effect of providing a fiber that has even more reinforced mechanical stability and/or strength and even less thinning of the fiber ends.
• the polymer mixture includes a polyethylene or a polyethylene-polyamide blend, where the quenching unit is a water bath, where the distance between the extrusion plate openings (also referred to as the fiber profile opening) and the quenching unit is 3.0 - 5.0 cm, and where a temperature of the water bath is 28°C - 34°C.
• these features have the benefit of providing parameters that optimize the amount of polymer mass flow upon extrusion and before quenching for mitigating thinning of the end portions of the fiber.
• the polymer mixture includes a polyamide as a main polymer component or a polyamide as an exclusive polymer component, where the quenching unit is a water bath, where the distance between the extrusion plate openings and the quenching unit is 2.0 - 4.0 cm, and where a temperature of the water bath is 18°C - 20°C.
• these features have the benefit of providing parameters that optimize the amount of polymer mass flow upon extrusion and before quenching for mitigating thinning of the end portions of the fiber.
• the polymer mixture is at least a two-phase polymer mixture, where a first phase of the polymer mixture includes a first polymer and a first dye and a second phase of the polymer mixture includes a second polymer and a second dye, where a color of the second dye is different than a color of the first dye, where the second polymer is of a same or of a different type as the first polymer, where the first and the second phases are immiscible, and where the extruded fiber has a marbled appearance.
• the first phase forms polymer beads within the second phase
• the polymer mixture further comprises a nucleating agent and/or a compatibilizer and/or the first polymer is any one of the following: polyamide, polyethylene terephthalate, and polybutylene terephthalate
• the second polymer is any one of the following: polyethylene, polypropylene, and a mixture thereof.
• This may have the advantage of further increasing the surface roughness, because the nucleating agent may induce or boost the formation of polymer microcrystals at the surface of the fiber during or after the extrusion process.
• the nucleating agent may be a substance or substance mixture selected from a group comprising: talcum; kaolin (also known as "China clay”); calcium carbonate; magnesium carbonate; silicate: aluminum silicate and; as e.g. sodium aluminosilicate (in particular zeolites of natural and synthetic origin); amorphous and partially amorphous silica and mixed morphologies hereof, e.g. fumed silica; silicic acid and silicic acid esters; e.g.
• coal fly ash is a fine recovered e.g. from coal-fires of electric generation power plants; wherein the organic nucleating agent consists of one of the following items or a mixture thereof: 1,2-cyclohexane dicarbonic acid salts (also known as main component of "Hyperform ® "); in particular calcium salts of the 1,2-cyclohexane dicarbonic acid; benzoic acid; benzoic acid salt; the benzoic acid salt may be, in particular, an alkaline metal salt of the benzoic acid (e.g. sodium and potassium salts of the benzoic acid); and an alkaline earth metal salt of the benzoic acid (e.g. magnesium and calcium salts of the benzoic acid); sorbic acid; and sorbic acid salt.
• 1,2-cyclohexane dicarbonic acid salts also known as main component of "Hyperform ® "
• calcium salts of the 1,2-cyclohexane dicarbonic acid also known as main component of "Hyperform ®
• 0.01 % - 3.0 % by weight of the artificial turf fiber consists of the nucleating agent. preferably, 0.2 %- 0.4 % by weight of the artificial turf fiber consists of the nucleating agent.
• This is a comparatively low amount. Nevertheless, applicant has observed that this small amount is sufficient to achieve a diffuse light scattering that is almost indistinguishable from the light scattering on natural grass. It is possible to use only very small amounts of the nucleating agent, because the diffuse scattering is not only caused by the crystals on the fiber surface, but also by the undulations of the fiber profile.
• nucleating agent may be beneficial as the crystalline portions induced by the nucleating agent at the surface and within a fiber may increase the brittleness of the fiber, thereby increasing the tendency to break or splice.
• an extrusion plate for artificial turf fibers includes at least one fiber profile opening, the fiber profile opening including first and second end portion openings, and a curved middle portion opening connected with the first and second end portion openings.
• the curved middle portion opening has at least a first spine opening proximate to the first end portion opening and a second spine opening proximate to the second end portion opening.
• the features of the extrusion plate result in a fiber that has less thinning of the fiber end portions, more resistance to curling of the end of the fiber, and hence more mechanical stability and/or strength.
• the one or more spine openings of the extrusion plate result in a net polymer mass flow, which occurs between extrusion of a polymer mass from an extrusion plate (in the form of an unquenched polymer fiber) and quenching of the fiber via, for example, a quenching unit.
• the extruded fiber may travel a specified distance before entering the quenching unit.
• the net polymer mass flow which is in the direction from a region of the extruded fiber (corresponding to the spine opening of the extrusion plate) to the closest end portion of the fiber, mitigates or prevents a reduction in width of the first and second end portions of the quenched fiber in comparison to a width of the end portion openings of the extrusion plate, thereby increasing dimensional stability and/or mitigating or preventing curling of the end of the quenched fiber.
• a maximum width of the first spine opening is larger than 110%, in particular larger than 115%, in particular 110% to 160%, in particular 115% to 135% of an average width of the middle portion opening, where the average width of the middle portion opening is determined without considering a width of an optional central bulge opening, if any, and where a maximum width of the second spine opening is larger than 110%, in particular larger than 115%, in particular 110% to 160%, in particular 115% to 135% of the average width of the middle portion opening, where the average width of the middle portion opening is determined without considering the width of the optional central bulge opening, if any.
• an extruded artificial turf fiber has a cross-sectional profile including first and second end portions connected via a curved middle portion, where the middle portion includes at least a first spine proximate to the first end portion and at least a second spine proximate to the second end portion.
• first and second spine indicate that that fiber has been formed by extruding a polymer mass through a dye having spine openings, thereby providing a fiber with end portions that are approximately to specification (i.e., end portions having dimensions that are approximately the same as the dimensions of the end portion openings of the dye), resulting in a fiber with increased strength and resilience against flattening and curling.
• a width of the first spine is less than 125%, in particular less than 115%, in particular 101% to 115 % of an average width of the middle portion, where the average width of the middle portion is determined without considering a width of an optional central bulge, if any, and where a width of the second spine is less than 125%, in particular less than 115%, in particular 101% to 115 % of the average width of the middle portion, where the average width of the middle portion is determined without considering the width of the optional central bulge, if any.
• an "undulation” as used herein is a curve having a continuous up and down shape.
• a boundary line consisting of uninterrupted undulations may be described as a boundary line not having a vertical tangent.
• a boundary line consisting of uninterrupted undulations may also be described as a mathematically differentiable curve.
• Figure 1 is a perspective 3D view of the inside of a section of an artificial turf fiber 100.
• the fiber may be made of polyethylene or polypropylene or polyamide or a mixture of two or more of these polymers.
• the fiber may be generated in an extrusion process and the cross-sectional area 102 of the fiber may have essentially the same shape along the entire length of the fiber.
• Figure 1 shows the inner surface 104 of the fiber defined by the concave part of the boundary line of the shape of the fiber profile.
• the length of the fiber (measured from the upper surface of a carrier to the free ends of the fibers) may be different.
• the fiber length may be in the range of e.g., 2.0 cm to 9.0 cm, preferably 3.0 cm to 7.0 cm.
• Figure 2 is a perspective 3D view of the outside of a section of the fiber 100 shown already in figure 1.
• Figure 2 shows the outer surface 202 of the fiber defined by the outer, convex part of the boundary line of the shape of the fiber profile.
• Figure 3 shows the cross-section of the fiber 100 depicted already in figures 1 and 2 .
• the fiber comprises a first end 302 connected to the center 306 of the fiber via a first fiber arm and comprises a second end 304 connected to the center of the fiber via a second arm.
• the fiber has an arced cross-sectional shape, in this case the shape of a circle segment arc.
• the arced cross-sectional shape is defined by a boundary line consisting of uninterrupted undulations. This means that there are therefore no tapering elevations or recesses and no planar surface areas.
• the boundary profile may be described as a curve being free of "spinodes” or "cusps", i.e., a point on a curve where a moving point must reverse direction, or as a curve having no discontinuities in slope (i.e., having continuous values of slope) as measured at points along the curve, where slope may be defined as dy/dx at each point (x,y) on the curve, where points (x,y) that define the curve are points defined with respect to a cartesian coordinate system x-y that may be placed anywhere in the plane of Fig. 3 , for example.
• the particular form of the boundary line consisting of uninterrupted undulations may imply that - apart from the cross-sectional area of the fiber at the upper and lower fiber ends where the fiber is cut during or after integration into a carrier - the fiber surface is basically free of any planar areas. This may be highly beneficial, because planar areas reflect the incident light directionally, not diffusely, so that the artificial turf is at least partially highly reflective and can even dazzle the observer. This creates a visual impression that is clearly different from that of a natural lawn, which is undesirable.
• the undulations comprise alternating depressions 308 and elevations 312 on the outer fiber surface and alternating depressions 310 and elevations 314 on the inner fiber surface.
• the thickness of the fiber at the thickenings 318 at the two ends is slightly greater than the thickness of the thickest portions of the fiber arms connecting the ends 302, 304 with the center 306. Moreover, there is a further thickening at the center of the fiber resulting in a protrusion/undulation 316 from the outer surface 312. In the depicted example, the central thickening does not result in a protrusion from the inner surface 102 of the fiber.
• Figure 4 shows the fiber cross-section of Fig. 3 with height h and width w annotated.
• the width w can be measured as straight line indicating the distance of the most outer points of the two fiber ends.
• the height h of the fiber may be measured as the distance of the "lowest" points of the fiber ends to the "highest” point at the fiber center.
• the height h may be significantly smaller than the radius defining the curvature of the arced shape of the fiber profile, meaning that in case the arced shape is defined by a circle, the fiber profile may cover a segment that is significantly smaller than the 180° segment. In other words, the radius of this circle may be significantly longer than h.
• Figure 5 shows the fiber cross-section of Fig. 3 with the circles defining the curvature of the corrugations and the ends annotated.
• the undulations of the boundary line defining the shape of the outer surface of the fiber are defined by multiple circles 508 sharing the same radius/diameter D3.
• the undulations of the boundary line defining the shape of the inner surface of the fiber are defined by multiple circles 510 sharing the same radius/diameter D4.
• the fiber has thickenings at the center and at the two ends to increase the mechanical stability.
• the curvature of the ends is defined by the radius/diameter D1 of the circles 502.
• the curvature of the protrusion 316 induced by the thickening at the center is defined by the radius/diameter D2 of circle 506.
• D1 and D2 are significantly larger than D3 and D4.
• D3 and D4 are identical.
• D1 is slightly larger than D2.
• D3 and D4 may be similar, but not identical.
• D1 and D2 may be identical.
• both D1 and D2 may represent a diameter which is chosen such that the ratio of D1 (or D2) to D3 (or D4) approximately is the golden ratio.
• Figure 6 shows the fiber cross-section, where the fiber thicknesses at different cross-sectional areas are annotated.
• the thickness of the fiber cross section is not constant but varies only slightly: the thickness w1 602 is slightly greater than the thickness w2 604 at the two points in the fiber arms equidistant from the ends, because in the depicted example, the fiber ends comprise a thickening.
• the thickness w3 606 at two other points in the fiber arms equidistant from the ends is slightly greater than the thickness w2.
• the fiber center represents the thickest and hence stiffest portion of the fiber having a thickness w4 608 being greater than w1, w2 and w3.
• w2 is the smallest with in the fiber arm and w3 is the largest width of the fiber arm.
• w1 and w2 may be identical, but preferably w1 is greater than the smallest width w2 of the fiber arms, and preferably also greater than the largest width w3 of the fiber arm.
• the fiber profile is axisymmetric with respect to a vertical axis through the center of the fiber profile as shown in figures 3-6 .
• the undulations may be shifted such that the fiber profile is not axisymmetric with respect to the vertical axis.
• Figures 7A and 7B show an example of a fiber cross-section annotated with concrete dimensions.
• the fiber cross section corresponds to the cross section of the fibers depicted in figures 1-6 .
• the dimensions of the fiber 100 shown in figures 7A and 7B correspond to a 1100 dtex fiber.
• the numbers are given in cm.
• the width of the fiber profile measured from the outermost points of the two ends is 1.0 cm, or 0.9 cm if the distance between the centers of the two fiber ends is measured.
• the fiber profile can be scaled to provide fibers of different fiber weights. For example, by scaling the outer width of the fiber profile from 1.0 cm to 1.351 cm, and scaling all other dimensions given in figure 7 proportionally, a fiber of 2000 dtex can be obtained. By using a different scaling factor, many different versions of the artificial turf fiber having different fiber weights can be obtained.
• the cross-section of the fiber is shaped like the arc of a segment of a circle having a radius referred to as "fiber profile circle radius".
• the radius to the topmost point of the outer surface is 0.59 cm.
• the width of the fiber profile when the outmost points of the fiber ends are considered is 1.0 cm.
• the ratio of the width of the fiber profile and the fiber profile radius is 1.0/0.59, i.e., 1.694. This value is in the range of 1.40 to 1.80, in particular 1.50 to 1.70, and hence approximately the golden ratio.
• the radius of the circle 506 defining the undulation at the center of the fiber is 0.081 cm.
• the shared radius of the multiple smaller circles defining the undulation at the outer surface of the fiber 100 is 0.05 cm.
• the shared radius of the multiple smaller circles defining the undulation at the inner surface of the fiber 100 is also 0.05 cm.
• the ratio of the radius defining the curvature of the protrusion 316 at the fiber center to the radius of the circles defining the undulations at the outer (and/or inner) surface of the fiber is 0.081/0.05, i.e., 1.62. This value is in the range of 1.40 to 1.80, in particular 1.50 to 1.70, and hence approximately the golden ratio.
• Figure 8 shows an example of a cross-section of a further fiber 800 having more undulations than the fiber cross section depicted in figures 1-7 .
• the curvature of the whole fiber profile is the same as the profile curvature of the fibers depicted in figures 1-7 .
• Figure 9 shows an example of a cross-section of a further fiber 900 having more undulations than the fiber cross section depicted in figures 1-7and having an extended curvature compared to the fiber cross sections depicted in figures 1-7 .
• Extended curvature means that the fiber profile corresponds to the arc of a circular segment having a larger angle than the circular segment whose arc corresponds to the fiber profile curvature of the fibers shown in Figures 1-7 .
• Figure 10 shows the cross-section of an example of a further fiber 1000.
• the depicted fiber has a thickening at its center which leads to a bulge on both the outer and inner surface of the fiber.
• Figure 11 shows the cross-section of an example of a further fiber 1100.
• the cross-section of the depicted fiber has the shape of a catenary.
• Figure 12 shows the cross-sectional profile of an extruded artificial turf fiber 1200, according to another embodiment.
• the artificial turf fiber is similar to artificial turf fiber 100 of Figs. 1-3 , and reference numbers that are the same as those in Figs. 1-3 reference identical elements.
• the cross-sectional profile of the fiber 1200 includes a first end 302 (also defined as a first end portion 302), a second end 304 (also defined as a second end portion 304), a curved middle portion 1202, and a center 306 of the middle portion 1202.
• the middle portion 1202 has a curved cross-sectional shape, and the first and second end portions are connected via the curved middle portion.
• the curved cross-sectional shape is formed from one or more arced-cross sectional shapes.
• the curved cross-sectional shape is the arc of a segment of a circle.
• the curved cross-sectional shape of the middle portion 1202 is defined by a first boundary line 1206 and a second boundary line 1208 opposite the first boundary line.
• the first boundary line 1206 is a line on the outer surface 202 ( Fig.
• the first boundary line 1206 includes or includes exclusively of first uninterrupted undulations represented collectively by the indentations 308 and protrusions 312, and the second boundary line 1208 includes or include exclusively of second uninterrupted undulations represented collectively by the indentations 310 and protrusions 314.
• the curved cross-sectional shape of the fiber 1200 has a longitudinal direction 1210 (also referred to as a longitudinal dimension), along which a length of the cross-sectional shape lies.
• the curved cross-sectional shape of the fiber 1200 also has a transverse direction that is defined by a direction that Is perpendicular to the longitudinal direction.
• a thickness w (also referred to as a width, a transverse width or an amplitude) of the curved cross-sectional shape of the middle portion 1202, as measured between corresponding points on first and second boundary lines 1206, 1208, where corresponding points are the two points that lie on a line that is transverse to the longitudinal direction and that also lie on the first and second boundary lines, respectively, is constant or substantially constant along the longitudinal direction 1210 of the curved cross-sectional shape.
• thicknesses i.e., widths
• w1, w2 and w3 are equal to one another, and moreover, a thickness w of the curved cross-sectional shape of the middle portion 1202 measured at all positions along the longitudinal direction is constant or substantially constant.
• the first uninterrupted undulations 308, 312 have a first wavelength 1212 and the second uninterrupted undulations 310, 314 have a second wavelength 1214, where the first and second wavelengths are selected such that the thickness w of the curved cross-sectional shape of the middle portion 1202 is constant or substantially constant along the longitudinal direction 1210.
• the length of the second boundary line 1208 (i.e., as measured from either the first or second end portion to a position on the second boundary line 1208 opposite the center 306 along the inner surface 104 of the fiber) is shorter than the length of the first boundary line 1206 (i.e., as measured from either the first or second end portion to a position on the first boundary line 1206 opposite the center 306 along the outer surface 202 of the fiber), and the difference between the lengths depend upon the extent of the curvatures of the inner and outer surfaces of the fiber 1200.
• the radius of curvature of the inner surface 104 (and the second boundary line 1208) is smaller than the radius of curvature of the outer surface 202 (and the first boundary line 1206), and thus the length of the second boundary line 1208 is shorter than the length of the first boundary line 1206.
• the wavelength (also referred to as the spatial frequency, which is the inverse of the wavelength) of the second uninterrupted undulations 310, 314 is selected to be smaller than the wavelength (i.e. spatial frequency) of the first uninterrupted undulations 308, 312.
• thicknesses 318 of the first and second end portions 302, 304 of the fiber are greater than the constant thickness w of the curved cross-sectional shape of the middle portion 1202.
• Figure 13 shows the cross-section of an extruded artificial turf fiber 1300 according to yet another embodiment.
• the artificial turf fiber 1300 is similar to artificial turf fiber 1200 of Fig. 12 , and reference numbers that are the same as those in Fig. 12 reference identical elements.
• a thickness w of the curved cross-sectional shape of the middle portion 1202, as measured between corresponding points on the first and second boundary lines 1206, 1208, is not constant along the longitudinal direction 1210 of the curved cross-sectional shape. That is, in contrast to the Fig. 12 embodiment, the first uninterrupted undulations 308, 312 of the first boundary line 1206 of the curved cross-sectional shape of the middle portion 1202 may have a phase offset 1216 from the second uninterrupted undulations 310, 314 of the second boundary line 1208 of the curved cross-sectional shape of the middle portion 1202.
• a phase offset such as phase offset 1216
• the middle portion 1202 having a variable thickness, independent of whether the wavelengths 1212 and 1214 (i.e., spatial frequencies) are equal or not (i.e., the thickness w of the curved cross-sectional shape of the middle portion 1202at positions along the longitudinal direction 1210 is not constant (i.e., it is variable, or non-constant)).
• a thickness w of the curved cross-sectional shape of the middle portion 1202 is not constant along the longitudinal direction 1210 of the curved cross-sectional shape when the width varies by more the ⁇ 5%.
• the first and second uninterrupted undulations may have the same (or substantially the same) wavelength (i.e., spatial frequency).
• the first uninterrupted undulations 308, 312 have a first wavelength 1218 (also referred to as a first spatial frequency) and the second uninterrupted undulations 310, 314 have a second wavelength 1220 (also referred to as a second spatial frequency), where the first and second wavelengths (spatial frequencies) are selected to be approximately equal to one another.
• the thickness w of the curved cross-sectional shape of the middle portion 1202 is variable (i.e., non-constant) along the longitudinal direction 1210, independent on whether or not there is a phase offset.
• the thicknesses 318 of the first and second end portions 302, 304 of the fiber 1300 are greater than a maximum thickness of the variable thickness w of the curved cross-sectional shape of the middle portion 1202. For example, if w5 is the maximum thickness of the variable thickness of the curved cross-sectional shape of the middle portion 1202, then the thicknesses 318 of the first and second end portions 302, 304 of the fiber 1300 are greater than w5.
• the curved cross-sectional shape of each of the first and second end portions 302, 304 are defined by boundary lines 1222, 1224, respectively. Although the boundary lines 1222, 1224 are curved, they do not include undulations. However, in an alternate embodiment, the curved cross-sectional shapes of each of the first and second end portions 302, 304 are defined by boundary lines 1226, 1228, respectively, that consist of third uninterrupted undulations. In yet another embodiment, wavelengths (i.e., spatial frequencies) of the third uninterrupted undulations of boundary lines 1226, 1228 are greater than or equal to the wavelengths (i.e. spatial frequencies) of the first and second undulations of the first and second boundary lines 1206, 1208.
• each of the first and second end portions 302, 304 of fiber 1300 may also be defined by boundary lines consisting of third uninterrupted undulations as described with respect to the fiber 1200 ( Fig. 12 ).
• the curved cross-sectional shape of the extruded artificial turf fiber 1200, 1300 comprises one of: an arc of a segment of a circle, an arc of a segment of an ellipse, an arc of at least a segment of a horseshoe, an arc of at least a segment of a U, or an arc of at least a segment of a ⁇ .
• Each point on an arc of an ellipse has a different radius from neighboring points.
• the scope of the disclosed embodiments of the curved cross-sectional shapes of the extruded artificial turf fibers include arcs defined by boundary lines that have a varying radius of curvature along the longitudinal direction of the cross-sectional shapes.
• the first boundary line 1206 is an outer, convex boundary line (i.e., a line on the outer surface 202 ( Fig. 2 ) of the fiber) and the second boundary line 1208 is an inner, concave boundary line (i.e., line on the inner surface 104 of the fiber), where at least 70%, in particular at least 80%, e.g., 100% of the undulations of the outer boundary line 1206 are defined by first circles having a same first diameter D3, and where at least 70%, in particular at least 80%, e.g., 100% of the undulations of the inner boundary line 1208 are defined by second circles having a same second diameter D4.
• the center 306 of the middle portion 1202 of the fiber 1200, 1300 comprises a thickening that forms a rounded protrusion 316 to at least one side of the fiber.
• the embodiments of Figs. 12 and 13 illustrate a thickening at the center 306 of the middle portion 1202 of the fiber resulting in a protrusion 316 from an outer surface, such as outer surface 202 ( Fig. 2 )
• the central thickening may result in a protrusion only from the inner surface, such as inner surface 104 ( Fig. 1 ), or a first protrusion from the outer surface 202 and a second protrusion from the inner surface 104, where the protrusions are formed opposite one another on the two surfaces.
• the center 306 does not have any thickening or bulge.
• the bulge has a thickness that is 10-20% thicker than a maximum thickness of the other portions of the middle portion.
• Fig. 14 shows the cross-section of an extruded artificial turf fiber 1400 according to another embodiment.
• Reference numbers that are the same as those in Figs. 12 and 13 reference identical elements.
• an average thickness (also referred to as an average width) of the curved cross-sectional shape of the middle portion 1202 is not constant along the longitudinal direction 1210, but increases as the longitudinal distance from the center 306 decreases.
• the average thickness of the middle portion is the transverse distance between a first base line 1518 and a second baseline 1520, where the first and second baselines are lines that pass through, e.g., all the peaks of the protrusions of the undulations on both the first and second boundary lines 1508, 1510, respectively.
• the baselines may be defined to be any line that passes through points on the boundary lines that have the same amplitude values (e.g., see baselines 1618, 1620 of Fig. 16 and baselines 1718, 1720 of Fig. 17 ).
• the average thickness w3 is larger than the average thickness w2, which is larger than the average thickness w1.
• the middle portion 1202 has at least one spine proximate to respective end portions 302 and/or 304.
• the middle portion 1202 includes at least a first spine 1402 proximate to the first end portion 302 and at least a second spine 1404 proximate to the second end portion 304.
• the first boundary line 1206 of the middle portion 1202 has the first spine 1402 and the second spine 1404.
• a spine is defined as a protrusion that is slightly larger in amplitude than neighboring protrusions, and in other embodiments, as a protrusion that is slightly larger in amplitude that all other protrusions on both the first and second boundary lines of the cross-sectional shape of the middle portion 1202.
• a slightly larger amplitude is defined to be an amplitude that is about 2-5% larger than amplitudes of neighboring protrusions, or alternatively may be defined to represent a thickness of the middle portion (corresponding to a spine) that is less than about 10% larger than an average thickness of the middle portion, or less than about 5% larger than the average thickness of the middle portion, or between about 2-5% larger than the average thickness of the middle portion.
• a width (i.e., thickness or amplitude) of the first spine 1402 is less than 125%, in particular less than 115%, in particular 101% to 115 % of an average width (i.e., thickness or amplitude) of the middle portion 1202, and/or a width of the second spine 1404 is less than 125%, in particular less than 115%, in particular 101% to 115 % of the average width of the middle portion 1202, where the average width of the middle portion 1202 is determined without considering (i.e., to the exclusion of) the width of an optional central bulge (e.g., the optional bulge 316 at the center 306 of the middle portion 1202).
• an optional central bulge e.g., the optional bulge 316 at the center 306 of the middle portion 1202
• the first boundary line 1206 of the middle portion 1202 includes at least one spine (e.g., spines 1402 and 1404) that is continuous with neighboring first uninterrupted undulations.
• the at least one spine (e.g., spines 1402 and 1404) are positioned on an outer half, or on an outer third, of the middle portion 1202, as measured from the center 306 of the middle portion to the respective end portions 302, 304.
• the positioning of the spine(s) will be discussed further below in conjunction with Fig. 17 , applicable to the Fig. 14 embodiment as well.
• one or more spines e.g., an even number of spines
• the thicknesses w4, w5 of the middle portion corresponding to the location of the spines 1402, 1404, respectively, represent the maximum thickness of the middle portion 1202, excluding the thickness of the middle portion 1202 at the center 306 that corresponds to the bulge 316, for those embodiments that include a thickening at the center 306.
• Fig. 14 illustrates an embodiment in which the average thickness of the curved cross-sectional shape of the middle portion 1202 (excluding regions that contain the spines) is not constant along the longitudinal direction 1210 (i.e., it increases as the longitudinal distance from the center 306 decreases), the scope of the invention includes other embodiments in which the thickness of the curved cross-sectional shape of the middle portion 1202, including the central portion and including the regions containing the spines, is constant along the longitudinal direction.
• the thickness of the curved cross-sectional shape of the middle portion 1202, excluding the regions containing the spines and/or excluding the center 306 of the middle portion 1202, is either constant along the longitudinal direction or monotonically increasing along the longitudinal direction from either or both end portions 302, 304 towards the center 306 of the middle portion 1202.
• Figs. 15 , 16 and 17 illustrate, in respective lower panels, a cross-section of an extrusion dye (also referred to as an extrusion plate) though which a polymer mixture is extruded as part of the process of forming an extruded artificial turf fiber, and in respective upper panels, a photo of the artificial turf fiber (i.e., the product) extruded through the dye.
• an extrusion dye also referred to as an extrusion plate
• a photo of the artificial turf fiber i.e., the product
• Fig. 15 illustrates a cross-section of an extrusion dye 1502 and a photo of an artificial turf fiber 1504 formed in part by extruding a polymer mixture, as disclosed according to the embodiments in the present application, through the extrusion dye 1502.
• An outline 1506 of the extrusion dye 1502 is superimposed on the artificial turf fiber 1504 for purposes of comparing the shape of the final product 1504 with the desired shape 1506.
• Fig. 15 illustrates a cross-section of an extrusion dye 1502 and a photo of an artificial turf fiber 1504 formed in part by extruding a polymer mixture, as disclosed according to the embodiments in the present application, through the extrusion dye 1502.
• An outline 1506 of the extrusion dye 1502 is superimposed on the artificial turf fiber 1504 for purposes of comparing the shape of the final product 1504 with the desired shape 1506.
• the average width wd of the extrusion dye 1502 is constant along a longitudinal length of the dye, where the average width wd is defined as a transverse distance between corresponding pairs of points, where first points of pairs of corresponding points are located on a first baseline 1518 that passes through the peaks of the protrusions of the undulations on an outer boundary line 1508 (on an outer surface of the dye) and second points of the pairs of corresponding points are located on a second baseline 1520 that passes through the peaks of the protrusions of the undulations on an inner boundary line 1510 (on an inner surface of the dye).
• the cross-sectional shape of the extrusion dye 1502 has uninterrupted undulations, the cross-sectional shape of the extrusion dye 1502 does not include any spines.
• a comparison of the photo of the artificial turf fiber 1504 with the desired shape 1506 shows a reduction in curvature of the artificial turf fiber 1504, and a thinning of the thickness of at least one end portion 1512 of the fiber.
• Fig. 16 illustrates a cross-section of an extrusion dye 1602 and a photo of an artificial turf fiber 1604 formed in part by extruding a polymer mixture, as disclosed according to the embodiments in the present application, through the extrusion dye 1602.
• the average width wd of the extrusion dye 1602 monotonically increases along a longitudinal length of the dye from the end portions 1605 to a center 1606, where the average width wd at the center 1606 is a maximum width of the dye and the average width wd adjacent the end portions 1605 is a minimum width of the dye.
• the cross-sectional shape of the extrusion dye 1602 has uninterrupted undulations, but does not include any spines.
• a comparison of the photo of the artificial turf fiber 1604 with the desired shape shows a reduction in curvature of the artificial turf fiber 1604.
• the thicknesses of the end portions 1608 of the fiber appear to show a thinning when compared to the thickness of the end portions 1605 of the dye 1602.
• the end portions 1608 of the Fig. 16 embodiment appear to be better defined with respect to the adjacent uninterrupted undulations.
• Fig. 17 illustrates a cross-section of an extrusion dye 1702 and a photo of an artificial turf fiber 1704 formed in part by extruding a polymer mixture, as disclosed according to the embodiments in the present application, through the extrusion dye 1702.
• extrusion dye 1702 includes one fiber profile opening (i.e., first and second end portion openings 1703 and 1705, a curved middle portion opening 1707 connected with the first and second end portion openings, and at least a first spine opening 1710 proximate to the first end portion opening 1703 and a second spine opening 1712 proximate to the second end portion opening 1705), other extrusion dye embodiments (not shown) include two or more fiber profile openings.
• first and second end portion openings 1703 and 1705 i.e., first and second end portion openings 1703 and 1705, a curved middle portion opening 1707 connected with the first and second end portion openings, and at least a first spine opening 1710 proximate to the first end portion opening 1703
• the average width wd of the extrusion dye 1702 monotonically increases along a longitudinal length of the dye from the end portion openings 1703, 1705 to a center 1706 of the curved middle portion opening 1707, where the average width wd1 in the center 1706 is a maximum width of the dye and the average width wd2 adjacent the end portion openings 1703, 1705 is a minimum width of the dye.
• the rate of increase in the average width with respect to longitudinal distance is less than the rate of increase in average width as illustrated by the Fig. 16 embodiment.
• the cross-sectional shape of the extrusion dye has uninterrupted undulations, however unlike Figs.
• the cross-sectional shape of the extrusion dye of the Fig. 17 embodiment includes the spine openings 1710 and 1712.
• the cross-sectional shape of the extrusion dye 1702 also has an optional rounded bulge opening 1714 at the center 1706.
• a comparison of the photo of the artificial turf fiber 1704 with the desired shape shows a better retention of curvature of the artificial turf fiber 1704 in comparison to Figs. 15 and 16 .
• the end portions i.e., first and second end portions 1715, 1717
• the fiber appear to show a better retention of the thickness in comparison to Figs. 15 and 16 .
• the average width wd of the extrusion dye 1702 is constant (or substantially constant) along a longitudinal length of the dye from the end portion openings 1703, 1705 to the center 1706, the cross-sectional shape of the extrusion dye 1702 still includes spine openings, for example spine openings 1710 and 1712, and the curved middle portion opening 1707 is not bulged at the center 1706 (i.e., the cross-sectional shape of the extrusion dye 1702 does not have the optional rounded bulge opening 1714 at the center 1706).
• a maximum width of the first spine opening wmax 1 is larger than 110%, in particular larger than 115%, in particular 110% to 160%, in particular 115% to 135% of an average width wd of the middle portion opening, where the average width of the middle portion opening is determined without considering (i.e., exclusive of) a width (wo + wd1) of the optional central bulge opening 1714, if any, and where a maximum width of the second spine opening wmax 2 is larger than 110%, in particular larger than 115%, in particular 110% to 160%, in particular 115% to 135% of the average width wd of the middle portion opening, where the average width of the middle portion opening is determined without considering the width of the optional central bulge opening, if any.
• Fig. 17 further illustrates positioning of the spine openings 1710, 1712 of the middle portion opening 1707, according to embodiments of the present invention.
• the first spine opening 1710 is positioned in the middle portion opening 1707 on a first arc length AL 1 subtended by a first angle ⁇ 1 of less than or equal to 60°, or between 35°- 55°, or between 40°- 50°, or at 45°.
• the first arc length AL 1 is measured along the curved middle portion opening 1707 from the first end portion opening 1703.
• the second spine opening 1712 is positioned in the middle portion opening 1707 on a second arc length ALzsubtended by a second angle ⁇ 2 of less than or equal to 60°, or between 35°- 55°, or between 40°- 50°, or at 45°.
• the second arc length AL 2 is measured along curved middle portion opening 1707 from the second end portion opening 1705.
• ⁇ 1 is subtended by a first straight line drawn between a first distal end point 1709 of the first end portion opening 1703 and a center point 1713, and a second straight line drawn between a peak of the first spine 1710 and the center point 1713.
• ⁇ 2 is subtended by a third straight line drawn between a second distal end point 1711 of the second end portion opening 1705 and the center point 1713, and a fourth straight line drawn between a peak of the second spine 1712 and the center point 1713.
• the center point 1713 is defined as a midpoint on the straight line drawn between the first distal end point 1709 and the second distal end point 1711.
• a first center point is defined as a point on a first straight line 1 ⁇ 4 wavelength from a first distal end point of a first end portion opening and a second center point is defined as a point on a second straight line 1 ⁇ 4 wavelength from a second distal end point of a second end portion opening.
• a first spine opening is positioned in the middle portion opening on a first arc length subtended by a first angle ⁇ 1 of less than or equal to 60°, or between 35°- 55°, or between 40°- 50°, or at 45°.
• the first arc length is measured along a curved middle portion opening from the first end portion opening.
• the second spine opening is positioned in the middle portion opening on a second arc length subtended by a second angle ⁇ 2 of less than or equal to 60°, or between 35°- 55°, or between 40°- 50°, or at 45°.
• the second arc length is measured along the curved middle portion opening from the second end portion opening.
• ⁇ 1 is subtended by the first straight line and a third straight line drawn between a peak of the first spine and the first center point.
• ⁇ 2 is subtended by the second straight line and a fourth straight line drawn between a peak of the second spine and the second center point.
• positioning of at least one spine opening, preferentially in the middle portion opening 1707 on a first arc length AL 1 defined by a first angle ⁇ 1 of less than or equal to 60°, or between 35°- 55°, or between 40°- 50°, or at 45° provides a fiber that has reinforced mechanical stability and/or strength (i.e., retains its shape and maintains its structural integrity (less prone to splitting) after repeated loading by external forces, such as forces applied to the fibers from people, animals and/or weather events when the fibers are incorporated into carriers of artificial turfs.
• positioning at least one spine according to the embodiments described above and/or sizing the width (also referred to as the amplitude) of the spine openings relative to the average width of the middle portion opening, where the average width of the middle portion opening is determined without considering the width (wo +wd1) of the optional central bulge opening advantageously enables a net polymer mass flow in the polymer mixture of the extruded fiber, which occurs between the time that the polymer mixture exists the extrusion plate (in the form of an unquenched extruded fiber) and time that the extruder fiber is quenched via, for example, a quenching unit such as a water bath.
• the spines according to embodiments of the present invention enable a net polymer mass flow (that occurs in the unquenched fiber as the fiber travels between the extrusion plate and the quenching unit), where the net polymer mass flow is in a direction from a position of the first spine opening (i.e., from a position on the extruded fiber that coincides with the position of the first spine opening of the extrusion plate) to the first end portion of the fiber, and in a direction from a position of the second spine opening (i.e., from a position on the extruded fiber that coincides with the position of the second spine opening of the extrusion plate) to the second end portion of the fiber.
• a position of the first spine opening i.e., from a position on the extruded fiber that coincides with the position of the first spine opening of the extrusion plate
• a position of the second spine opening i.e., from a position on the extruded fiber that coincides with the position of the second spine opening of the
• the net polymer mass flow in the extruded polymer fiber which occurs between extrusion and quenching, and which is caused by the extrusion plate having one or more spine openings, mitigates or prevents a reduction in width of the first and second end portions of the quenched fiber in comparison to a width of the end portion openings of the extrusion plate, thereby increasing dimensional stability and/or mitigating or preventing curling of the end of the quenched fiber.
• an artificial turf fiber includes a first spine created by extruding a polymer mass through a first spine opening of an extrusion plate and includes a second spine created by extruding the polymer mass through a second spine opening of the extrusion plate.
• the artificial turf fiber 1704 extruded through extrusion dye 1702 has barely visible spines 1722, 1724, however other embodiments of extruded artificial turf fibers have more prominent spines.
• extruded through respective extrusion dyes (not shown) having differently-shaped fiber profile openings include spines 1802, 1804, spines 1902, 1904, spines 2002, 2004, spines 2202, 2204, spines 2302, 2304, and spines 2402, 2404, respectively.
• Shapes of the fiber profile openings of the extrusion dyes corresponding to Figs. 18-25 will be discussed further below.
• the ratio of an area of the first spine opening 1710 to an area of the first end portion opening 1703 is larger than the ratio of a cross-sectional area of the first spine 1722 of the fiber 1704 to a cross-sectional area of the first end portion 1715 of the fiber
• the ratio of an area of the second spine opening 1712 to an area of the second end portion opening 1705 is larger than the ratio of a cross-sectional area of the second spine 1724 of the fiber 1704 to a cross-sectional area of the second end portion 1717 of the fiber.
• the second end portion 1717 of the fiber is formed by extruding a polymer mass through the second end portion opening 1705 and the first end portion 1715 of the fiber is formed by extruding the polymer mass through the first end portion opening 1703.
• an amplitude (also referred to as width) of the first spine 1722 of the fiber 1704 is less than an amplitude wmax1 (also referred to as width) of the first spine opening 1710, and an amplitude of the second spine 1724 of the fiber 1704 is less than an amplitude wmax2 of the second spine opening 1712.
• a width wep1 of the first end portion opening 1703 is larger than a width wd2 of a first section 1726 of the middle portion opening 1707 adjacent to the first end portion opening 1703
• a width wep2 of the second end portion opening 1705 is larger than a width wd2 of a second section 1728 of the middle portion opening 1707 adjacent to the second end portion opening 1705
• a width wf1 of the first end portion 1715 of the fiber 1704 is larger than a width wfa1 of a first section 1730 of a middle portion 1732 of the fiber 1704 adjacent to the first end portion of the fiber
• a width wf2 of a second end portion 1717 of the fiber 1704 is larger than a width wfa2 of a second section 1734 of the middle portion of the fiber adjacent to the second end portion of the fiber.
• the width of the first and second end portion openings wep1, wep2 are respectively larger than a maximum width of the middle portion opening 1707, and the width of the first and second end portions wf1, wf2 are respectively larger than a maximum width of a middle portion 1732 of the fiber.
• a center 1706 of the curved middle portion opening 1707 includes a bulge opening 1714, and a maximum width of the middle portion opening 1707 including the bulge opening 1714 is greater than a maximum width of the first and second end portion openings 1703, 1705.
• the fiber 1704 includes either no spines or no spines visible to the human eye at positions (i.e., corresponding to positions) of the first and second spine openings 1710, 1712.
• the curved middle portion opening 1707 has two opposing longitudinal contours 1206, 1208 (also referred to as boundary lines), where at least one of the contours includes or includes exclusively of uninterrupted undulations.
• the curved middle portion opening 1707 as illustrated by the Fig 17 embodiment has the shape of an arc
• the curved middle portion opening 1707 has a shape of one or more sinusoidal waves.
• the radius of curvature of the middle portion opening 1707 may decrease from a location at the center 1706 of the middle portion opening towards locations near or at the end portion openings 1703, 1705, and/or where the arc may include one of: an arc of a segment of a circle, an arc of a segment of an ellipse, an arc of a segment of a horseshoe, an arc of a segment of a U, or an arc of a segment of a ⁇ .
• Figs. 18, 19 and 20 illustrate cross-sections of extruded artificial turf fibers according to other embodiments.
• Fibers 1800, 1900, and 2000 are similar to fibers 1400 and 1704, however the extruded artificial turf fiber 1800 includes a curved middle portion 1801 having a shape of an arc of a horseshoe, the extruded artificial turf fiber 1900 includes a curved middle portion 1901 having a shape of an arc of an ⁇ , and the extruded artificial turf fiber 2000 includes a curved middle portion 2001 having a shape of an arc of a U.
• the curved middle portion 1801 of fiber 1800 is connected with first and second end portions 1806, 1808, and includes at least a first spine 1802 proximate to the first end portion 1806 and a second spine 1804 proximate to the second end portion 1808.
• the curved middle portion 1901 of fiber 1900 is connected with first and second end portions 1906, 1908, and includes at least a first spine 1902 proximate to the first end portion 1906 and a second spine 1904 proximate to the second end portion 1908.
• the curved middle portion 2001 of fiber 2000 is connected with first and second end portions 2006, 2008, and includes at least a first spine 2002 proximate to the first end portion 2006 and a second spine 2004 proximate to the second end portion 2008.
• Each of fibers 1800, 1900, and 2000 are manufactured by extrusion of a polymer mass through corresponding extrusion plates (not shown) having fiber profile openings including middle portion openings in the shape of an arc of a horseshoe, an arc of an ⁇ , and an arc of a U, respectively, including respective spine openings coinciding with the spines of fibers 1800, 1900 and 2000.
• the fibers 1800, 1900 and 2000 have visible spines, in other embodiments of the present invention, the spines are either not visible via a visual inspection or are not present, although the effects produced by the spine openings of the corresponding extrusion plates, when a polymer mass is extruded through the fiber profile openings, still occur (i.e., mitigation of a thinning of the fiber end portions relative to the thickness of the end portion openings of the extrusion plates)
• an average thickness of the curved cross-sectional shapes of each middle portion of the fibers 1800, 1900 and 2000, excluding the regions containing the spines may either be constant along the longitudinal direction, or increasing in the longitudinal direction as the center is approached (i.e., increasing as the distance from the center decreases).
• Figs. 21 and 22 show photographs of extruded artificial turf fibers according to other exemplary embodiments.
• fibers 2100 and 2200 have shapes (i.e., cross-sectional shapes when viewed in a longitudinal plane of the fiber) that approximate sinusoids, where the fibers include middle portions having undulations and thickened end portions.
• the middle portions of the fibers 2100 and 2200 include two approximately circular arcs (e.g., similar to the shapes of the approximately circular arcs of the middle portions of fibers 1200, 1300, 1400, or the shape of the approximately circular arc of a middle portion of the extrusion dye 1702, with or without: a rounded bulge at the center, non-constant average thickness and/or spines) that form a middle portion that approximates the shape of a sinusoid.
• two approximately circular arcs e.g., similar to the shapes of the approximately circular arcs of the middle portions of fibers 1200, 1300, 1400, or the shape of the approximately circular arc of a middle portion of the extrusion dye 1702, with or without: a rounded bulge at the center, non-constant average thickness and/or spines
• An average width of the curved cross-sectional shape of the middle portions 2102, 2104 of fiber 2100 increases at a greater rate (along a longitudinal distance of the fiber from either of the end portions 2106, 2108 to the respective center 2110, 2112 closest to the respective end portion) than the average width of the curved cross-section of corresponding middle portions of fiber 2200, and the fiber 2100 is extruded from an extrusion dye that does not include spine openings.
• the fiber 2200 is extruded from an extrusion dye that include spine openings, which are slightly visible as spines 2202 and 2204. As illustrated, fiber 2200 has less thinning of the thicknesses of the end portions 2206, 2208.
• Figs. 23, 24 and 25 show photographs of extruded artificial turf fibers according to yet other exemplary embodiments.
• fibers 2300, 2400 and 2500 have shapes (i.e., cross-sectional shapes when viewed in a longitudinal plane of the fiber) that approximate an arc of the letter "U," an arc of a horseshoe, and an arc of a segment of a circle, respectively.
• each of the fibers 2300, 2400 and 2500 have end portions without any reduction (or only slight reduction) in thickness (as compared to the thickness of the end portions of the respective extrusion dyes (not shown)), and without any flattening (or only slight flattening) or distortion to the curvatures of the fibers when compared to the curvatures of the respective extrusion dyes (not shown).
• the extruded artificial turf fiber 1200, 1300, 1400, 1500, 1600, 1700, 1800, 1900, 2000, 2100, 2200, 2300, 2400 and/or 2500 is formed from a polymer mixture, where the polymer mixture is at least a two-phase polymer mixture, where a first phase of the polymer mixture includes a first polymer and a first dye and a second phase of the polymer mixture includes a second polymer and a second dye, where a color of the second dye is different than a color of the first dye, where the second polymer is of a same or of a different type as the first polymer, where the first and the second phases are immiscible, and where the extruded artificial turf fiber has a marbled appearance.
• the two different dyes are separated in two different phases wherein one of the phases is "emulsified" in the second phase in the form of beads.
• This is advantageous as it is not necessary to use or create customized extruders which mechanically prevent a premature intermixing of the two dyes, thereby ensuring that a monofilament with a marbled pattern rather than a monofilament with a color being the intermediate of the first and second color is created.
• the polymer mixture is extruded into a monofilament including a marbled pattern of the first and second color.
• the monofilament is then heated, and then stretched to deform the polymer beads (containing one of the dyes) into threadlike regions and to form the monofilament into an artificial turf fiber.
• the polymer mixture further includes a compatibilizer.
• the compatibilizer (which may be considered a third phase of the polymer mixture) is added to the polymer mixture and interfaces the first and second polymers, thereby further preventing the delamination of the two different types of polymers.
• the compatibilizer is added to the polymer mixture whose phase separation is caused by a polarity difference between a polar and an apolar polymer. The first phase forms polymer beads surrounded by the third phase within the second phase.
• the first polymer is any one of the following: polyamide, polyethylene terephthalate, and polybutylene terephthalate
• the second polymer is any one of the following: polyethylene, polypropylene, and a mixture thereof.
• a method of a method of manufacturing an artificial turf fiber includes extruding a polymer mixture through at least one fiber profile opening of an extrusion plate (e.g., 1702) allowing the extruded polymer mixture to travel along a distance between the at least one fiber profile opening of the extrusion plate to a quenching unit, and quenching the extruded polymer mixture in the quenching unit to form the artificial turf fiber.
• the fiber profile opening includes first and second end portion openings 1703, 1705, and a curved middle portion opening 1707 connected with the first and second end portion openings.
• the curved middle portion opening has at least a first spine opening 1710 proximate to the first end portion opening and a second spine opening 1712 proximate to the second spine opening.
• the first and second spine openings are sized and positioned such that the extruded polymer mixture, when traveling along the distance between the at least one fiber profile opening of the extrusion plate to the quenching unit, incurs a net polymer mass flow from a position on the middle portion of the fiber corresponding to the first spine opening to a first end portion of the fiber and from a position on the middle position of the fiber corresponding to the second spine opening to a second end portion of the fiber. Quenching of the fiber halts any further movement (i.e. flow) of the polymer mass in the fiber.
• the net polymer mass flow mitigates or prevents a reduction in width of the first and second end portions of the quenched fiber in comparison to a width of the end portion openings of the extrusion plate, thereby increasing dimensional stability and/or mitigating or preventing curling of the end of the quenched fiber.
• the quenched fiber includes a first spine created by extruding the polymer mass through the first spine opening and a second spine created by extruding the polymer mass through the second spine opening.
• the quenched fiber includes no spines at positions (i.e., corresponding to positions) of the first and second spine openings, or alternatively, no visible (to the human eye without magnification) spines at positions (i.e., corresponding to positions) of the first and second spine openings.
• the ratio of an area of the first spine opening to an area of the first end portion opening is larger than the ratio of a cross-sectional area of the first spine of the quenched fiber to a cross-sectional area of the first end portion of the quenched fiber, where the first end portion of the fiber is created by extruding the polymer mass through the first end portion opening, and/or the ratio of an area of the second spine opening to an area of the second end portion opening is larger than the ratio of a cross-sectional area of the second spine of the quenched fiber to a cross-sectional area of the second end portion of the quenched fiber, where the second end portion of the fiber is created by extruding the polymer mass through the second end portion opening.
• an amplitude (also referred to as width) of the first spine of the quenched fiber is less than an amplitude (also referred to as width) of the first spine opening, and/or an amplitude of the second spine of the quenched fiber is less than an amplitude of the second spine opening.
• a width of the first end portion opening is larger than a width of a first section of the middle portion opening adjacent to the first end portion opening
• a width of the second end portion opening is larger than a width of a second section of the middle portion opening adjacent to the second end portion opening
• a width of the first end portion of the quenched fiber is larger than a width of a first section of a middle portion of the quenched fiber adjacent to the first end portion of the quenched fiber
• a width of the second end portion of the quenched fiber is larger than a width of a second section of the middle portion of the quenched fiber adjacent to the second end portion of the quenched fiber.
• widths of first and second end portion openings are respectively larger than a maximum width of the middle portion opening, and widths of first and second end portions are respectively larger than a maximum width of a middle portion of the quenched fiber.
• a center of the curved middle portion opening includes a bulge opening, and a maximum width of the middle portion opening including the bulge opening is greater than a maximum width of the first and second end portion openings.
• the curved middle portion opening has two opposing longitudinal contours, where at least one of the contours includes (or includes entirely of) uninterrupted undulations.
• the curved middle portion opening has a shape of one or more sinusoidal waves. In other embodiments, the curved middle portion opening has a shape of an arc, and optionally a radius of curvature of the middle portion opening decreases from a center of the middle portion opening towards the end portion openings. In some embodiments, a shape of the middle portion opening comprises one of: an arc of a segment of a circle, an arc of a segment of an ellipse, an arc of a segment of a horseshoe, an arc of a segment of a U, or an arc of a segment of a ⁇ .
• the polymer mixture includes a polyethylene or a polyethylene-polyamide blend, where the quenching unit is a water bath, where the distance between the extrusion plate openings and the quenching unit is 3.0 - 5.0 cm, and wherein a temperature of the water bath is 28°C - 34°C.
• the polymer mixture includes a polyamide as a main polymer component or includes exclusively of the polyamide, where the quenching unit is a water bath, where the distance between the extrusion plate openings and the quenching unit is 2.0 - 4.0 cm, and wherein a temperature of the water bath is 18°C - 20°C.
• the polymer mixture is at least a two-phase polymer mixture, where a first phase of the polymer mixture includes a first polymer and a first dye and a second phase of the polymer mixture includes a second polymer and a second dye, where a color of the second dye is different than a color of the first dye, where the second polymer is of a same or of a different type as the first polymer, where the first and the second phases are immiscible, and where the extruded fiber has a marbled appearance.
• the first phase forms polymer beads within the second phase
• the polymer mixture further includes a nucleating agent and/or a compatibilizer.
• the first polymer is any one of the following: polyamide, polyethylene terephthalate, and polybutylene terephthalate
• the second polymer is any one of the following: polyethylene, polypropylene, and a mixture thereof.
• Figure 26 shows three plots 2602, 2604, 2606 illustrating the mass flow u of the polymer mixture in the fiber profile opening of the extrusion plate at the moment when the polymer mass is pressed through the fiber profile opening, whereby the mass flow depends on the shape of the fiber profile opening.
• the grey areas illustrate the walls of the extrusion plate defining extrusion openings.
• the y coordinate of each plot indicates the dotted line ("neutral line") within the fiber profile opening depicted in the middle portion of each plot.
• the lower portion of each plot illustrates the polymer mass flow u at various positions along the neutral line and hence depicts a mass flow profile u(y) along the neutral line.
• the top-view cross-section of the fiber profile opening is indicated in the middle of each plot and a photo of the real, extruded and processed fibers is shown at the top of each plot.
• Plot 2602 illustrates the polymer mass flow in a fiber profile opening having a middle portion opening between the first and second end portion opening with approximately constant width.
• the polymer mass flow profile 2608 depends on the distance from the walls of the extrusion plate. As can be seen from the lower part of plot 2602, the mass flow is approximately homogeneous across the whole distance y. However, the curvature of the resulting fiber depicted in the upper part of the plot is quite flat and hence the fiber may be flattened easily when it is transported, processed and used. Furthermore, the fiber ends are thinned as a result of an undesired mass flow from the fiber ends towards the center of the fiber.
• the plot 2604 shows the mass flow profile observed in a different fiber profile opening.
• This fiber profile opening was designed with an attempt to improve the mechanical stability of the fiber by increasing the width of the middle portion of the fiber.
• the polymer mass flow was observed to significantly change and to be much higher in the middle portion than at the fiber ends (see high peak of the mass flow profile 2610).
• the thinning of the ends was observed to have increased. The thinning of the fiber ends is undesirable, as this results in a reduced robustness of the ends of the artificial turf fiber against curling.
• the plot 2606 shows a polymer mass flow profile obtained for a still different fiber profile opening according to an embodiment of the invention.
• This embodiment was able to overcome both disadvantages of the fiber profiles depicted in plots 2602 and 2604: thanks to the spine openings and thanks to the increased size of the first and second end portion openings in the fiber profile opening of the extrusion plate, the polymer flow is basically constant over most of the neutral line (dotted midline between the first and second boundary lines, represented by coordinate y), even though the central part of the middle portion opening has a greater width than the fiber end portion openings.
• the introduction of the spine openings and also the increasing of the width/cross-sectional area of the fiber end portion opening results in a more homogeneous distribution of the polymer flux along the midline (compared to a fiber profile shown in plot 2604 lacking spine openings and having smaller end portion openings.
• the introduction of the spine openings induces a net polymer flow from the position of the spine openings to the end portions in the extruded fiber.
• a thinning of the fiber ends is prevented and the resulting, extruded fiber has an arc-shaped (and hence mechanically stable) cross section and has ends which are approximately as thick as the middle portion of the fiber profile, resulting in an increased robustness against the curling of the fiber ends.
• This desirable effect has been observed to be enhanced by increasing the width of the fiber end portion openings.
• the width of the first and second fiber end portions of the extruded fiber is approximately identical to the average width of the middle portion of the extruded fiber.
• the average width may be the width between a first baseline of the undulations of the first boundary line and a second baseline of the undulations of the second boundary line.
• a with being approximately identically to another width can be a width that differs less than 15%, in particular less than 10%, in particular less than 5% from the width of said other width.
• the width of the first end portion opening is larger than the width of the first end portion of the extruded fiber
• the width of the second end portion opening is larger than the width of the second end portion of the extruded fiber
• the area of the first end portion opening is larger than the area of the first end portion of the extruded fiber
• the area of the second end portion opening is larger than the area of the second end portion of the extruded fiber.
• the 'area' in this context may mean 'cross-sectional area'.
• the width is measured along a dimension that is basically orthogonal to the curvature of the fiber profile.
• the width of the three fiber profile openings depicted in the middle portion of the three plots 2602, 2604 and 2608 is indicated in the form of arrows which are oriented basically orthogonally to the dotted neutral line and basically orthogonally to a first and a second boundary line.
• the first and second boundary lines of a fiber profile may represent, for example, the lines connecting the maxima peaks (outward directed peaks) of the undulations in one fiber side in the middle portion of the fiber, or lines connecting the minima of the peaks (inward directed peaks) of the undulations in one fiber side in the middle portion of the fiber, or lines connecting the base line of the peaks (average of the peaks) of the undulations in one fiber side in the middle portion of the fiber.

Landscapes

• Engineering & Computer Science (AREA)
• Textile Engineering (AREA)
• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Mechanical Engineering (AREA)
• Architecture (AREA)
• Civil Engineering (AREA)
• Structural Engineering (AREA)
• Manufacturing & Machinery (AREA)
• Artificial Filaments (AREA)

Priority Applications (3)

Applications Claiming Priority (1)

Publications (1)

Family

ID=91431483

Family Applications (1)

Country Status (2)

Citations (8)

• 2024
  • 2024-06-05 EP EP24180277.6A patent/EP4660355A1/fr active Pending
  • 2024-07-12 US US18/771,343 patent/US20250376806A1/en active Pending

Patent Citations (9)

Also Published As

Similar Documents

Legal Events