Artificial turf production using a nucleating agent

Abstract

A method of manufacturing artificial turf includes the steps of: creating a polymer mixture including at least one polymer and a nucleating agent for crystallizing the at least one polymer, extruding the polymer mixture into a monofilament; quenching the monofilament; reheating the monofilament; stretching the reheated monofilament to form the monofilament into an artificial turf fiber, wherein during the stretching the nucleating agent boosts the creation of crystalline portions of the polymer within the monofilament; incorporating the artificial turf fiber into an artificial turf backing, thereby mechanically fixing the monofilaments of the arranged artificial turf fibers in the artificial turf backing.

Claims

1. An artificial turf, comprising: a carrier comprising a bottom side, a top side and perforations; an artificial turf backing formed on the bottom side of the carrier, in the perforations of the carrier and on the top side of the carrier; and a plurality of artificial turf fibers fixed to the artificial turf backing such that first parts of the artificial turf fibers are mechanically fixed at the bottom side of the carrier and some portions of second parts of the artificial turf fibers are mechanically fixed at the top side of the carrier, wherein each artificial turf fiber is formed by a process comprising: creating a polymer mixture comprising at least one polymer and a nucleating agent for crystallizing the at least one polymer, the nucleating agent being a mixture of an inorganic substance and an organic substance, wherein the polymer mixture comprises 0.2% to 0.4% by weight the inorganic substance; extruding the polymer mixture into a monofilament; quenching the monofilament; reheating the monofilament; and stretching the reheated monofilament to form the monofilament into each artificial turf fiber, wherein during the stretching the nucleating agent boosts the creation of crystalline portions of the at least one polymer within the monofilament as compared to crystalline portions that would be created from stretching the reheated monofilament extruded from the polymer mixture without the nucleating agent, and wherein the boosting of the creation of the crystalline portions increases a surface roughness of the monofilament.

2. A method of manufacturing artificial turf that is durable to mechanical stress, the method comprising: creating a polymer mixture comprising at least one polymer and a nucleating agent for crystallizing the at least one polymer, the nucleating agent being a mixture of an inorganic substance and an organic substance, wherein the polymer mixture comprises 0.2% to 0.4% by weight the inorganic substance; wherein the inorganic substance acting as the nucleating agent consists of one or more of: talcum; kaolin; calcium carbonate; magnesium carbonate; silicate; silicic acid; silicic acid ester; aluminium trihydrate; magnesium hydroxide; meta- and/or polyphosphates; and coal fly ash; wherein the organic substance acting as the nucleating agent consists of one or more of: 1,2-cyclohexane dicarbonic acid salt; benzoic acid; benzoic acid salt; sorbic acid; or sorbic acid salt; extruding the polymer mixture into a monofilament; quenching the monofilament; reheating the monofilament; stretching the reheated monofilament to form the monofilament into an artificial turf fiber, wherein during the stretching the nucleating agent boosts the creation of crystalline portions of the at least one polymer within the monofilament as compared to crystalline portions that would be created from stretching the reheated monofilament extruded from the polymer mixture without the nucleating agent, wherein the boosting of the creation of the crystalline portions increases a surface roughness of the monofilament; incorporating the artificial turf fiber into an artificial turf backing by arranging a plurality of the artificial turf fibers on a carrier having perforations, wherein first parts of the monofilaments of the arranged artificial turf fibers are exposed to a bottom side of the carrier and second parts of said monofilaments are exposed to a top side of the carrier; adding a fluid on the bottom side of the carrier such that at least the first parts and some portions of the second parts of the monofilaments become embedded in the fluid, wherein the perforations are configured to allow the fluid on the bottom side of the carrier to flow to the top side of the carrier; and causing the fluid to solidify into a film, the film surrounding and thereby mechanically fixing at least the first parts and the some portions of the second parts of the monofilaments of the arranged artificial turf fibers, the solid film acting as the artificial turf backing.

3. The method of claim 2, wherein the at least one polymer comprises crystalline portions and amorphous portions, wherein the presence of the nucleating agent in the polymer mixture during the stretching causes an increase in the size of the crystalline portions relative to the amorphous portions.

4. The method of claim 2, wherein some or all parts of the surface of the artificial turf fiber embedded in the fluid are wetted by the fluid.

5. The method of claim 2, wherein the fluid is a suspension comprising at least 20 percent by weight styrene-butadiene, at least 40% of chemically inert filler material, and at least 15% dispersion fluid; wherein the solidification of the fluid into the film comprises drying the suspension.

6. The method of claim 5, wherein the suspension comprises 22-28 percent by weight of the styrene-butadiene, 50-55 percent by weight of the filler material, and at least 20% of water acting as the dispersion fluid.

7. The method of claim 2, wherein the fluid is a mixture of polyols and polyisocyanates, the polyols being compounds with multiple hydroxyl functional groups available for organic reactions; wherein the solidification of the fluid into the film comprises executing a polyaddition-reaction of the polyols and the polyisocyanates for generating polyurethane, the solid film being a polyurethane film.

8. The method of claim 2, wherein the at least one polymer is any one of the following: polyethylene, polypropylene, or a mixture thereof.

9. The method of claim 2, wherein creating the artificial turf fiber comprises: forming the stretched monofilament into a yam; or weaving, spinning, twisting, rewinding, and/or bundling the stretched monofilament into the artificial turf fiber.

10. The method of claim 2, wherein incorporating the artificial turf fiber into the artificial turf backing comprises one of: weaving the artificial turf fiber into the artificial turf backing; or tufting the artificial turf fiber into the artificial turf backing and binding the artificial turf fibers to the artificial turf backing.

11. The method of claim 2, wherein the polymer mixture is at least a three-phase system, wherein the polymer mixture comprises a first polymer, the at least one polymer as second polymer, and a compatibilizer, wherein the first polymer and the second polymer are immiscible, wherein the first polymer forms polymer beads surrounded by the compatibilizer within the second polymer; wherein the method further comprises adding a first dye before the extruding; and wherein the stretching results in a deformation of the polymer beads into threadlike shaped regions.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In the following embodiments of the invention are explained in greater detail, by way of example only, making reference to the drawings in which:

(2) FIG. 1 shows a flowchart which illustrates an example of a method of manufacturing artificial turf;

(3) FIG. 2a shows a diagram which illustrates a cross-section of a polymer mixture;

(4) FIG. 2b shows a further example of a polymer mixture;

(5) FIG. 2c is a legend for FIGS. 2a and 2b;

(6) FIG. 3a shows a further example of a polymer mixture;

(7) FIG. 3b is a legend for FIG. 3a;

(8) FIG. 4 shows a further example of a polymer mixture;

(9) FIG. 5 illustrates the extrusion of the polymer mixture into a monofilament;

(10) FIG. 6 shows the tufting of an artificial turf fiber;

(11) FIG. 7 illustrates first and second parts of the fiber; and

(12) FIG. 8 shows the first parts and portions of second parts of the fibers embedded in the turf backing.

DETAILED DESCRIPTION

(13) Like numbered elements in these figures are either equivalent elements or perform the same function. Elements which have been discussed previously will not necessarily be discussed in later figures if the function is equivalent.

(14) FIG. 1 shows a flowchart which illustrates an example of a method of manufacturing artificial turf. First in step 102 a polymer mixture such as the mixture 200 depicted in FIG. 2a is created. The polymer mixture 200 comprises at least one polymer, typically polyethylene 204 and a nucleating agent 202, e.g. talcum of the above described scales (“nano scale talcum”) for crystallizing the at least one polymer 204.

(15) The polymer mixture may be created by putting all of the components that make it up together at once. For instance the at least one polymer 204, the nucleating agent 202 and the optional additives 206 and dyes 208 could be all added together at the same time. The polymer mixture could be thoroughly mixed for instance by using a mixer device. The desired distribution of the components can be achieved by using the proper rate or amount of mixing. The generated mixture could be forwarded to a one-screw feed or a two-screw feed for the extrusion.

(16) In other examples there may be additional substances, e.g. an additional dye, as depicted in FIG. 2b, or additional polymers such as in the polymer mixture 400 depicted in FIG. 4. Alternatively, a substance 302 may be used instead of talcum which acts as dye and as nucleating agent (see FIG. 3).

(17) Next in step 104, the polymer mixture is extruded into a monofilament 506 as depicted in greater detail in FIG. 5. Next in step 106 the monofilament is quenched or rapidly cooled down. Next in step 108 the monofilament is reheated. In step 110 the reheated monofilament is stretched to form a monofilament that can directly be used as an artificial turf fiber or that can be bundled with additional monofilaments into an artificial turf fiber. Additional steps may also be performed on the monofilament to form the artificial turf fiber. For instance the monofilament may be spun or woven into a yarn with desired properties. Next in step 112 the artificial turf fiber is incorporated into an artificial turf backing. The incorporation comprises a step 114 of arranging a plurality of the artificial turf fibers on a carrier 704 (see FIGS. 7 and 8). The carrier may be a textile plane, for example. The artificial turf fibers are arranged such that first parts 706 of the monofilaments are exposed to a bottom side of the carrier and second parts 702 of said monofilaments are exposed to a top side of the carrier. The arranging could be accomplished by tufting or weaving the artificial turf fiber into the carrier, but other methods of arranging the fibers within the carrier are also possible.

(18) Then in step 116 a fluid is added on the bottom side of the carrier such that at least the first parts become embedded in the fluid. Finally, in step 118, the fluid is caused to solidify into a film. The film surrounds and thereby mechanically fixes at least the first parts 706 (and optionally also some portions 804 of the second parts 702) of the monofilaments in the film. The film, i.e., the solidified fluid, constitutes the backing 802.

(19) FIG. 2a shows a cross section of a polymer mixture 200 comprising at least a first polymer 204, preferentially a non-polar polymer such as polyethylene, and a nucleating agent 202 such as nanoscale talcum. The polymer mixture may comprise further additives such as fungicides or the like. The nucleating agent 202 boosts the creation of crystalline portions of polyethylene, in particular during the stretching step 110. The increased fraction of crystalline portions results in an increased surface roughness of the monofilaments and also eases the wettening of the monofilaments by the fluid used for embedding 116 at least the first parts of the monofilaments. In combination, said effects result in a strong mechanical fixing of the artificial turf fiber in the backing 802 and thus result in an increased resistance against wear and tear of the resulting artificial turf 800.

(20) FIG. 2b shows a polymer mixture 250 comprising all the components of the mixture 200 of FIG. 2a and in addition a dye 208, e.g. titanium dioxide for white color or a azo-nickel-complex pigment for yellow color. Said dyes are not able to act as nucleating agent and are not capable of boosting the creation of crystalline portions of the polymer 204 to a sufficient degree. However, as the nucleating agent 202 is present in mixture 250, it is not necessary that the dye itself has any nucleating capabilities, and any kind of dye can be chosen freely and combined with each other.

(21) FIG. 2c is a legend for FIGS. 2a and 2b.

(22) FIG. 3a shows a cross section of a polymer mixture 300 comprising at least a first polymer 204 such as polyethylene, and a nucleating agent 302 such as phthalocyanine green, which in addition acts as a dye for generating artificial turf fibers of green color. Alternatively, or in addition, the substance 302 may consist of phthalocyanine blue, which acts as a nucleating agent and as a dye for generating artificial turf fibers of blue color. Using dyes which are capable of acting as a dye may be advantageous as the amount of nucleating agent may be reduced without reducing the strength of the mechanical fixing of the fiber in the turf backing 802.

(23) In case the desired color consists of a mixture of two or more dyes of different color, it is possible to combine a dye 208 being incapable of acting as a nucleating agent (e.g. azo-nickel-complex pigment providing yellow color) with another dye 302 capable of acting as nucleating agent (e.g. phthalocyanine blue) in order to provide the desired color, e.g. green, without adding additional nucleating agents such as talcum or sorbic acid. This eases the process of manufacturing the artificial turf. FIG. 3b is a legend for FIG. 3a.

(24) FIG. 4 shows a diagram which illustrates a cross-section of a polymer mixture 400. The polymer mixture 400 comprises a first polymer 402 and the above mentioned at least one polymer which is referred to in this section as “second polymer” 204. The second polymer may be, for example, ethylene. The mixture 400 further comprises a compatibilizer 404 and a nucleating agent 202. The first polymer 402 and the second polymer 204 are immiscible. The first polymer 402 is less abundant than the second polymer 204. The first polymer 402 is shown as being surrounded by compatibilizer 404 and being dispersed within the second polymer 204. The first polymer 402 surrounded by the compatibilizer 404 forms a number of polymer beads 408. The polymer beads 408 may be spherical or oval in shape or they may also be irregularly-shaped depending up on how well the polymer mixture is mixed and the temperature. The polymer mixture 400 is an example of a three-phase system. The three phases are the regions of the first polymer 402. The second phase region is the compatibilizer 404 and the third phase region is the second polymer 204. The compatibilizer 404 separates the first polymer 402 from the second polymer 204.

(25) The mixture 400 may in addition comprise polymers such as a third, fourth, or even fifth polymers that are also immiscible with the second polymer. There also may be additional compatibilizers which are used either in combination with the first polymer or the additional third, fourth, or fifth polymer. The first polymer forms polymer beads 408 surrounded by the compatibilizer. The polymer beads may also be formed by additional polymers which are not miscible in the second polymer. The polymer beads are surrounded by the compatibilizer and are within the second polymer or mixed into the second polymer.

(26) A first mixture is formed by mixing the first polymer with the compatibilizer. Additional additives may also be added during this step. Then the first mixture is heated and the heated first mixture is extruded. Then the extruded first mixture is granulated or chopped into small pieces. The granulated first mixture is mixed with the second polymer. Additional additives may also be added to the polymer mixture at this time. Finally the granulated first mixture is heated with the second polymer and a nucleating agent to form the polymer mixture. The heating and mixing may occur at the same time.

(27) FIG. 5 illustrates the extrusion of the polymer mixture into a monofilament 506. Shown is an amount of polymer mixture 200. Within the polymer mixture 200 there is a large number of nucleating agents 202 and optionally also additional substances 206 such as UV-stabilizers or the like. A screw, piston or other device is used to force the polymer mixture 200 through a hole 502 in a plate 504. This causes the polymer mixture 200 to be extruded into a monofilament 506. The monofilament 506 is shown as containing the nucleating agent 202 and the additives 206 also.

(28) In the case of extruding polymer mixture 400 (not shown), the second polymer 204 and the polymer beads 408 would be extruded together. In some examples the second polymer 204 will be less viscous than the polymer beads 408 and the polymer beads 408 will tend to concentrate in the center of the monofilament 506. This may lead to desirable properties for the final artificial turf fiber as this may lead to a concentration of the thread-like regions in the core region of the monofilament 506.

(29) FIGS. 6 and 7 show how a plurality of artificial turf fibers can be arranged in a carrier 704, e.g. a textile plane, by means of tufting. Tufting is a type of textile weaving in which an artificial turf fiber 701 (that may be a monofilament 506 or a bundle of multiple monofilaments) is inserted on a carrier 704. After the inserting is done, as depicted in FIG. 6, short U-shaped loops of the fiber point outside of the carrier's surface. Then, one or more blades cut 602 through the loops. As a result of the cutting step, two artificial turf fiber ends per loop and monofilament point out from the carrier and a grass-like artificial turf surface is generated. Thereby, first parts 706 of the monofilaments of the artificial turf fibers having been inserted in the carrier 704 are exposed to a bottom side of the carrier and second parts 702 of said monofilaments are exposed to a top side of the carrier.

(30) FIG. 8 depicts the carrier 704 with the inserted filaments having been embedded within (FIG. 8a) or next to a surface of (FIG. 8b) an artificial turf backing 802. This is performed by adding a fluid in step 116 (see FIG. 1) on the carrier 704 such that the first parts 706 of the monofilaments become embedded in the fluid (FIG. 8a) or the first parts and some portions 804 of the second parts 702 of the monofilaments (FIG. 8b) become embedded in the fluid. The carrier may be a textile mesh or may comprise perforations that allow the fluid 802.2 at the bottom side of the carrier to flow to the upper side of the carrier and vice versa, thereby creating a portion 802.1 of the backing on top of the carrier. Thus, the carrier and parts of the fibers inserted in the carrier may become embedded in the backing 802. The artificial turf fibers 701 are shown as extending a distance 806 above the carrier 704. The distance 806 is essentially the height of the pile of the artificial turf fibers 701.

(31) The fluid may be a styrene-butadiene suspension that solidifies into a latex backing or may be a mixture of polyols and polyisocyanates that solidifies into a polyurethane backing or any other kind of fluid that is capable of solidifying after a defined time period into a solid film. The fluid solidifies into a film 802, e.g. by a drying process or by a chemical reaction resulting in a solidification of the fluid. Such a chemical reaction can be, for example, a polymerization. The film surrounds and thereby mechanically fixes at least the first parts of the monofilaments of the arranged artificial turf fibers. The solid film acts as the artificial turf backing. In some examples, additional coating layers may be added on the bottom of the artificial turf backing.

LIST OF REFERENCE NUMERALS

(32) 102-118 steps 200 put in the mixture 202 nucleating agent 204 polyethylene 206 further additive substances 208 dye 300 polymer mixture 302 substance acting as a nucleating agent 400 polymer mixture 402 first polymer, polyamide 404 compatibilizer 408 polymer bead 502 hole in a plate 504 plate 506 monofilament of artificial turf fiber 602 cutting artificial turf fibers during tufting 701 individual artificial turf fiber 702 second parts of fibers 704 carrier 706 first parts of fibers first parts of fiber 800 artificial turf (cross-section) 802 backing made from solidified fluid 804 portions of the second parts of the fibers embedded in the fluid 806 distance <carrier-surface-upper ends of fibers>