U.S. patent application number 15/129456 was filed with the patent office on 2017-05-04 for artificial turf and production method.
The applicant listed for this patent is Polytex Sportbelage Produktions-GmbH. Invention is credited to Bernd JANSEN, Dirk SANDER, Dirk SCHMITZ, Stephan SICK.
Application Number | 20170121856 15/129456 |
Document ID | / |
Family ID | 50424226 |
Filed Date | 2017-05-04 |
United States Patent
Application |
20170121856 |
Kind Code |
A1 |
SICK; Stephan ; et
al. |
May 4, 2017 |
ARTIFICIAL TURF AND PRODUCTION METHOD
Abstract
The invention provides for a method of manufacturing artificial
turf (1000). The method comprising the steps of: creating (100) a
polymer mixture (100, 400, 500), wherein the polymer mixture is at
least a three-phase system, wherein the polymer mixture comprises a
first polymer (402), a second polymer (404), and a compatibiiizer
(406), wherein the first polymer and the second polymer are
immiscible, wherein the first polymer forms polymer beads (408)
surrounded by the compatibiiizer within the second polymer;
extruding (102) the polymer mixture into a monofilament (606);
quenching (104) the monofilament; reheating (106) the monofilament;
stretching (108) the reheated monofilament to deform the polymer
beads into threadlike regions (800) and to form the monofilament
into an artificial turf fiber (1004); incorporating (110) the
artificial turf fiber into an artificial turf carpet (1002).
Inventors: |
SICK; Stephan;
(Willich-Neersen, DE) ; SANDER; Dirk; (Kerken,
DE) ; JANSEN; Bernd; (Nettetal, DE) ; SCHMITZ;
Dirk; (Weeze, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Polytex Sportbelage Produktions-GmbH |
Grefrath |
|
DE |
|
|
Family ID: |
50424226 |
Appl. No.: |
15/129456 |
Filed: |
March 27, 2014 |
PCT Filed: |
March 27, 2014 |
PCT NO: |
PCT/EP2014/056149 |
371 Date: |
September 27, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
D01F 1/10 20130101; D10B
2321/022 20130101; D01F 6/90 20130101; D10B 2331/02 20130101; D01D
5/098 20130101; D01D 5/0885 20130101; D01F 6/92 20130101; E01C
13/08 20130101; D01F 6/46 20130101; D10B 2505/202 20130101; D10B
2321/021 20130101 |
International
Class: |
D01F 1/10 20060101
D01F001/10; D01D 5/088 20060101 D01D005/088; E01C 13/08 20060101
E01C013/08; D01F 6/90 20060101 D01F006/90; D01F 6/92 20060101
D01F006/92; D01D 5/098 20060101 D01D005/098; D01F 6/46 20060101
D01F006/46 |
Claims
1. A method of manufacturing artificial turf (1000), the method
comprising the steps of: creating (100) a polymer mixture (100,
400, 500), wherein the polymer mixture is at least a three-phase
system, wherein the polymer mixture comprises a first polymer
(402), a second polymer (404), and a compatibilizer (406), wherein
the first polymer and the second polymer are immiscible, wherein
the first polymer forms polymer beads (408) surrounded by the
compatibilizer within the second polymer; extruding (102) the
polymer mixture into a monofilament (606); quenching (104) the
monofilament; reheating (106) the monofilament; stretching (108)
the reheated monofilament to deform the polymer beads into
threadlike regions (800) and to form the monofilament into an
artificial turf fiber (1004); incorporating (110) the artificial
turf fiber into an artificial turf backing (1002).
2. The method of claim 1, wherein the polymer bead comprises
crystalline portions and amorphous portions, wherein stretching the
polymer beads into threadlike regions causes an increase in the
size of the crystalline portions relative to the amorphous
portions.
3. The method of claim 1 or 2, wherein the creating of the polymer
mixture comprises the steps of: forming (200) a first mixture by
mixing the first polymer with the compatibilizer; heating (202) the
first mixture; extruding (204) the first mixture; granulating (206)
the extruded first mixture; mixing (208) the granulated first
mixture with the second polymer; and heating (210) the granulated
first mixture with the second polymer to form the polymer
mixture.
4. The method of claim 1 or 2, wherein the polymer mixture is at
least a four phase system, wherein the polymer mixture comprises at
least a third polymer (502), wherein the third polymer is
immiscible with the second polymer, wherein the third polymer
further forms the polymer beads surrounded by the compatibilizer
within the second polymer.
5. The method of claim 4, wherein the creating of the polymer
mixture comprises the steps of: forming (300) a first mixture by
mixing the first polymer and the third polymer with the
compatibilizer; heating (302) the first mixture; extruding (304)
the first mixture; granulating (306) the extruded first mixture;
mixing (308) the first mixture with the second polymer; and heating
(310) the mixed first mixture with the second polymer to form the
polymer mixture.
6. The method of claim 4 or 5, wherein the third polymer is a polar
polymer.
7. The method of any one of the preceding claims, wherein the third
polymer is any one of the following: polyamide, polyethylene
terephthalate (PET), and polybutylene terephthalate (PBT).
8. The method of any one of the preceding claims, wherein the
polymer mixture comprises 1 to 30 percent by weight the first
polymer and the third polymer combined.
9. The method of any one of claims 1 to 7, wherein the polymer
mixture comprises 1 to 20 percent by weight the first polymer and
the third polymer combined.
10. The method of any one of claims 1 to 7, wherein the polymer
mixture comprises 5 to 10 percent by weight the first polymer and
the third polymer combined.
11. The method of claim 1, 2, or 3, wherein the polymer mixture
comprises 1 to 30 percent by weight the first polymer.
12. The method of claim 1, 2, or 3, wherein the polymer mixture
comprises 1 to 20 percent by weight the first polymer.
13. The method of claim 1, 2, or 3, wherein the polymer mixture
comprises 5 to 10 percent by weight the first polymer.
14. The method of any one of the preceding claims, wherein the
first polymer is a polar polymer.
15. The method of any one of the preceding claims, wherein the
first polymer is any one of the following: polyamide, polyethylene
terephthalate (PET), and polybutylene terephthalate (PBT).
16. The method of any one of the preceding claims, wherein the
second polymer is a non-polar polymer.
17. The method of any one of the preceding claims, wherein the
second polymer is any one of the following: polyethylene,
polypropylene, and a mixture thereof.
18. The method of any one of the preceding claims, wherein the
compatibilizer is any one of the following: a maleic acid grafted
on polyethylene or polyamide; a maleic anhydride grafted on free
radical initiated graft copolymer of polyethylene, SEBS, EVA, EPD,
or polyproplene with an unsaturated acid or its anhydride such as
maleic acid, glycidyl methacrylate, ricinoloxazoline maleinate; a
graft copolymer of SEBS with glycidyl methacrylate, a graft
copolymer of EVA with mercaptoacetic acid and maleic anhydride; a
graft copolymer of EPDM with maleic anhydride; a graft copolymer of
polypropylene with maleic anhydride; a
polyolefin-graft-polyamidepolyethylene or polyamide; and a
polyacrylic acid type compatibilizer.
19. The method of any one of the preceding claims, wherein the
polymer mixture comprises 80 to 90 percent by weight the second
polymer.
20. The method of any one of the preceding claims, wherein the
polymer mixture further comprises any one of the following: a wax,
a dulling agent, a UV stabilizer, a flame retardant, an
anti-oxidant, a pigment, and combinations thereof.
21. The method of any one of the preceding claims, wherein creating
the artificial turf fiber comprises forming the stretched
monofilament into a yarn.
22. The method of any one of the preceding claims, wherein creating
the artificial turf fiber comprises weaving, spinning, twisting,
rewinding, and/or bundling the stretched monofilament into the
artificial turf fiber.
23. The method of any one of the preceding claims, wherein
incorporating the artificial turf fiber into the artificial turf
backing comprises: tufting the artificial turf fiber into the
artificial turf backing and binding the artificial turf fibers to
the artificial turf backing.
24. The method of any one of claims 1 through 22, wherein
incorporating the artificial turf fiber into the artificial turf
backing comprises weaving the artificial turf fiber into the
artificial turf backing.
25. A artificial turf manufactured according to the method of any
one of the preceding claims.
26. An artificial turf (1000) comprising an artificial turf textile
backing (1002) and artificial turf fiber (1004) incorporated into
the artificial turf backing, wherein the artificial turf fiber
comprises at least one monofilament, wherein each of the at least
one monofilament comprises: a first polymer (402) in the form of
threadlike regions (800); a second polymer (404), wherein the
threadlike regions are embedded in the second polymer, wherein the
first polymer is immiscible in the second polymer; a compatibilizer
(406) surrounding each of the threadlike regions and separating the
at least one first polymer from the second polymer.
27. The artificial turf of claim 26, wherein the threadlike regions
have a diameter less than 50 micrometers.
28. The artificial turf of claim 26, wherein the threadlike regions
have a diameter less than 10 micrometers.
29. The artificial turf of claim 26, wherein the threadlike regions
have a diameter of between 1 and 3 micrometers.
30. The artificial turf of any one of claims 27 to 30, wherein the
artificial turf fiber extends a predetermined length (1008) beyond
the artificial turf backing, and wherein threadlike regions have a
length less than one half of the predetermined length.
31. The artificial turf of any one of claims 27 to 31, wherein the
threadlike regions have a length less than 2 mm.
Description
FIELD OF THE INVENTION
[0001] The invention relates to artificial turf and the production
of artificial turf which is also referred to as synthetic turf. The
invention further relates to the production of fibers that imitate
grass, and in particular a product and a production method for
artificial turf fibers based on polymer blends and of the
artificial turf carpets made from these artificial turf fibers.
BACKGROUND AND RELATED ART
[0002] Artificial turf or artificial grass is surface that is made
up of fibers which is used to replace grass. The structure of the
artificial turf is designed such that the artificial turf has an
appearance which resembles grass. Typically artificial turf is used
as a surface for sports such as soccer, American football, rugby,
tennis, golf, for playing fields, or exercise fields. Furthermore
artificial turf is frequently used for landscaping
applications.
[0003] An advantage of using artificial turf is that it eliminates
the need to care for a grass playing or landscaping surface, like
regular mowing, scarifying, fertilizing and watering. Watering can
be e.g. difficult due to regional restrictions for water usage. In
other climatic zones the re-growing of grass and re-formation of a
closed grass cover is slow compared to the damaging of the natural
grass surface by playing and/or exercising on the field. Artificial
turf fields though they do not require a similar attention and
effort to be maintained, may require some maintenance such as
having to be cleaned from dirt and debris and having to be brushed
regularly. This may be done to help fibers stand-up after being
stepped down during the play or exercise. Throughout the typical
usage time of 5-15 years it may be beneficial if an artificial turf
sports field can withstand high mechanical wear, can resist UV, can
withstand thermal cycling or thermal ageing, can resist
inter-actions with chemicals and various environmental conditions.
It is therefore beneficial if the artificial turf has a long usable
life, is durable, and keeps its playing and surface characteristics
as well as appearance throughout its usage time.
[0004] United States Patent application US 2010/0173102 A1
discloses an artificial grass that is characterized in that the
material for the cladding has a hyprophilicity which is different
from the hyprophilicity of the material which is used for the
core.
SUMMARY
[0005] The invention provides for a method of manufacturing
artificial turf in the independent claims. Embodiments are given in
the dependent claims.
[0006] In one aspect the invention provides for a method of
manufacturing artificial turf carpet. The method comprises the step
of creating a polymer mixture. The polymer mixture as used herein
encompasses a mixture of different types of polymers and also
possibly with various additives added to the polymer mixture. The
term `polymer mixture` may also be replaced with the term `master
batch` or `compound batch`. The polymer mixture is at least a
three-phase system. A three-phase system as used herein encompasses
a mixture that separates out into at least three distinct phases.
The polymer mixture comprises a first polymer, a second polymer,
and a compatibilizer. These three items form the phases of the
three-phase system. If there are additional polymers or
compatibilizers added to the system then the three-phase system may
be increased to a four, five, or more phase system. The first
polymer and the second polymer are immiscible. The first polymer
forms polymer beads surrounded by the compatibilizer within the
second polymer.
[0007] The method further comprises the step of extruding the
polymer mixture into a monofilament. To perform this extrusion the
polymer mixture may for instance be heated. The method further
comprises the step of quenching the monofilament. In this step the
monofilament is cooled. The method further comprises the step of
reheating the monofilament. The method further comprises the step
of stretching the reheated filament to deform the polymer beads
into thread-like regions and to form the monofilament into an
artificial turf fiber. In this step the monofilament is stretched.
This causes the monofilament to become longer and in the process
the polymer beads are stretched and elongated. Depending upon the
amount of stretching the polymer beads are elongated more.
[0008] The method further comprises the step of incorporating the
artificial turf fiber into an artificial turf backing. In some
examples the artificial turf backing is a textile or a textile
matt.
[0009] The incorporation of the artificial turf fiber into the
artificial turf backing could for example be performed by tufting
the artificial turf fiber into an artificial turf backing and
binding the tufted artificial turf fibers to the artificial turf
backing. For instance the artificial turf fiber may be inserted
with a needle into the backing and tufted the way a carpet may be.
If loops of the artificial turf fiber are formed then may be cut
during the same step. The method further comprises the step of
binding the artificial turf fibers to the artificial turf backing.
In this step the artificial turf fiber is bound or attached to the
artificial turf backing. This may be performed in a variety of ways
such as gluing or coating the surface of the artificial turf
backing to hold the artificial turf fiber in position. This for
instance may be done by coating a surface or a portion of the
artificial turf backing with a material such as latex or
polyurethane.
[0010] The incorporation of the artificial turf fiber into the
artificial turf backing could for example be performed
alternatively by weaving the artificial turf fiber into artificial
turf backing (or fiber mat) during manufacture of the artificial
turf carpet. This technique of manufacturing artificial turf is
known from United States patent application US 20120125474 A1.
[0011] The term `polymer bead` or `beads` may refer to a localized
region, such as a droplet, of a polymer that is immiscible in the
second polymer. The polymer beads may in some instances be round or
spherical or oval-shaped, but they may also be irregularly-shaped.
In some instances the polymer bead will typically have a size of
approximately 0.1 to 3 micrometer, preferably 1 to 2 micrometer in
diameter. In other examples the polymer beads will be larger. They
may for instance have a size with a diameter of a maximum of 50
micrometer.
[0012] In some examples the stretched monofilament may be used
directly as the artificial turf fiber. For example the monofilament
could be extruded as a tape or other shape.
[0013] In other examples the artificial turf fiber may be a bundle
or group of several stretched monofilament fibers is in general
cabled, twisted, or bundled together. In some cases the bundle is
rewound with a so called rewinding yarn, which keeps the yarn
bundle together and makes it ready for the later tufting or weaving
process.
[0014] The monofilaments may for instance have a diameter of 50-600
micrometer in size. The yarn weight may typically reach 50-3000
dtex.
[0015] Embodiments may have the advantage that the second polymer
and any immiscible polymers may not delaminate from each other. The
thread-like regions are embedded within the second polymer. It is
therefore impossible for them to delaminate. The use of the first
polymer and the second polymer enables the properties of the
artificial turf fiber to be tailored. For instance a softer plastic
may be used for the second polymer to give the artificial turf a
more natural grass-like and softer feel. A more rigid plastic may
be used for the first polymer or other immiscible polymers to give
the artificial turf more resilience and stability and the ability
to spring back after being stepped or pressed down.
[0016] A further advantage may possibly be that the thread-like
regions are concentrated in a central region of the monofilament
during the extrusion process. This leads to a concentration of the
more rigid material in the center of the monofilament and a larger
amount of softer plastic on the exterior or outer region of the
monofilament. This may further lead to an artificial turf fiber
with more grass-like properties.
[0017] A further advantage may be that the artificial turf fibers
have improved long term elasticity. This may require reduced
maintenance of the artificial turf and require less brushing of the
fibers because they more naturally regain their shape and stand up
after use or being trampled.
[0018] In another embodiment the polymer bead comprises crystalline
portions and amorphous portions. The polymer mixture was likely
heated during the extrusion process and portions of the first
polymer and also the second polymer may have a more amorphous
structure or a more crystalline structure in various regions.
Stretching the polymer beads into the thread-like regions may cause
an increase in the size of the crystalline portions relative to the
amorphous portions in the first polymer. This may lead for instance
to the first polymer to become more rigid than when it has an
amorphous structure. This may lead to an artificial turf with more
rigidity and ability to spring back when pressed down. The
stretching of the monofilament may also cause in some cases the
second polymer or other additional polymers also to have a larger
portion of their structure become more crystalline.
[0019] In a specific example of this the first polymer could be
polyamide and the second polymer could be polyethylene. Stretching
the polyamide will cause an increase in the crystalline regions
making the polyamide stiffer. This is also true for other plastic
polymers.
[0020] In another embodiment the creating of the polymer mixture
comprises the step of forming a first mixture by mixing the first
polymer with the compatibilizer. The creation of the polymer
mixture further comprises the step of heating the first mixture.
The step of creating the polymer mixture further comprises the step
of extruding the first mixture. The creating of the polymer mixture
further comprises the step of extruding the first mixture. The
creation of the polymer mixture further comprises the steps of
granulating the extruded first mixture. The creating of the polymer
mixture further comprises the step of mixing the granulated first
mixture with the second polymer. The creation of the polymer
mixture further comprises the step of heating the granulated first
mixture with the second polymer to form the polymer mixture. This
particular method of creating the polymer mixture may be
advantageous because it enables very precise control over how the
first polymer and compatibilizer are distributed within the second
polymer. For instance the size or shape of the extruded first
mixture may determine the size of the polymer beads in the polymer
mixture.
[0021] In the aforementioned method of creating the polymer mixture
for instance a so called one-screw extrusion method may be used. As
an alternative to this the polymer mixture may also be created by
putting all of the components that make it up together at once. For
instance the first polymer, the second polymer and the
compatibilizer could be all added together at the same time. Other
ingredients such as additional polymers or other additives could
also be put together at the same time. The amount of mixing of the
polymer mixture could then be increased for instance by using a
two-screw feed for the extrusion. In this case the desired
distribution of the polymer beads can be achieved by using the
proper rate or amount of mixing.
[0022] In another embodiment the polymer mixture is at least a
four-phase system. The polymer mixture comprises at least a third
polymer. The third polymer is immiscible with the second polymer.
The third polymer further forms the polymer beads surrounded by the
compatibilizer within the second polymer.
[0023] In another embodiment the creating of the polymer mixture
comprises the step of forming a first mixture by mixing the first
polymer and the third polymer with the compatibilizer. The creating
of the polymer mixture further comprises the step of heating the
first mixture. The creating of the polymer mixture first comprises
the step of extruding the first mixture. The creating of the
polymer mixture further comprises the step of granulating the
extruded first mixture. The creating of the polymer mixture further
comprises mixing the first mixture with the second polymer. The
creating of the polymer mixture further comprises the step of
heating the first mixture with the second polymer to form the
polymer mixture. This method may provide for a precise means of
making the polymer mixture and controlling the size and
distribution of the polymer beads using two different polymers. As
an alternative the first polymer could be used to make a granulate
with the compatibilizer separately from making the third polymer
with the same or a different compatibilizer. The granulates could
then be mixed with the second polymer to make the polymer
mixture.
[0024] As an alternative to this the polymer mixture could be made
by adding the first polymer, a second polymer, the third polymer
and the compatibilizer all together at the same time and then
mixing them more vigorously. For instance a two-screw feed could be
used for the extruder.
[0025] In another embodiment the third polymer is a polar
polymer.
[0026] In another embodiment the third polymer is polyamide.
[0027] In another embodiment the third polymer is polyethylene
terephthalate, which is also commonly abbreviated as PET.
[0028] In another embodiment the third polymer is polybutylene
terephthalate, which is also commonly abbreviated as PBT.
[0029] In another embodiment the polymer mixture comprises between
1% and 30% by weight the first polymer and the third polymer
combined. In this example the balance of the weight may be made up
by such components as the second polymer, the compatibilizer, and
any other additional additives put into the polymer mixture.
[0030] In another embodiment the polymer mixture comprises between
1 and 20% by weight of the first polymer and the third polymer
combined. Again, in this example the balance of the weight of the
polymer mixture may be made up by the second polymer, the
compatibilizer, and any other additional additives.
[0031] In another embodiment the polymer mixture comprises between
5% and 10% by weight of the first polymer and the third polymer
combined. Again in this example the balance of the weight of the
polymer mixture may be made up by the second polymer, the
compatibilizer, and any other additional additives.
[0032] In another embodiment the polymer mixture comprises between
1% and 30% by weight the first polymer. In this example the balance
of the weight may be made up for example by the second polymer, the
compatibilizer, and any other additional additives.
[0033] In another embodiment the polymer mixture comprises between
1% and 20% by weight of the first polymer. In this example the
balance of the weight may be made up by the second polymer, the
compatibilizer, and any other additional additives mixed into the
polymer mixture.
[0034] In another embodiment the polymer mixture comprises between
5% and 10% by weight of the first polymer. This example may have
the balance of the weight made up by the second polymer, the
compatibilizer, and any other additional additives mixed into the
polymer mixture.
[0035] In another embodiment the first polymer is a polar
polymer.
[0036] In another embodiment the first polymer is polyamide.
[0037] In another embodiment the first polymer is polyethylene
terephthalate which is commonly known by the abbreviation PET.
[0038] In another embodiment the first polymer is polybutylene
terephthalate which is also known by the common abbreviation
PBT.
[0039] In another embodiment the second polymer is a non-polar
polymer.
[0040] In another embodiment the second polymer is
polyethylene.
[0041] In another embodiment the second polymer is
polypropylene.
[0042] In another embodiment the second polymer is a mixture of the
aforementioned polymers which may be used for the second
polymer.
[0043] In another embodiment the compatibilizer is any one of the
following: a maleic acid grafted on polyethylene or polyamide; a
maleic anhydride grafted on free radical initiated graft copolymer
of polyethylene, SEBS, EVA, EPD, or polyproplene with an
unsaturated acid or its anhydride such as maleic acid, glycidyl
methacrylate, ricinoloxazoline maleinate; a graft copolymer of SEBS
with glycidyl methacrylate, a graft copolymer of EVA with
mercaptoacetic acid and maleic anhydride; a graft copolymer of EPDM
with maleic anhydride; a graft copolymer of polypropylene with
maleic anhydride; a polyolefin-graft-polyamidepolyethylene or
polyamide; and a polyacrylic acid type compatibalizer.
[0044] In another embodiment the polymer mixture comprises between
80-90% by weight of the second polymer. In this example the balance
of the weight may be made up by the first polymer, possibly the
second polymer if it is present in the polymer mixture, the
compatibilizer, and any other chemicals or additives added to the
polymer mixture.
[0045] In another embodiment the polymer mixture further comprises
any one of the following: a wax, a dulling agent, a ultraviolet
stabilizer, a flame retardant, an anti-oxidant, a pigment, and
combinations thereof. These listed additional components may be
added to the polymer mixture to give the artificial turf fibers
other desired properties such as being flame retardant, having a
green color so that the artificial turf more closely resembles
grass and greater stability in sunlight.
[0046] In another embodiment creating the artificial turf fiber
comprises weaving the monofilament into the artificial turf fiber.
That is to say in some examples the artificial turf fiber is not a
single monofilament but a combination of a number of fibers.
[0047] In another embodiment the artificial turf fiber is a
yarn.
[0048] In another embodiment the method further comprises bundling
stretched monofilaments together to create the artificial turf
fiber.
[0049] In another embodiment the method further comprises weaving,
bundling, or spinning multiple monofilaments together to create the
artificial turf fiber. Multiple, for example 4 to 8 monofilaments,
could be formed or finished into a yarn.
[0050] In another aspect the invention provides for an artificial
turf manufacture according to any one of the aforementioned
methods.
[0051] In another aspect the invention provides for an artificial
turf comprising an artificial turf backing and artificial turf
fiber tufted into the artificial turf backing. The artificial turf
backing may for instance be a textile or other flat structure which
is able to have fibers tufted into it. The artificial turf fiber
comprises at least one monofilament. Each of the at least one
monofilament comprises a first polymer in the form of thread-like
regions. Each of the at least one monofilament comprises a second
polymer, wherein the thread-like regions are embedded in the second
polymer. Each of the at least one monofilaments comprises a
compatibilizer surrounding each of the thread-like regions and
separating the at least one first polymer from the second polymer.
This artificial turf may have the advantage of being extremely
durable because the thread-like regions are embedded within the
second polymer via a compatibilizer. They therefore do not have the
ability to delaminate. Having the second polymer surrounding the
first polymer may provide for a stiff artificial turf that is soft
and feels similar to real turf. The artificial turf as described
herein is distinct from artificial turf which is coextruded. In
coextrusion a core of typically 50 to 60 micrometer may be
surrounded by an outer cover or sheathing material which has a
diameter of approximately 200 to 300 micrometer in diameter. In
this artificial turf there is a large number of thread-like regions
of the first polymer. The thread-like regions may not continue
along the entire length of the monofilament. The artificial turf
may also have properties or features which are provided for by any
of the aforementioned method steps.
[0052] In another embodiment the thread-like regions have a
diameter of less than 20 micrometer.
[0053] In another embodiment the thread-like regions have a
diameter of less than 10 micrometer.
[0054] In another embodiment the thread-like regions have a
diameter of between 1 and 3 micrometer.
[0055] In another embodiment the artificial turf fiber extends a
predetermined length beyond the artificial turf backing. The
thread-like regions have a length less than one half of the
predetermined length.
[0056] In another embodiment the thread-like regions have a length
of less than 2 mm.
[0057] It is understood that one or more of the aforementioned
embodiments of the invention may be combined as long as the
combined embodiments are not mutually exclusive.
BRIEF DESCRIPTION OF THE DRAWINGS
[0058] In the following embodiments of the invention are explained
in greater detail, by way of example only, making reference to the
drawings in which:
[0059] FIG. 1 shows a flowchart which illustrates an example of a
method of manufacturing artificial turf;
[0060] FIG. 2 shows a flowchart which illustrates one method of
creating the polymer mixture;
[0061] FIG. 3 shows a flowchart which illustrates a further example
of how to create a polymer mixture;
[0062] FIG. 4 shows a diagram which illustrates a cross-section of
a polymer mixture;
[0063] FIG. 5 shows a further example of a polymer mixture;
[0064] FIG. 6 illustrates the extrusion of the polymer mixture into
a monofilament;
[0065] FIG. 7 shows a cross-section of a small segment of the
monofilament;
[0066] FIG. 8 illustrates the effect of stretching the
monofilament;
[0067] FIG. 9 shows an electron microscope picture of a
cross-section of a stretched monofilament; and
[0068] FIG. 10 shows an example of a cross-section of an example of
artificial turf.
DETAILED DESCRIPTION
[0069] 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.
[0070] FIG. 1 shows a flowchart which illustrates an example of a
method of manufacturing artificial turf. First in step 100 a
polymer mixture is created. The polymer mixture is at least a
three-phase system. The polymer mixture comprises a first polymer.
The polymer mixture further comprises a second polymer and a
compatibilizer. The first polymer and the second polymer are
immiscible. In other examples there may be additional polymers such
as a third, fourth, or even fifth polymer 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 surrounded by the compatibilizer.
The polymer beads may also be formed by additional polymers which
are not miscible in the second polymer.
[0071] The polymer beads are surrounded by the compatibilizer and
are within the second polymer or mixed into the second polymer. In
the next step 102 the polymer mixture is extruded into a
monofilament. Next in step 104 the monofilament is quenched or
rapidly cooled down. Next in step 106 the monofilament is reheated.
In step 108 the reheated monofilament is stretched to deform the
polymer beads into thread-like regions and to form the monofilament
into the 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 110 the artificial turf fiber is
incorporated into an artificial turf backing. Step 110 could for
example be, but is not limited to, tufting or weaving the
artificial turf fiber into the artificial turf backing. Then in
step 112 the artificial turf fibers are bound to the artificial
turf backing. For instance the artificial turf fibers may be glued
or held in place by a coating or other material. Step 112 is an
optional step. For example if the artificial turf fibers are woven
into the artificial turf backing step 112 may not need to be
performed.
[0072] FIG. 2 shows a flowchart which illustrates one method of
creating the polymer mixture. In this example the polymer mixture
is a three-phase system and comprises the first polymer, a second
polymer and the compatibilizer. The polymer mixture may also
comprise other things such as additives to color or provide flame
or UV-resistance or improve the flowing properties of the polymer
mixture. First in step 200 a first mixture is formed by mixing the
first polymer with the compatibilizer. Additional additives may
also be added during this step. Next in step 202 the first mixture
is heated. Next in step 204 the first mixture is extruded. Then in
step 206 the extruded first mixture is then granulated or chopped
into small pieces. Next in step 208 the granulated first mixture is
mixed with the second polymer. Additional additives may also be
added to the polymer mixture at this time. Finally in step 210 the
granulated first mixture is heated with the second polymer to form
the polymer mixture. The heating and mixing may occur at the same
time.
[0073] FIG. 3 shows a flowchart which illustrates a further example
of how to create a polymer mixture 100. In this example the polymer
mixture additionally comprises at least a third polymer. The third
polymer is immiscible with the second polymer and the polymer
mixture is at least a four-phase system. The third polymer further
forms the polymer beads surrounded by the compatibilizer with the
second polymer. First in step 300 a first mixture is formed by
mixing the first polymer and the third polymer with the
compatibilizer. Additional additives may be added to the first
mixture at this point. Next in step 302 the first mixture is
heated. The heating and the mixing of the first mixture may be done
at the same time. Next in step 304 the first mixture is extruded.
Next in step 306 the extruded first mixture is granulated or
chopped into tiny pieces. Next in step 308 the first mixture is
mixed with the second polymer. Additional additives may be added to
the polymer mixture at this time. Then finally in step 310 the
heated first mixture and the second polymer are heated to form the
polymer mixture. The heating and the mixing may be done
simultaneously.
[0074] FIG. 4 shows a diagram which illustrates a cross-section of
a polymer mixture 400. The polymer mixture 400 comprises a first
polymer 402, a second polymer 404, and a compatibilizer 406. The
first polymer 402 and the second polymer 404 are immiscible. The
first polymer 402 is less abundant than the second polymer 404. The
first polymer 402 is shown as being surrounded by compatibilizer
406 and being dispersed within the second polymer 404. The first
polymer 402 surrounded by the compatibilizer 406 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 406 and the third phase region is the second
polymer 404. The compatibilizer 406 separates the first polymer 402
from the second polymer 406.
[0075] FIG. 5 shows a further example of a polymer mixture 500. The
example shown in FIG. 5 is similar to that shown in FIG. 4 however,
the polymer mixture 500 additionally comprises a third polymer 502.
Some of the polymer beads 408 are now comprised of the third
polymer 502. The polymer mixture 500 shown in FIG. 5 is a
four-phase system. The four phases are made up of the first polymer
402, the second polymer 404, the third polymer 502, and the
compatibilizer 406. The first polymer 402 and the third polymer 502
are not miscible with the second polymer 404. The compatibilizer
406 separates the first polymer 402 from the second polymer 404 and
the third polymer 502 from the second polymer 404.
[0076] In this example the same compatibilizer 406 is used for both
the first polymer 402 and the third polymer 502. In other examples
a different compatibilizer 406 could be used for the first polymer
402 and the third polymer 502.
[0077] FIG. 6 illustrates the extrusion of the polymer mixture into
a monofilament. Shown is an amount of polymer mixture 600. Within
the polymer mixture 600 there is a large number of polymer beads
408. The polymer beads 408 may be made of one or more polymers that
is not miscible with the second polymer 404 and is also separated
from the second polymer 404 by a compatibilizer. A screw, piston or
other device is used to force the polymer mixture 600 through a
hole 604 in a plate 602. This causes the polymer mixture 600 to be
extruded into a monofilament 606. The monofilament 606 is shown as
containing polymer beads 408 also. The second polymer 404 and the
polymer beads 408 are extruded together. In some examples the
second polymer 404 will be less viscous than the polymer beads 408
and the polymer beads 408 will tend to concentrate in the center of
the monofilament 606. 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
606.
[0078] FIG. 7 shows a cross-section of a small segment of the
monofilament 606. The monofilament is again shown as comprising the
second polymer 404 with the polymer beads 408 mixed in. The polymer
beads 408 are separated from the second polymer 404 by
compatibilizer 406 which is not shown. To form the thread-like
structures a section of the monofilament 606 is heated and then
stretched along the length of the monofilament 606. This is
illustrated by the arrows 700 which show the direction of the
stretching.
[0079] FIG. 8 illustrates the effect of stretching the monofilament
606. In FIG. 8 an example of a cross-section of a stretched
monofilament 606 is shown. The polymer beads 408 in FIG. 7 have
been stretched into thread-like structures 800. The amount of
deformation of the polymer beads 408 would be dependent upon how
much the monofilament 606' has been stretched.
[0080] Examples may relate to the production of artificial turf
which is also referred to as synthetic turf. In particular, the
invention relates to the production of fibers that imitate grass.
The fibers are composed of first and second polymers that are not
miscible and differ in material characteristics as e.g. stiffness,
density, polarity and a compatibilizer.
[0081] In a first step, a first polymer is mixed with the a
compatibilizer. Color pigments, UV and thermal stabilizers, process
aids and other substances that are as such known from the art can
be added to the mixture. This may result in granular material which
consist of a two phase system in which the first polymer is
surrounded by the compatibilizer.
[0082] In a second step, a three-phase system is formed by adding
the second polymer to the mixture whereby in this example the
quantity of the second polymer is about 80-90 mass percent of the
three-phase system, the quantities of the first polymer being 5% to
10% by mass and of the compatibilizer being 5% to 10% by mass.
Using extrusion technology results in a mixture of droplets or of
beads of the first polymer surrounded by the compatibilizer that is
dispersed in the polymer matrix of the second polymer. In a
practical implementation a so called master batch including
granulate of the first polymer and the compatibilizer is formed.
The master batch may also be referred to as a "polymer mixture"
herein. The granulate mix is melted and a mixture of the first
polymer and the compatibilizer is formed by extrusion. The
resulting strands are crushed into granulate. The resultant
granulate and granulate of the second polymer are then used in a
second extrusion to produce the thick fiber which is then stretched
into the final fiber.
[0083] The melt temperature used during extrusions is dependent
upon the type of polymers and compatibilizer that is used. However
the melt temperature is typically between 230.degree. C. and
280.degree. C.
[0084] A monofilament, which can also be referred to as a filament
or fibrillated tape, is produced by feeding the mixture into an
fiber producing extrusion line. The melt mixture is passing the
extrusion tool, i.e., a spinneret plate or a wide slot nozzle,
forming the melt flow into a filament or tape form, is quenched or
cooled in a water spin bath, dried and stretched by passing
rotating heated godets with different rotational speed and/or a
heating oven.
[0085] The monofilament or type is then annealed online in a second
step passing a further heating oven and/or set of heated
godets.
[0086] By this procedure the beads or droplets of polymer 1,
surrounded by the compatibilizer are stretched into longitudinal
direction and form small fiber like, linear structures which stay
however completely embedded into the polymer matrix of the second
polymer.
[0087] FIG. 9 shows a microscopic picture of a cross-section of a
stretched monofilament manufactured using an example of a method
described above. The horizontal white streaks within the stretched
monofilament 606 are the thread-like structures 800. Several of
these thread-like structures are labeled 800. The thread-like
structures 800 can be shown as forming small linear structures of
the first polymer within the second polymer.
[0088] The resultant fiber may have multiple advantages, namely
softness combined with durability and long term elasticity. In case
of different stiffness and bending properties of the polymers the
fiber can show a better resilience (this means that once a fiber is
stepped down it will spring back) In case of a stiff first polymer,
the small linear fiber structures built in the polymer matrix are
providing a polymer reinforcement of the fiber.
[0089] Delimitation due to the composite formed by the first and
second polymers is prevented due to the fact that the short fibers
of the second polymer are embedded in the matrix given by the first
polymer. Moreover, complicated coextrusion, requiring several
extrusion heads to feed one complex spinneret tool is not
needed.
[0090] The first polymer can be a polar substance, such as
polyamide, whereas the second polymer can be a non-polar polymer,
such as polyethylene. Alternatives for the first polymer are
polyethylene terephthalate (PET) or polybutylene terephthalate
(PBT) for the second polymer polypropylene. Finally a material
consisting of 3 polymers is possible (e.g. PET, PA and PP, with PP
creating the matrix and the other creating independent from each
other fibrous linear structures. The compatibilizer can be a maleic
anhydride grafted on polyethylene or polyamide.
[0091] FIG. 10 shows an example of a cross-section of an example of
artificial turf 1000. The artificial turf 1000 comprises an
artificial turf backing 1002. Artificial turf fiber 1004 has been
tufted into the artificial turf backing 1002. On the bottom of the
artificial turf backing 1002 is shown a coating 1006. The coating
may serve to bind or secure the artificial turf fiber 1004 to the
artificial turf backing 1002. The coating 1006 may be optional. For
example the artificial turf fibers 1004 may be alternatively woven
into the artificial turf backing 1002. Various types of glues,
coatings or adhesives could be used for the coating 1006. The
artificial turf fibers 1004 are shown as extending a distance 1008
above the artificial turf backing 1002. The distance 1008 is
essentially the height of the pile of the artificial turf fibers
1004. The length of the thread-like regions within the artificial
turf fibers 1004 is half of the distance 1008 or less.
LIST OF REFERENCE NUMERALS
[0092] 100 create a polymer mixture [0093] 102 extrude the polymer
mixture into a monofilament [0094] 104 quench the monofilament
[0095] 106 reheat the monofilament [0096] 108 stretch the reheated
monofilament to deform the polymer beads into threadlike regions
and to form the monofilament into an artificial turf fiber [0097]
110 incorporate the artificial turf fiber into an artificial turf
carpet [0098] 112 optionally bind the artificial turf fibers to the
artificial turf carpet [0099] 200 form a first mixture by mixing
the first polymer with the compatibilizer [0100] 202 heat the first
mixture [0101] 204 extrude the first mixture [0102] 206 granulate
the extruded first mixture [0103] 208 mix the granulated first
mixture with the second polymer [0104] 210 heat the granulated
first mixture with the second polymer to form the polymer mixture
[0105] 300 form a first mixture by mixing the first polymer and the
third polymer with the compatibilizer [0106] 302 heat the first
mixture [0107] 304 extrude the first mixture [0108] 306 granulate
the extruded first mixture [0109] 308 mix the first mixture with
the second polymer [0110] 310 heat the mixed first mixture with the
second polymer to form the polymer mixture [0111] 400 polymer
mixture [0112] 402 first polymer [0113] 404 second polymer [0114]
406 compatibilizer [0115] 408 polymer bead [0116] 500 polymer
mixture [0117] 502 third polymer [0118] 600 polymer mixture [0119]
602 plate [0120] 604 hole [0121] 606 monofilament [0122] 606'
stretched monofilament [0123] 700 direction of stretching [0124]
800 threadlike structures [0125] 1000 artificial turf [0126] 1002
artificial turf carpet [0127] 1004 artificial turf fiber (pile)
[0128] 1006 coating [0129] 1008 height of pile
* * * * *