JP2001098508A - Artificial lawn for stadium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the frictional resistance of a lawn surface without impairing its external appearance in an artificial lawn for a stadium made from a slit yarn. SOLUTION: When a slit yarn 10 is spread in the width direction to form a meshy expanded lattice body, the ratio a/b between the frame width (a) of a vertical lattice frame 11 appearing along the longitudinal direction of the yarn 10 and the frame width b of a horizontal lattice frame 12 appearing to cross the vertical lattice frame 11 at the prescribed angle is set in the range of 1.5-4.0.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an artificial turf for a stadium laid on a soccer field or the like, and more particularly to an artificial turf for a stadium using slit yarns as artificial turf yarn.

[0002]

2. Description of the Related Art Artificial turf is obtained by embedding a large number of artificial turf yarns on a sheet-like base material. The yarns used for artificial turf yarns generally include slit yarns (also called split yarns) and monofilament yarns. There is.

A slit yarn is prepared by extruding a raw resin compound by an extruder to a width of 50 to 100 mm and a thickness of 40 to 100 μm.
It is extruded into a film having a thickness of about 10 mm, and is then subdivided into an elongated tape of 10 to 20 mm. Then, it is sent to a cut forming step by a cutter, and a length of 10 to 40 m
About m slits are periodically formed along the length direction. Since the yarn is spread by the slit, an artificial turf having a good appearance can be obtained.

[0004]

By making the slits finely and densely, a better voluminous feel can be obtained, but on the other hand, the frictional resistance increases, and for example, the player may be scratched when sliding. . In order to prevent this, it is only necessary to roughly form the slit. However, this is not preferable because the volume feeling peculiar to the slit yarn is reduced.

[0005]

DISCLOSURE OF THE INVENTION The present invention has been made to solve such problems, and an object of the present invention is to improve the appearance and the frictional resistance of a turf surface. An object of the present invention is to provide an artificial grass for a stadium using slit yarn.

According to the present invention, it is an object of the present invention to provide a tape-shaped yarn having a predetermined width in which slits are periodically formed at a predetermined pitch for each of a plurality of imaginary lines set parallel to each other along the longitudinal direction. In the artificial grass for a stadium, the slit yarns are formed and implanted in a sheet-like base material as artificial grass yarns in which slits on adjacent imaginary lines are alternately arranged. When expanded to form a mesh-shaped expanded lattice body, the frame width of the vertical lattice frame (stem) that appears along the longitudinal direction of the yarn is a,
Assuming that the width of the horizontal lattice frame (branch portion) that appears to intersect the vertical lattice frame at a predetermined angle is b, the ratio of a / b is 1.5 to
Achieved by setting the range of 4.0.

When the ratio a / b is less than 1.5, the slit portion is easily expanded, so that the covering property (appearance for covering the base material) is good. On the other hand, the surface area of the yarn is increased. This is not preferable because the frictional resistance of the turf surface increases.

On the other hand, if the ratio a / b exceeds 4.0, the frictional resistance of the turf surface is reduced because the slit portion is difficult to expand, but the width of the yarn is not so widened. This is not preferred because the properties are sacrificed.

According to a preferred embodiment of the present invention, the grass of the artificial lawn is filled with particulate matter such as silica sand or rubber chips. In this case, the ratio of a / b is 1.
It is preferably in the range of 5 to 3.0.

In the case of a slit yarn, the expansion of the slit creates a space in which sand moves. Therefore, the above a
When / b is less than 1.5, the slit portion is easily expanded, and the space is appropriately secured. Therefore, at the beginning of the construction, the space portion functions as a cushion, and the tightness of sand is suppressed, and the artificial grass Moderate elasticity is maintained. However, over time, the fine slits accelerate the progress of fibrillation (pre-cracking phenomenon), the ends of the fibrillated yarn become entangled, and the elasticity of the artificial turf is lost, which is not preferable.

Conversely, if the ratio a / b exceeds 3.0, the spread of the slit portion becomes small. As a result, there is little space for the sand to move, and the filled sand starts to tighten soon after construction, causing the elasticity of the artificial grass to be lost at an early stage, which is also undesirable.

In the present invention, the material of the slit yarn is usually polypropylene, polyethylene, nylon, or the like.
There is no particular limitation as long as it is a synthetic resin used for the production of yarn for artificial turf, as long as it can produce slit yarn.

The method of planting the slit yarn on the sheet-like base material is generally tufting, but is not limited to this. Any method can be used as long as the yarn can be planted regularly and efficiently. Either can be adopted. The planted artificial grass yarn (pile) may be either a cut pile or a loop pile.

[0014]

FIG. 1 is a perspective view showing a slit yarn 10 used for an artificial grass for a stadium according to the present invention. The slit yarn 10 is made of, for example, a band of synthetic resin such as polypropylene or polyethylene, and has a width W of about 5 to 20 mm and a thickness T of 40 to 10 mm.
It may be 0 μm.

The slit yarn 10 has a plurality of slits S formed along its longitudinal direction. In forming the slit S, a plurality of virtual lines parallel to each other along the longitudinal direction of the slit yarn 10, in this example, six virtual lines L <b> 1 to L <b> 6 are set.
The slits S are periodically formed at a predetermined pitch every 1 to L6. In this case, the slits S of the adjacent virtual lines are arranged alternately.

That is, the odd-numbered virtual lines L1, L3,
Each slit S of L5 and the even-numbered virtual line L2
Although the slits S of L4 and L6 are arranged side by side, the slits S of the odd-numbered virtual lines L1, L3 and L5 and the slits S of the even-numbered virtual lines L2, L4 and L6 are Each end is shifted by approximately 1/2 pitch so that a predetermined overlap length δ occurs.

Preferably, each slit S has the same length Ls. The length Ls is not particularly limited, but will generally be appropriately selected, for example, from a range of 10 to 40 mm. It is preferable that the overlap length δ is equal to or less than の of the length Ls of the slit S.

According to the present invention, the slit S on each virtual line
The interval between them is specified as follows. If this is replaced by the line width of each virtual line, three consecutive adjacent lines will be described.
As for the virtual lines, for example, the virtual lines L1, L2 and L3, the line width between the virtual lines L1 and L3 located on the left and right sides is a, and the virtual line L2 located between them is the right side in FIG. Assuming that a line width between the virtual line L1 and the virtual line L1 is b, a / b is in the range of 1.5 to 4.0.

Similarly, with respect to the virtual lines L3, L4, and L5, the line width a between the virtual lines L3 and L5 located on the left and right sides is similarly set.
And the line width b between the virtual line L4 located between them and one virtual line L3 adjacent thereto has a ratio a / b of 1.
It is in the range of 5 to 4.0.

FIG. 2 schematically shows a state in which the slit yarn 10 is expanded in the width direction (the direction of the arrow in the figure) to form a mesh-like expanded lattice. Thus, when the slit yarn 10 is expanded, a vertical lattice frame 11 having a line width a appears along the longitudinal direction of the yarn in a trunk shape, and a line width intersecting the vertical lattice frame 11 at a predetermined angle. The horizontal lattice frame 12 as a bridging portion having b appears in a branch shape.

As described above, in the present invention, a / b
Is in the range of 1.5 to 4.0, preferably a /
b is preferably 1.8 to 3.0, particularly preferably 2.0 to 2.5. In the above embodiment, the imaginary lines L1, L2, and L3 are used as a repetition unit in forming the slit S. However, in some cases, the imaginary lines L3, L4, and L5 adjacent to the imaginary lines L4, L5, and L4 are different from each other. The line width between the virtual line L5 located on the left side in FIG. 1 and the virtual line L5 may be b. In short, the way of setting the line width b may be any one between L1 and L2 or between L2 and L3 for the three virtual lines L1, L2, and L3.

Each slit S can be formed by, for example, a drum-shaped slitter 20 shown in FIG. The slitter 20 includes a large number of cutters 22 provided on a body surface of a rotating drum 21.

The distance between the cutters 52 in the axial direction of the rotary drum 21 corresponds to the above-mentioned virtual lines L1 to L6, and the odd-numbered cutters and the even-numbered cutters extend in the circumferential direction of the rotary drum 21. For example, it is displaced by about ピ ッ チ pitch.

The slitter 20 rotates in a direction opposite to the running direction of the tape-shaped yarn, and forms a slit S in the yarn. In the example of FIG. 3, the yarn is slitter 2
0, and the traveling direction is the right direction,
The slitter 20 rotates clockwise. The length L _{S of the} slit increases as the difference between the rotational speed of the slitter 20 and the running speed of the yarn increases.

As another slit forming method, needles are set up and down at positions corresponding to the imaginary lines L1 to L6, and the needles are lowered for a running yarn for a predetermined time. The slit S may be formed by piercing the yarn.

FIG. 4 shows an artificial turf 30 in which the slit yarn 10 thus formed is planted on a sheet-like base material 31. The slit yarn 10 is planted in a sheet-like base material 31 by, for example, a tufting machine in a state where several of the slit yarns 10 are bundled,
2 fixed.

The sheet-like base material 31 may be a commonly used plain woven fabric made of, for example, polypropylene fibers. The backing material 32 may also be a commonly used latex or the like, and in the present invention, the sheet-like base material 31 and the backing material 32 are not particularly limited.

The gauge width and stitch width of the slit yarn 10 may be set arbitrarily. The implanted slit yarn 10 may be either a cut pile or a loop pile. The means for implanting the yarn is not limited to a tufting machine. Any method can be used as long as the yarn can be regularly and efficiently implanted.

The present invention also includes so-called artificial grass containing sand. That is, as shown in FIG. 3, a granular material 33 such as silica sand or a rubber chip may be filled in a gap between artificial grass yarns made of the slit yarn 10. Granular material 3
The particle size of 3 may be arbitrarily selected.

In the case of artificial turf containing sand, the ratio of a / b is preferably 1.8 to 3.0. According to this, sand compaction is suppressed and fibrillation becomes difficult. As a result, the elasticity of the artificial turf is maintained for a long time.

[0031]

Next, specific examples of the present invention and comparative examples will be described. In each case, artificial grass was produced, and artificial grass was produced using the artificial grass. Then, a granular material was filled between the grasses to form a so-called artificial grass containing sand. The matters common to each example are as follows.

In each case, the artificial turf yarn has a denier number of 760.
0, a slit yarn having a tape width of 15 mm and a tape thickness of 70 μm, and a length per slit (Ls) of 15 mm;
The slit interval on the same imaginary line was 1 mm, and the overlap length (δ) of adjacent slits was 4 mm.

Then, the lawn length is 25 mm and the basis weight is 1200.
After tufting a plain woven fabric made of polypropylene fiber as a sheet-like substrate at g / square m, the back surface was backed with latex to produce an artificial lawn.

The artificial turf (100
× 100cm) is laid on the ground, and 14 ~
Silica sand having a particle size of 100 mesh was filled to a thickness of about 23 mm. Immediately after the construction and one year after the construction, the resistance when the needle penetrated 20 mm was measured using a Yamanaka hardness tester to measure the tightness of the sand, and the state of fibrillation of the yarn was also observed. .

As shown in FIG. 5, a polyester woven cloth 41 is laid on the grass surface of the artificial turf, and
A weight 42 of 0 kg was placed thereon, and the polyester woven fabric 41 was pulled in a substantially horizontal direction by a spring balance 40, and the load at the time of starting to move was read to measure the dynamic friction coefficient.

<< Example 1-1 >> [Specification of split yarn] Material: polypropylene a / b = 1.5 [Evaluation] Covering property: good (base fabric cannot be seen through). Dynamic friction coefficient: 0.72. Sand tightness: 1.3 immediately after construction, 1 year later
3 (kgf / cm ² ). Fibrillation: No fibrillation.

<< Example 1-2 >> [Specifications of split yarn] Material: polypropylene a / b = 2.0 [Evaluation] Covering property: extremely good. Dynamic friction coefficient: 0.68. 1. Tightness of sand: 1.2 immediately after construction, 1 year later.
1 (kgf / cm ² ). Fibrillation: No fibrillation.

<< Example 1-3 >> [Specifications of split yarn] Material: polypropylene a / b = 2.5 [Evaluation] Covering property: extremely good. Dynamic friction coefficient: 0.68. 1. Tightness of sand: 1.2 immediately after construction, 1 year later.
1 (kgf / cm ² ). Fibrillation: No fibrillation.

<< Example 1-4 >> [Specifications of split yarn] Material: polypropylene a / b = 3.0 [Evaluation] Covering property: good. Dynamic friction coefficient: 0.67. 1. Tightness of sand: 1.2 immediately after construction, 1 year later.
1 (kgf / cm ² ). Fibrillation: No fibrillation.

<< Example 1-5 >> [Specifications of split yarn] Material: polypropylene a / b = 4.0 [Evaluation] Covering property: good. Dynamic friction coefficient: 0.65. 1. Tightness of sand: 1.2 immediately after construction, 1 year later.
3 (kgf / cm ² ). Fibrillation: Slight fibrillation was observed.

<Comparative Example 1-1> [Specifications of split yarn] Material: polypropylene a / b = 1.3 [Evaluation] Covering property: good. Dynamic friction coefficient: 0.79. Sand tightness: 1.3 immediately after construction, 1 year later
7 (kgf / cm ² ). Fibrillation: Due to fibrillation, the sand hardens.

<Comparative Example 1-2> [Specifications of split yarn] Material: polypropylene a / b = 4.2 [Evaluation] Covering property: poor (base fabric is seen through). Dynamic friction coefficient: 0.64. Sand tightness: 1.7 immediately after construction and 3.0 (kgf / cm ² ) after one year because sand is difficult to move. Fibrillation: No fibrillation.

Example 2-1 [Specification of split yarn] Material: linear low-density polyethylene a / b = 1.5 [Evaluation] Covering property: good. Dynamic friction coefficient: 0.68. Sand tightness: 0.5 immediately after construction, 1 year after 1 year.
2 (kgf / cm ² ). Fibrillation: No fibrillation.

Example 2-2 [Specification of split yarn] Material: linear low-density polyethylene a / b = 2.0 [Evaluation] Covering property: extremely good. Dynamic friction coefficient: 0.65. Sand tightness: 0.5 immediately after construction and 0 after one year.
9 (kgf / cm ² ). Fibrillation: No fibrillation.

<< Example 2-3 >> [Specifications of split yarn] Material: linear low-density polyethylene a / b = 2.5 [Evaluation] Covering property: extremely good. Dynamic friction coefficient: 0.65. Sand tightness: 0.5 immediately after construction and 0 after one year.
9 (kgf / cm ² ). Fibrillation: No fibrillation.

Example 2-4 [Specification of Split Yarn] Material: Linear low-density polyethylene a / b = 3.0 [Evaluation] Covering property: good. Dynamic friction coefficient: 0.64. Sand tightness: 0.5 immediately after construction and 0 after one year.
9 (kgf / cm ² ). Fibrillation: No fibrillation.

Example 2-5 [Specification of Split Yarn] Material: Linear low-density polyethylene a / b = 4.0 [Evaluation] Covering property: good. Dynamic friction coefficient: 0.64. Sand tightness: 0.5 immediately after construction, 1 year after 1 year.
5 (kgf / cm ² ). Fibrillation: Slight fibrillation was observed.

<Comparative Example 2-1> [Specifications of split yarn] Material: linear low-density polyethylene a / b = 1.3 [Evaluation] Covering property: good. Dynamic friction coefficient: 0.73. 1. Tightness of sand: 0.5 immediately after construction, 1 year later
5 (kgf / cm ² ). Fibrillation: Due to severe fibrillation, the sand was hardened.

<Comparative Example 2-2> [Specifications of split yarn] Material: linear low-density polyethylene a / b = 4.2 [Evaluation] Covering property: poor. Dynamic friction coefficient: 0.62. Sand tightness: 1.0 immediately after construction and 3.0 (kgf / cm ² ) after one year since sand is difficult to move. Fibrillation: No fibrillation.

For reference, Table 1 summarizes the specifications and evaluations of the above Examples and Comparative Examples.

[Table 1]

From these results, it was found that a / b was 1.5
Artificial turf made with slit yarn of ~ 4.0,
Both polypropylene and linear low-density polyethylene have good covering properties (appearance) and low friction resistance. In particular, when the a / b is in the range of 2.0 to 2.5, the appearance is extremely good.

Also, in the case of so-called artificial turf containing sand, in the case of using the slit yarn having the a / b of 1.5 to 4.0, fibrillation is unlikely to occur, and sand aging due to aging is difficult. It can be said that there is little tightening. In particular, fibrillation was not observed in the artificial turf produced with the slit yarn having the a / b of 1.5 to 3.0.

When the material is linear low-density polyethylene, the difference between the embodiment and the comparative example in sand tightness is more remarkable than in the case of polypropylene in comparison with polypropylene, and the effect of the difference in slit is large. This seems to be because the linear low-density polyethylene is softer in material.

[0054]

As described above, according to the present invention,
When the slit yarn is expanded in the width direction to form a mesh-shaped expanded lattice body, the width of the vertical lattice frame appearing along the longitudinal direction of the yarn is a, and the horizontal lattice frame appears to intersect the vertical lattice frame at a predetermined angle. A / b is 1.5 to
By using the slit yarn in the range of 4.0, an artificial turf for an athletic field having good appearance properties and low frictional resistance of a turf surface is provided.

In the case of a so-called artificial turf containing sand, in which the grass is filled with particulate matter, the elasticity is maintained for a long time with less sand compaction,
It is possible to construct an artificial grass with sand in which the yarn is less likely to fibrillate.

[Brief description of the drawings]

FIG. 1 is a perspective view of a slit yarn used for an artificial grass for a stadium of the present invention.

FIG. 2 is a schematic diagram showing a state in which the slit yarn is expanded to form an expanded lattice body.

FIG. 3 is a schematic view showing an example of a slit forming method of the slit yarn.

FIG. 4 is a schematic cross-sectional view of an artificial lawn made of the slit yarn.

FIG. 5 is an explanatory diagram showing a state in which the dynamic friction resistance of the artificial grass is measured.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Slit yarn 11 Vertical lattice frame 12 Horizontal lattice frame 20 Drum-shaped slitter 21 Rotary drum 22 Cutter 30 Artificial turf 31 Sheet base material 32 Backing material 33 Granular material (sand) L1-L6 Virtual line S Slit

Claims (2)

[Claims] 1. A plurality of imaginary lines set in parallel with each other along a longitudinal direction of a tape-shaped yarn having a predetermined width, and slits are periodically formed at a predetermined pitch and are adjacent to each other. In artificial turf for an athletic field, in which slit yarns in which imaginary lines are alternately arranged are planted on a sheet-like substrate as artificial turf yarn, the slit yarn is expanded in the width direction to form a mesh-shaped expanded lattice. Where a / b is 1 and a is the width of the vertical lattice frame appearing along the longitudinal direction of the yarn, and b is the frame width of the horizontal lattice frame that appears to intersect the vertical lattice frame at a predetermined angle.
An artificial turf for a stadium, which satisfies a range of 5 to 4.0. 2. The method according to claim 1, wherein said a / b is in the range of 1.5 to 3.0, and said artificial grass yarn is filled with granular material in the grass. The artificial grass for the stadium described.