JPS5996308A - Athletic field made of artificial turf - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an athletic field made of artificial turf, and more particularly to an athletic field made of artificial turf, which is formed by filling the artificial turf with dry sand.

Generally, artificial lawns are made of flat pile threads made from synthetic resins such as polyamide, acrylic, vinylidene chloride, or polypropylene, which are grafted onto a backing fabric using various methods. The pile length and turf density will vary slightly depending on the playing field to which it is applied, such as a tennis court, turf field, etc., but the length is generally 7.
It is around 12 mm. Artificial lawns have become rapidly popular in recent years because they are more durable and easier to maintain than natural lawns, but there are still issues that need to be resolved in terms of their characteristics and construction. left behind.

According to previous examples, it has been reported that by filling the grains of an artificial lawn with dried sand (mineral particles), the characteristics of the artificial lawn can be made to more closely resemble those of a natural lawn. Although this dry sand satisfies the buffering capacity of the artificial lawn and the ability to prevent spikes from getting caught, the following points must be kept in mind.

In other words, in order to increase the water retention capacity of this sand layer, the finer the grain size, the better; however, if too fine sand is used,
Not only does it harden over time and lose its proper cushioning properties, but the sand gets blown up by the wind during or after sanding, which is unfavorable in terms of occupational safety and health and environmental health. This dust generation is particularly problematic in indoor courts. For this reason, in the past, soil fixatives were sprinkled on top of the filled sand layer to harden the surface, or the particle size of the sand was kept to a certain level, and moisture retaining agents such as vermiculite or calcium chloride were used instead. Some ingredients are mixed in.

However, methods using soil fixatives are not very permanent;
This is troublesome in terms of maintenance and management, and is also undesirable in terms of cost. On the other hand, as for the moisture retaining material, mixing it into the sand layer requires a certain amount of effort, and like the former, cost problems remain.

Therefore, the object of the present invention is to provide a flat stadium surface that has characteristics similar to natural grass in terms of buffering capacity and ability to prevent spikes from getting caught, as well as water absorption capacity, and which is easy to maintain after rain. To provide an artificial grass athletic field that is easy to construct and has a sand layer that generates extremely little dust due to wind or the like.

The above object is achieved by first forming a lower layer of fine dry sand below the grain of the artificial lawn, and filling and layering coarse dry sand on top of the lower layer. In this case, the fine dry sand preferably contains 80% or more of a particle size of 100 mesh to 28 mesh, and the coarse dry sand preferably contains 80% or more of a particle size of 70 mesh to 14 mesh.

Further, according to the present invention, the ground below where the artificial lawn is laid is made of crushed stone, volcanic gravel, or/and sand and is made of water permeable material, and the upper surface thereof is made of synthetic fibers such as polypropylene, polyamide, polyester, etc. A bulky felt-like nonwoven fabric sheet formed by a spunbond method, a needle punch method, or the like is spread to form a substantially flat sheet.

In the permeable ground of the present invention formed in this way, the recesses formed between the individual crushed stones, etc. constituting the upper surface thereof are filled with the nonwoven fabric, and the ridges of each crushed stone, etc. The intertwining with the nonwoven fabric prevents each crushed stone from moving, and as a result, it is constructed as a flat and firm ground.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

This athletic field consists of a ground (11) whose upper surface is finished substantially flat and an artificial lawn (1) laid on this ground (1).
2) and dry sand (3) filled into the grass grains of this artificial lawn (2). In this example, the ground (1)
consists of stabilized crushed stone, volcanic gravel or/and sand. That is, a stabilizer such as cement or quicklime is mixed into the crushed stone, etc., and an appropriate amount of clay as a moisture donor is added as needed, and then it is spread evenly and the surface is compacted or not compacted. Level it roughly evenly. However, the ground (1) is usually made of the above-mentioned crushed stone with a particle size of about 25 mm in order to have sufficient support capacity against the load applied from above after completion, so its upper surface is uneven. , and there are many gaps between the crushed stones, making it unstable.

Therefore, in this example, a felt-like nonwoven fabric sheet (4) made of polypropylene is spread on the surface of the ground (1) to form a substantially flat surface.

By laying this non-woven fabric sheet (4), the ground (1), which has a relatively large diameter and an uneven surface, is created by simply spreading crushed stones, etc., which has many gaps between the crushed stones and lacks stability.
Since the upper surface of the lawn is flattened and stabilized, the artificial lawn can be laid more evenly and stably.

The artificial lawn (2) consists of a lining base fabric (5) and this base fabric (5).
) and a pile yarn (6) planted in the pile yarn (6). In this case, the base fabric (5) is made of crushed stone, volcanic gravel, or/and sand that has been treated to stabilize the ground (1), and prevents its stability from being compromised and weakened by rainwater penetration. Therefore, it is made non-water permeable. This water impermeability can be obtained, for example, by banking rubber or urethane resin on the base fabric (5).

The pile yarn (6) can be made from various synthetic resins, but in terms of appearance and texture, it is more similar to natural grass, and in terms of durability, polyamide, polyethylene terephthalate, polyurethane, polyvinylidene chloride, polypropylene, etc. or an acrylic resin is preferable, and is made from a slit yarn obtained by cutting a film of these resins into pieces, or a flat yarn formed by melt spinning through a nozzle having irregular cross-sectional holes. Considering that this artificial grass (2) is used in place of conventional natural grass in tennis courts, soccer fields, baseball fields, etc., its pile length is between 10 mm and 40 mm.
Preferably, a+m. According to this invention, the dry sand (3) has a lower layer (7) made of fine sand filled on the base fabric (5) and an upper layer (7) made of coarse sand layered thereon. It consists of a two-layer structure with 8). In this case, fine sand is defined as containing preferably 80% or more of sand with a grain size of 100 to 2 days (approximately 0.15 mm to approximately 0.6 mm), while coarse sand is defined as having a grain size of 70 mesh to 14 mesh (approx. 0.21
mm to about 1.2 mm), preferably 80%
It is defined as including the above. This dry sand (3) is spread on the artificial lawn (2) to fill the turf within its grain, but if the particle size is finer than 100 mS, it will be too much due to the pressure of the competitors. It tends to harden and harden, and there is a risk that it will rise as dust, which is unfavorable from the standpoint of occupational safety and health as well as environmental health, especially in indoor facilities. In view of this, in this invention, the grain size of the fine sand used in the lower layer is within the above range, so that when the wind friction speed is about 15 cm per second (corresponding to the wind speed on the ground of about 4 m per second), the pile yarn ( Coupled with the erosion control effect in 6), there is almost no blowing away, and therefore the amount of dust generated during construction is extremely small. Furthermore, considering the relationship with the particle size, the water retention capacity and drainage performance were both satisfactory to some extent, and the results were almost comparable to those of conventional methods, even without the addition of moisture retention materials such as vermiculite and calcium chloride. water retention capacity is shown. Furthermore, since the coarse sand having the particle size range described above is layered on the lower layer of fine sand, there is almost no risk that the entire layer will be blown away by the influence of the wind.

On the other hand, dry sand (3) including the lower layer (7) and the upper layer (8)
) has a layer thickness of about 70% to 1 of the length of the pile yarn (6).
10% is appropriate. Note that this value is based on the time of completion of construction, and in reality, the level decreases over time due to rainfall and tread pressure, and stabilizes after about a month. The layer thickness is selected in consideration of, for example, the bouncing characteristics of the ball and the aesthetic appearance of the artificial lawn. In other words, if you add enough sand to cover the tip of the pile yarn (6), the pile yarn (6) will stand upright and become rigid, increasing the ball's pitch and improving its durability. However, on the other hand, the green color of the artificial lawn (2) becomes less conspicuous and the aesthetic appearance is slightly different.

On the other hand, if the amount of sand (3) is reduced so that more of the tips of the pile threads (6) protrude from the top surface of the sand layer, the playing surface will become more flexible and the ball's pitch will be lower.
Although the green color of the artificial lawn (2) stands out and is aesthetically pleasing, on the contrary, the pile yarn (6) wears out more quickly. Note that the ratio of the layer thicknesses of the lower layer (7) and the upper layer (8) can be appropriately determined by taking into consideration water retention and the like.

As is clear from the above description of the embodiments, according to the present invention, the base is made of crushed stone, volcanic gravel, sand, etc. to have a water-permeable structure, and moreover, the grass grains of the artificial lawn are filled with a large amount of sand. Because of this, water drainage is good even when there is a relatively large amount of rainfall, and maintenance work during rainy periods is significantly reduced.
Because the ground is formed from easily available materials such as crushed stone, volcanic gravel, and sand, it is cheaper and easier to construct than asphalt ground when converting a conventional clay court or Antuca court into an all-weather court. can. Moreover, the upper surface of the ground, which is made of a material with relatively sharp edges and many surface irregularities, such as crushed stone, is smoothed with a bulky non-woven fabric sheet before the artificial lawn is laid.
In addition, the transfer of the crushed stones is suppressed, and the ground is constructed as a flat and firm ground.

This means that an aesthetically and dimensionally stable artificial grass sports field is obtained.

Further, according to the present invention, a lower layer of fine sand containing 80% or more of sand in the range of 100 to 28 mesh is formed between the grains of the artificial lawn, that is, between the pile threads;
By layering the upper layer of coarse sand containing 80% or more of sand within the range of 14 mesh to 14 mesh, it is possible to spread the sand onto the artificial lawn and fill it into the grass grains. The amount of scattering is small, and there is almost no risk of causing occupational safety and health problems. In addition, since the fine sand in the lower layer is held down by the coarse sand in the upper layer, there is no need to spread a soil fixing agent on the sand layer to harden the surface of the sand layer in order to prevent the sand from scattering as in the conventional method. Furthermore, since it exhibits a good value for water retention capacity, there is no need to mix water retention materials such as permiculite or calcium chloride. Therefore, it is easy to construct and is advantageous in terms of cost.

[Brief explanation of the drawing]

The figure is a cross-sectional view showing a portion of an athletic field made of artificial grass according to the present invention. In the figure, 1 is the ground, 2 is artificial grass, 3 is dry sand 4 is a layer 5 consisting of slag dust etc. and soil fixative, lining base fabric, 6
is a pile yarn, 7 is a lower layer, and 8 is an upper layer. Patent applicant: Sumitomo Rubber Industries, Ltd.

Claims (2)

[Claims] (1) A permeable ground made of crushed stone and/or sand with a substantially flat upper surface, an artificial lawn laid on the ground, and a base fabric and an artificial lawn planted on the base fabric. 10m
said artificial lawn consisting of pile threads having a length in the range of from 70 mm to 40 mm, and from 70% to 11% of said pile length;
The artificial lawn is filled with dry sand with a thickness of 0%, and the dry sand is thicker than a lower layer of rope sand layered on the base fabric and coarse sand layered on the lower layer. The artificial turf sports stadium has a two-layer structure with an upper layer consisting of an upper layer, and the upper surface of the permeable ground is formed substantially flat by spreading a bulky nonwoven fabric sheet. Artificial grass sports field. (2) The lower layer of the two-layered dry sand filled in the artificial lawn contains 80% or more of sand with a particle size in the range of 100 to 28 mm, and the upper layer of the dry sand has a particle size of 100 mm to 28 mm. Claim No. 1 containing 80% or more of sand in the range of 70 mesoyu to 14 mesoyu
) An athletic field made of artificial grass as described in item 2.