Artificial turf structure, method for laying the same, and ground using the same

Abstract

To constitute an artificial turf structure by using a filler that is made of natural materials and is hard to float in water.SOLUTION: In an artificial turf structure 1 in which a filler 5 is filled between piles 4 of artificial turf, the filler 5 contains a woody material, and the bulk specific gravity of the woody material in a wholly dried condition is 0.2 g / cm3 or more. The woody material having the bulk specific gravity set to the above value is formed by once compressing the material itself, and the porosity in the woody material is reduced by the compression to reduce air layers, so that the woody material hardly floats in water.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an artificial turf structure laid on the grounds of stadiums for soccer, baseball, other sports arenas, and other facilities to form a field suitable for sports competitions.

Background Art

[0002] Grounds covered with artificial turf are easier to construct and maintain than natural turf fields and can be used regardless of the weather, so they are incorporated into various sports fields such as futsal fields and outfield fields of baseball stadiums.

[0003] Artificial turf sports fields are filled with granular filling materials made of elastic materials or silica sand in the pile of artificial turf in order to reduce the impact on athletes and reduce the frictional resistance when athletes run, fall, or slide on them. Currently, as filling materials to be filled in the pile of artificial turf, crushed materials of waste rubber products such as waste tires, and rubber chips made of SBR (styrene-butadiene rubber) and EPDM (ethylene-propylene-diene rubber) are widely used (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Recently, the issues of marine plastics and microplastics have been in the spotlight. From the perspective of environmental protection, the use of plastic products is being restricted in various business fields, and the use of products made of natural materials as an alternative is being considered. In artificial turf, switching the rubber filler to a natural material filler has been considered. For example, attempts have been made to use materials formed by cutting trees such as coconut shells, coconut fibers, and cork and peeling off the bark tissue by mixing them into the filler.

[0006] However, although the filler made of the above-mentioned trees can impart cushioning properties to artificial turf, when there is a large amount of rainfall and water accumulates in the artificial turf, the filler may float out from the gaps between the piles of artificial turf and flow out to the outside of the field where the artificial turf is laid.

[0007] When the filler flows out, the artificial turf loses its cushioning property, which not only reduces the performance of the athletes competing on it but also makes them more prone to injury. In addition, the filler that has flowed out of the field becomes a factor in clogging the drainage channels of the facility, and when it flows onto the track or court of the stadium, it interferes with the competition. Therefore, it is necessary to immediately recover the flowed-out filler. Although the use of natural material fillers for artificial turf fillers has been considered, the actual situation is that no suitable substitute has been used in place of the rubber filler.

[0008] In view of such problems of the prior art, an object of the present invention is to constitute an artificial turf structure using a filler made of natural materials and difficult to float in water.

Means for Solving the Problems

[0009] To solve the above problems, the present invention includes the following aspects. 〔1〕 In an artificial turf structure in which a filler is filled between the piles of artificial turf, the filler contains a woody material, and the bulk specific gravity of the woody material in a completely dry state is 0.2 g / cm 3 or more, characterized by the artificial turf structure. 〔2〕 The artificial turf structure according to the above 〔1〕, wherein the porosity of the wood material is 80% or less. 〔3〕 The artificial turf structure according to the above 〔1〕 or 〔2〕, wherein the pore volume of the wood material is 4.0 cm 3 / g or less. 〔4〕 The artificial turf structure according to any one of the above 〔1〕 to 〔3〕, wherein the average pore diameter of the wood material is 1.0 μm or less. 〔5〕 The artificial turf structure according to any one of the above 〔1〕 to 〔4〕, wherein the wood material is obtained by immersing and decomposing wood pellets in water. 〔6〕 The artificial turf structure according to any one of the above 〔1〕 to 〔5〕, wherein the pile of the artificial turf is a crimped pile. 〔7〕 The artificial turf structure according to any one of the above 〔1〕 to 〔6〕, wherein the filler layer, which is the part filled with the filler, consists of at least two layers, the filler in the uppermost layer of the filler layer contains a wood material, and the filler in the layer below it contains silica sand. 〔8〕 The artificial turf structure according to any one of the above 〔1〕 to 〔6〕, wherein the filler layer, which is the part filled with the filler, is formed by mixing a filler containing silica sand and a wood material. 〔9〕 The artificial turf structure according to any one of the above 〔1〕 to 〔8〕, wherein the artificial turf is provided on a buffer material layer. 〔10〕 A method for laying an artificial turf structure, comprising: a step of laying the artificial turf; a step of spraying wood pellets on the artificial turf; a step of burying the sprayed wood pellets between the piles of the artificial turf; a step of watering the buried wood pellets to allow them to absorb water; and a step of decomposing the water-absorbed wood pellets. 〔11〕 A method for laying an artificial turf structure, comprising: a step of laying the artificial turf; a step of immersing wood pellets in water to allow them to absorb water; a step of decomposing the water-absorbed wood pellets; A method for laying an artificial turf structure having the same. 〔12〕A sports ground configured using the artificial turf structure according to any one of 〔1〕 to 〔9〕 above. 〔13〕A tee ground configured using the artificial turf structure according to any one of 〔1〕 to 〔9〕 above.

[0010] As described above, wood chips obtained by finely cutting wood or its bark can impart appropriate cushioning properties to artificial turf if used as a filler, but there is a problem that they float in water and are likely to flow out. Generally, it is known that the true specific gravity of wood excluding voids is about 1.5 regardless of the tree species. It is presumed that the reason why wood with this specific gravity floats in water is that, in addition to the buoyancy exerted by the air bubbles accumulated in the tracheids in the wood, lignin, which is a hydrophobic substance contained in the wood, acts to prevent water absorption.

[0011] In order to prevent the buoyancy from acting, it is possible to compress the wood so that air does not accumulate in the wood and crush its fibers to make it difficult for air to be retained in the wood. Also, if the bulk specific gravity is less than 1.0 but it has hydrophilicity, it can be made to have no buoyancy by absorbing water. As shown in the examples described later, it was confirmed that by compressing the wood chips to increase their bulk specific gravity, the water absorption of the wood chips increased and the wood chips could be precipitated in water. This is presumably due to the fact that during the compression process of the wood chips, the lignin in the wood acts as an adhesive and is consumed and reduced during compression, thereby increasing the hydrophilicity of the wood chips. In addition, by crushing the inside of the wood, the porosity becomes smaller and the capillary phenomenon effect due to the decrease in the pore diameter contributes to this.

[0012] As described above, in the artificial turf structure of the present invention, a filler is filled between the piles of the artificial turf. This filler contains a compressed woody material, and the bulk specific gravity of the woody material in the completely dry state is 0.2 g / cm 3 or more, which is a feature. The filling material is made of natural wood materials, such as wood chips obtained by finely cutting wood or its bark. By compressing this material to crush the fibers of the wood chips, when the compressed wood chips are released and expanded, their bulk specific gravity increases compared to before compression, and their water absorption capacity also increases. Therefore, even if water accumulates in the artificial turf due to rainfall, it will not float but will settle in the water and remain within the artificial turf, without flowing out to the outside of the field where the artificial turf is laid. Also, it can exhibit a cushioning property equivalent to that of conventionally used natural material filling materials. In addition to the wood material, the filling material may contain granular materials such as silica sand and other materials. Moreover, the filling material made of the wood material has a surface that is brown, warm-colored, or white, and is less likely to absorb heat than black rubber chips, suppressing the rise in the surface temperature of the artificial turf on sunny days. Also, because it is porous and easily contains water, it is possible to suppress the rise in the surface temperature of the artificial turf during the day by spraying water on the artificial turf to allow the filling material to absorb water and store it.

[0013] For the artificial turf structure with the above configuration, it is preferable that the porosity of the wood material constituting the filling material is 80% or less. If the wood material has a porosity of 80% or less, it becomes difficult for air to be retained within the material, and it can be made less likely to float in water.

[0014] The pore volume of the wood material is preferably 4.0 cm 3 / g or less. If the wood material has a pore volume of 4.0 cm 3 / g or less, the false tracheids in the material are sufficiently crushed, making it difficult for air to be retained, and it can be made less likely to float in water.

[0015] Also, it is preferable that the average pore diameter of the wood material is 1.0 μm or less. If the wood material has an average pore diameter of 1.0 μm or less, in addition to making it difficult for air to be retained within the material as described above, the small pore diameter makes it easier for water to penetrate into the material due to the effect of capillary action, increasing the water absorption and making it less likely to float in water.

[0016] In the artificial turf structure of the above-described configuration, as the woody material constituting the filler, those obtained by immersing and decomposing wood pellets in water can be used. Wood pellets, which are obtained by drying and crushing wood chips and then compression molding them into granular masses, are in a state where the fibers of the wood chips are crushed as described above. When these are immersed in water, their volume expands to nearly two to five times. By decomposing and spreading them from this expanded state, wood chips with a bulk specific gravity higher than before compression can be obtained, and these can be used as a filler. Any type of wood pellet, such as white pellets or all-wood pellets, can be used as the above-described woody material.

[0017] In the artificial turf structure of the above-described configuration, curled piles can be used for the artificial turf piles. Even with curled piles, a texture similar to that of natural turf can be created, and appropriate flexibility is imparted to the piles, improving the cushioning property of the artificial turf surface. Also, in the mode where the filler is filled inside the artificial turf piles, since the curled piles cover the filler with the shrunk piles, compared to straight piles, less filler is knocked out by raindrops during rainfall. Furthermore, since the filler is pressed down by the curled piles, the filler is less likely to scatter even when receiving an impact due to the bounce of the ball during strong winds or when playing a ball game on the artificial turf, and the outflow of the filler during heavy rainfall can be suppressed. Also, the adoption of curled piles has the effect of making it difficult for sunlight to directly reach the filler, suppressing the temperature rise of the filler, and the turf surface dispersing light and reducing glare, which is gentle on the eyes of players and spectators. As the curled piles, those made of appropriate materials and specifications such as curled processed monofilaments made of green or dark green polyethylene can be used, and as the processing method for curling the piles, appropriate methods such as buckling processing, false twisting processing, and knit-denit processing can be adopted.

[0018] In the artificial turf structure having the above-described configuration, a filler layer which is a portion filled with a filler in the pile of the artificial turf is formed, and this filler layer is composed of at least two layers. The filler in the uppermost layer of the filler layer contains the woody material, and the filler in the layer below that can be provided to contain silica sand. Since the silica sand contained in the filler layer has a certain weight, arranging this in the lower layer can prevent movement such as the curling of the artificial turf, block heat to the artificial turf base fabric, and since it is inorganic, it can make it difficult for insects, etc. to emerge. By arranging a filler containing a woody material in the upper layer thereof, the upper layer becomes a buffer layer and cushioning properties are imparted to the artificial turf, reducing the burden on the body such as the knees and waist of those competing on the artificial turf, preventing abrasions, and improving the performance of the athletes. By arranging a filler containing a woody material in the upper layer, the appearance and performance of the artificial turf can be improved, and the artificial turf can be protected and its durability can be increased. As will be described later, the filler composed of wood pellets has moisture retention performance and is effective for heat countermeasures (generation of heat of vaporization), and can provide a comfortable activity environment for the athletes, adults, and children who play or engage in outdoor activities on the artificial turf. The filler layer formed in the pile of the artificial turf may be composed of three or more layers. In this case, it is preferable to arrange a filler containing the woody material in the uppermost layer. Also, silica sand and a filler containing the woody material may be mixed, and this mixed filler layer may be laminated in one or more layers in the pile of the artificial turf. The length of the pile of the artificial turf and the thickness of the filler layer formed in the pile can be appropriately set according to the type of ball game performed using the artificial turf field, the structural standards of the artificial turf defined in that ball game, and other uses of the artificial turf.

[0019] Also, in the artificial turf structure having the above-described configuration, the artificial turf can be provided on top of a buffer material layer. According to this, a cushioning material made of an elastic material is laid on the foundation of the field to provide a cushioning material layer, and a base fabric with artificial turf piles implanted thereon is spread over it, and a filling material containing a woody material is filled into the piles to form an artificial turf field. By appropriately selecting the elastic material forming the cushioning material and its thickness, etc., the cushioning property of the artificial turf surface can be appropriately set, and for a sports ground configured using an artificial turf structure, it can meet the specifications defined by the rules of that sport, for example, in the case of a soccer field, it can conform to the standards of the JFA and FIFA. Depending on the use of the artificial turf, the artificial turf may be configured without providing a cushioning material layer.

[0020] Also, as one aspect of the method for laying the artificial turf structure with the above configuration, it can be carried out through the steps of laying the artificial turf, a step of spraying wood pellets on the artificial turf, a step of burying the sprayed wood pellets between the piles of the artificial turf, a step of spraying water on the buried wood pellets to make them absorb water, and a step of loosening the water-absorbed wood pellets. The method for laying the artificial turf structure is as follows: First, a cushioning material is laid on the foundation of the field as described above to form a cushioning material layer, and a base fabric with artificial turf piles implanted thereon is spread over this cushioning material layer to lay the artificial turf. Depending on the use of the artificial turf, a base fabric with artificial turf piles implanted directly on the foundation may be spread to lay the artificial turf. Next, wood pellets are evenly sprayed on the upper surface of the artificial turf and buried between the piles. The spraying of the wood pellets can be carried out using, for example, a top dresser used when spreading sand on the artificial turf. Sprinkling an appropriate amount of silica sand on the artificial turf before spraying the wood pellets is carried out as required. Once the wood pellets are buried between the piles, water is released onto the surface of the artificial turf to allow the wood pellets to absorb a sufficient amount of water. When the wood pellets expand due to water immersion, they are loosened and spread, and entangled with the piles of the artificial turf and immersed into the artificial turf. The operation of loosening the expanded wood pellets can be carried out using, for example, a turf tuner used when standing up the piles. Then, if necessary, the filling material is dug up and the level is adjusted, etc., and the laying of the artificial turf structure is completed.

[0021] Also, as another aspect of laying the artificial turf structure, it can be carried out by a method having steps of laying artificial turf, immersing wood pellets in water to absorb water, decomposing the water-absorbed wood pellets, and filling the decomposed wood pellets between the piles of artificial turf. The method of laying the artificial turf structure of the above configuration is not limited to the above aspects, and can be laid by an appropriate method according to the place and environment where the artificial turf is laid, the laying area, etc. An appropriate method can also be adopted for the method of maintaining the laid artificial turf.

[0022] The artificial turf structure of the above configuration can be applied to various sports grounds such as baseball, soccer, futsal, rugby, tennis, hockey, etc. to form an artificial turf field. In addition, it can also be applied to golf tee grounds, grounds (yards) of educational facilities and recreational facilities, ski slopes, etc. In this specification, the names of ground, field, court, and pitch are used in the same meaning as the place where artificial turf is laid.

Brief Description of the Drawings

[0023]

Figure 1

Figure 2

Figure 3

Figure 4

Modes for Carrying Out the Invention

[0024] Hereinafter, the present invention will be described in detail based on its preferred embodiments. It should be noted that the present invention is not limited to the following embodiments. The embodiments are illustrative, and can be implemented with appropriate modifications without departing from the gist of the present invention.

[0025] FIG. 1 shows an artificial turf structure according to an embodiment of the present invention. The illustrated artificial turf structure 1 is configured by laying a cushioning material 2 made of an elastic material on a field foundation (not shown), spreading a base fabric 3 with artificial turf piles 4 planted thereon over the cushioning material 2, and filling the piles 4 with a filling material 5 made of a wood material.

[0026] The filling material 5 made of the wood material is obtained by subjecting wood chips to compression processing to crush its fibers, and then increasing the bulk specific gravity by expanding from the compressed state. The bulk specific gravity in the completely dry state is 0.2 g / cm 3 The above is used.

[0027] Wood pellets can be used as the wood material constituting the filling material 5. In that case, the laying of the artificial turf structure 1 can be performed as follows as an example. That is, first, the cushioning material 2 is laid on the field foundation, the base fabric 3 with the piles 4 planted thereon is spread over it to lay the artificial turf, then wood pellets are scattered on the artificial turf piles 4 and buried between the piles 4. Next, the buried wood pellets are watered to absorb water and expand the wood pellets. Then, the expanded wood pellets are loosened and expanded, and this is entangled with the piles 4 to adjust the level of the entire artificial turf. Through processes such as these, the artificial turf structure 1 can be laid.

[0028] According to the artificial turf structure 1 of this embodiment, the filling material 3 is made of wood chips that have been compression processed, and its bulk specific gravity in the completely dry state is 0.2 g / cm 3Since it is as described above, the bulk specific gravity is increased and the water absorption is enhanced compared to the wood chips before compression. Therefore, even if water accumulates in the artificial turf due to rainfall, it will not float but will precipitate in the water and remain within the artificial turf, without flowing out to the outside of the field where the artificial turf is laid. Also, it is possible to exhibit a cushioning property equivalent to that of the natural material fillers conventionally used. The filler 5 made of a woody material has a surface color such as brown or warm colors, so it is difficult to absorb heat from sunlight irradiation, and it is possible to suppress the rise in the surface temperature of the artificial turf on sunny days. Also, since the filler 5 is porous, it easily contains water, and by spraying water on the artificial turf to store water in the filler 5, it is also possible to suppress the rise in the surface temperature of the artificial turf during the day.

Example

[0029] Regarding the filler 5 made of a woody material that constitutes the artificial turf structure 1, the following evaluations were conducted according to the type of material made of natural materials.

[0030] (Example 1) As the woody material that constitutes the filler, white pellets (Solo pellets; manufactured by Catalog House Co., Ltd.), which are wood pellets, were used. 8 g of white pellets were placed in a container, and water was poured into it so that the whole was immersed. After 2 minutes had passed since the water was poured in, the white pellets absorbed water and swelled to about 4.6 times their volume before the water injection. The weight at the time of water absorption saturation was 34 g. These swollen white pellets were dried, and evaluations were conducted when using them as fillers.

[0031] (Example 2) As the woody material that constitutes the filler, whole wood pellets (PURE No. 1; manufactured by Kamiina Forestry Cooperative), which are wood pellets, were used. 6 g of whole wood pellets were placed in a container, and water was poured into it so that the whole was immersed. After 4 minutes had passed since the water was poured in, the white pellets absorbed water and swelled to about 2.6 times their volume before the water injection. The weight at the time of water absorption saturation was 26 g. The expanded whole-wood pellets were dried, and an evaluation was conducted when using them as a filler.

[0032] (Comparative Example 1) An evaluation was conducted when using cedar sawdust (cedar fresh sawdust; manufactured by Takejima Lumber Store) as a filler as the wood material.

[0033] (Comparative Example 2) An evaluation was conducted when using a natural filler made of natural palm and coconut (manufactured by RIS Corporation) as a filler as the wood material.

[0034] (Comparative Example 3) An evaluation was conducted when using the raw material of white pellets before being processed into wood pellets (manufactured by Catalog House Co., Ltd.) as a filler as the wood material.

[0035] 〔Measurement of bulk density〕 The bulk density of the fillers in the fully dry state (dried in a thermostat at 103 ± 2°C for 4 hours) and the air-dried state of each example and comparative example was measured. The results are shown in Table 1.

[0036] 〔Measurement of voids inside the material〕 For the fillers of Example 1 and Comparative Examples 1 and 2, the average pore diameter, pore volume, and porosity were measured using an automatic mercury porosimeter pore size distribution measuring device (Autopore IV 9520; manufactured by Shimadzu Science East Japan Co., Ltd.). The results are shown in Table 1.

[0037] 〔Measurement of luminance〕 For the fillers of Examples 1 and 2 and Comparative Examples 2 and 3, the luminance was measured using a color luminance meter (CS-160; manufactured by Konica Minolta Inc.). The measurement was carried out by capturing the measurement object with a viewfinder in the same indoor environment, and the displayed luminance value was recorded. The results are shown in Table 1.

[0038] 〔Outflow evaluation〕 An outflow evaluation of the fillers of each example and comparative example was conducted. The evaluation was carried out by putting 50 mL of the filling material into a beaker, adding 100 mL of water thereto, and checking whether the filling material floated on the water. The state of the filling materials in each Example and Comparative Example after adding water to the beaker is shown in Figure 2. As shown in the figure, most of the filling materials of Example 1 and Example 2 remained sunk to the bottom of the beaker. The results are marked with "〇" in Table 1. On the other hand, most of the filling material of Comparative Example 1 and the raw material of Comparative Example 3 floated, and almost all of the filling material of Comparative Example 2 floated. The results are marked with "×" in Table 1.

[0039] 〔Temperature suppression effect 1〕 Regarding the filling materials of Example 1, 2 and Comparative Example 2, the temperature suppression effect of the dried filling material was confirmed using a solar power meter (SPM-SD; manufactured by Sato Shoji Co., Ltd.) and a thermographic camera (E6-XT; manufactured by Flir Systems). The confirmation was carried out by spreading the dried filling material evenly in a container of 140 cm 3 and simultaneously measuring the surface temperature of the filling material with a thermographic camera and the solar radiation intensity with a solar power meter under sunny conditions in summer. The results are shown in Figure 3. In the graph in the figure, the horizontal axis represents the solar radiation intensity and the vertical axis represents the surface temperature of the filling material. Also, the reaching temperature of the surface of the filling material at a solar radiation intensity of 715 W / m 2 is shown in Table 1.

[0040] 〔Temperature suppression effect 2〕 Regarding the filling materials of Example 1, 2 and Comparative Example 2, the temperature suppression effect of the moistened filling material was confirmed using the above-mentioned thermographic camera and an electronic balance (FX-500i; manufactured by A&D Co., Ltd.). The confirmation was carried out by spreading the dried filling material evenly in a container of 140 cm 3 and after pouring water corresponding to a precipitation of 6 mm into this container, measuring the change over time in the weight of the filling material in the container and the surface temperature of the filling material with a thermographic camera under sunny conditions in summer. The results are shown in Fig. 4. In the graph in this figure, the horizontal axis represents the measured time, and the vertical axis represents the ratio of the change in weight from the initial wet state (100%) of the filler and the surface temperature of the filler. Also, the maximum temperature reached on the filler surface is shown in Table 1.

[0041]

Table 1

[0042] As is clear from the test results of the outflow evaluation, among the fillers of natural materials, it was confirmed that the fillers of Examples 1 and 2 did not float in water, while the fillers of Comparative Examples 1 to 3 and the materials floated in water. The filler of Comparative Example 2 is a filler of a general natural material, and has a problem that when water accumulates in artificial turf, it flows out to the outside of the artificial turf pitch. Most of the fillers of Examples 1 and 2 do not float in water and remain precipitated in water, and there is no risk of outflow like the filler of Comparative Example 2. The fillers of both Examples 1 and 2 are made of wood pellets. In the process of compressing wood chips into pellets, the fibers of the wood are crushed, the bulk specific gravity increases, and it becomes difficult to hold air inside. This is also clear from the comparison of the average pore diameter, pore volume, and porosity between the fillers of Comparative Example 2, which are uncompressed natural material fillers, and those of both Examples. The values of the fillers of Examples 1 and 2 are extremely smaller than the values of the filler of Comparative Example 2, and it can be said that this is evidence that it has become difficult to hold air in the filler. Also, although the bulk specific gravity of the fillers of Examples 1 and 2 is smaller than 1.0, they do not float in water. This is because in addition to the wood chips being altered by compressing the wood chips into pellets and the hydrophilicity being improved, the pore rate decreases by crushing the inside of the wood, and the capillary phenomenon effect by reducing the pore diameter absorbs water, so that the buoyancy does not act and the submerged state is maintained.

[0043] The luminance (cd / m 2) For Example 1 it was 157.1, for Example 2 it was 121.0, for Comparative Example 1 it was 118.3, for Comparative Example 2 it was 30.5, and for Comparative Example 3 it was 169.5. Since the fillers of both examples have a higher brightness than the filler of Comparative Example 2, it is considered that the degree of heat absorption when receiving sunlight is smaller, and there is an effect of suppressing the temperature rise of the artificial turf surface during the day. Also, in the temperature suppression effect 1, the degree of increase in the warm surface temperature of the dried filler when receiving sunlight was confirmed. When the solar radiation intensity was 715 (W / m 2 ), the surface temperature (°C) of the filler for Example 1 was 64, for Example 2 was 70, and for Comparative Example 2 was 77. As shown in Figure 3, since each filler is a filler of natural materials, no difference was observed in the temperature rise rate with respect to the solar radiation intensity. It was confirmed that the fillers of Example 1 and Example 2 are more capable of suppressing the temperature rise even when the solar radiation intensity increases, compared to the filler of Comparative Example 2 which is a general filler of natural materials. Furthermore, in the temperature suppression effect 2, the degree of increase in the warm surface temperature of the wet filler when receiving sunlight was confirmed. As shown in Figure 4, the rate at which the 100% wet filler reduces its wetness ratio when receiving sunlight was not significantly different among the fillers of Example 1, Example 2, and Comparative Example 2. The surface temperature (°C) of each filler reaches its maximum around 2 pm when the solar radiation amount is the largest. However, the filler of Comparative Example 2 reached 55, while the fillers of both Example 1 and Example 2 were 46, and a temperature difference of nearly 10°C was confirmed. It is considered that for the artificial turf using the fillers of Example 1 and Example 2, it is effective to sprinkle water on the artificial turf surface in advance to make the filler contain water in order to suppress the temperature rise of the artificial turf surface during the day.

[0044] From the above evaluation results, the fillers of Example 1 and Example 2 are not easily buoyant in water. If they are included in the piles of artificial turf to form an artificial turf field, even if water accumulates in the artificial turf due to rainfall, they will stay inside the artificial turf without floating and prevent outflow outside the field. Also, since they have a temperature suppression effect when receiving sunlight, it is possible to suppress the temperature rise of the artificial turf surface during the day. It can be said that they are extremely useful as fillers to replace the general natural material fillers used in conventional artificial turf.

[0045] The configuration and form of the artificial turf structure described and illustrated above are merely examples, and the present invention is not limited to the configurations and forms described and illustrated, and other appropriate configurations and forms are possible.

Explanation of Signs

[0046] 1 Artificial turf structure, 2 Buffer material, 3 Base fabric, 4 Pile, 5 Filling material

Claims

1. In an artificial turf structure in which a filler is filled between piles of artificial turf, the filler contains a woody material, The bulk specific gravity of the woody material in a completely dry state is 0.2 g / cm ３ or more, and the artificial turf structure is characterized by this.

2. The artificial turf structure according to claim 1, wherein the porosity of the woody material is 80% or less.

3. The pore volume of the woody material is 4.0 cm ３ / g or less, and the artificial turf structure according to claim 1 or 2.

4. The artificial turf structure according to claim 1 or 2, wherein the average pore diameter of the woody material is 1.0 μm or less.

5. The artificial turf structure according to claim 1 or 2, wherein the woody material is obtained by immersing and decomposing wood pellets in water.

6. The artificial turf structure according to claim 1 or 2, wherein the pile of the artificial turf is a crimped pile.

7. The filler layer, which is the portion filled with the filler, consists of at least two layers, the filler in the uppermost layer of the filler layer contains a woody material, and the filler in the layer below that contains silica sand. The artificial turf structure according to claim 1 or 2.

8. The artificial turf structure according to claim 1 or 2, wherein the filler layer, which is the portion filled with the filler, is formed by mixing a filler containing silica sand and a woody material.

9. The artificial turf structure according to claim 1 or 2, wherein the artificial turf is provided on a buffer material layer.

10. A step of laying artificial turf, a step of spraying wood pellets on the artificial turf, a step of burying the sprayed wood pellets between the piles of the artificial turf, a step of watering the buried wood pellets to make them absorb water, a step of decomposing the water-absorbed wood pellets, A method for laying an artificial turf structure having the above steps.

11. A step of laying artificial turf, a step of immersing wood pellets in water to make them absorb water, a step of decomposing the water-absorbed wood pellets, a step of filling the decomposed wood pellets between the piles of the artificial turf, A method for laying an artificial turf structure having the above steps.

12. A playing ground configured using the artificial turf structure according to claim 1 or 2.

13. A tee ground configured using the artificial turf structure according to claim 1 or 2.

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