Method of constructing artificial turf

Abstract

To provide an artificial lawn having a low environmental load by using a material as a substitute for rubber chips conventionally used as a filling material for the artificial lawn.SOLUTION: An artificial turf, comprising: piles planted on a base; and a filling layer formed by filling a mixture of sawdust and sand between the piles.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for laying artificial turf. [Background technology]

[0002] The following Patent Document 1 discloses an artificial turf that can be used for track and field events, particularly throwing events. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-138403 Summary of the Invention [Problem to be solved by the invention]

[0004] Currently, sand and rubber chips are the main filling materials for artificial turf. During construction, the ratio of sand to rubber chips and the filling order are considered to ensure shock absorption suitable for sports, and for example, to ensure that the javelin will penetrate the ground in the case of javelin throwing.

[0005] Regarding rubber chips used as infill material, there have been cases where a rubber smell has spread during construction, and if there is heavy rain immediately after construction before the infill layer has settled, the rubber chips can be washed away. Also, when removing the artificial turf to dismantle the stadium, it is difficult to separate the sand and rubber chips mixed as infill.

[0006] In view of the above, an embodiment of the present disclosure aims to provide an artificial turf and its installation method that has a low environmental impact by using a material that is an alternative to the rubber chips that have traditionally been used as a filling material for artificial turf. [Means for solving the problem]

[0007] In view of the above-mentioned problems, the artificial turf of the embodiment of the present disclosure comprises piles planted in a base and an infill layer formed by filling the spaces between the piles with a mixture of sawdust and sand. Preferably, the piles have a length of 130 mm or more, the infill layer has a thickness of 100 mm or more, and the piles protrude from the infill layer by a length of 15 mm to 30 mm.

[0008] In addition, in the construction method of the artificial turf according to the embodiment of the present disclosure, sawdust and sand are alternately filled between the piles planted in the base, and after each filling, the sawdust and sand are mixed by brushing the piles. It is preferable that the sawdust and sand are each filled multiple times. [Effects of the Invention]

[0009] Since the embodiments of the present disclosure are configured as described above, by using a material that can replace the rubber chips that have traditionally been used as filling material for artificial turf, an artificial turf with a low environmental impact and a construction method therefor are provided. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a schematic diagram showing a cross section of an artificial turf according to an embodiment. [Figure 2] 1A to 1C are schematic diagrams illustrating steps of an artificial turf installation method according to an embodiment. [Figure 3] 1A to 1C are schematic diagrams illustrating steps of an artificial turf installation method according to an embodiment. [Figure 4] 1A to 1C are schematic diagrams illustrating steps of an artificial turf installation method according to an embodiment. [Figure 5] 1A to 1C are schematic diagrams illustrating steps of an artificial turf installation method according to an embodiment. [Figure 6] 1A to 1C are schematic diagrams illustrating steps of an artificial turf installation method according to an embodiment. [Figure 7] 1A to 1C are schematic diagrams illustrating steps of an artificial turf installation method according to an embodiment. [Figure 8] 1A to 1C are schematic diagrams illustrating steps of an artificial turf installation method according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Note that the materials, dimensions, weights, and volumes mentioned in the following description are merely examples and are not intended to limit the scope of the present disclosure.

[0012] FIG. 1 is a schematic diagram showing a cross section of an artificial turf 10 according to an embodiment of the present disclosure. The artificial turf 10 according to this embodiment comprises pile 30 planted in a base 20, and an infill layer 40 formed by filling the spaces between the pile 30 with a mixture 43 of sawdust 42 and sand 41. The base 20 can be formed as a base fabric, for example, by forming a synthetic resin such as polypropylene, nylon, or polyethylene into a plain weave fabric and punching and planting polypropylene or polyethylene terephthalate cotton. The pile 30, for example, made of a material such as polyethylene or nylon and molded using a split method or a monofilament method to a thickness of 10,000 dtex or more, is planted on the base 20 at a planting density of 6,000 to 9,000 threads / m. 2 The pile 30 can be planted by folding the middle part of the pile 30 back on the back of the base 20. The length of the folded pile 30 is preferably 130 mm or more. The back side of the base 20 is coated with a mixture of, for example, SBR latex / ethylene emulsion and calcium carbonate filler, which serves as a backing material 50. In this state, the base 20 is laid on top of the crushed stone roadbed 60.

[0013] The filling layer 40 is a mixture of sawdust 42 and sand 41. Hinoki sawdust, which has a pleasant fragrance, antibacterial properties, is resistant to decay, and has water retention, is preferably used as the sawdust 42. The hinoki sawdust preferably has a particle size of 3 mm or less. By using such sawdust 42 as part of the filling layer 40 instead of the conventionally used rubber chips, it is possible to prevent the sand 41 from caking, and it has the advantage of absorbing less heat than rubber chips. Furthermore, because offcuts of building materials can be used as raw materials, it has the advantages of being environmentally friendly and inexpensive.

[0014] The type of sand 41 is not particularly limited, but it is preferable to use silica sand with a particle size of 0.2 mm to 1.5 mm.

[0015] The artificial turf 10 shown in FIG. 1 is constructed by alternately filling sawdust 42 and sand 41 between the piles 30 planted in the base 20, and then brushing the piles with water after each filling to mix the filled sawdust 42 and sand 41. This mixing is preferably performed so that the sawdust 42 and sand 41 are as uniform as possible. The sawdust 42 and sand 41 are each filled multiple times. For example, by making the thickness of this infill layer 40 100 mm or more, the protrusion length of the piles 30 from the infill layer 40 can be 15 mm to 30 mm. Artificial turf 10 with this infill layer 40 is designed to ensure that spears can be thrust into it, making it suitable for javelin throwing.

[0016] The construction method of the artificial turf 10 of FIG. 1 is carried out, for example, as follows. First, as shown in FIG. 2, a portion of sand 41 is filled at the base of the pile 30. Next, as shown in FIG. 3, a portion of sawdust 42 is filled on top of the filled sand 41. Then, by brushing from above the pile 30, the already filled sand 41 and the newly filled sawdust 42 are mixed to form a mixture 43, as shown in FIG. 4. Next, as shown in FIG. 5, a portion of sand 41 is filled again on top of the mixture 43. Then, by brushing from above the pile 30, the already filled mixture 43 and the newly filled sand 41 are mixed to form a new mixture 43, as shown in FIG. 6. Next, as shown in FIG. 7, a portion of sawdust 42 is filled again on top of the mixture 43. Then, by brushing from above the pile 30, the already filled mixture 43 and the newly filled sawdust 42 are mixed to form a new mixture 43, as shown in FIG. 8. By repeating this process, the artificial turf 10 is finally created, as shown in Figure 1, in which a mixture 43 of sawdust 42 and sand 41 mixed in the desired ratio is filled between the piles 30 as an infill layer 40.

[0017] In the above description, sand 41 is filled first, but sawdust 42 may be filled first. Also, sand 41 may be filled again immediately after filling sand 41 to form mixture 43, or similarly, sawdust 42 may be filled again immediately after filling sawdust 42 to form mixture 43. [Example]

[0018] (1) Weather resistance test of cypress sawdust The weather resistance of cypress sawdust used as the filling layer material was tested as follows. A 30 cm long, 15 cm wide, and 10 cm high acrylic tray was prepared by drilling drainage holes in the bottom, covering the bottom and interior with cloth, and filling the tray with cypress sawdust to a height of approximately 7 cm. This sample was placed in the chamber of a flat-tray accelerated weathering tester (Q-SUN Xe3, Q-LAB) and repeatedly irradiated with xenon arc light (full spectrum, including ultraviolet, visible, and infrared light) for 500 cycles, totaling 1,000 hours, with Steps 1 and 2 shown in Table 1 below counting as one cycle. However, after 250 cycles, the sample was rotated back and forth in the chamber. This treatment exposed the sample to a typical radiation exposure equivalent to 220 MJ, which is equivalent to five years of exposure to the external environment.

[0019] [Table 1]

[0020] As a result of the above test, although discoloration of the sawdust surface due to direct exposure to ultraviolet light was observed, there was no noticeable change in shape. This suggests that cypress sawdust has sufficient weather resistance and can withstand long-term outdoor use.

[0021] (2) Odor sensory test Fresh cypress sawdust (sawdust A) and sawdust B after the weathering test described in (1) above were subjected to odor sensory testing. Specifically, a plastic bottle with an inner diameter of approximately 8 cm was filled with cypress sawdust to a height of approximately 10 cm, and the top was covered with a ventilated plastic film. The bottle was then placed in a 50 L solid odor sampling bag (Fleck Sampler®, Omi Odor Air Service). The bottle was then filled with odorless air and allowed to stand in a test room at room temperature (13.2–26.2°C, averaging 19.0°C) for approximately 3 days until the odor intensity reached a level suitable for odor sensory testing. After standing, the air in the sampling bag was aliquoted into 3 L odor measurement bags (smell bags, Omi Odor Air Service) and subjected to two odor sensory tests: "odor intensity" and "pleasantness / unpleasantness."

[0022] The sensory test was conducted by a panel (persons recognized as having a sense of smell suitable for the evaluation test) under the supervision of an odor evaluator, as defined in Article 1 of the Environment Agency Notification No. 63 of 1995. To ensure a significant gender bias, a total of six panelists were selected: three men in their 50s, one man in his 40s, one woman in her 50s, and one woman in her 20s.

[0023] The odor intensity was scored by each panelist according to the six-level odor intensity rating system shown in Table 2 below, as outlined in the Olfactory Measurement Manual (compiled by the Odor and Fragrance Environment Association, a public interest incorporated association).

[0024] [Table 2]

[0025] The maximum and minimum values ​​(or one of the values ​​if they were the same) were excluded from the evaluation scores for each panel, and the remaining evaluation scores were averaged. If the decimal point of the average was 0.25 or more and less than 0.75, it was rounded to 0.5, and if it was 0.75 or more or less than 0.25, it was rounded to an integer. The results are shown in Table 3 below.

[0026] [Table 3]

[0027] As shown in Table 3 above, sawdust B had a lower odor intensity than sawdust A. It is thought that the scent of cypress, a natural material, was diluted during the weathering test, which is why sawdust B had a lower odor intensity.

[0028] As shown in Table 4 below, each panelist assigned a score to the pleasantness / unpleasantness scale on a nine-point scale as described in the "Fourth Edition: Olfactory Measurement Method for Odors - Triangle Comparison Odor Bag Method Measurement Manual (Author: Iwasaki Yoshiharu, Publisher: Odor and Fragrance Environment Association, a public interest incorporated foundation)."

[0029] [Table 4]

[0030] The judgement scores of each panel were processed in the same manner as for the odor intensity. The results are shown in Table 5 below.

[0031] [Table 5]

[0032] For sawdust A, the result was "somewhat pleasant." It is thought that many of the panelists responded in the pleasant direction, as it is generally said that Japanese people like the scent of cypress. For sawdust B, the result was "neither pleasant nor unpleasant." It is thought that the number of panelists who found it "pleasant" decreased as the cypress scent weakened following the weathering test. On the other hand, just like sawdust A, few panelists found sawdust B, the sample after the weathering test, unpleasant, and no putrid smell was detected, suggesting that no unpleasant odor was generated due to the decay of the sawdust during the weathering test.

[0033] (3) Antifungal effect of cypress sawdust (3-1) Experiment 1 Next, the antifungal effect of cypress sawdust used as the sawdust material for the filling layer was tested as follows. Agar containing 10, 20, and 30 parts by weight of agar added to 100 parts by weight of agar, as well as agar without cypress sawdust (0 parts by weight), were poured into a 9 cm diameter Petri dish and allowed to solidify. Blue mold growing on a citrus fruit (Dekopon) was then dipped in water, and a cotton swab was dipped in the water and applied in a line to the surface of the agar, which was then left at room temperature.

[0034] As a result, with agar without added cypress sawdust, mold was observed on the applied line 8 days after application, mold began to spread around the applied line by 12 days, and mold had spread to areas other than the applied line by 18 days. With agar containing 10 parts by weight of cypress sawdust, slight mold growth was observed on the applied line 8 days after application, mold increased on the applied line by 12 days, and slight mold growth was observed in areas other than the applied line by 18 days. With agar containing 20 parts by weight and agar containing 30 parts by weight of cypress sawdust, no clear mold growth was observed on the applied line 8 days after application, slight mold growth was observed on the applied line by 12 days, and mold growth only increased on the applied line by 18 days, but mold growth was not observed outside the applied area. The results of Experiment 1 demonstrated that cypress sawdust has the effect of suppressing mold growth.

[0035] (3-2) Experiment 2 Next, agar was poured into two petri dishes and allowed to solidify. One petri dish (dish A) was covered with 40 mL of cypress sawdust, while the other (dish B) contained only agar. Summer mandarin peel, cut into approximately 5 cm cubes, was then placed on top of the cypress sawdust in petri dish A and on top of the agar in petri dish B. The dishes were then covered and left at room temperature.

[0036] As a result, in both petri dishes, mold began to grow on the summer mandarin peel from the 8th day, and as the days passed, the mold continued to grow on the peel on the 11th and 14th days. When the peel was removed on the 15th day, mold had grown on the agar that had been under the peel in petri dish B, but in petri dish A, mold had not grown on the sawdust that had been under the peel, and no mold was found on the surface of the agar after the sawdust had been removed. The results of this experiment 2 also confirmed that cypress sawdust has the effect of suppressing mold growth.

[0037] (4) Silica sand filling alone Next, artificial turf filled with silica sand alone as the infill layer material was tested as follows. Omnisand Y (Sumitomo Rubber Industries, Ltd.: 1.59 kg per 1 L) was used as silica sand 1. Omnisand T3 (Sumitomo Rubber Industries, Ltd.: 1.56 kg per 1 L) was used as silica sand 2. Omnisand T3 (Sumitomo Rubber Industries, Ltd.: 1.56 kg per 1 L) was used as silica sand 3. Furthermore, silica sand No. 3 (Sumitomo Rubber Industries, Ltd.: 1.39 kg per 1 L) was used as silica sand 4, which will be described later.

[0038] The above-mentioned silica sand 1, silica sand 2, and silica sand 3 were filled to heights of 84 mm, 90 mm, and 105 mm, respectively, on artificial turf with a pile length of 130 mm, laid in a wooden box measuring 50 cm in length, 25 cm in width, and 12 cm in height. Immediately after filling, the presence or absence of javelin penetration, the depth of javelin penetration, impact absorption, and vertical displacement were observed in accordance with the "Guidelines for the Installation of Artificial Turf for Throwing" (Japan Association of Athletics Federations, Facilities Equipment Committee, September 2018) (hereinafter referred to as the "Guidelines").

[0039] Specifically, the presence or absence of spear penetration was determined by dropping a men's javelin (Nemeth Classic 85m) from a height of 2 m and determining whether the spear penetrated the concrete and remained standing. The penetration depth of the spear was measured by dropping the men's javelin from a height of 2 m. Impact absorption was calculated by dropping a 20 kg weight from a height of 55 mm, recording the acceleration, and calculating the force reduction rate and the theoretical force applied to the concrete surface. Vertical displacement was determined as the amount of penetration of the surface during the impact absorption measurement. Water was then sprayed onto the filled silica sand. Similar observations were conducted in accordance with the guidelines for silica sand 1 16 hours after spraying, and for silica sands 2 and 3 4 hours after spraying. The results are shown in Table 6 below.

[0040] [Table 6]

[0041] First, none of the silica sands were penetrated by spears either immediately after filling or after watering. Furthermore, according to the guidelines, the standard value for impact absorption is 50-70%, and the standard value for penetration depth is 60mm or more, but none of the silica sands met these standards. Furthermore, the standard value for vertical displacement is 4-11mm, and while all of the silica sands met these standards immediately after filling, only silica sand 3 met them after watering. From the above, it was concluded that none of the above silica sands 1 to 3 are suitable for use alone as an infill layer for throwing artificial turf.

[0042] (5) Alternate filling of silica sand and cypress sawdust Next, artificial turf filled alternately with silica sand and cypress sawdust was tested as follows. First, artificial turf with a pile length of 130 mm was laid in a wooden box measuring 50 cm in length, 25 cm in width, and 12 cm in height. Infill layer 1 was filled alternately with sawdust and silica sand 1 seven times in the filling order shown in Table 7 below. After each filling, the pile was brushed to ensure thorough mixing with the mixture already filled. The volume ratio of silica sand to sawdust was 8.2:7.0 (≒1.17:1), and the thickness of the infill layer immediately after filling was 95 mm.

[0043] [Table 7]

[0044] Additionally, as infill layer 2, sawdust and silica sand 2 were alternately filled seven times on the same artificial turf in the filling order shown in Table 8 below. After each filling, the pile was brushed to ensure thorough mixing with the mixture already filled. The volume ratio of silica sand to sawdust was 8.33:7.0 (≒1.19:1), and the thickness of the infill layer immediately after filling was 100 mm.

[0045] [Table 8]

[0046] Additionally, infill layer 3 was created on the same artificial turf by alternately filling sawdust and silica sand 2 five times, and then alternately filling sawdust and silica sand 3 two times, in the filling order shown in Table 9 below. Each time a layer was filled, the pile was brushed to ensure thorough mixing with the mixture already filled. The volume ratio of silica sand to sawdust was 8.6:7.0 (≒1.23:1), and the thickness of the filled layer immediately after filling was 105 mm.

[0047] [Table 9]

[0048] The artificial turfs with the above infill layers 1 to 3 were observed in accordance with the guidelines in the same manner as in (3) above immediately after infilling, and 16 hours after watering (infill layer 1) or 4 days after watering (infill layers 2 and 3). The results are shown in Table 10 below.

[0049] [Table 10]

[0050] First, all of the infill layers were penetrated by a spear both immediately after filling and after watering, and the penetration depth also met the standard value (60 mm or more). Furthermore, all of the infill layers met the standards for impact absorption (50-70%) and vertical displacement (4-11 mm), at least after watering. From the above, it was demonstrated that all of the above infill layers 1 to 3 are suitable as infill layers for throwing artificial turf.

[0051] Here, from Tables 6 and 10, the values ​​of impact absorption, vertical displacement and penetration depth are extracted for the cases where silica sand 1 and silica sand 2 are used alone and where they are combined with sawdust (i.e., packed bed 1 and packed bed 2), and are shown in comparison in Table 11 below.

[0052] [Table 11]

[0053] As shown in Table 11 above, all values ​​were improved by combining sawdust, and it was shown that the standard values ​​were met.

[0054] (6) Another filling example Next, we will show a different filling example from (5) above. Specifically, for filling 4, 1.33 L of silica sand 4 was filled twice into the same artificial turf as (5) above, and then sawdust and silica sand 2 were filled alternately six times in the filling order shown in Table 12 below. After each filling, the pile was brushed over to ensure thorough mixing with the mixture already filled. The volume ratio of silica sand 2 to sawdust and silica sand 4 was 7.1:6.0:2.7, and the volume ratio of silica sand to sawdust was 9.8:6.0 (≒1.63:1). The thickness of the filled layer immediately after filling was 101 mm.

[0055] [Table 12]

[0056] In addition, 1.33 L of silica sand 4 was filled twice into the same artificial turf as infill layer 5, in the filling order shown in Table 13 below. Then sawdust and silica sand 2 were filled alternately five times, and then silica sand 2 was filled twice more. After each filling, the pile was brushed to ensure thorough mixing with the mixture already filled. The volume ratio of silica sand 2 to sawdust and silica sand 4 was 8.3:5.0:2.7, and the volume ratio of silica sand to sawdust was 11.0:5.0 (≒2.2). The thickness of the infill layer immediately after filling was 105 mm.

[0057] [Table 13]

[0058] In addition, 1.44 L of silica sand 4 was filled twice into the same artificial turf as infill layer 6, in the filling order shown in Table 14 below. Then sawdust and silica sand 2 were filled alternately five times, and then silica sand 2 was filled twice more. After each filling, the pile was brushed to ensure thorough mixing with the mixture already filled. The volume ratio of silica sand 2 to sawdust and silica sand 4 was 9.0:4.0:2.9, and the volume ratio of silica sand to sawdust was 11.9:4.0 (≒2.98:1). The thickness of the infill layer immediately after filling was 115 mm.

[0059] [Table 14]

[0060] The artificial turf having the above infill layers 4 to 6 was observed in accordance with the guidelines in the same manner as in (3) above immediately after infilling, and 16 hours after watering (infill layer 4) or 4 days after watering (infill layers 5 and 6). The results are shown in Table 15 below.

[0061] [Table 15]

[0062] First, all of the filled layers were penetrated by a spear both immediately after filling and after watering, and the penetration depth also met the standard value (60 mm or more). Furthermore, all of the filled layers met the standard for vertical displacement (4 to 11 mm), at least after watering. Furthermore, the impact absorption (50 to 70%) of all filled layers slightly exceeded the standard value, but in actual field filling work, it is likely that the pressure from the wheel load of the machinery used will bring it within the standard range.

[0063] (7) For short pile Finally, we also verified whether an infill layer made of a combination of silica sand and sawdust could be used for artificial turf with a pile length of 50 mm, which is shorter than the piles in (4) and (5) above.

[0064] A 50mm pile length artificial turf was laid in a wooden frame measuring 70.7cm long, 70.7cm wide, and 3cm high, and sawdust and silica sand 2 were alternately filled three times as infill layer 7 in the filling order shown in Table 16 below. After each filling, the pile was brushed to ensure thorough mixing with the mixture already filled. The volume ratio of silica sand to sawdust was 8.0:6.0 (≒1.33:1), and the thickness of the infill layer immediately after filling was 30mm.

[0065] [Table 16]

[0066] Before installing the artificial turf on the wooden frame, a 10mm thick foamed polyurethane underpad was attached, and then sawdust and silica sand 2 were filled in the same way as in filling layer 7 above, in the filling order shown in Table 17 below.After each filling, the pile was brushed over to ensure that the mixture already filled was thoroughly mixed, and this was used to create filling layer 8.

[0067] [Table 17]

[0068] Additionally, infill layer 9 was created by filling an artificial turf similar to infill layer 7 with silica sand 2 once, then sawdust once, and finally silica sand 2 once, in the filling order shown in Table 18 below. Each time a layer was filled, the pile was brushed over to ensure sufficient mixing with the mixture already filled. The volume ratio of silica sand to sawdust was 5.6:8.4 (≒0.67:1), and the thickness of the infill layer immediately after filling was 30 mm.

[0069] [Table 18]

[0070] Before installing the artificial turf on the wooden frame, a 10mm thick foamed polyurethane underpad was attached, and then sawdust and silica sand 2 were filled in the same way as in filling layer 9 above, in the filling order shown in Table 19 below.After each filling, the pile was brushed over to ensure that the mixture already filled was thoroughly mixed, and this was used to create filling layer 10.

[0071] [Table 19]

[0072] For the above packed beds 7 to 10, the impact absorption and vertical displacement were observed in accordance with the guidelines in the same manner as in (3) above. Note that for packed beds 8 and 10, the observations were made immediately after filling and after water was sprayed. Each test was performed three times. The results for impact absorption and vertical displacement are shown in Table 20 and Table 21, respectively.

[0073] [Table 20]

[0074] [Table 21]

[0075] First, regarding the impact absorption shown in Table 20 above, neither of the filling layers 7 and 9, which do not have an underpad, met the standard value (50-70%), but both of the filling layers 8 and 10, which do have an underpad, met the standard value. Note that after watering, filling layer 8 met the standard value when rounded off to the nearest whole number.

[0076] Next, with regard to the vertical displacement shown in Table 21 above, packed beds 7 and 9, which did not have underpads, were both near the lower limit of the standard value (4 to 11 mm), but packed beds 8 and 10, which had underpads, both cleared the standard value.

[0077] The above results show that even with artificial turf with a short pile length, by attaching an underpad, the infill layer filled with sawdust and sand can meet the standard values ​​set out in the guidelines. [Explanation of symbols]

[0078] 10 Artificial Grass 20 Base 30 Pile 40 Filling layer 41 Sand 42 Sawdust 43 Mixture 50 Backing material 60 Crushed stone base

Claims

1. The piles planted in the base are alternately filled with sawdust and sand, This is an artificial turf construction method, in which the sawdust and sand filled in are mixed by brushing the pile each time the filling is carried out.

2. The artificial turf construction method according to claim 1 , wherein the sawdust and the sand are each applied multiple times.

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