JP7361231B2 - artificial grass - Google Patents

Description

The present invention relates to artificial turf that can continue to suppress temperature increases at the installation site for a long time and is effective as a countermeasure against microplastics.

In recent years, as the number of people playing sports has increased and become more active, outdoor sports facilities such as baseball fields, soccer, hockey, and rugby fields, tennis courts, gateball fields, and multipurpose plazas are being replaced with existing natural grass or clay courts. As such, artificial turf is widely used. The reasons for this include that artificial turf is not easily affected by weather conditions, always maintains constant ground conditions, is easy to maintain, and can reduce convenience and management costs.

While artificial turf has these advantages, in the past it mainly had short piles, i.e. leaf fibers, and low shock absorption, and the bottom of the artificial turf was often concrete or other paved surfaces. It has been said that there are safety issues for athletes compared to However, in recent years, impact-absorbing materials have been developed, which are made by planting long-pile artificial turf with spacing between the pile threads, and filling the spaces between the pile threads with inorganic granules such as sand or elastic granules such as rubber chips. Excellent products are being developed and improved, and they are used so widely that international organizations for various sports officially recognize or certify them.

However, one problem common to all-weather sports fields with artificial turf pavement is that the surface temperature rises under the scorching sun outdoors in summer, often exceeding 70°C. In particular, long-pile artificial turf containing granules, which has been widely used in recent years, has many air spaces between long piles and granules, so it is harder for heat to escape than artificial turf with short piles, and temperature increases are more likely to occur. There is a problem. As a result, it is harsh for the athletes, there is a risk of heat stroke, and it also has an adverse effect on the environmental temperature and may even cause the heat island effect, which has become a problem, and countermeasures have been sought.

For example, U.S. Pat. No. 5,000,303 describes a lawn or lawn primary layer consisting of a mat on which a plurality of blades of artificial material are woven to form a blade protruding from one side of the mat creating the lawn: said blades. an artificial lawn comprising: a filler disposed between; said filler comprising a measured amount of a coarse product obtained from a raw material based on finely crushed coconut; The granular and fibrous portion consists essentially of a single granular and fibrous portion contained in the raw material based on finely ground coconut, and the granular and fibrous portion is obtained by subjecting the raw material based on finely ground coconut to a step of separating the granular and fibrous portion from the powder portion. The granular and fibrous parts obtained and contained in the coarse product are obtained by sieving the raw material based on finely crushed coconut, and the granular and fibrous parts are reduced to 90% by weight up to 500 microns (μm). ) or more is disclosed.

Further, Patent Document 2 discloses an artificial lawn in which grass threads are planted on a base fabric and a filler is filled between the planted grass threads to provide a filling layer, the filling layer comprising: The coconut filling comprises a lower layer containing a coconut filling material which is a crushed product of natural palm, and a surface layer disposed at the uppermost part of the filling layer, and the filling material constituting the surface layer retains water to the limit. An artificial lawn characterized in that the particles are particles having a solar reflectance higher than the solar reflectance of the material, and the surface layer provided to cover the lower layer suppresses rapid drying of the palm filling material. , has been disclosed.

Special Publication No. 2010-523855 Patent No. 6849453 specification

The artificial lawn described in Patent Document 1 is designed to obtain good drainage by adjusting the particle size distribution of a coconut-based raw material that suppresses overheating of the artificial lawn. If the coconut-based raw material dries out due to factors, there is a risk that its effectiveness in suppressing temperature rise will be prematurely reduced.

In the embodiment of the invention of Patent Document 2, the filler constituting the packed bed includes hard grains, elastic grains that elastically deform when subjected to external force, and coconut filling based on natural coconut. The elastic particles used are styrene resin elastomer particles, but other synthetic resin elastomers such as olefin resin elastomers, synthetic rubber and natural rubber particles, and crushed waste rubber products are also used. It is stated that recycled products such as are used. That is, the artificial lawn described in Patent Document 2 uses so-called microplastics as a filler. This microplastic is a cause of ocean pollution. According to the results of a survey of 100 locations such as rivers, ports, and lakes in 12 prefectures conducted by a specific research organization from June to November 2019, microplastics were found in all surveyed locations, and pieces of artificial grass were found in 75 locations. There are reports that.

The present invention has been made in view of the problems of the conventional technology, and its purpose is to provide artificial turf that has a sufficient heat shielding effect without causing pollution. .

In order to achieve the above object, the first invention of the present application provides an artificial turf comprising a base material and piles planted on one side of the base material, and a filler is filled between the piles. , the filler is made of natural wood fibers made from cedar and cypress bark collected from thinned wood with a specific gravity of 0.1 or more, and hard particles, and the average fiber length of the natural wood fibers is 0. This artificial turf is characterized by having a thickness of .5 to 20.0 mm.

A second invention of the present application is an artificial grass according to the first invention of the present application, characterized in that the natural wood fibers account for 10% by mass or more of the filler.

A third invention of the present application is the artificial turf according to the first or second invention, characterized in that the filler contains dried and/or crushed eggshell membrane.

According to the first invention of the present application, natural wood fibers made from cedar and cypress, which are barks collected from thinned wood, are used as fillers, and these natural wood fibers have low heat absorption and water retention properties. This makes it possible to suppress the rise in surface temperature of artificial turf. Furthermore, since cedar and cypress are natural raw materials, they emit little carbon dioxide, and there is no risk of causing health damage or environmental problems even if they flow into rivers or the sea. According to the second invention of the present application, the above effects can be fully enjoyed. According to the third invention of the present application, since the eggshell membrane has the effect of absorbing carbon dioxide, it is possible to provide an environmentally friendly artificial turf.

FIG. 1 is a side sectional view of one embodiment of the artificial turf of the present invention. FIG. 2 is a diagram schematically showing a side cross section of the artificial turf of the present invention. FIG. 3 is a diagram showing changes in surface temperature of wood fibers and rubber chips. FIG. 4 is a diagram showing the CO ₂ absorption performance of eggshell membranes.

Embodiments of the present invention will be described below, but various changes and modifications can be made without departing from the technical scope of the present invention.

FIG. 1 is a side sectional view of one embodiment of the artificial turf of the present invention. FIG. 2 is a diagram schematically showing a side cross section of the artificial turf of the present invention. In FIG. 2, 1 is a base material, 2 is a pile, 3 is a resin layer, and 4 is a filler.

Examples of the fibers constituting the base material 1 include natural cellulose fibers such as cotton and hemp, regenerated cellulose fibers such as viscose rayon, high wet modulus rayon, polynosic, cupro, and lyocell, wool, angora, cashmere, silk, etc. Animal fibers, semi-synthetic fibers such as triacetate and diacetate, and synthetic fibers such as polyester, polyamide, acrylic, polypropylene, polyethylene, polyvinyl alcohol, and vinyl chloride can be used. These fibers can be used alone or in combination. Combinations of fibers for mixed use include polyester and cotton, polyamide and cotton, and the like.

The form of the base material 1 is not particularly limited, and for example, woven fabrics, knitted fabrics, nonwoven fabrics, etc. can be adopted, but woven fabrics and knitted fabrics are generally preferred. In this case, the woven structure and knitted structure are not particularly limited, and the woven structure includes, for example, a three-dimensional structure such as a plain weave, a twill weave, a satin weave, a variation thereof, a two-dimensional structure such as a warp double weave, a weft double weave, etc. Heavy texture and textured double weave can be used. On the other hand, in the case of weft knitting, the knitting structure is flat knitting (sweft knitting, pique knitting, fleece knitting, plated knitting (bare jersey, etc.), jacquard knitting, etc.), elastic knitting (smooth knitting, interlock knitting, Milan rib knitting, etc.), and elastic knitting (smooth knitting, interlock knitting, Milan rib knitting, etc. , single piquet, double piquet, ripple, katabe knit, katabukuro knit, punch roma, etc.), pearl knit, etc. In the case of warp knitting, single denby knit, single atlas knit, single cord knit, double denby knit, double atlas knit, double cord knit, half tricot knit, queen's cord knit, satin knit, fleece knit, jacquard knit, etc. can be exemplified. The number of layers of the knitted fabric may be a single layer or a multilayer of two or more layers.

The material and form of the pile 2 are not limited as long as they can achieve the appearance of grass blades, but for example, the pile 2 can be formed using flat filament threads (yarn) made of a resin material. As the resin material, thermoplastic resins such as polyethylene, polypropylene, nylon, and vinylon can typically be selected. Moreover, the pile 2 of this embodiment is fixed to the base material 1 by sewing the plastic thread (yarn) that will become the pile 2 into the base material 1 using a tufting machine. The length (average value) from the surface of the base material 1 to the tip of the pile 2 is not particularly limited, but it can be relatively short, such as 6 mm or more and less than 50 mm (generally called short pile), or 50 mm or more. It is also possible to make it relatively long, such as 70 mm or less (generally called long pile).

As the resin constituting the resin layer 3, known resins such as SBR resin, urethane resin, acrylic resin, polyester resin, silicone resin, vinyl chloride resin, and nylon resin can be used. In this embodiment, SBR resin was used as the resin for the resin layer 3.

The filler 4 is made of natural wood fibers made from cedar and cypress and having a specific gravity of 0.1 or more and hard particles. The average fiber length of cedar and cypress is preferably 0.5 to 20.0 mm, more preferably 0.5 to 10.0 mm. As the hard particles, hard particles such as silica sand, pebbles, sand, ceramic grains, and resin pellets can be used alone or in combination.

Natural wood fibers made from cedar and cypress have low heat absorption and retain water supplied by rainwater or sprinkling.When the temperature rises, this evaporates and the heat of evaporation causes the surface of the artificial turf to grow. Suppress temperature rise. By containing natural wood fibers in the filler, it is possible to effectively lower the temperature of the area where the artificial turf is laid, especially during seasons when temperatures tend to rise, such as in the summer, thereby suppressing the occurrence of heatstroke.

Natural wood fibers made from cedar and cypress trees contribute to the health of forests and reduce carbon dioxide emissions by utilizing the bark collected from thinned wood.

In order to sufficiently obtain the above temperature rise suppressing effect, it is preferable that the filler contains 10% by mass or more of natural wood fibers made from cedar and cypress having a specific gravity of 0.1 or more. It is more preferable that the filler contains 15 to 25% by mass of natural wood fibers and 75 to 85% by mass of hard particles. The ratio of cedar and cypress in the natural wood fibers is free. That is, all of the natural wood fibers may be cedar wood, or all of the natural wood fibers may be cypress wood. 50% by mass of the natural wood fibers may be cedar wood and 50% by mass may be cypress wood. In short, it is sufficient that the natural wood fibers contain cedar wood and/or cypress wood, and the ratio of cedar wood to cypress wood is not limited.

The above-mentioned filler contains natural wood fibers that retain water that comes into contact with it during drying, thereby lowering the temperature when the temperature rises, but especially in stadiums for sports such as ball games and track and field. In some cases, water is sprinkled on the artificial turf to lower the temperature, and competitions are held in the rain. At this time, it is preferable that the sensation of a player stepping on the artificial turf and the way a ball bounces during a ball game will vary little between the dry and wet conditions of the artificial turf. In addition, in cases where standards have been established for artificial turf used in stadiums such as soccer, it is possible to deviate from the established standards by minimizing the change in feel between dry and wet conditions. It can also be expected to have the effect of making it more difficult.

Furthermore, by including eggshell membrane in the filler, the effect of absorbing carbon dioxide can be added. The eggshell membrane content in the filler is preferably 4 to 8% by mass. If there is too little eggshell membrane, the carbon dioxide absorption effect cannot be expected. On the other hand, if there is too much eggshell membrane, filling becomes difficult, and because eggshell membrane has a small specific gravity and is chip-shaped, it is easily washed away by rainwater. This is because it is inconvenient.

Next, a method for manufacturing the artificial turf shown in FIG. 1 will be described. First, a needle through which the pile yarn 2 is passed is moved up and down with respect to the base material 1, and the head of the pile 2 is cut with a knife. Next, as shown in FIG. 2, with the pile 2 on top of the base material 1, an SBR resin is applied to the bottom surface of the base material 1 to form a resin layer 3, and the pile is placed on the top surface of the base material 1. 2 to obtain artificial turf having a resin layer 3 on the lower surface of the base material 1. After this artificial turf is laid, natural wood fibers and hard particles are spread using a top sand spreader, and filler 4 is filled between the piles 2 by brushing with a rotating brush or the like.

Experiments to demonstrate the effects of the artificial turf of the present invention will be described below.
(1) Water retention The water retention properties of wood fibers consisting of 70% by mass of cedar wood with an average fiber length of 5 mm and 30% by mass of cypress wood with an average fiber length of 5mm, and artificial lightweight soil ("Viva Soil" manufactured by Toho Leo) were evaluated. investigated. As a result, the maximum water holding capacity of wood fibers was 470 to 560 kg/ ^m2 , while the maximum water holding capacity of artificial lightweight soil was 260 to 320 kg/ ^m2 . It can be seen that wood fibers have a maximum water retention capacity approximately twice that of artificial lightweight soil. The maximum water holding capacity is the amount of water contained in the wood fibers or artificial lightweight soil relative to the surface area of the wood fiber or artificial lightweight soil in a state where water does not seep out from the surface of the wood fiber or artificial lightweight soil and is not discharged to the outside. This refers to the amount of water in the water.

(2) Water absorption A square waterproof panel measuring 1 m long and 1 m wide is installed outdoors at an angle of 5° to the horizontal. The artificial lightweight soil was layered, and the cumulative amount of natural rainfall that fell on the wood fibers or the artificial lightweight soil and the amount of rainwater that ran off without being absorbed by the wood fibers or the artificial lightweight soil were measured. The results are shown in Table 1.

As shown in Table 1, wood fibers have excellent water absorption performance. In Table 1, the water absorption rate can be determined as follows. Since the cumulative amount of rainfall means the amount of rainfall per an area of 1 m ² , for example, the water absorption rate (%) when the cumulative amount of rainfall is 23 mm can be determined as follows.
[(0.0230-0.0002)/0.0230]×100=99.1

(3) Surface temperature In Figure 3, line A is the change in surface temperature of artificial turf filled with a filler made of wood fibers (paragraph 0029) and silica sand, which is a hard particle size material (wood fibers are 16.1% by mass). Line B shows a material obtained by crushing synthetic rubber and filling it with a filler (rubber chips: 20.0% by mass) consisting of rubber chips with a particle size in the range of 0.5 mm to 4.0 mm and silica sand, which is a hard particle size material. This shows the change in surface temperature of artificial turf. That is, FIG. 3 shows an artificial turf filled with the same wood fibers (paragraph 0029) and silica sand, which is a hard particle size material, with a length of 230 mm, a width of 150 mm, and a thickness of 40 mm; Artificial grass filled with the above rubber chips with a diameter of 40 mm and silica sand, which is a hard particle size material, was irradiated with a 500 W halogen lamp from a height of 450 mm, and 5 minutes, 10 minutes, and 15 minutes later. The changes in surface temperature (°C) after 20 minutes, 25 minutes, and 30 minutes were obtained by measuring the changes in surface temperature (°C) using an infrared radiation thermometer (trade name: SK-87002, manufactured by Sato Keiki Seisakusho). As shown in Figure 3, the surface temperature of artificial turf filled with wood fibers and hard particles (line A) is smaller than that of artificial turf filled with rubber chips and hard particles (line B). I understand that.

(4) Deodorizing performance Deodorizing performance for ammonia and hydrogen sulfide was measured using the detection tube method. That is, 2 g of test pieces of natural wood fibers made from cedar and cypress (paragraph 0029) were sealed in 5 liters of Tetra Pak (registered trademark), and the initial concentration of ammonia in the Tetra Pak (registered trademark) was set to 45 ppm. , The initial concentration of hydrogen sulfide was 20 ppm, and the respective concentrations in Tetra Pak (registered trademark) were measured with a detection tube after 2 hours and 24 hours [ammonia]
As a result, the ammonia concentration in Tetra Pak (registered trademark) after 2 hours was 20 ppm, and after 24 hours was 7.5 ppm. That is, it was confirmed that ammonia was reduced by 83.3% in 24 hours.

[Hydrogen sulfide]
As a result, the concentration of hydrogen sulfide in Tetra Pak (registered trademark) after 2 hours was 13 ppm, and the concentration of hydrogen sulfide after 24 hours was 2.5 ppm. That is, it was confirmed that hydrogen sulfide was reduced by 87.5% in 24 hours.

(5) Bactericidal performance The bactericidal performance of the above wood fiber (paragraph 0029) against Staphylococcus aureus (ATCC6538P) was investigated. As a result, the results shown in Table 2 below were obtained. The numerical values in Table 2 are the numbers obtained by dividing the number of Staphylococcus aureus contained in the test solution containing Staphylococcus aureus by the weight (g) of the test solution. That is, a test liquid containing Staphylococcus aureus is sprayed onto wood fibers, and one day later, the test liquid is collected from the wood fibers, the number of Staphylococcus aureus is counted, and the number of Staphylococcus aureus is counted per weight (g) of the test liquid. Similarly, after 4 days, collect the test solution from the wood fiber and count the number of Staphylococcus aureus, and calculate the number of Staphylococcus aureus per weight (g) of the test solution. After 7 days, a test liquid was collected from the wood fibers and the number of Staphylococcus aureus was counted to determine the number of Staphylococcus aureus per weight (g) of the test liquid. The control in Table 2 shows the number of Staphylococcus aureus per weight (g) of the test solution cultured on the petri dish.

As is clear from Table 2, it can be seen that wood fibers have excellent bactericidal performance against Staphylococcus aureus.

(6) CO ₂ absorption performance of eggshell membrane A CO ₂ monitor (trade name manufactured by C.H.C SYSTEM CO. LTD. "Marvel 003") was inserted and sealed, and the environment inside the acrylic resin case was set to a temperature of 19.0±0.5°C and a humidity of 39±0.5%. Then, we conducted a blank test in which there was nothing inside the acrylic resin case other than the above CO ₂ monitor, and an eggshell membrane insertion test in which 50 g of dried and crushed eggshell membrane was inserted into the acrylic resin case. The CO ₂ concentration was measured with the CO ₂ monitor every minute for a total of 30 minutes. The initial CO ₂ concentration in the acrylic resin case was 901 ppm in both the blank test and the eggshell membrane insertion test. The CO ₂ concentration measurement results are shown in FIG. 4.

In FIG. 4, line C shows the change in CO ₂ concentration in the acrylic resin case in the eggshell membrane insertion test, and line D shows the change in CO ₂ concentration in the acrylic resin case in the blank test. The vertical axis of FIG. 4 shows the CO ₂ concentration (ppm), and the horizontal axis shows the elapsed time (minutes). As is clear from FIG. 4, eggshell membranes have excellent CO ₂ absorption performance.

Based on the above experimental results, the artificial turf of the present invention has the following effects.
(1) It is effective as a measure against global warming because it can suppress the rise in surface temperature.
(2) By using the bark of thinned natural cedar and cypress as filler material, we aim to improve the health of forests and contribute to reducing carbon dioxide emissions.
(3) Since it has excellent water absorption and water retention properties, it can reduce water floating on a wet field.
(4) Its bactericidal action can suppress the proliferation of bacteria and suppuration of wounds.
(5) The effect of cedrol, a component of cedar, has the effect of repelling insects.
(6) Excellent carbon dioxide absorption effect can be expected due to the eggshell membrane.

Verification of workability using freeze-drying method Long pile artificial turf (having the side cross section shown in Figure 1) was laid on a rectangular area (38.5 m ² ) consisting of lengths of 3.5 m and 11 m. A test was conducted to fill with a filler made of natural wood fibers made from cedar and cypress (paragraph 0029) and silica sand (16.1% by mass of natural wood fibers) having a molecular weight of 0.1 or more. However, when trying to spread natural wood fibers made from cedar and cypress on the long pile artificial turf, due to their light specific gravity and fibrous nature, they tend to get entangled between the long piles and take a long time to fill. It took time. The time required for filling at that time was 3 hours, which was 1.5 times the average time (2 hours) required for filling ordinary rubber chips.

To solve this problem, cedar and cypress were made into solid pellets in order to shorten the filling time of natural wood fibers made from cedar and cypress. This solid pelletization shortens the filling time for the long pile artificial turf. However, when the wood was pelletized by applying heat and pressure using a pelletizer, the fibers of the natural wood fibers were not left behind and the wood became powdery. When artificial turf containing natural wood fiber pellets is actually laid on an outdoor sports facility such as a soccer field, it becomes muddy when wet with rainwater, causing the problem of water floating on the field. There is a concern that the repulsion performance of the ball will be impaired.

Therefore, the freeze-drying method (instantly freezing to -30°C and drying in a vacuum) is a method that is solid and easy to fill between the long piles and retains the fibrous nature of natural wood fibers after filling. ), we decided to solidify natural wood fibers made from cedar and cypress. Long pile artificial turf was laid in a rectangular area (38.5 m ² ) as above, and natural wood fibers made from cedar and cypress (paragraph 0029) with a specific gravity of 0.1 or more were solidified using a freeze-drying method. A filler consisting of wood and silica sand (16.1% by mass of natural wood fibers) was filled. The time required for filling at that time was 2 hours, which was approximately the same time as required for filling ordinary rubber chips. Furthermore, by solidifying natural wood fibers using the freeze-drying method, it is possible to return them to their original state without destroying the fibers.

The present invention is suitable for use as artificial turf.

1 Base material 2 Pile 3 Resin layer 4 Filler

Claims (2)

It has a base material and a pile planted on one side of the base material, and between the piles is made of cedar and cypress bark collected from thinned wood with a specific gravity of 0.1 or more, Artificial turf for outdoor sports facilities filled with a filler made of natural wood fibers with an average fiber length of 0.5 to 20.0 mm and hard particles, the filler being dried and/or crushed eggshell membrane. An artificial turf for outdoor sports facilities characterized by containing . 2. The artificial turf for outdoor sports facilities according to claim 1, wherein the natural wood fiber accounts for 10% by mass or more of the filler.

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