JP4417903B2 - Artificial turf structure and artificial turf stadium - Google Patents

Description

  The present invention relates to an artificial turf structure and an artificial turf stadium constructed by the artificial turf structure.

  So-called long pile artificial turf is rapidly spreading in place of conventional natural turf in soccer fields, baseball fields, rugby fields, multipurpose grounds and the like. This is because many advantages such as cost reduction and improvement in usable days are being recognized compared to natural turf cultivation and maintenance.

  For long pile artificial turf fillers, hard fillers such as silica sand and elastic fillers such as vulcanized rubber chips are used in consideration of total cost, structural stability, shock absorption, and playability in various competitions. As the rubber chips, pulverized products such as waste tires and automobile window frame rubber which are inexpensive and available in large quantities are used. However, silica sand and rubber chips have a large difference in particle size and specific gravity. Therefore, during filling work or play, the silica sand falls through the gap between the rubber chips, and the surface of the filler is essentially only black rubber chips. It is in a state. This is one of the factors that raises the temperature of the artificial turf surface in the summer and forces players to play in harsh conditions.

  As means for solving such a problem, Patent Document 1 discloses an artificial turf structure in which the uppermost layer of the filler contains a large amount of a specific filler having a lower true specific gravity and a lower heat absorption rate than the lower-side filler. Has been proposed.

  However, since the uppermost filler used in Patent Document 1 is a pulverized product of foamed rubber or a synthetic resin foam obtained by kneading a colorant directly into a raw material, there is a problem of high cost. .

JP 2003-34906 A

  An object of the present invention is to eliminate the above-mentioned drawbacks, effectively suppress the temperature increase of the artificial turf surface due to direct sunlight in summer, and provide an artificial turf structure excellent in playability and durability at low cost. To do.

That is, the artificial turf structure of the present invention is an artificial turf structure in which a filler is filled between piles, the uppermost layer filler is a core material made of recycled rubber chips, and the average thickness is 28 μm or more and 180 μm or less , It is a colored rubber chip comprising at least a resin and a pigment, and having a colored film having an L ^* value of 60 or more in the CIE 1976 L ^* a ^* b ^* color space.

  The artificial turf stadium of the present invention is constructed by the artificial turf structure.

  According to the present invention, it is possible to effectively suppress the surface of the artificial turf structure from becoming hot due to direct sunlight when the temperature rises in summer, and to maintain the effect for a long time. Comfortable playability can be maintained at various artificial grass competition facilities such as stadiums, baseball fields, and tennis courts.

  FIG. 1 is a partial cross-sectional view showing an example of an artificial turf structure according to the present invention. In FIG. 1, 1 is a base fabric, 2 is a pile, 3 is a lower layer filler, and 4 is a colored rubber chip. As shown in FIG. 1, the artificial turf structure according to the present invention has a pile 2 of tufts tufted at a predetermined interval on a base fabric 1 and a pile 2 between artificial turf piles on which the pile 2 is prevented from coming off. The lower layer filler 3 is filled, and the colored rubber chip 4 is filled in the uppermost layer.

  As the base fabric 1, for example, a fabric base yarn made of resin such as polypropylene, polyethylene, nylon, polyethylene terephthalate, or the like, which is made into a fabric by weaving a uniaxially stretched or short fiber close together to form a long fiber is used. be able to. It is preferable that the base fabric 1 be used in a stack of two sheets because it has high step stability and is less likely to be wrinkled by external force after laying. In this case, it is preferable to use a base fabric obtained by punching synthetic fiber in the form of cotton for the lower base fabric because dimensional stability and wrinkle prevention properties are improved.

  As the pile 2, for example, a split yarn or a monofilament yarn made of synthetic resin such as polypropylene, polyethylene, nylon, polyethylene terephthalate or the like can be used. The thickness of the pile 2 (when using a monofilament yarn, the total thickness of a plurality of single yarns) is preferably 5000 to 10000 dtex.

  Examples of the pile 2 retaining prevention process include a method of applying SBR latex rubber, urethane resin or the like to the back surface of the base fabric 1.

  The artificial turf structure of the present invention has a pile length H of 40 to 70 mm from the base fabric 1 to the tip of the pile 2 and is called a so-called long pile artificial turf. Between the piles 2, the lower layer filler 3 and the colored rubber chips 4 are filled so that the pile protrusion height Hh from the surface of the colored rubber chips 4 to the tip of the pile is 10 mm or more, and the appearance is similar to natural grass The filler is less likely to scatter while

  The lower layer filler 3 is filled with a hard filler and an elastic filler alone, or both as a multilayer or mixed, and has a predetermined thickness so as to obtain the elasticity required by the artificial turf. For example, if H = 60 mm, it is filled with a thickness of about 30 mm. As the elastic filler, recycled products of waste rubber products such as waste tires having a maximum particle size of 3 mm or less, automobile window frames, and the like are preferably used. As the hard filler, various ceramics and stones are preferably used, and cinnabar sand having a maximum particle size of 1.2 to 1.5 mm or less is more preferably used. The mixing ratio of the elastic filler and the hard filler may be arbitrarily selected according to the specifications.

  The uppermost colored rubber chip 4 is a colored rubber chip having a light colored film having an average thickness of 25 μm or more, preferably 70 μm or more, more preferably 80 μm or more. Although the upper limit of a colored film is not specifically limited, Preferably it is 180 micrometers or less, More preferably, it is 150 micrometers or less. If the average thickness of the colored film is less than 25 μm, even if it looks the same, it is inferior in heat reflection performance, so that heat rays are easily transmitted and absorbed by the rubber chip, and the effect of suppressing the temperature rise on the surface of the artificial turf structure Is small.

  As the rubber chip used as the core material of the colored rubber chip 4, a pulverized vulcanized rubber can be suitably used, more preferably a recycled chip of waste rubber, and more preferably a waste tire due to supply stability and quality uniformity of raw materials. Recyclable chips can be used.

  The resin that forms the colored film is elastic, has excellent adhesion to rubber chips, has the strength to withstand the intense movement of shoes, and has durability that resists aging in the outdoor climate. Choose any type. For example, a thermosetting resin such as an epoxy resin, an acrylic resin, a polyester resin, or a polyurethane resin, a thermoplastic resin may be used, and not only a 100% solid content liquid resin but also a water dispersion system or a solvent-soluble resin may be used. In view of the properties and covering workability, a polyurethane resin is preferable.

As the color of the colored film is closer to white, the solar heat reflecting ability is larger, which is preferable. However, it is preferable that the colored film is lightly colored such as light beige or light green in terms of design, and the color space of CIE 1976 L ^* a ^* b ^* The L ^* value is preferably 60 or more. If the L ^* value is less than 60, the heat reflection function tends to be lowered.

  The pigment contained in the colored film preferably contains 80% by weight or more, preferably 80 to 90% by weight of rutile-type titanium oxide as a white pigment from the viewpoint of heat reflectivity. In the case of a light colored film, for example, if it is beige, a commonly used pigment such as iron oxide brown, brick color, etc. may be added. If a pigment is added, the heat shielding effect can be further improved. For example, Fastogen Super Black MX (manufactured by Dainippon Ink & Chemicals, Inc.), Paliogen Schwarz S0084 (manufactured by BASF) as a black pigment if it is light gray, and NanoTec cobalt green if it is light green. (Cai Kasei Co., Ltd.), Fastogen Green 2YK (Dainippon Ink Chemical Co., Ltd.) and the like.

The pigment amount PQ with respect to 100 parts by weight of the rubber chip is preferably an amount represented by the following formula (1).
PQ [parts by weight] = K (0.5 t [μm]) ^1/2 / RQ [parts by weight] (1)
t: Average thickness of the colored coating RQ: Resin amount (solid content) with respect to 100 parts by weight of rubber chip, preferably 8-30 parts by weight K: 15-25, preferably 18-22

  Balloons and hollow spheres with low thermal conductivity may be added to the colored film. Examples of inorganic balloons include silica balloons, shirasu balloons, and alumina balloons. Examples of resin balloons include vinylidene chloride and acrylonitrile resin balloons. Moreover, you may add inorganic powder, such as barium sulfate, zinc oxide, an alumina, and flake-like mica which has the function to suppress the heat storage by sunlight.

  Although the particle size of the colored rubber chip 4 is not particularly limited, the maximum particle size is preferably 3.5 mm to 4 mm from the viewpoint of easy fit between the piles 2. Further, in order to make the colored rubber chips 4 easily stay in the uppermost layer and to suppress the temperature rise of the artificial turf surface for a longer period of time, the average particle size of the colored rubber chips 4 is set in the lower layer filler 3 immediately below the colored rubber chips 4. It is preferably larger than the average particle size of the elastic filler.

  The colored rubber chip 4 is filled with a predetermined thickness, for example, about 6 to 12 mm when H = 60 mm, so that the lower layer filler 2 can be sufficiently covered and the heat ray can be prevented from passing through the lower layer filler 2. Is preferred.

  Although the manufacturing method of the colored rubber chip 4 is not particularly limited, for example, it can be manufactured by the method described in Japanese Patent No. 3588591.

  In FIG. 1, the filler has a two-layer structure of a lower filler layer 3 and a colored rubber chip 4. Modifications such as providing an intermediate layer between the fillers are also included in the present invention.

  The artificial turf structure of the present invention can be applied to various artificial turf sports facilities such as a soccer field, a baseball field, and a tennis court.

  Hereinafter, the present invention will be described in more detail with reference to examples. In the examples, “part” means “part by weight”.

  The materials used for the production of colored rubber chips are as follows.

[Rubber chip]
Waste tire rubber chip “RG-814”, particle size 1.0-3.0 mm (Muraoka Rubber Industries, Ltd.)

[Urethane resin]
An average molecular weight of 3000, 300 parts of a bifunctional polyoxypropylene glycol and 120 parts of diphenylmethane diisocyanate were reacted at 80 ° C. for 4 hours in a nitrogen stream. The isocyanate group content was 7.4% and the viscosity was 4100 mPa.s. Urethane resin at s / 25 ° C

[catalyst]
Tertiary amine “Dabco33LV” (manufactured by Air Products)

[Pigment]
Made of titanium oxide white (rutile type) as the main component and colored in beige color (manufactured by Toda Kogyo Co., Ltd.)
Pigment A: Titanium oxide content 90.0% by weight, iron oxide yellow 7.3% by weight, iron oxide black 1.2% by weight, iron oxide brick 1.5% by weight (L ^* 73.08, a ^* 4. 77, b ^* 15.94)
Pigment B: Titanium oxide content 80.6% by weight, iron oxide yellow 14.2% by weight, iron oxide black 2.5% by weight, iron oxide brick 3.3% by weight (L ^* 67.50, a ^* 6. 03, b ^* 17.97)

In addition, the measuring method of L ^* a ^* b ^* is as follows. That is, 8 parts of pigment is added to 10 parts of urethane resin, and the pigment is uniformly dispersed with a high-speed stirrer, and then 5 parts of ethyl acetate is added and further stirred uniformly. This was put in a desiccator and defoamed with a vacuum pump, and then applied onto a black vulcanized rubber sheet with a 10 μm doctor blade. This process was repeated three times, and a 25 μm thick coating film obtained by drying and curing at room temperature for 3 days was measured using a colorimeter “MC-1000” (manufactured by Minolta Co., Ltd.).

<Examples 1 to 5 (Example 5 is a reference example) , Comparative Examples 2 and 3>
100 parts of a rubber chip was put in a stirring vessel, and a polyurethane resin and a pigment previously mixed with 1% by weight of a catalyst in advance were added at a ratio shown in Table 1 while rotating a stirring blade. The polyurethane resin gradually thickened and gelled and the whole aggregated, but it continued to mix, eventually the aggregated aggregates began to decompose and become smaller, and finally the aggregated grains were broken apart Agitation was discontinued.

  All the colored rubber chips had the same color visually.

  Several grains of the colored rubber chips obtained are collected, and the cross section of the chip is enlarged on a CRT of a personal computer by Micro Square manufactured by Micro Square, and the thickness of the colored film is measured at five points to obtain the average thickness of the colored film. It was. The results are shown in Table 1.

[Rubber chip surface temperature]
A transparent acrylic container having a size of 12 cm × 12 cm and a height of 10 cm was filled with the obtained colored rubber chip with a thickness of 15 mm, and the surface was leveled to obtain a test specimen. In addition, the height of the acrylic container was increased in order to minimize variations due to the influence of wind.

The specimen was left for 4 hours under the following conditions, and the surface temperature was measured by a radiation thermometer “IR-TA” (manufactured by Chino Co., Ltd.) after noon. The measurement positions were four places from the center of 4 to 5 cm from each corner, and the average value was obtained. The results are shown in Table 1 and FIG.
Condition 1: The temperature is 33 ° C, the sky is clear and the sun is very strong.
Condition 2: The temperature is 30 ° C. and it is sunny, but the sky is haze like a thin cloud and the sun is slightly weak.

  In Table 1, “decrease temperature” is a temperature difference from Comparative Example 1 having no colored film, and “decrease rate” is a relative ratio when the decrease temperature of Example 4 having the thickest colored film is 100. It is.

[Surface temperature of artificial turf structure]
The materials used for manufacturing the artificial turf structure are as follows.

Artificial turf: Polyethylene split yarn artificial turf 8800dtex, pile length 60mm, base fabric made of two layers of polypropylene woven fabric with cotton, backed by SBR latex rubber coating Hard filler: No. 4 silica sand, particle size 0.3 ~ 1.4mm
Elastic filler: Waste tire rubber chip “RG-0720”, particle size 0.5 to 2.0 mm (Muraoka Rubber Industries, Ltd.)

  Artificial turf was affixed to the bottom of an acrylic case having an inner size of 20 cm × 20 cm and a height of 120 mm with double-sided tape. As the lower packing layer, 1000 g of a hard filler and 240 g of an elastic filler were thoroughly stirred and filled so as to be 30 mm thick and flat. On this, the obtained colored rubber chip was carefully filled to a thickness of 10 mm. In addition, the height of the acrylic container was increased in order to minimize variations due to the influence of wind.

  The pile protruding from the filler of the artificial turf structure was left with a load of 1 kg through a plywood plate and left for 48 hours to forcibly lay the pile.

  After removing the load, the surface temperature was measured by a radiation thermometer “IR-TA” (manufactured by Chino Co., Ltd.) after noon for 4 hours under the above condition 1. The measurement positions were four points from the center of 8 to 10 cm from each corner, and the average value was obtained (however, the measurement value of the part where the artificial turf was extremely sparse was excluded). The results are shown in Table 1 and FIG.

<Comparative Example 1>
The surface temperature of the rubber chip and the surface of the artificial turf structure were measured in the same manner as in Example 1 except that no colored film was formed on the rubber chip (waste tire rubber chip “RG-814”). The results are shown in Table 1, FIG. 2 and FIG.

  In producing the artificial turf structure, the elastic filler was increased to 480 g and filled to a thickness of 40 mm.

<Example 6, Comparative Example 4>
Example 6: Artificial turf was affixed to the bottom of an iron cylindrical container having a diameter of 110 mm and a height of 140 mm with double-sided tape, and an artificial turf structure was produced in the same manner as in Example 2. The average particle size of the colored rubber chips was larger than the average particle size of the elastic filler.

  Comparative Example 4: Same as Example 1 except that 100 parts of rubber chips (waste tire rubber chip “RG-0720”), 10 parts of urethane resin, and 12 parts of pigment A used as the elastic filler for the artificial turf structure were used as raw materials. Thus, a colored rubber chip having an average colored film thickness of 23 μm was obtained. Using this colored rubber chip, an artificial turf structure was prepared in the same manner as in Example 6.

[Surface residue test of colored rubber chips]
The artificial turf structure was impacted for 30 minutes by a load drop type impact tester, and the remaining state of the colored rubber chips on the surface was visually confirmed. In addition, the impact tester is an iron disk (impact plate) having a load of 2.0 kg and Φ = 85 mm, with a rubber plate having a thickness of 3 mm and a hardness of 60 attached to the bottom surface. It is a device that makes it fall.

It is a fragmentary sectional view showing an example of the artificial turf structure of the present invention. It is a graph which shows the relationship between the surface temperature of a rubber chip, and a colored film thickness. It is a graph which shows the relationship between the surface temperature of an artificial turf structure, and a coloring film thickness.

Explanation of symbols

1 Base fabric 2 Pile 3 Lower layer filler 4 Colored rubber chip

Claims (6)

In the artificial turf structure in which the filler is filled between the piles, the uppermost layer filler is a core material made of recycled rubber chips, has an average thickness of 28 μm or more and 180 μm or less , and consists of at least a resin and a pigment ^. An artificial turf structure characterized by being a colored rubber chip having a colored film having an L ^* value of a ^* b ^* color space of 60 or more. The artificial turf structure according to claim 1, wherein the colored film is composed of at least a resin and a pigment, and the pigment amount PQ with respect to 100 parts by weight of a rubber chip is represented by the following formula (1).
PQ [parts by weight] = K (0.5 t [μm]) ^1/2 / RQ [parts by weight] (1)
t: Average thickness of the colored coating RQ: Resin amount (solid content) with respect to 100 parts by weight of rubber chip
K: Coefficient of 15-25   In the said Formula (1), RQ is 8-30 weight part, The artificial turf structure of Claim 2 characterized by the above-mentioned.   The artificial turf structure according to any one of claims 1 to 3, wherein the colored film contains a pigment containing 80% by weight or more of titanium oxide.   The artificial turf structure according to any one of claims 1 to 4, wherein an average particle diameter of the colored rubber chip is larger than an average particle diameter of an elastic filler filled immediately below the colored rubber chip.   An artificial turf stadium constructed by the artificial turf structure according to claim 1.

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