JPH07329210A - Artificial lawn - Google Patents

Abstract

PURPOSE:To provide the artificial lawn which has been made light in weight and imparted with cushioning properties and the artificial lawn which does not cause any problems in view of the manufacturing process of the artificial lawn or after making the artificial lawn into a product and is capable of adopting a simple manufacturing process. CONSTITUTION:The artificial lawn is constituted of a substrate part 1 and leaflike part 2 by taking thermoplastic resin as a material, a plurality of beltlike substrate parts 1, 1... are juxtaposed by arranging a longitudinal direction of them at specific intervals, a plurality of the leaflike parts 2, 2... are arranged at the specific intervals in a longitudinal direction of the substrate part 1 between the substrates 1, 1 adjoining to each other, a part of the leaflike part 2 is unified with the substrates 1 adjoining to each other and the substrate parts 1, 1... are formed of foams having flexibility and elasticity.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an artificial turf which is composed of a base portion and leaf portions and which is integrally formed of a thermoplastic resin.

[0002]

2. Description of the Related Art Conventionally, a plurality of strip-shaped base portions are arranged side by side in a longitudinal direction at a predetermined interval as an artificial turf having a thermoplastic resin as a main material, and a plurality of strip-shaped base portions are provided between adjacent base portions. There is known a structure in which leaf-shaped portions of a three-dimensional structure are arranged in a so-called matrix shape at predetermined intervals in the longitudinal direction of the base portion (see Japanese Patent Publication No. 51-46777). And this kind of artificial grass is used for gardens such as general houses, hotels, villas, rugs on balconies, etc., and recently, tennis, golf, baseball, gateball, slopes for artificial ski resorts,
Alternatively, it is often laid in other wide-area stadiums and practice areas.

Artificial grass made of such thermoplastic resin is
Even though the leaf-like part has elasticity, the elasticity of the base part is poor, so there is a so-called "bottom feeling" that feels like the bottom is harder than natural turf as a walking feeling on artificial turf, which is uncomfortable. There was a problem to remember. Also, when this artificial turf is constructed in various sports facilities, the amount of exercise of the athlete on the turf is large, so the lack of cushioning properties as described above,
There was an important problem not only as a feeling of discomfort, but also as an influence on the content of competition and safety. On the other hand, when the construction area is large, such as in sports facilities, long artificial grass is handled during construction, and the need for weight reduction has also been emphasized.

Therefore, as a conventional solution to this problem, for example, as described in Japanese Utility Model Laid-Open No. 4-108739, there is adopted a method of providing cushioning property by lining a foam under the artificial grass. Came.

[0005]

However, when a hot-melt adhesive is used as a laminating means for backing the foam, peeling of the foam due to poor adhesion, corrugation, large wrinkles, etc. may occur. It is difficult to obtain a neatly laminated product, and if a solvent-based adhesive is used,
The solvent contained inevitably causes problems in hygiene and fire prevention during the manufacturing process, and in addition, the solvent remaining in the product sometimes causes a bad odor. Furthermore, the laminating method using an adhesive not only has various problems after the manufacturing process and commercialization, but even if a good quality product is obtained,
There is also a problem that a secondary processing step called a laminating step has to be performed, resulting in an increase in cost.

The present invention provides a lightweight artificial turf with cushioning properties, and at the same time, does not cause any problems in the manufacturing process of the artificial turf or after commercialization, and is simple. It is an object of the present invention to provide an artificial turf which can adopt a simplified manufacturing process.

[0007]

According to the present invention, "a plurality of strip-shaped base portions are arranged side by side in a longitudinal direction at predetermined intervals, and a plurality of leaf-shaped portions are provided between adjacent base portions. In the artificial turf which is arranged at a predetermined interval in the longitudinal direction of the part, and a part of the leaf-shaped part is integrally formed with the adjacent base parts, the base part is made of a flexible elastic body. The above-mentioned object is achieved by this.

The artificial grass of the present invention will be described below in detail with reference to the drawings. 1A and 1B are drawings showing an embodiment of an artificial turf of the present invention, in which FIG. 1A is a perspective view thereof, and FIG. 1B is a sectional view showing a part of it in an enlarged manner.

In FIG. 1, reference numerals 1, 1 ... Denote a strip-shaped base body made of a thermoplastic resin foam, and a large number of the base bodies are arranged side by side with their longitudinal directions aligned at regular intervals. There is. 2, 2 ... are leaf-shaped parts, which are also made of thermoplastic resin, are arranged between the adjacent base parts 1 and 1, and a large number are arranged at regular intervals in the longitudinal direction of the base part 1. Has been done. Incidentally, the number of turf leaves in the leaf-shaped portion 2 is shown to be only four in order to avoid complication, but in the case of the present embodiment, it is actually eight.
It is a book. Further, the root 3 of the leaf-shaped portion 2 is integrally formed with the adjacent base portions 1 and 1.

To manufacture the above-mentioned artificial turf of the present invention, for example, as described in Japanese Patent Publication No. 51-46777 or JP-A-6-26005, which is a prior invention of the present applicant. The device can be used. Just in case,
Main parts of the device are shown in FIGS. FIG. 2 is a sectional view of only an essential part showing an example of the manufacturing apparatus, and FIG.
FIG. 4 is a sectional view taken along line A-A, and FIG. 4 is a sectional view taken along line B-B in FIG.

As shown in FIG. 2, the basic structure of the main part of the apparatus comprises a molding drum 10 and an extrusion head 20,
By supplying a thermoplastic resin from the extrusion head 20 onto the outer peripheral surface of the molding drum 10, the lawn body AL is successively molded in the rotation direction of the molding drum 10. Other details will be described in the examples.

The thermoplastic resin used for the base portion and leaf portions of the artificial grass of the present invention includes low density polyethylene, medium density polyethylene, high density polyethylene, linear low density polyethylene, polypropylene, ethylene-propylene copolymer. , Ethylene-propylene-diene copolymer, ethylene-vinyl acetate copolymer, polyvinyl chloride, polystyrene and the like. These resins may be used alone or in combination of two or more kinds. The base portion molding resin and the leaf portion molding resin preferably use the same type of resin, but may be a combination of different types of resins as long as they are compatible with each other.

The MI of the resin is preferably in the range of 0.1 to 20, more preferably 0.3 to 15. MI
When the value is less than 0.1, an attempt to obtain an extrusion amount required for artificial grass molding may result in an excessive load on the extruder, resulting in a difficult extrusion state. On the other hand, when the MI exceeds 20, the viscosity of the resin for molding the base portion at the time of foaming becomes too low to cause severe cell breakage, and a foam having a desired magnification cannot be stably obtained. MI is JIS-K-6760.
Refers to the value measured in accordance with the provisions of.

The foaming agent used when molding the base portion is not particularly limited as long as it does not deteriorate the above resin, and examples thereof include azodicarbonamide, azobisisobutyronitrile, dinitrosopentamethylenetetramine and sodium bicarbonate. One or more types of thermal decomposition type foaming agents can be used. Further, as the physical type foaming agent, aliphatic hydrocarbon compounds such as propane, butane, pentane and hexane, aromatic hydrocarbon compounds such as toluene, xylene and ethylbenzene, monochlorodifluoromethane, monochlorodifluoroethane, 1,1-dichloro Halogenation such as -1-fluoroethane, 2,2-dichloro-1,1,1-trifluoroethane, 1,1,1,2-tetrafluoroethane, difluoroethane, methyl chloride, methylene chloride, dichloromethane, chlorobenzene Examples include hydrocarbon compounds, alcohols such as methanol and ethanol, ethers, esters, and the like, and organic gases and volatile liquids. Further, an inorganic gas foaming agent such as carbon dioxide, nitrogen, air, oxygen, neon or argon can be used. These may be used alone or as a mixture of two or more. Further, the thermal decomposition type and physical type foaming agents may be used in combination.

In the present invention, a cell nucleating agent may be added to the resin in order to make the cells of the foam as fine as possible. For example, talc, zinc white, calcium carbonate, sodium bicarbonate, carbon black, glass beads, clay, magnesium oxide, zinc oxide, silicon dioxide, titanium oxide and the like can be used. Also, since it is artificial grass, a green pigment is usually added, but in addition, if necessary, a filler, a light stabilizer, an antioxidant, a pigment (other than green), a flame retardant, an external lubricant, etc. are added. can do.
A foaming aid may be added when the thermal decomposition type foaming agent is used.

In the production of the artificial turf of the present invention, when a thermal decomposition type foaming agent is used as a foaming agent, an ordinary extruder is used, and a physical type foaming agent (organic gas, volatile liquid, inorganic gas, water, etc.) is used. If a) is used, a vented extruder is used.

All of these foaming methods and apparatuses are known. Specifically, first, a thermoplastic resin is put into a hopper of an extruder, and the resin in a molten state is filled with a foaming agent provided in the extruder. An organic solvent type or inorganic gas type foaming agent is press-fitted through the press-fitting hole. Here, the injection pressure of each foaming agent is such that the pressure of the injection section attached to the extruder is in the range of ⁵ to 100 kg / cm ² . Within this range, a good foam can be obtained without scattering of resin from the nozzle for molding the base body during foaming. Examples of the method of injecting the foaming agent include a method of directly injecting with a gas or in a state of being pressurized / depressurized to a predetermined pressure, a method of injecting a liquid foaming agent with a plunger pump or the like.

Next, the resin having the foaming agent dissolved therein is discharged into a low pressure region through a substrate forming nozzle provided in an extrusion head maintained at a temperature suitable for foaming, whereby a substrate portion made of a foam is formed. obtain. Further, when a foam is produced using a pyrolytic foaming agent, the thermoplastic resin and the pyrolytic foaming agent are put into the hopper of the extruder, melted and kneaded in the extruder, and foamed at the decomposition temperature of the foaming agent or higher. After the agent is decomposed, it is similarly discharged into a low pressure region to obtain a base portion made of a foam.

When the above foaming method is adopted, the barrel temperature of the extruder is preferably in the range of + 110 ° C. from the melting point of the thermoplastic resin, and the extrusion head temperature is from −5 ° C. to + 90 ° C. of the melting point of the thermoplastic resin. It is preferably in the range. The extrusion rate from the nozzle is preferably in the range of 1 to 100 kg / h. Incidentally, for the purpose of improving the strength against external force, it is optional to adhere or heat press-bond a material such as an open mesh metal screen or a glass fiber non-woven fabric to the back surface of the base body portion. .

Further, when foaming the base portion, a pyrolytic foaming agent and a crosslinking agent typified by dicumyl peroxide are added to the thermoplastic resin and kneaded, and extruded at a temperature below the decomposition temperature of the foaming agent and the crosslinking agent. Then, after molding the artificial grass-like body, only the base portion is reheated to a decomposition temperature or higher to obtain an artificial grass having a foamed base portion. In this case, it is preferable to cool the leaf portion with cooling air when the base portion is heated to the decomposition temperature or higher.

The expansion ratio of the base portion is preferably in the range of 1.5 to 20 times. In particular, it is more preferably in the range of 1.8 to 15 times. If the expansion ratio exceeds 20 times, sufficient strength of the base portion cannot be obtained. Therefore, repeated walking causes the base portion to be cut, or uneven foaming to occur, resulting in waviness of the base portion. If the expansion ratio is less than 1.5 times, the desired cushioning property cannot be obtained.

[0022]

In the artificial turf of the present invention, a plurality of strip-shaped base portions are arranged side by side in the longitudinal direction at predetermined intervals, and a plurality of leaf-shaped portions are provided in the longitudinal direction of the base portion between adjacent base portions. Is an artificial turf which is arranged at a predetermined interval and in which a part of the leaf-shaped portion is integrally formed with an adjacent base portion, wherein the base portion is formed of a flexible elastic body. Therefore, it is an artificial turf that is lightweight and has cushioning properties as a whole.

Further, the foamed body molded separately on the lawn body is not laminated with an adhesive or the like, but the base body itself integrally molded at the manufacturing stage is a foamed body, so that the conventional laminated type Compared with the artificial turf, the foam does not peel off due to long-term use, has excellent durability, and a simplified manufacturing process can be adopted.

[0024]

EXAMPLES Examples of the present invention will be described in detail below.

The artificial grass of the present invention shown in FIG.
It was manufactured using the apparatus shown in. The apparatus will be described. On the outer peripheral surface 10a of the forming drum 10, a large number of base portion forming grooves 11, 11 ... (See FIG. 3) are arranged along the circumferential direction in the width direction (in FIG. 2, relative to the paper surface). And the base portion forming grooves 11 are formed at equal intervals, and leaf-shaped portion forming cavities 12, 12, ... A large number are provided at intervals, and are arranged so as to have a matrix shape as a whole.

Then, each leaf-shaped portion forming cavity 12 is formed.
Is the through hole 12a and the insertion member 12 fitted therein.
With b, the molding surface of the leaf-shaped portion 2 including the root is formed. Further, the partitioning convex portion 1 is provided between the cavities 12.
3 is provided. Then, when the outer peripheral surface 10a of the molding drum 10 is closed by the front surface 20a of the extrusion head 20, a leaf-shaped portion molding space is formed.

Further, on the front surface 20a side of the extrusion head 20, partition members 24, 24, ... which are fitted into the respective base portion forming grooves 11 of the forming drum 10, the base portion forming nozzle 21, and the leaf portion forming portion. And a nozzle 22 for use. The shape of the partition member 24 is also shown in FIG.
The tip of the base portion forming nozzle 21 into the base portion forming groove 11 is arranged at a position corresponding to the partition member 24,
Further, the tip of the leaf-shaped portion forming nozzle 22 to the leaf-shaped portion forming cavity 12 is arranged between the partition members 24, 24.

When the device having the above structure is operated,
First, the leaf-shaped portion molding resin 22 is extruded into the respective cavities 12 arranged in the width direction of the molding drum 10 from the leaf-shaped portion molding nozzles 22 also arranged in the width direction of the extrusion head 20. When finished, molding drum 1
According to the rotation of 0, it is similarly extruded into each of the cavities 12 in the next row, and is sequentially extruded thereafter.

The cavities 12 in each row in which the resin is injected in this manner are sequentially fed at a constant pitch in the rotational direction according to the rotation of the molding drum 10, and then to the respective base portion forming grooves 11, 11 of the molding drum 10 in the width direction. The base part molding resin is extruded from the base part molding nozzles 21 arranged in a line,
As the molding drum 10 rotates, the base portion is successively and continuously molded. At this time, the leaf-shaped resin already injected in the previous step between the resin-injected base portions is fused and joined to the base resin to be integrated. By continuing these molding processes, it is possible to obtain a long artificial turf AL having the structure shown in FIG.

In the artificial turf of the present invention, since the base portion 1 which constitutes the turf body is a foam and the leaf-shaped portion 2 is a non-foam, each of the nozzles 21 and 22 is used by using a dedicated extruder. The molten resin is supplied onto the molding drum 10. Here, as in the above-described embodiment, the base portion 1 may be formed after forming the leaf portion 2, or the leaf portion 2 may be formed after forming the base portion 1. Further, the resin may be foamed in the extruder for molding the base portion, or the base portion 1 may be foamed after the base portion 1 and the leaf-shaped portion 2 are integrally molded to obtain an artificial grass-like body.

[Example 1] Low-density polyethylene resin (M
(I = 8, density = 0.920 g / cm ² , melting point 120 ° C.)
A blended resin obtained by dry blending 100 parts by weight of a green colorant with 5 parts by weight was used as a raw material and continuously molded using a device shown in FIGS. That is, the compounded resin was supplied to the hopper of the leaf-shaped portion forming extruder, melted and kneaded, and then extruded into the leaf-shaped portion forming cavity 12 on the forming drum 10. In addition, a blended resin prepared by dry blending 100 parts by weight of the low-density polyethylene resin described above with 5 parts by weight of a green colorant and 2 parts by weight of azodicarbonamide (decomposition temperature of 200 ° C.) as a thermal decomposition type foaming agent is used as a raw material, and a substrate After being melted and kneaded after being supplied to the hopper of the extruder for molding a leaf portion, it is continuously extruded into the base portion molding groove 11 of the line in which the injection of the resin for molding a leaf portion is completed, and the leaf portions 2, 2, ... The base parts 1, 1 ... Made of foam were fused and integrated at the root 3 of the leaf-shaped part 2 to obtain a long artificial grass AL. However, the barrel temperature of the extruder for molding the base portion is set to 205 ° C., and the extrusion head 20
The temperature was 180 ° C.

The overall shape of the obtained artificial turf AL is an elongated body having a width of 100 cm, and the thickness of the base portion 1 is 3 m.
m, width = 4 mm, and the leaf-shaped portions 2 of the three-dimensional structure stand upright on the base portion 1 in a matrix with a pitch width of 10 mm. Further, the leaf-shaped portion 2 has a length of turf =
25 mm, root thickness (height) = 1 mm, turf tip thickness = 0.3 mm, and 8 tufts are formed adjacent to each other on the root 3 that draws a circle with a diameter of 7 mm. It has become a thing.

Example 2 In Example 1, 3 parts of sodium bicarbonate (decomposition temperature of 100 ° C.) was used as a thermal decomposition type foaming agent.
Example 1 except that parts by weight were blended, the barrel temperature was 130 ° C, and the temperature of the extrusion head 20 was 150 ° C.
An artificial turf AL was obtained in the same manner as.

Example 3 In Example 1, 100 parts by weight of a low-density polyethylene resin (MI8, density: 0.920 g / cm ³ , melting point: 120 ° C.) was added as a base part molding resin, and 5 parts by weight of a green colorant, A blended resin obtained by dry blending 5 parts by weight of a thermal decomposition type foaming agent azodicambonamide (decomposition temperature of 200 ° C.) and 0.6 part by weight of dicumyl peroxide (1 minute half-life temperature of 171 ° C.) as a raw material, An artificial grass-like body was obtained in the same manner as in Example 1 except that the barrel temperature of the extruder for molding the base portion was 130 ° C and the temperature of the extrusion head was 140 ° C.

Subsequently, the obtained artificial turf-like body was fed with its base portion facing down onto an endless belt made of Teflon heated to 210 ° C. to foam the base portion for 5 minutes. An artificial turf AL having the following base part was obtained. In addition, in the zone in which the lawn was supplied on the endless belt, cold air was blown to the leaf-shaped portion.

[Example 4] A vent type extruder was used as a base part molding extruder, and carbon dioxide gas was supplied from an injection port provided in the vent part of the extruder instead of the thermal decomposition type foaming agent.
An artificial turf AL was obtained in the same manner as in Example 1 except that pressure was applied at a pressure of ² kg / cm ² and the temperature of the base portion forming nozzle was 140 ° C.

[Comparative Example 1] An artificial turf was obtained in the same manner as in Example 2 except that the thermal decomposition type foaming agent was not added.

Comparative Example 2 The base portion of the artificial turf obtained in Comparative Example 1 was heated to 150 ° C. In addition, a polyethylene foam sheet with a thickness of 3 mm and an expansion ratio of 5.2 is 5 kg / cm.
Under the pressure of ² , heat and pressure were applied for 30 seconds to perform heat fusion lamination to obtain artificial turf.

With respect to the artificial turf samples obtained in the above Examples and Comparative Examples, a peelability test was conducted to evaluate the adhesive strength. The results are shown in Table 1.

The measurement / evaluation methods are as follows. Peelability between leaf-shaped part and base part; 30 × 30 of the obtained artificial grass
It was cut into cm and judged by the presence or absence of peeling after a person weighing 62 kg stepped 100,000 times. Foaming ratio of the base portion 1; the obtained artificial turf is cut into 3 × 4 mm, and an electronic hydrometer (ED-120T, manufactured by Mirage Co.)
Was used to measure the specific gravity, and the value was obtained by dividing the average density of the raw material by that value.

[0041]

[Table 1]

[0042]

EFFECT OF THE INVENTION The artificial turf of the present invention is a lightweight artificial turf because the base portion is made of a flexible foam. Therefore, not only is the walking feeling improved and so-called discomfort is eliminated,
When playing a competition on artificial grass, it is possible to absorb the impact on the body during exercise, and it is possible to achieve results that are equal to or better than those on natural grass. In addition, construction efficiency can be improved by reducing the weight, and construction cost can be reduced.

Further, since the base body itself is made of foam, the amount of resin required for molding can be small, and since a molding method called integral molding can be adopted, the molding process is simplified and the manufacturing cost is reduced. In addition to being able to reduce the number, it is not a foam molded separately on the grass as a laminate with an adhesive or the like, but the base body itself that is integrally molded at the manufacturing stage is a foam, so conventional lamination Compared with artificial turf of the type, it does not peel off the foam due to long-term use, has excellent durability, has no bad odor of the adhesive, and has excellent quality.

The artificial turf obtained by the present invention is extremely useful as a rug for outdoor and indoor rugs of various houses and as an alternative to natural turf of various facilities in a wide area.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of an artificial turf of the present invention,
The figure (a) is the perspective view, and the figure (b) is an enlarged sectional view showing a part thereof.

FIG. 2 is a partially cutaway sectional view showing only an essential part showing an example of the artificial turf manufacturing apparatus of the present invention shown in FIG.

FIG. 3 is a view taken along line AA of the above.

FIG. 4 is a view taken along the line B-B in the same as above.

FIG. 5 is a partially cutaway perspective view showing a partition member on the extrusion head of the above.

[Explanation of symbols]

 1 base part 2 leaf-shaped part

Claims (1)

[Claims] 1. A plurality of strip-shaped base portions are arranged side by side in a longitudinal direction at a predetermined interval, and a plurality of leaf-shaped portions are provided at predetermined intervals in the longitudinal direction of the base portion between adjacent base portions. An artificial turf that is disposed and a part of the leaf-shaped portion is integrally formed with an adjacent base portion, wherein the base portion is made of a flexible elastic foam.