JPH11269811A - Artificial lawn - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the napping property and abrasion-resistance of an artificial lawn by implanting pile threads made of a mixed resin compound including linear polyethylene having a density within a specified range and high density polyethylene in a range of respectively specified weight %. SOLUTION: Pile threads composed of uniaxially orientated fiber made of a mixed resin compound including 5-80 wt.% of high density polyethylene to 95-20 wt.% of linear polyethylene having 0.918-0.940 g/cm<3> density are implanted to form an artificial lawn. These pile threads are tufted on a plain-woven base cloth 2 and a packing materl is applied as a solid material and then dried to obtain a plurality of artificial lawns. Since the artificial lawn has a napping property and a high abrasion-resistance, top-dressing can be efficiently charged and it can be used in a favorable condition for a long period of time even if top-dressing is not charged.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an artificial lawn developed as a means for artificially expressing the appearance and function of natural lawn over a long period of time.

[0002]

2. Description of the Related Art In recent years, artificial grass has been widely used in practice fields and stadiums such as tennis courts, golf, gate balls, baseball, and soccer. The artificial grass is shown in Fig. 1 (a)
(3) tufting a pile yarn on a base fabric 2 such as a woven or non-woven fabric made of polypropylene or polyester as shown in (c);
A pile yarn is formed so as to give a lawn-like appearance, and there is also an artificial lawn according to the present invention in which sand 3 is scattered on the surface and used. For conventional pile yarns, a uniaxially stretched tape made of a material obtained by adding a weather-resistant pigment or light stabilizer to polyvinylidene chloride, polypropylene, polyamide, high-density polyethylene, etc., is spread into a desired shape and twisted. Yarns or yarns obtained by twisting a plurality of monofilaments of the same material and having an irregular cross section are used. Putting sand into the artificial turf using polypropylene pile yarns in particular (working to lay sand uniformly on the surface of the artificial turf)
Excellent workability and long-term fading and weather resistance,
In addition, it has been widely used due to its cost advantage.

[0003]

However, the artificial turf using the pile yarn made of polypropylene has the drawback that the tip of the pile yarn has a strong tendency to fibrillate and wear due to the accumulation of stress accompanying use.
Further tests were performed on artificial grass using a high-density polyethylene pile yarn with further improvements.Although the abrasion resistance was superior to that of the artificial grass using the polypropylene pile yarn, the pile yarn resilience was improved. In particular, when a sand spreader is used in sanding work, pile piles fall down, which makes it difficult to evenly distribute a desired sand weight.

The present invention has been made in view of the above circumstances, and provides an artificial turf having excellent pile yarn independence and abrasion resistance over a long period of time, and also having excellent sanding workability. Aim.

[0005]

The artificial turf according to the present invention made to solve the above-mentioned problems has a density of 0.918.
The pile yarn was constructed and implanted from a uniaxially drawn strip of a mixed composition containing 95 to 20 weight percent of linear polyethylene of .about.0.940 grams per cubic centimeter and 95 to 20 weight percent of high density polyethylene. Features.

As described above, linear polyethylene and high-density polyethylene are selected as raw materials for the mixed resin composition which is the material of the uniaxially stretched strip constituting the pile yarn, and the density of the linear polyethylene and the mixing ratio of the two materials are set to appropriate values. By doing so, the abrasion resistance and uprightness of the pile yarn in the artificial grass are improved.

The linear polyethylene which can achieve the above object includes a copolymer of ethylene and one or more comonomers comprising C4 to C10 α-olefins, for example, butene-1, octene, hexene and the like. A mixture of the copolymers having a density (JIS K7112) of 0.1.
918-0.940 grams / cubic centimeter. Among them, those having 0.920 g / cubic centimeter or more are desirable in bending recovery property, tensile strength and abrasion resistance. In particular, when it is 0.930 g / cubic centimeter or more, better results can be expected in the above-mentioned properties. . On the other hand, when linear polyethylene having a density of less than 0.918 g / cm 3 is used, the workability and abrasion resistance of sand pits are inferior, and the density is 0.940.
Using linear polyethylene in excess of grams / cubic centimeter results in poor abrasion resistance.

[0008] Also, a linear polyethylene melt flow rate (JIS K) suitable for obtaining artificial turf having high commercial value.
7210) is 0.3 to 10.0 g / 1 according to a rule of thumb.
0 minutes, preferably 0.5-5.0 grams / 10 minutes. That is, the melt flow rate is 0.3
In the case of an example lower than gram / 10 minutes, the surface of the artificial yarn for artificial turf constituting the pile yarn is liable to have irregularities and the appearance is easily impaired, and the melt flow rate is 10.0 g / 10 minutes.
In the case where the time exceeds minutes, sufficient strength is not obtained as a material for the raw yarn for artificial turf and the wear resistance is inferior.

On the other hand, the high-density polyethylene blended with the linear polyethylene is preferably a homopolymer of high-density polyethylene or a copolymer with propylene, butene, or the like, but this impairs the physical properties of the raw yarn for artificial grass. A mixture of these may be used to the extent that they are not present. Melt flow rate for high density polyethylene (JIS K721
For 0), an appropriate range is 0.3 to 20.0 g / 10 min, and preferably 0.5 to 15.0 g / 10 min. Even in the case of this high-density polyethylene, when the melt flow rate is lower than 0.3 g / 10 minutes, the appearance as a raw yarn for artificial turf is easily impaired as described above, and the melt flow rate is 20.0 g / 10 min. In the case where the time exceeds minutes, sufficient abrasion resistance is not obtained.

It is considered that the mixing ratio of both necessary to achieve the above object is 5 to 80% by weight of high-density polyethylene to 95 to 20% by weight of linear polyethylene, and 90 to 30% by weight of linear polyethylene. If the high-density polyethylene is 10 to 70% by weight, a certain effect can be obtained. When the high-density polyethylene is lower than 5% by weight, the flexibility of the material is excessively increased, and it is difficult to split the uniaxially stretched tape. On the other hand, if it exceeds 80% by weight, a pile yarn having excellent abrasion resistance cannot be obtained.

The mixed resin composition of the linear polyethylene and the high-density polyethylene may have a heat stabilizer of 0.05 to 0.3 parts by weight, a light stabilizer of 0.1 to 1.0 parts by weight, if necessary. 0.1 to 2.0 parts by weight of lubricant, 0.1 to antistatic agent
2.0 parts by weight, 0.1 to 1.0 part by weight of antibacterial agent, pigment 0.1.
5 to 5.0 parts by weight, 3 to 15 parts by weight of a flame retardant, 0.5 to 5.0 parts by weight of an inorganic filler and a dispersant thereof are added and melt-kneaded.

[0012] The uniaxially stretched strip as a raw yarn for artificial grass according to the present invention is manufactured through the following steps. The first method is
The mixed resin composition of the linear polyethylene and the high-density polyethylene is melt-extruded in the range of 200 to 250 degrees Celsius, and solidified by cooling to form a film having a thickness of 50 to 300 micrometers. Cut into a tape shape of about 70 to 70 mm) in a take-off direction at 90 to 150 degrees Celsius by a known method using an oven, a roll, a hot plate or the like.
The film is stretched 0 to 9.0 times, and for example, 10 degrees Celsius using an oven.
A heat treatment for relaxation of 3 to 15 percent at 0 to 160 degrees is performed. After these steps, denier: 100-
15000 grams / 9000 meters, thread width: 0.3-
A flat artificial grass lawn yarn having a thickness of 40 mm and a yarn thickness of 30 to 150 micrometers is obtained.

In a second method, the mixed resin composition of the linear polyethylene and the high-density polyethylene is melt-extruded and solidified by cooling to form a monofilament having a denier of 100 to 15000 g / 9000 meters. The monofilament is stretched 3.0 to 10.0 times in the take-off direction at 90 to 150 degrees Celsius, and subjected to a 3 to 15 percent relaxation heat treatment at 90 to 150 degrees Celsius using, for example, a hot water bath or an oven. After these steps, denier: 10
0-15000 grams / 9000 meters, thread diameter:
A 0.1 to 0.5 millimeter artificial grass yarn is obtained.
The cross-sectional shape of the monofilament is such that the ratio of the major axis to the minor axis is 5
An elliptical shape having a ratio of 0: 1 to 2: 1, a hollow cross-sectional shape, a continuous yarn shape, or a different shape may be used.

The pile yarn used for the artificial turf of the present invention may be a thin tape uniaxially stretched by the first method or a second yarn.
Of monofilaments obtained by the above method, and a plurality of monofilaments, a monoaxially stretched tape split and twisted, or a further processed bulk.

The artificial turf according to the present invention is formed by tufting the pile yarn for artificial turf on a woven base cloth called a primary base cloth with a 4/16 stitch using a tufting machine such as a 5/16 gauge. The woven fabric uses a uniaxially stretched tape of 250 to 1500 denier for the warp and 500 to 1500 denier for the weft,
The number of shots is 13 to 24 lengths / inch width, 10 to 2 widths
Weaving is performed using, for example, a Sulzer-type loom so that the width becomes 0 / inch width. Plain weave, twill weave, or the like is used as the weave structure.

Subsequently, a styrene-butadiene rubber latex containing an inorganic filler such as calcium carbonate is applied from the back of the base fabric (coating amount: 200 to 800 g / g).
Square meters (solid content)), and after a drying treatment at 100 to 140 degrees Celsius in a hot air circulation type oven or the like, the tufted pile yarn adheres to the base fabric and becomes a product.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an example of an artificial lawn according to the present invention will be described in detail with reference to the drawings. As the base material of the artificial grass fiber used in this embodiment, the linear polyethylene (melt flow rate: 1.0 g / 10 min) and the high density polyethylene (melt flow rate: 0.6 g / 10 min) were used. Mixed resin composition, mixed resin composition of linear polyethylene (melt flow rate: 1.0 g / 10 min) and polypropylene (melt flow rate: 2.3 g / 10 min), high density polyethylene (melt flow rate:
0.6 g / 10 min), and a uniaxially stretched tape was formed through the following steps.

Each substrate is melted at 220 degrees Celsius,
It is extruded into a film with a 65 mm φ extruder and an inflation die, and cooled and solidified while being taken off at a speed of 12 m / min to form a film. continue,
The film was cut into a tape, stretched 6 times in the take-off direction at 115 degrees Celsius in the take-off direction (hot plate stretching method), and subjected to relaxation heat treatment at 125 degrees Celsius and a relaxation rate of 8 percent in a hot air circulation type oven, 12 mm wide and 8 thick
A 0 micrometer uniaxially stretched tape is obtained.

In the pile yarn 1 used in the present embodiment, the uniaxially stretched tape is processed by a needle blade roll to form a split yarn of about 8000 deniers forming a continuous network structure. One that had been subjected to a metric twisting process was used.

The pile yarn 1 is laid with a uniaxially stretched polypropylene tape at a length of 20 threads / inch and a width of 13 threads / inch by using, for example, a 5/16 gauge tufting machine. The cloth 2 is tufted with 4 to 8 stitches so as to have a pile height of 20 mm, and the backing material 4 is applied as a solid component to a thickness of 700 g / m 2, and dried through a drying process at 110 degrees Celsius. Prototype of artificial grass.

With respect to the artificial turf obtained as described above, the abrasion mass of the uniaxially stretched tape as the pile yarn by the Taber abrasion method, and the pile by our own abrasion resistance test method (hereinafter referred to as sand-containing abrasion method). The abrasion mass of the yarn, the measurement results of the bending recovery of various uniaxially stretched tapes, and the results of the visual evaluation of sandability were measured by changing the composition of the base material constituting the uniaxially stretched strip, and the measurement results were shown in Tables 1 to 4. It is shown in FIG.

[0022]

[Table 1]

[0023]

[Table 2]

[0024]

[Table 3]

[0025]

[Table 4]

Here, as shown in FIG. 3, the wear resistance by the Taber abrasion method is such that a test piece 5 of artificial grass having a diameter of 130 mm is fixed on the upper surface of a disk-shaped turntable 4 which rotates at a speed of 70 times / minute with a vertical axis. The test piece 5 is rotated freely with the horizontal axis.
The two disk-shaped wear wheels 6 provided to rub the
The circumferential surfaces of the circumferential surfaces of the test pieces 5 abut against the same portions (hereinafter, referred to as wear portions 13) with a load of 1 kg. The test is performed using a test device set so that the direction of movement of the wear portion 13 with which the peripheral surface of the abutment comes into contact. Before the test, the mass of three or more test pieces 5 of the same type was 0.001.
g, and after rotating the rotary table 4 10,000 times, the fine particles and the like of the fiber generated by the abrasion are removed from the test piece 5 by brushing or suction, and the mass of the test piece 5 after removing the fine dust is measured. Measure to the nearest 0.001 g. Then, a difference between the test pieces 5 before and after the test is determined, and an average value thereof is used as a measurement result. The wear wheel 6
The diameter is 70 ± 1 mm and the width is 13 ± 1 mm.

The sand-containing abrasion method has been devised to evaluate abrasion resistance under conditions similar to the actual state of sand-containing artificial turf, and as shown in FIG. A circular test piece 8 having a diameter of 40 cm collected from the opposite side was fixed on a rotating test table 9 rotating at a constant speed of 36 times / minute, and sand 10 was previously filled between the piles. Then, a 50 cm 2 friction material 11 made of a bottom material of tennis shoes is pressed with a constant load of 5 kg and left for 3 hours, and the difference in mass between the test pieces 8 before and after the test is determined as the mass lost by friction.
In addition, the test piece 8 was subjected to a drying treatment for 24 hours in a thermostat at 60 degrees Celsius before the mass measurement before and after the test.
The test piece 8 after the test is washed with water before the drying treatment.

As shown in FIG.
In a state where the test piece 12 of a uniaxially stretched tape was taken and double-folded from the center in the longitudinal direction, a load of 2 kg was applied to the entire surface for 10 minutes, and the load was removed. The angle θ is read in units of 5 degrees.

In the case of sand-filling properties, the artificial turf produced on a trial basis was each 4 meters wide on an asphalt pavement road surface.
It is laid over a length of 20 meters, and sand having an average particle size of 0.53 mm containing silica as a main component is uniformly spread on a surface of the artificial grass pile at a rate of 25 kg / m 2 using a sand spreader. Workability during sanding was visually evaluated.

As for the artificial lawn, the one made for the same purpose as the artificial lawn according to the present invention is disclosed in JP-A-8-333709.
No. 6,086,045. The pile yarn of the artificial turf disclosed in this document is composed of a raw yarn based on linear polyethylene and polypropylene. The most remarkable difference between Table 4 and Tables 1 to 3 is the abrasion resistance obtained by the Taber abrasion method and the sand-containing abrasion method. It is thought to be. It has been established that pile yarns made of high-density polyethylene have extremely poor restorability after lodging. However, no such tendency is observed from the data on the bending recovery of the artificial grass according to the present invention measured this time.

From these data, it can be recognized that there is a band in which the abrasion mass falls in the mixing ratio of the linear polyethylene and the high-density polyethylene. Polyethylene 9
The high-density polyethylene is 5 to 80% by weight with respect to 5 to 20% by weight. In addition, in that band, a sufficiently practical evaluation result has been obtained for the bending recovery property and the sand-filling property.

[0032]

As described above, when the artificial turf according to the present invention is used, the uprightness (shape resilience) of the pile yarn and the abrasion resistance in the artificial turf are increased, so that the sand pitting operation can be performed efficiently. In addition, even if sand filling is not performed, it can be used in a good state for a long period of time.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an example of an artificial lawn according to the present invention.

FIGS. 2A and 2B are cross-sectional views illustrating aspects of artificial grass.

FIG. 3 is a schematic view of a test apparatus using a Taber abrasion method.

FIG. 4 is a schematic view of a test apparatus using a sand-containing abrasion method.

FIG. 5 is a schematic view of a test apparatus used for measuring bending recovery.

[Explanation of symbols] 1 pile yarn 2 base cloth

Claims (1)

[Claims] (1) a density of 0.918 to 0.940 gram /
A pile yarn (1) is formed and planted from a uniaxially drawn strip composed of a mixed resin composition containing 5-80% by weight of high-density polyethylene with respect to 95-20% by weight of linear polyethylene having a cubic centimeter. And artificial grass.