JPH09220781A - Artificial turf - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide artificial turf excellent in sanding workability and abrasion resistance and high in shape retention. SOLUTION: Artificial turf is formed by using pile yarns 1 obtained from uniaxlally stretched stripes composed of a resin compsn. prepared by compounding 5-110 pts.wt. of a polyamide component B and 0.5-20 pts.wt. of a component C composed of low mol.wt. polyolefin with a number average mol.wt. of 800-20,000 at least partially modified with an acid at its terminal with 100 pts.wt. of an ethylenic polymer component A.

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 a natural lawn.

[0002]

2. Description of the Related Art In recent years, tennis, golf, gate balls,
Artificial grass is widely used in practice fields and stadiums for baseball and soccer. Artificial lawn is, for example, as shown in Fig. 1, tufted with pile yarns on a woven or non-woven fabric made of polypropylene or polyester to form a pile so as to give a grass-like appearance. There is also something to sprinkle and use. For conventional pile yarn,
A yarn obtained by splitting and twisting a uniaxially stretched tape made of polyvinylidene chloride, polyamide, polypropylene, high-density polyethylene, etc., to which a pigment or a light stabilizer with good weather resistance is added in a desired shape, or the same material. A yarn obtained by twisting a plurality of monofilaments having a modified cross section is used. In particular, artificial grass using polypropylene pile yarn is excellent in workability of sanding (working to spread the sand evenly on the surface of artificial grass), fading and weather resistance due to long-term use, and cost. It has been widely used due to its superiority.

[0003]

However, in the artificial lawn using polypropylene pile yarn, there is a drawback that the tip of the pile yarn becomes fibrillated due to the accumulation of stress during use, and the pile yarn is apt to be worn away. In the artificial lawn provided with the pile yarn made of high-density polyethylene, which has been further improved, it is superior to the artificial lawn using the polypropylene pile yarn in terms of abrasion resistance, but it is a sand spreader for sanding. However, it was difficult to spread a desired amount of sand evenly when the pile yarn fell down.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an artificial lawn which is excellent in workability for sanding and abrasion resistance and has high shape retention.

[0005]

The artificial turf according to the present invention, which has been made to solve the above-mentioned problems, comprises 100 parts by weight of a component A composed of an ethylene polymer and 5 to 110 parts of a component B composed of a polyamide. Component C: 0.5 to 20 parts by weight based on parts by weight and a low molecular weight polyolefin having a number average molecular weight of 800 to 20000 (hereinafter referred to as an acid modified low molecular weight PO) at least a part of which is acid modified at the end. It is characterized in that the pile yarn is formed by a uniaxially drawn thread made of a resin composition containing parts.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of an artificial lawn according to the present invention will be described in detail below. This artificial lawn comprises a component A made of an ethylene polymer, a component B made of a polyamide, and an acid-modified low molecular weight PO having a predetermined number average molecular weight.
A uniaxially stretched strip made of a resin composition containing a component C whose main component is is planted as a pile yarn 1 in a base fabric 2.

Examples of the ethylene polymer as the component A include high density polyethylene and linear polyethylene.

Among them, the high-density polyethylene is
Examples thereof include a homopolymer of ethylene, a copolymer of ethylene with an α-olefin such as propylene or butene-1, and a mixture thereof. The density of the high-density polyethylene used (JIS K7112) is 0.942 to 0.9.
About 60 g / cm ³ is suitable. That is, the density is 0.9
If it is less than 42 g / cm ^3, it becomes difficult to obtain a raw yarn for artificial grass with excellent abrasion resistance, and 0.960 g / cm ³
If it exceeds, it becomes difficult to obtain a raw yarn for artificial grass with good workability for sanding. The high-density polyethylene has a melt flow rate (JIS K7210) of 0.3 to 2.
Around 0 g / 10 minutes is suitable, and when it is lower than 0.3 g / 10 minutes, the surface roughness of the raw yarn for artificial grass becomes remarkable, and when it exceeds 2.0 g / 10 minutes, it is difficult to obtain sufficient strength. Become.

On the other hand, as linear polyethylene, for example, butene-1, octene, hexene and the like C4 to C10α-
Included are copolymers of ethylene with one or more comonomers of olefins, and mixtures thereof. The density of the linear polyethylene used is 0.918-0.
About 940 g / cm ³ is suitable. That is, the density is 0.
If it is less than 918 g / cm ^3, it becomes difficult to obtain a raw yarn for artificial grass excellent in abrasion resistance, and 0.941 g / cm 3
^When it exceeds ³ , it becomes difficult to obtain a raw yarn for artificial grass with good workability in a sand container. A suitable melt flow rate of the linear polyethylene is around 0.3 to 10 g / 10 minutes, and when these are lower than 0.3 g / 10 minutes, the occurrence of surface roughness of the artificial grass raw yarn becomes remarkable, 1
This is based on the fact that it will be difficult to obtain sufficient strength if it exceeds 0 g / 10 minutes.

As the polyamide, aliphatic polyamides such as nylon 6, nylon 4.6, nylon 6.6, nylon 6.6, nylon 6/10, nylon 11 and nylon 12 are suitable for use, but they are economical and processed. It can be said that nylon 6 and nylon 6.6 are preferable in terms of excellent properties.

The acid-modified low molecular weight PO is not suitable for low molecular weight polyolefins having a terminal double bond such as low molecular weight polypropylene and low molecular weight polyethylene (preferably those having 2 to 7 terminal double bonds per 1000 carbons). At least one of a saturated carboxylic acid and its anhydride is adjusted to 0.
It is chemically added at a rate of 1 to 12% by weight (preferably 1 to 10% by weight), and has a softening point of about 90 to 170 ° C and an acid value of 10 to 60 mgKOH / g.
The front and back are suitable. That is, if the number of terminal double bonds is less than 2, the desired acid modification cannot be carried out,
Those exceeding 7 are not preferable because the heat resistance of the acid-modified low molecular weight PO decreases. Examples of the unsaturated carboxylic acid include (meth) acrylic acid, maleic acid, fumaric acid, and itaconic acid, and as its anhydride, maleic anhydride, itaconic anhydride, citraconic anhydride, acrylic succinic anhydride, and anhydrous. Nasic acid may be mentioned.

The acid modification is carried out by a melt grafting method or a solution grafting method.
It is carried out at 170 (preferably 130 to 240) ° C. and a reaction time of 0.5 to 30 hours.

The above resin composition (component A, component B, component C) is kneaded in a kneading device such as a single or twin screw extruder, a Banbury mixer, a kneader mixing roll, etc., and the mixed composition is used for artificial grass. It is used as the raw material for the yarn.
Alternatively, a so-called dry blend may be used by mixing with a blender equipped with a stirring blade before processing the uniaxially stretched strip. Incidentally, each of the resin composition, if necessary, a heat stabilizer, a light stabilizer, an ultraviolet absorber, a lubricant, an antistatic agent,
In some cases, an antibacterial agent, a flame retardant, a pigment, an inorganic filler or a dispersant therefor may be added as appropriate.

As a method for producing the pile yarn 1, for example, the above-mentioned mixed composition is melt-extruded at 240 to 280 ° C., cooled and solidified to form a film having a thickness of 50 to 300 μm, and the film is a tape of 1 to 70 mm. Cut into an oven,
Using a roll, a hot plate, etc., it is stretched 2.5 to 8.0 times in the take-up direction at about 80 to 150 ° C, and a relaxation heat treatment of 3 to 15% at 80 to 160 ° C using a hot air circulation type oven or the like. There is a method of going through the steps such as
0000 denier, thread width: 0.3-40 mm, thread thickness: 3
A raw yarn for an artificial grass having a thickness of 0 to 150 μm can be obtained.
As another method, for example, a monofilament obtained by melting and extruding the mixed composition through a nozzle having pores and cooling and solidifying is used by using a hot water tank, a hot air circulating oven, or the like.
It is stretched 2.5 to 9.0 times in the take-up direction at ˜150 ° C. and 90 to 160 by using a hot water tank or a hot air circulation type oven.
50 to 1 through the process of performing relaxation treatment of 3 to 15% under ℃
5000 denier, thread diameter: about 0.08-1.5 mm
It is also possible to obtain raw yarn for artificial grass.

The monofilament may have an elliptical cross section, a hollow section, a continuous yarn shape, or any other irregular shape. Also, multiple uniaxially stretched thin tapes or monofilaments twisted, uniaxially stretched tape split and twisted,
Further, those processed by utilizing existing technology, such as those processed by bulking, may be mentioned.

An example of a general method for manufacturing artificial grass will be described below. That is, the above-mentioned raw yarn for artificial grass is used as the primary base cloth 2
A woven base cloth or the like is tufted into 4 to 8 stitches with a tufting machine such as a 5/16 gauge, and a backing material 4 such as styrene / butadiene rubber latex containing an inorganic filler such as calcium carbonate is used as the base cloth 2. According to the present invention, the tufted pile yarn 1 is fixed to the base fabric 2 by applying from the back surface (solid content: 200 to 800 g / m ² ), and dried at 100 to 140 ° C. in a hot air circulation type oven or the like. An artificial lawn is formed. The woven base fabric 2 has 25 warp threads.
0 to 1500 denier, 500 to 1500 denier uniaxially stretched tape for weft, and the number of threads is 13 to 24
Weaving is performed using a sulzer loom to a book / inch width. Examples of the woven structure include plain weave and twill weave.

Below, some examples of stretched tapes 7 formed from a resin composition that is considered to be usable as a raw material for raw yarn for artificial grass are given, and a trial of an artificial lawn selected from the samples is shown. Illustrate the works and consider their characteristics.

Each sample of the artificial turf yarn was prepared by mixing the above-mentioned mixed composition, high-density polyethylene and polypropylene with each other.
25 using a 5 mmφ extruder and inflation die
It is melt extruded into a film at 0 ° C, cooled and solidified while taking it off at 12 m / min to form a film, and the film is cut into a tape, and is drawn by a hot air circulation type oven at 115 ° C in the taking direction 5.5 times. And then subjected to relaxation heat treatment at a relaxation rate of 8% at 125 ° C., width: 5 mm, thickness: 80 μ
m drawn tape 7. Table 1 shows the properties and mixing ratio of each sample, and Table 2 shows the measurement results of the tensile strength, tensile elongation, and wear resistance of each sample.

Those not specifically indicated in the column A of Table 1 are those having a density of 0.952 g / cm ³ and a melt flow rate of 0.6 g / 10 minutes, and 100 parts by weight of high density polyethylene and a density of 0. It is a blend of 40 parts by weight of linear polyethylene having a melt flow rate of 1.020 g / cm ³ , a melt flow rate of 1.0 g / 10 minutes, and a symbol a indicates density: 0.952 g / cm ³ , melt flow. Rate: High density polyethylene 100 at 0.6 g / 10 minutes
Parts by weight are used alone as component A. What was indicated as b was 100 parts by weight of linear polyethylene having a density of 0.935 g / cm ³ and a melt flow rate of 1.0 g / 10 minutes, which was used alone as the component A, and was indicated as c. The thing has a density: 0.952 g / c
m ³ , melt flow rate: 0.6 g / 10 minutes 100 parts by weight of high-density polyethylene and density: 0.935 g / cm
^3. Melt flow rate: 1.0 g / 10 minutes of 40 parts by weight of linear polyethylene. N6 in the column of component B indicates the use of nylon 6, and the units of softening point, acid value and blending ratio are ° C and mgKO, respectively.
H / g, parts by weight.

[0020]

[Table 1]

[0021]

[Table 2]

Here, the tensile strength and the tensile elongation are JIS
The abrasion resistance is measured by L-1070, and the abrasion resistance is measured by the test device shown in FIG. 2 until the stretched tape 7 is cut. In this experimental apparatus, sandpaper (# 100) was attached to the peripheral surface of a rotating roll 5 having an outer diameter of 120 mm, and the rotating roll 5 was rotated at 20 m / min in the direction of the arrow in the drawing to draw a stretched tape 7 that was in contact with the sandpaper. The stretched tape 7 is rubbed, and is stretched by fixing one end and suspending a weight 6 of 500 g on the other end.

On the other hand, a prototype artificial turf is a uniaxially stretched tape having a width of 12 mm and a thickness of 80 μm obtained by the same manufacturing method as that of the sample and processed by a needle blade roll to form a continuous mesh structure of about 10,000 denier. A split yarn is formed, and the split yarn is subjected to a twisting process of 50 times / m to form a pile yarn 1 for artificial grass, and the pile yarn 1 is made of 1200 denier polypropylene uniaxially stretched tape 22 lengths / inch. Using a 5/16 gauge tufting machine on a plain weave base fabric 2 that is punched at a width of 20 lines / inch width, tufting to a pile height of 20 mm with 4.8 stitches is carried out, and carbonized as a solid content. A backing material 4 made of styrene-butadiene rubber latex containing an inorganic filler such as calcium is applied so as to be 700 g / m 2, and It was dried at 0 ° C.

Table 3 shows the sanding workability and wear resistance of these prototypes. Regarding sanding workability, the sand 3 was laid on the road surface of asphalt pavement over a width of 4 m and a length of 20 m, and the sand 3 containing silica as a main component and having an average particle diameter of 0.53 mm was used with a sand spreader. Two
It is spread evenly at 5 kg / m ² and the work situation is observed with the naked eye to evaluate it in 3 grades of good, good and bad. For abrasion resistance (JIS L1021), use artificial grass before sanding. The abrasion amount (unit: mg) measured by a Taber abrasion tester was used for evaluation. In addition, "good" indicates that the spraying can be performed uniformly in a short time, "good" indicates that it takes slightly longer than "good", and "not good" indicates that the pile yarn 1 is laid down and sanding is difficult.

[0025]

[Table 3]

Considering the results, according to Table 3, the prototype No. Sample NO. Prototype NO. It can be seen that the wear resistances of 1 to 4 are extremely excellent, that is, the prototype according to the present invention has a significantly smaller amount of wear than the prototype using polypropylene. Reading the properties of these samples from Table 2, the tensile strength is 3
Around g / d, tensile elongation of about 30-40%, wear resistance of 3
Sample N that was about 00 seconds and obtained similar values
O. It can be estimated that the same effect can be obtained with the artificial grass using 1 to 9, 11, and 12. Moreover, these prototypes have obtained favorable results even in the workability of sanding.

On the contrary, considering from the viewpoint of workability of sand pit,
Prototype NO. Sample Nos. 10, 16
Since both do not contain Component B (polyamide), it can be said that the importance of Component B relating to the workability of sand putting appears. In addition, the sample Nos.
From the data of 5 and 6, it seems that high density polyethylene and linear polyethylene can be used practically, but the sanding workability in Table 3 shows that the prototype N
O. Sample No. 1 used for No. 1 No linear polyethylene was blended in the component A of the sample No. 5, and although it was practical, a good evaluation was not obtained. Considering this point, the presence of linear polyethylene should not be ignored, and a mixture of 100 parts by weight of high-density polyethylene and 5% to 100 parts by weight of linear polyethylene should be used. Is more desirable.

Further, sample No. 12 and NO. 14 differs from Component 14 only in the number average molecular weight of Component C, but this difference is noticeable as a difference in abrasion resistance.
Whether or not the sample No. is closely related to the possibility of continuous stable operation when obtaining the yarn. 12 and NO. It can be confirmed by comparison with 15. Originally, acid-modified low molecular weight PO
(Component C) is blended with the intention of improving the adhesion (compatibility) between the incompatible resins, that is, the ethylene resin and the polyamide. It was expected that the dispersibility of fillers and the like and the various physical properties (good appearance, strength, and tear resistance) would be improved. Here, it can be said that by using the acid-modified low-molecular weight PO, both were homogenously and microscopically compatibilized, and improvement in wear resistance and processing stability was confirmed.

As shown in Table 2, when the acid-modified low molecular weight PO obtained directly by the acid modification is used as it is, the number average molecular weight is about 800 to 20,000 in a practical range. That is, if the number average molecular weight is less than 800, the appearance of the flat yarn tends to be uneven and the strength tends to be low, and if the number average molecular weight exceeds 20,000, acid modification cannot be carried out. It is also known that the same effect can be obtained by diluting the acid-modified low molecular weight PO directly obtained by the acid modification with an unmodified one. Although there are various modes of dilution, it cannot be mentioned in any way, but in view of the tendency that the above-mentioned various physical properties are deteriorated due to a decrease in acid value, it is desired to suppress the degree of dilution as much as possible.

As described above, when the range in which the characteristics are inferior is excluded from the data shown above, the preferable blending ratio is 10 to 100 parts by weight of polyamide to 100 parts by weight of the ethylene polymer (component A). The proper blending amount of the acid-modified low molecular weight PO is ethylene-based polymer 1
The range of 1 to 15 parts by weight with respect to 00 parts by weight can be mentioned. That is, if the blending amount of the polyamide is less than 10 parts by weight with respect to 100 parts by weight of the ethylene polymer, there is a high possibility that an artificial lawn excellent in abrasion resistance cannot be obtained, and the blending amount exceeds 100 parts by weight. Therefore, there is a high possibility that yarn breakage will occur during drawing and splitting. If the amount of the acid-modified low-molecular weight PO compounded is less than 1 part by weight based on 100 parts by weight of the ethylene polymer, the frequency of yarn breakage during drawing processing increases, and if the compounded amount exceeds 15 parts by weight, the appearance is improved. Not only does it deteriorate, but the abrasion resistance of the pile yarn tends to become unsuitable for practical use.
The practical range is slightly wider than the above-mentioned preferable range, and the component B is 5 to 110 parts by weight with respect to the component A: 100 parts by weight,
Component C: 0.5 to 20 parts by weight.

[0031]

As described above, by using the artificial lawn according to the present invention, the sand can be efficiently put into operation, and it can be used in a good condition with excellent shape retention for a long period of time.

[Brief description of drawings]

1 (a), (b) and (c) are cross-sectional views showing an example of an artificial lawn according to the present invention.

FIG. 2 is a schematic diagram of an experimental apparatus used for measuring wear resistance.

[Explanation of symbols]

1 pile yarn, 2 base cloth, 3 sand, 4 backing material, 5 rotating rolls, 6 weights, 7 drawing tape

Claims (1)

[Claims] 1. A component 10 comprising an ethylene polymer.
Component B consisting of polyamide: 0 to 11 parts by weight: 5 to 11
A uniaxial resin composition containing 0 part by weight and component C mainly composed of a low molecular weight polyolefin having a number average molecular weight of 800 to 20000 and at least a part of which is acid-modified at 0.5 to 20 parts by weight. An artificial lawn, characterized in that the pile yarn (1) is formed by drawing lines.