JPH07197308A - Preparation of yarn for field of artificial turf - Google Patents

Abstract

PURPOSE: To provide a production method of yarns for artificial grass improved in mechanical properties. CONSTITUTION: This production method of a yarn for a field of artificial grass comprises extruding a polymeric material into a monofilament, stretching the monofilament at high temperature, relaxing it to obtain a band and twisting bands into a yarn. The extrusion is carried out using a spinning plate having protrusions 2 separated at regular intervals in the cross section and such a form that the filament having 100 to 700 μm thickness and 1 to 5 mm width is obtained. The stretching is carried out at 1:2 to 1:10 stretching ratio to obtain a band having 0.5 to 2 mm width and 50 to 350 μm thickness after relaxing and cooling and subsequently 5 to 10 pieces of bands are twisted together.

Description

Detailed Description of the Invention

The present invention relates to a yarn for the field of artificial turf by extruding a polymeric material into a monofilament, stretching this monofilament at a high temperature, relaxing it to obtain bands, and twisting several bands into the yarn. Manufacturing method.

A method of this kind is known from EP-A-417,832, in which the yarn is extruded from granules and a band with a width of 2-3 mm is produced from the extrudate, which band has a width of 1-2 mm after drawing. While the thickness is between 50 and 50 of the original thickness of the extruded band.
70%), 5 to 10 bands are twisted on the yarn. It has been found that the mechanical properties of the yarn are improved by extruding it into a monofilament and giving the yarn the predetermined shape obtained by drawing the monofilament in the environment described below.

The process according to the invention is such that the extrusion has a thickness of 10-40% of the monofilament thickness without ridges in cross section.
Of a monofilament having regularly spaced ridges having a height of 100 .mu.m and a thickness of 100-700 .mu.m and a width of 1-5 mm. : 2 to 1:10 draw ratio, whereby after relaxation and cooling, a band with a width of 0.5 to 2 mm and a thickness of 50 to 350 μm is obtained, after which 5 to 10 bands are formed on the yarn. Characterized in that they are twisted together to obtain.

In the present invention, the polymer used is preferably a block copolymer of polypropylene and polyethylene sold by Solvay, Belgium. More specifically, the monofilaments have a thickness of 100-150 μm and a width of 1-1.5 mm after stretching. This is achieved when using a draw ratio of 1: 3-6.

The yarn produced according to EP-A-417,832 is more uptill than conventional yarn when post-fibrillated.
It has the property of being low, resulting in a long life of the yarn, and the field of artificial turf obtained with this yarn can be used for a long time. This property is maintained for a long time. It may be because the fields are not compressed as much. Another advantage of using the method according to the invention is that the yarn is less likely to break. This is achieved in particular by providing a hump-like structure in the cross section of the thread, whereby the hump is provided in a regularly spaced relationship to the monofilament and the thread made from this monofilament.

In FIG. 1, the monofilament core is designated by 1 and the protrusions are designated by 2. The thickness of the monofilament is about 100 μm, and the protrusion has a height of 10 to 20 μm. The monofilament shown in Fig. 1 is 1 to 5 mm
And the protrusions are preferably arranged on both sides of the monofilament.

The present invention will be described in more detail by the following examples. Example 1 An extruder was fed with a block copolymer of polyethylene and polypropylene sold by Solvay, Belgium having a melt index of about 4. By using a spinning plate with many mouths, FIG.
A monofilament such as that shown in Figure 1 was simultaneously produced. This monofilament had a thickness of 300 μm and 2.8 mm before drawing.
Had a width of. This stretching is carried out in a hot air oven at a temperature of 130 ° C. with a stretching ratio of 1: 5 and a thickness of 115 μm,
A band with a size of 1.1 mm wide was obtained. For relaxation, the band was reheated by feeding it to a roll having a contact temperature of 115 ° C and then cooled by contacting it with a slowly rotating roll having a contact temperature of 25 ° C. The band was thus finely upset, and the size of the upset band was 125 μm thick and 1.2 mm wide. The relaxation made the yarn less likely to shrink during high temperature processing. Then, from this band, a yarn was manufactured by twisting 6 bands. By tufting the obtained yarn, a turf for artificial grass is manufactured. This field is for hockey with 280 stitches per meter and a pile height of 25 mm. The carpet thus obtained was tested to determine its mechanical properties. This mechanical property was investigated by the treadwheel test. This test is 22
Carpets made from yarns obtained according to the invention, carried out at 50 and 5000 revolutions, were compared with carpets made from yarns obtained according to European Patent Application 417,832. The results are shown in Table 1.

Example 2 An extruder was fed with a block copolymer of polyethylene and polypropylene sold by Solvay, Belgium, having a melt index of 4. By using a spinning plate with many mouths, a monofilament as shown in Figure 1 was simultaneously produced. This monofilament had a thickness of 300 μm and 2.25 mm before drawing.
Had a width of. This stretching was carried out in a hot air oven at a temperature of 130 ° C. with a stretching ratio of 1: 3. After relaxation, thickness 13
A band with a size of 5 μm and a width of 1.2 mm was obtained.
A yarn was produced by twisting eight bands from this band. A field of artificial grass was manufactured by tufting the obtained yarn.

The yarn thus obtained was tested to determine its mechanical properties. This mechanical property was investigated by the treadwheel test. This test was carried out at 2250 and 5000 rpm. The results are shown in Table 1.

[0010]

[Table 1]

The carpet obtained from the known yarn showed a rupture at 3000 revolutions, whereas the carpet produced from the yarn according to the invention showed no pile rupture even at 5000-7500 revolutions.

Example 3 The procedure of Example 1 was repeated using polypropylene instead of the block copolymer. The results obtained with this polypropylene were the same as those obtained in Example 1.

[Brief description of drawings]

1 is a cross-sectional view of a monofilament produced by the method of the present invention.

[Explanation of symbols]

 1 ... Core 2 ... Protrusion

Claims (5)

[Claims] 1. Manufacture of a yarn for the field of artificial turf by extruding a polymeric material into a monofilament, stretching the monofilament at elevated temperature, relaxing it to obtain bands, and twisting several bands into the yarn. The method, wherein the extrusion has regularly spaced apart protrusions having a height of 10-40% of the thickness of the monofilament without protrusions in cross-section, the thickness being 100-700 μm, And it is carried out by means of a spinning plate having a shape such that a monofilament having a width of 1-5 mm is obtained, said drawing is carried out at a draw ratio of 1: 2-1: 10, whereby after relaxation and cooling, a width of 0.5-2 mm. And a band having a thickness of 50 to 350 μm is obtained, after which 5 to 10 bands are twisted together to obtain said yarn. 2. Process according to claim 1, characterized in that the polymer used is a block copolymer consisting of polypropylene and polyethylene. 3. The monofilament has a thickness of 100 to 150 μm.
3. A method according to claim 1 or 2, characterized in that it is stretched to have a thickness of 1 and a width of 1 to 1.5 mm. 4. The method according to claim 1, wherein the stretch ratio is 1: 3-6. 5. The method according to claim 1, characterized in that 6 to 9 bands are twisted together in a thread.