CN1961101B - Process for producing synthetic fibers suitable for artificial turf sports fields and such synthetic fibers - Google Patents

Abstract

The present invention relates to a method for preparing a synthetic fibre for an artificial grass sports field, comprising the steps of: i) providing a synthetic material layer; and ii) producing synthetic fibres from the synthetic material layer. The invention also relates to such a synthetic fibre and to an artificial lawn suitable for sports fields, which artificial lawn consists of a substrate on which the synthetic fibre according to the invention is attached. It is therefore an object of the present invention to provide a more versatile fiber which on the one hand can be used for special purposes and on the other hand saves production and material costs. According to the invention, the synthetic material layer is composed of at least two layers of different synthetic materials by means of a coextrusion process. This co-extrusion step provides a separation of the different properties of the synthetic materials used.

Description

Process for producing synthetic fibers suitable for artificial turf sports fields and such synthetic fibers

technical field

The present invention relates to a kind of preparation method that is applicable to the synthetic fiber of artificial turf sports field, it comprises the following steps:

i) providing a synthetic material layer; and

ii) Synthetic fibers are produced from the layer of synthetic material.

The invention also relates to such synthetic fibers and to artificial turf suitable for use in sports fields, the turf consisting of a substrate to which the synthetic fibers according to the invention are attached.

Background technique

Synthetic materials are currently being used for various purposes. In recent years, the use of various synthetic materials has increased remarkably, especially with regard to artificial turf for sports fields.

In this regard, research has particularly focused on the improvement of synthetic fibers for use in artificial turf for sports fields in which lengths of fibers are attached to a substrate by means such as tufting. People have carried out the improvement of artificial turf fibers and the resulting artificial turf sports fields, so that it is now possible to build artificial turf sports fields not only in appearance, but especially in sports performance, which are not much different from natural turf sports fields. .

Unlike natural turf sports fields, artificial turf sports fields can be used longer and more intensively, regardless of weather conditions. At present, the development of new artificial grass fibers is mainly focused on obtaining a fiber that can further reduce the incidence of injuries, such as abrasions and burns caused by sliding, or sprained joints.

Existing fibers, which have been specifically modified for use in artificial turf sports fields, can be produced from layers of synthetic material, for example by a shearing process. The synthetic material layer may consist of a mixture of different synthetic materials, for example, where one synthetic material imparts a specific length (resistance to breaking or tearing) to the fibers and another synthetic material in the mixture provides the fibers with a specific Elasticity or flexibility or better sliding properties.

A disadvantage of this existing synthetic fiber is that, due to its homogeneous structure, all (secondary) properties of the fiber are homogeneously incorporated in the fiber. As a result, fibers have certain properties that are less pronounced than desired, while others are more pronounced than desired. Consequently, the composition of existing fibers is often standardized, and their production and material costs are often unnecessarily high.

Contents of the invention

It is therefore an object of the present invention to provide a more versatile fiber which, on the one hand, can be used for a specific application and, on the other hand, saves production and material costs. According to the invention, said layer of synthetic material consists of at least two layers of different synthetic materials, produced by coextrusion.

The coextrusion step enables the separation of the various properties of the synthetic materials used. By imparting a layered structure to synthetic fibers, it is possible to impart function-specific properties to the individual layers which need not, or only need to be present to a significantly reduced extent, elsewhere in the fiber. This enables the selection of fiber formulations tailored for specific applications, which, in addition to more efficient material consumption, result in a synthetic fiber with significantly improved movement and fibrous properties compared to known fibers of homogeneous composition.

According to the present invention, the movement of synthetic fibers can be significantly improved by drawing the fibers after the coextrusion process. In addition to the increase in length, a correct choice of material according to the invention after the stretching process provides fibers with such strength in the transverse direction that they are less likely to break, for example. When used on artificial turf sports fields, the fibers, and consequently the artificial turf, have a longer lifespan, and the artificial turf does not require as much maintenance so it stays active longer. In addition, the risk of injury for athletes is also significantly reduced.

According to the invention, the fibers consist of at least one or several twisted monofilaments. The fibers may be formed into ribbons, more specifically, the ribbon fibers may be formed into fibrillated ribbon fibers.

In a first embodiment of the method according to the invention, the layer of synthetic material consists of a core layer of a first synthetic material covered on both sides by one or more outer layers each made of a different synthetic material composition.

A functional separation of the different properties of the different synthetic materials can thus be achieved, wherein each synthetic material layer has specific functional properties which are not necessary or have no effect elsewhere in the fiber.

The layer of synthetic material may have different thicknesses depending on the specific functional properties desired for the synthetic fiber to be produced.

In a first embodiment, the first synthetic material consists of a mixture of polymers and plastomers, wherein the proportion of plastomers in the core layer is especially 30-80% by weight, and the proportion of plastomers in the core layer is more particularly 30-50% by weight . From a specific functional point of view, this enables fibers with a core to exhibit a very favorable non-breakability.

In another embodiment, at least one other synthetic material may include a hydrophilic additive. The artificial grass fibers thus obtained have specific functional properties of being able to absorb moisture (water). This allows the artificial turf sports field to remain wet longer, which has a positive effect on sports performance (sliding, etc.). When playing on a sports field, the absorbed moisture is released as it is on natural grass.

An example of a hydrophilic additive that can be used as the top or outer layer of a coextruded fiber is ethylene vinyl alcohol copolymer. Depending on the amount of vinyl alcohol in the copolymer, the polymer is able to absorb more water.

Another hydrophilic additive embodiment is the use of polyhydroxyethylmethacrylate.

In yet another embodiment, at least one other synthetic material includes an antistatic additive. The result is that any static electricity built up while playing on the playing field is able to be discharged. Typically, the inter-fiber dispersion material used in many artificial turf sports fields generates static electricity during play and consequently migrates up the field. Thus, the granular dispersion material can spread throughout the air, which is unpleasant in motion.

Plus, antistatic additives ensure that no static discharges can occur through the athlete.

More particularly, antistatic additives, especially permanent antistatic agents, may be polymers, such as polyamides or polyether block amides. In another embodiment, the additive is a polyester block copolymer.

Description of drawings

The present invention will be explained in more detail below with reference to the accompanying drawings, wherein:

Figures 1A-1D show different embodiments of synthetic fibers according to the invention;

Figures 2A and 2B schematically show some embodiments of artificial turf sports fields having synthetic fibers made using the method of the present invention.

Detailed ways

The fibers (10, 20, 30, 40) are produced from sheets of synthetic material, obtained by coextrusion, consisting of at least two layers of different synthetic materials (11, 12), as shown in Figure 1A. Contrary to existing known synthetic fibers that consist of homogeneous synthetic material mixtures, the layered structure of the synthetic fibers (10, 20, 30, 40) according to the invention enables the individual layers (layers 11 in this embodiment and 12) have specific functional properties. As a result, the use of a synthetic material with specific properties in a specific location of the synthetic fiber avoids or significantly reduces the need for the synthetic material and its associated specific functional properties to be present elsewhere in the fiber.

For example, a synthetic material can be used for the layer 11, which in principle imparts the required mechanical strength (and hardness) to the synthetic fibers, in particular non-tearability, so that sports on said artificial turf field cannot be used as an artificial turf. Synthetic tearing of turf sports fields.

In another embodiment, as shown in FIG. 1B , the synthetic fiber 20 is composed of three layers of three different synthetic materials indicated at 21 , 22 , 23 . The middle layer 21 consists of an inexpensive synthetic material that gives the fibers 20 mechanical strength, while the outer layers 22 and 23 can consist of different synthetic materials, each layer exhibiting different specific functional properties, which are most pronounced in the outer layers of synthetic fibers Protrude, not in the middle.

Thus, the outer layers 21 and 22 may be elastic, such as in contrast to the inner layer 21, which provides the fibers with a specific stiffness (resistance to breakage and tearing), the elasticity of said outer layers 21 or 22 having a significant effect on the mobility of the artificial turf sports field. have a positive impact.

In the embodiment shown in Figure IB, outer layers 22 and 23 may be composed of different synthetic materials, while Figure 1C shows an embodiment in which outer layers 32A and 32B are composed of the same synthetic material.

Figure ID further shows a more complex layered structure of synthetic fibers according to the invention. By co-extrusion of different synthetic materials, a layered synthetic fiber is produced consisting of an intermediate core layer 41 covered by different types of outer layers 42A-42B or 43A-43B, respectively.

The essence of the method according to the invention and of the synthetic fibers produced according to the invention is that, contrary to known synthetic fibers, they do not have a homogeneous structure in which all the different synthetic materials and related properties are homogeneously incorporated in the fibre. The homogeneous structure or composition of existing artificial turf sports fields renders some properties of the fibers less pronounced than desired, while others are more pronounced than desired.

Using the method of the invention it is possible to obtain synthetic fibers based on specific formulations which, in contrast to standardized fibers, exhibit in certain parts of them specific functionalities which are considered unnecessary or undesirable in other parts.

This enables a more efficient use of various (synthetic) materials, which not only reduces costs, but also results in a more versatile synthetic fiber which, according to the invention, has a significantly improved movement than known fibers of homogeneous construction and fiber properties. In this particular embodiment, the inner layers 11 , 21 , 31 and 41 consist of a cheaper synthetic material, which in principle gives the fibers a certain strength against breaking or tearing. The outer layers 12, 22, 23, 32A-32B, 42A-42B and 43A-43B are composed of a synthetic material which is not necessarily present in the fibrous core layer.

In this context, a particular embodiment is that the outer layer may consist of antistatic additives. Antistatic additives inhibit fibers from being charged by static electricity generated by playing on artificial turf sports fields. Conversely, antistatic additives can ensure that static electricity generated is discharged by the artificial turf sports field and, for example, not by the player (which would lead to an unpleasant experience).

In addition, in most artificial turf sports fields, due to the generation of static electricity, the granular dispersion material used (usually composed of rubber-like materials) migrates upward in the artificial turf sports field, and the result of the movement on the sports field is to spread the dispersion material. in the whole air. Airborne granular and dispersed material can have unsettling effects on athletes.

Antistatic agents, especially permanent antistatic agents, can be polymers, such as polyamides or polyether block amides. In another embodiment, the additive is a polyester block copolymer.

In another embodiment, one (or both) of the outer layers (12, 22-23, 32a-32b, 43a-43b) may include a hydrophilic additive. The artificial grass fibers thus obtained have specific functional properties of being able to absorb moisture (water) from the air, for example rainwater. This makes the artificial turf sports field moisturised for a longer period of time like a natural turf sports field, which has a positive effect on sports performance (especially when sliding, etc.), while at the same time when playing on the sports field, the absorbed moisture is released as on natural turf .

An example of a hydrophilic additive that can be used as the top or outer layer (12, 22-23, 32a-32b, 43a-43b) of the coextruded fiber is ethylene vinyl alcohol copolymer. Depending on the amount of vinyl alcohol in the copolymer, the copolymer can absorb more water.

In this case, the middle layer (11, 21, 31, 41) imparts strength to the fibres, while the relatively thin upper layer (12, 22-23, 32a-32b, 43a-43b) absorbs moisture. Moisture may be absorbed from the air (in the form of rain, fog, etc.) or provided by effective sprinklers. (Usually, sprinkle water before playing on artificial turf sports fields.)

During exercise, the absorbed moisture is released again, which reduces the risk of injury, for example when sliding. Moreover, the absorbed moisture lowers the temperature of the sports field, which can be as high as 70°C under adverse conditions, since the artificial turf sports field can be heated by sunlight.

Another embodiment for use as a hydrophilic additive for the outer layers (12, 22-23, 32a-32b, 43a-43b) is the use of polyhydroxyethylmethacrylate. To prevent bonding problems with the intermediate layers (11, 21, 31, 41), a five-layer coextruded structure is required, as shown in Figure 1D. In this case, the layers 32 a - 42 b are combined layers of the hydrophilic layers 43 a - 43 b and the intermediate layer 41 .

For purposes of illustration, the various layers of artificial grass fibers (as shown in FIGS. 1A-1D ) are shown to have different thicknesses. However, the shown thickness does not correspond to the actual thickness of the obtained artificial grass fibers.

In the embodiment shown in Figure ID, the bonding layers 42a-42b are much thinner than shown, typically 1-5% of the total fiber thickness, while the other layers 41-43a-43b are relatively thicker. If polyethylene is used as the intermediate layer 11-21-31-41, ethylene-vinyl alcohol copolymer as a hydrophilic additive can be bonded to the intermediate layer without using any filled bonding layer.

Figures 2A and 2B show several embodiments of artificial turf sports fields in which synthetic fibers according to the invention are used. In both figures, the artificial turf sports field comprises a substrate 1 to which several synthetic fibers 2 obtained by using the method according to the invention are attached at positions indicated by reference 3, for example by tufting. The synthetic fibers 2 are produced from layers of synthetic material obtained by coextrusion of at least two different synthetic materials. The synthetic fibers may be attached to the substrate individually, or as, for example, intertwined fiber bundles 2a-2c. More particularly, the fibers produced by coextrusion may be fibrillated ribbon-shaped fibers.

In another embodiment, as shown in Figure 2B, the synthetic fibers according to the present invention may be monofilaments. In this case, several monofilaments can be wound into a bundle, after which each bundle is attached to the substrate 1 . In Fig. 2B, the substrate has an open structure and consists of a grid of supporting yarns 1a-1b to which synthetic fibers 2 are attached.

Claims (26)

1. method of using co-extrusion techniques to be ready for use on the synthetic fiber of artificial turf playing field, this method may further comprise the steps:

I) first synthetic material is provided;

At least other synthetic material ii) is provided;

Iii) constitute by the layer of this first synthetic material at least and layer synthetic material layer of forming of said other synthetic material through coextrusion; It is characterized in that this synthetic material layer comprises the sandwich layer of first synthetic material, the two sides of said sandwich layer is coated with one or more skins of being made up of different synthetic materials.

2. according to the method for claim 1, it is characterized in that at the step I said synthetic material layer that stretches after ii).

3. according to method any among the claim 1-2, it is characterized in that said fiber is made up of at least one monofilament.

4. according to the method for claim 3, it is characterized in that said fiber is made up of the monofilament of several windings.

5. according to method any among the claim 1-2, it is characterized in that said fiber is for banded.

6. according to the method for claim 5, it is characterized in that said ribbon-like fibre is the ribbon-like fibre of fibrillation.

7. according to the method for claim 1, it is characterized in that said each layer has different thickness.

8. according to method any among the claim 1-2, it is characterized in that said first synthetic material is made up of the mixture of polymer and plastic body.

9. according to Claim 8 method, the ratio that it is characterized in that plastic body in the said sandwich layer is 30-80wt%.

10. according to the method for claim 9, the ratio that it is characterized in that plastic body in the said sandwich layer is 35-50wt%.

11., it is characterized in that at least a other synthetic material comprises hydrophilic additive according to method any among the claim 1-2.

12., it is characterized in that said hydrophilic additive is an ethylene-vinyl alcohol copolymer according to the method for claim 11.

13., it is characterized in that said hydrophilic additive is a poly hydroxy ethyl acrylate according to the method for claim 11.

14., it is characterized in that at least a other synthetic material comprises antisatic additive according to method any among the claim 1-2.

15., it is characterized in that said antisatic additive is a polymer according to the method for claim 14.

16., it is characterized in that said antisatic additive is polyamide or polyether block amide according to the method for claim 14.

17. according to claim 1, any one method in 2,4,6,7,9,10,12,13,15 and 16 is characterized in that between this sandwich layer and each said skin, having further binder course.

18., it is characterized in that between this sandwich layer and each said skin, having further binder course according to the method for claim 3.

19., it is characterized in that between this sandwich layer and each said skin, having further binder course according to the method for claim 5.

20. method according to Claim 8 is characterized in that between this sandwich layer and each said skin, having further binder course.

21., it is characterized in that between this sandwich layer and each said skin, having further binder course according to the method for claim 11.

22., it is characterized in that between this sandwich layer and each said skin, having further binder course according to the method for claim 14.

23. the synthetic fiber that make through the method for using above-mentioned any claim; Said synthetic fiber are made up of the synthetic material layer; Wherein said layer comprises the sandwich layer of first synthetic material, and the two sides of said sandwich layer is coated with one or more skins of being made up of different synthetic materials.

24. be applicable to the chinampa of sports ground, have according to the synthetic fiber of the method for any claim 1-22 preparation or according to the synthetic fiber of claim 23.

25., it is characterized in that said lawn comprises the substrate that is attached with synthetic fiber on it according to the chinampa of claim 24.

26., it is characterized in that bulk material is scattered between synthetic fiber according to the chinampa of claim 24 or 25.

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