CZ292592B6 - Synthetic grass surface - Google Patents

Abstract

In the present invention there is disclosed a synthetic grass surface (1) for playing fields, having a flexible backing member (3), parallel rows (5) of synthetic ribbons (7), representing blades of grass, projecting upwardly from the backing member (3), the rows (5) of ribbons spaced apart from each other, wherein the surface includes a relatively thick layer of particulate material (9) on the backing member (3) supporting the ribbons (7) in a relatively upright position relative to the backing member (3), wherein the length "L" of the ribbons (7), that is, the distance from the backing member (3) to the their free ends (17), is at least twice the spacing (A) between the rows (5) of ribbons (7) and preferably between three and six times the spacing "A" and thickness (T) of the particulate material (9) layer relative to the ribbon (7) length (L) is substantially 2/3 of the ribbon length, where A is the row spacing, L is length of the ribbons and T is the particulate material layer thickness.

Description

Artificial grass surface

Technical field

The present invention relates to improved artificial grass surfaces. More specifically, it relates to improved artificial grass sports surfaces. It also relates to a process for preparing improved artificial grass surfaces and to an apparatus for carrying out the process. The invention is further directed to an improved artificial grass sports surface with marked lines on the surface and to a method for preparing the line marked surfaces.

BACKGROUND OF THE INVENTION

Artificial grass sports surfaces are well known. They are used as a replacement for natural grass surfaces that are easy to wear and require considerable maintenance. Natural grass surfaces also do poorly in partially or fully enclosed sports stadiums. Artificial grass surfaces are more resistant to wear than natural grass surfaces, do not require much maintenance and can also be used in enclosed stadiums. Some artificial grass surfaces have rows of strips or strips of artificial material vertically extending from the backing mat, the gaps on the backing mat between the rows of strips being filled with bulk material. The strips of artificial material usually protrude a shorter section of their length above the surface of the bulk material and represent grass blade. Typically, the bulk material is sand as in U.S. Pat. No. 3,995,079, Haas Jr., 1976 and U.S. Pat. No. 4,389,435, Haas Jr., 1983, but may include other materials or a mixture of sand and other materials such as See, e.g., U.S. Patent 4,337,283 to Haas Jr., 1982. Loose material provides elasticity to artificial grass surfaces, and these surfaces are often placed on resilient pads to increase surface elasticity.

Existing sand-filled artificial grass sports surfaces have some disadvantages. Surfaces usually harden after prolonged use, as the sand between the rows of strips compacts and becomes compact. This is partly because the rows of strips are close together and the sand cannot move sideways sufficiently under operating conditions. This is due in part to the fact that the close proximity of the rows of strips retains in the sand fragments of the strips caused by abrasion and tearing, even if the bulk material contains rounded particles of sand. With the compaction process the surface gradually hardens and loses its elasticity. The service life of the surface will be shortened and its sporting quality will deteriorate. During use, the surfaces harden because the elastic pads slowly collapse and their density increases. The removal and replacement of the compact bulk material and its mere loosening are made more difficult due to the close proximity of the rows of these strips. Sometimes removal and replacement, as well as mere disintegration of a compact bulk material, may require costly equipment, and this may increase the cost of surface maintenance.

Another problem of known artificial grass sports surfaces is dewatering. Water generally flows slowly through these surfaces. The strips are usually attached to the mat by the tufting technique and then the bottom of the mat is coated with a coating layer that connects the ends of the strips to the mat. and

This coating layer is not porous. To provide the necessary porosity, the coated mat is perforated to form holes. However, the particulate material often flows into these openings, clogging them and impairing the drainage ability of these surfaces. The flow of these particles into the holes makes it necessary to replace the top of the mat and thereby increase the maintenance costs of these surfaces. The compacting of this surface also prevents its drainage.

Known artificial surfaces also have relatively poor sporting properties. When the rows are filled with sand particles that are round rather than square because, in the opinion that the round particles are less compact and less abrasive when falling, the surface becomes too slippery, especially when the strips are only slightly longer than the thickness of the bulk material layer . Fine strips of artificial grass

In densely cramped rows, moldings on the soles of sports shoes retain more firmly when stepped on and do not tear as easily as grass, making it difficult to release these moldings and making play on these surfaces more difficult and dangerous. If moldings on the player's soles are not easily released, injury to the player's lower extremities, knee or ankle may result. It has also been found that when these moldings on an athlete's shoe sink in the mat joint area, the likelihood that the shoe will not loosen or rotate around the point of contact is much greater.

Known artificial surfaces with strips of grass in densely cramped rows also increase the speed of a rolling ball compared to the speed at which it rolls on natural grass. The densely packed strips 10 create an almost rigid, low resistance surface for the rolling ball, thereby adversely affecting the sporting surface quality. When using surfaces deposited on an elastic mat, the balls bounce off the surface more than in the case of natural grass and thus change the character of the game somewhat. For tennis players, less resistance also makes surfaces more slippery.

Known surfaces also have other drawbacks. The strips used are quite narrow, which causes them to curl and do not look like grass. The narrow strips are also more easily subject to scuffing and the resulting fragments increase the compactness of the surface. Densely cramped rows of stripes also cause scratches to players when they fall or slip on the surface.

SUMMARY OF THE INVENTION

According to the present invention, it has been found that improved artificial grass surfaces can be achieved by strips of about twice the gap between the rows of strips. The present invention uses strips 25 well longer than those previously used. Longer strips allow a thicker layer of bulk material to be applied, which can eliminate the need for an elastic pad, making surface installation simpler and cheaper. A thicker layer of loose material or fill between the rows improves drainage because the artificial turf creates a higher water level. Preferably, the bulk material layer has a thickness of at least two thirds of the length of the strips. Longer strips mean more artificial grass over the loose filler between rows for some sports, creating a surface that mimics a more realistic natural grass, which, along with wider spacing between strips, allows players' outsole to penetrate better into the surface to improve both grip and grip release. Moldings on the players' soles can push artificial grass and padding to the sides for easier release.

Another object of the present invention is to provide improved artificial grass sports surfaces that are more elastic and resilient to remain longer than known artificial grass surfaces.

It is another object of the present invention to provide improved artificial grass sports surfaces that are better drained and have better sports characteristics.

It is another object of the present invention to provide improved artificial sports surfaces having relatively lower manufacturing costs, lower laying costs, and particularly maintenance.

Yet another object of the present invention is to provide artificial sports surfaces in which it is relatively less expensive to manufacture, install and particularly maintain.

Yet another object of the present invention is to provide artificial sports surfaces that are less abrasive, easier to line, and whose parts are easier to join.

It is a further object of the present invention to provide a method of one embodiment of the present invention which results in improved drainage properties and apparatus for carrying out the method.

-2GB 292592 B6

According to the present invention, it has been found that improved artificial grass surfaces can be achieved by using larger spacing between individual rows of strips. The wider spacing of the rows of strips reduces the compacting of the loose fill between rows that normally occurs with more cramped rows, thereby extending the surface life in terms of elasticity. Lower density also ensures better drainage. Wider strip lines also contribute to less strip wear and abrasion, thereby extending surface life and minimizing the formation of strip fragments affecting compaction and drainage. Wider rows also allow better penetration of the moldings on the outsoles and easier release, which improves the quality of the game and reduces the risk of injury. Wider lines also result in the ball rolling in a way that is more similar to the movement of the ball on natural grass, which increases the quality of the game. The wider rows also make it easy to disassemble bulk material that begins to compact, clean and replace. The wider strip lines also reduce the abrasion of the players that have come into contact with the surface. Wider rows can facilitate joining of surface parts.

According to another embodiment of the present invention, the improved artificial grass surface is designed to better allow drainage, thereby providing a method and style of attachment of the strips. According to the present invention, the rows of strips are fastened with strips of coating material applied to the backing mat from below. The strips of coating material are sometimes displaced aside to leave some areas of the mat uncovered. Because in this embodiment, the mat is porous, the exposed areas allow perfect drainage. In realizing a surface with considerable gaps between the rows, it is possible to apply strips of coating material so as to form relatively wide portions of the porous mat therebetween. The invention is also directed to a device for simple and easy application of the cover strips to the bottom of the substrate.

Improved dewatering is also achieved by providing at least one of the bottom layers of the ironed fabric on one or both surfaces with crimped fibers. Curled fibers improve the drainage of the backing layer and hence the entire surface, as they drain moisture from the system.

According to the present invention, the surface is provided with an improved filler layer of the bulk material, at least a portion of the bulk material being in the grain size range between 1 mm (15 mesh) and 0.5 mm (30 mesh).

Preferably, the filler comprises a mixture of silica sand and cryogenically ground rubber particles. Cryogenically ground rubber particles are easier to wet than rubber particles milled by another technique and thus allow faster dewatering. Cryogenically ground rubber has less angular particles than rubber otherwise ground and tends to bind microscopic air bubbles. The ratio of sand to rubber may vary according to the end use of the surface; the more flexible the surface is required, the more rubber must be. This reduces the tendency of the rubber particles to float to the surface when flooding the pitch, which could result in loss of material and a change in the sporting properties of the surface.

According to the present invention, this surface is prepared to form lines that are distinguished on the playing field according to the rules of the sport. An example of such lines is the lines dividing the football pitch, which divide the pitch at regular intervals. These lines are usually applied to the surface of the pitch <

ground chalk or other similar marking material. According to the invention, the surface may be provided with permanent lines embedded in the surface. They are inserted when joining dílů individual parts of the underlying surface layers.

The invention is particularly directed to an artificial grass surface with a resilient backing layer and parallel rows of artificial strips corresponding to natural grass blades vertically protruding from the backing layer, wherein the rows of strips are spaced from five eighth of an inch to two and one quarter inches (5.715 cm). This surface also includes a relatively thick layer of bulk material deposited on the backing layer between the artificial grass strips, which keeps them in an upright position relative to the backing layer.

-3GB 292592 B6

The invention is also particularly directed to an artificial grass surface having a flexible and porous backing layer and rows of strips separated by spaces and representing grass blades penetrating the backing layer upwards. The strips of coating material at the bottom of the backing layer cover the sewn 5 rows of strips and attach the strips to the backing layer. This coating material is applied in rows at a certain spacing to form bands of uncoated substrate material to improve drainage of the system.

The invention is also particularly directed to an artificial grass surface having a flexible backing layer 10 and parallel rows of artificial strips representing natural grass blades facing upwardly from the backing layer. The surface also includes a necessarily thick layer of bulk material deposited on the backing layer and keeping the artificial grass strips in a substantially upright position relative to the backing layer, wherein the bulk material comprises a mixture of cryogenically ground rubber and silica sand.

Cryogenically ground rubber means rubber particles prepared by removing rubber from used tires by cryogenic grinding of rubber. Disintegration of the rubber in the frozen state leads to the formation of rubber particles with smoother and less rugged surfaces than that produced by non-cryogenic processes.

BRIEF DESCRIPTION OF THE DRAWINGS

After a general description of the subject matter of the invention, reference is now made to the accompanying drawings which illustrate, by way of illustration, a preferred embodiment of the invention:

Figure 1 is a cross-section of an artificial grass surface according to the invention,

Figure 2 is similar to Figure 1 and shows the free ends of the strips in a natural lodged position;

Figure 3 is a side view of a coating machine;

Figure 4 shows a cross-section along line 4-4 of Figure 3;

Figure 5 shows a top view of the machine;

Figure 6 shows a detailed top view;

Figure 7 shows a perspective view of a substrate after coating with a covering material;

Figure 8 shows an exploded end view of the sports surface joint, the joint forming the 35 signal line of the sports field,

Figure 9 shows an overall view of the joint of Figure 8.

DETAILED DESCRIPTION OF THE INVENTION

The artificial grass surface 1 according to the invention has, as shown in FIG. 1, a thin and flexible substrate 3 with parallel rows of strips 5 or strips 7 extending upwardly from the substrate 3. On the substrate 3 lies a relatively thick layer of filler bulk material 9, which keeps the strips 7 in an approximately upright position on the substrate 3.

As can be seen, the flexible backing 3 may consist of two backing layers 11 and 13. The backing layer 11 may be a woven or needled polypropylene fabric. The topsheet 13 may also be a woven or needled polypropylene fabric. Plastic strips or strips 7 are tufted in the substrate 3 and pass through both layers as shown in Figure 2.

-4GB 292592 B6

Although the substrate 3 has been bilayered, it can also be formed from a single layer or vice versa from multiple layers, for example three. The one or more layers in the substrate 3 may be a needled woven fabric to improve drainage, but when only one layer is used, it must be relatively thick. At least one of the layers 11 in the substrate 3 may be needled by crimped fibers (flw) 15, as shown in Figure 2, to remove moisture through the layer. These crimped fibers further improve surface drainage.

The strips 7 are made of suitable synthetic plastics extruded into a tape that is relatively wide and thin. The preferred material is polyethylene, which is soft and has good wear resistance. However, polypropylene can also be used to prepare the strips. The tape may have a width ranging from one quarter inch (0.635 cm) to one inch (2.54 cm), but a width of about half inch (1.27 cm) is preferred. The tape thickness is between 65 and 150 microns. Strips 7 are cut from the extruded tape and fastened in substrate 3 by tufting in parallel rows 5. Per inch of the row of strips are sewn 2 to 8 strips (0.7874 strips per cm to 3, 15 strips per cm). 4 strips per inch (1,575 strips per cm). These strips are mechanically spun or split to a width of one eighth of an inch (0.3175 cm) or more.

Spinning, which is carried out mechanically in the production of the tape, results in a hair-like strip because the resulting fibers are interconnected.

The distance between the rows of strips depends on the type of sport for which the course is intended. For example, the moldings on the soles of shoes for various athletic disciplines are about three-quarters of an inch apart. Moldings on soles of American football or European football shoes may be wider than moldings on basketball shoes. The distance between rows of strips depends on the type of sport for which the pitch is intended and is the result of the distance between the moldings on the players' shoes. Similarly, it is believed that for sports such as horseback riding, considerable distance between rows will be required due to the wider hoofs of horses. For equestrian disciplines, it is anticipated that gaps between rows of up to 2 and a quarter inches (5,715 cm) will be required with proportionally longer strips of artificial grass up to 5 inches (12.7 cm).

Relatively wide strips, at least half an inch (1.27 cm) wide, are preferred because the wider strips do not twist as easily as narrower and better resist wear and abrasion. The wider strips 7 also better cover and retain the loose filler material in the lodged position as shown in Figure 2. At least the free ends of the strips 7 are fiberized over the bulk material layer 9, giving the impression of a more dense grassing. The ends of the strips can be further spun using a steel brush and other mechanical spinning agents even after the installation of an artificial turf and loose packing.

Here, too, it is possible to combine strips of different thicknesses. Depending on the intended use of the pitch, for example, stiffer and softer stripes can be combined to control the ball rolling speed. The stiffer strips have more memory, which, in comparison with the softer ones, returns them to an upright position. An example of such a blend is a thicker strip having a weight of 11,000 denier and a thickness of about 100 to 120 microns. The softer strip could be from 5700 denier more and 80 micron thick. Any combination of these stiffer and softer strips will result from the special requirements for the course. The ratio of stiff and soft strips may be 1: 1. These stiffer and softer strips may alternate or be sewn together.

According to the present invention, the rows of 5 strips 7 are spaced at a distance A that is between five eighth of an inch and two and a quarter of an inch. These gaps between rows depend on the sporting purpose of the course, with narrower gaps used for surfaces designed for less demanding physical activities, such as golf greens, and larger spacings used when greater physical strain is expected, such as horse racing.

-5GB 292592 B6

The relatively wide gaps between the rows of strips have several advantages. The wide spacing between the rows reduces the tendency of the surface to compact. With reduced compactness, surface drainage is improved. Wide gaps also reduce the amount of strip preparation material. Wide gaps further improve the sporty surface quality. A player doing sports on this surface has the advantage of having more grip 5 on the shoe, since his moldings on the sole better sink into the bulk material between the rows of strips. At the same time, the moldings are easier to release because there is more space between the rows to allow loose material to be dislodged. The wide spacing between the rows also facilitates loosening, cleaning and even replacement of loose filling material. Sufficient space between the rows allows pneumatic uncoupling of this material and cautiously loosening it. The loose and loosened material can be removed, cleaned, debris-free and returned to the backing layer between rows. The service life of the surface is prolonged and the cost of replacing the bulk material is reduced. The wide spacing between the rows also makes it easier to stitch adjacent parts of the surfaces without producing significant seams, as there is more room for these joints.

The length of the strips is also an important feature of the invention. The length L of the strips 7, i.e. the distance between the substrate 3 and the ends of the strips 17, is at least twice the distance (gap) A between the rows 5 of the strips and is preferably three to six times its length. The length L of the strips is between one and a quarter inches (3.175 cm), but preferably between three inches (7.62 cm) and five inches (12.7 cm), the shorter strips being used on surfaces with less 20 gaps between rows and longer strips are used for larger row spacing. Longer strips (as compared to previously used) allow the use of a thicker padding layer 9, thereby providing a more flexible layer not requiring resilient pads. This eliminates the cost of this washer and its installation. The thicker filler layer 9 allows for better drainage, since a higher water level is generated and thus a higher pressure altitude is created on the ground surface. Longer strips can also provide a greater length of strips above the padding layer, even with a thicker layer of the bulk padding, while the loose strips above the padding protect the player from falling with sand and other bulk material when dropped. The strips may overlap the filler layer in lengths from one quarter of an inch (0.635 cm) to one inch and a half (3.81 cm). Depending on the end use of the surface, the thickness of the padding layer may be from one inch (2.54 cm) to four inches (10.16 cm). The padding layer 30 typically has a thickness T of about two-thirds of the length of the strips L.

Preferably, the layer 9 comprises a mixture of hard rock sand such as silica and cryogenically ground rubber pulp. Cryogenically ground rubber pulp is preferred because its particles are more rounded, reducing abrasion and preventing compaction. The less angular rubber particles 35 also become easier to wet, which facilitates dewatering. In addition, the particles have less tendency to flush away when the playground is flooded because the rounded particles are less bound to microscopic air bubbles. The particle size can vary between four and seventy mesh, but it is preferred that they are between fifteen and thirty mesh in the case of sports where players are at risk of abrasion on contact with the surface and between four and thirty mesh where they are not. The quartz sand may be replaced by a sorted hard rock crush 40, a hard plastic of a higher weight, or other bulk sand type material.

The cryogenically ground rubber pulp may be replaced by other elastic materials such as cork, styrene, EPDM rubber, neoprene or other similar materials as long as the particle shape resembles that of cryogenically ground rubber. In some cases, some or all of the resilient materials may be replaced by other materials with specific tasks. As an example, perlite may serve as a substitute for elastic material, which additionally reduces compaction and possibly absorbs moisture.

The mixture of sand and elastic material may have different compositions depending on the intended use of the surface. When it requires more flexibility, more rubber is used. With relatively thick layers, the 50 layer of bulk material 9 can be divided into two layers, of which the lower 17 on the substrate 3 of Figure 2 has smaller particles and the upper layer 19 has larger particles, which facilitates drainage. The particle in the backsheet 17 may mainly be sand of about forty to seventy mesh. In this case, the topsheet 19 comprises larger sand particles in conjunction with the rubber particles

The grain size is about thirty mesh. The predominant or exclusive use of sand in the bottom layer reduces the cost of the surface.

The surface 1 is prepared by sewing the strips 7 into the substrate 3 in rows 5 spaced from five to eight inches (1.5875 cm) to two and a half inches (6.35 cm), with 2 to 8 strips per sewn inch. After sewing the strips 7, a material can be applied to the underside of the substrate to adhere the strips to the substrate. In this way, the entire substrate can be coated.

One embodiment of the present invention using a porous substrate is preferred, but only some portions of the substrate are coated to improve drainage and reduce costs. In this embodiment, after sewing the strips 7, the substrate 3 passes through the top side down with a standard device for coating the underside of carpets. This applicator 31 schematically shown in Figures 3, 4, 5 and 6 has a support plate 33 on which, as it passes through the machine, the substrate 3 of the sewn-on strip is displaced. There is a device (not shown) for moving the substrate 3 along the support plate 33 from one side to the other, as shown by arrow 34 in Figure 3. The support 3, when moved on the support plate 33, passes under the ridge-shaped device 35 with a row of parallel fingers. 37 resting on the bottom of the substrate 3 against the support plate 33. The distance between the fingers 37 may be varied so that one finger covers the gap between each pair of adjacent rows of artificial grass strips 5 on the substrate 3. A spreading knife 39 is positioned above the fingers 37 fingers 37 than their ends. There is an application device 40 which, prior to the spreading knife 39, applies coating material M to said comb device 35 over its entire width. As the substrate 3 is moved to the right under the applicator as shown in Figure 3, the coating material M to the spreading knife 39 is also carried along with the substrate, where it is spread and laid on narrow zones 41 of the substrate 3 not covered by fingers 37. 5 and the ends of the strips in these rows are covered with a coating material M which adheres the strips 7 to the substrate 3. The fingers 37 prevent the coating material M from being applied to the narrow zones 43 of the substrate 3 adjacent the rows of strips 5. is the back of the substrate 3, as shown in FIG. 7, provided with strips 45 of coating material M covering the rows of strips 5, the adjacent strips 43 on the substrate 3 being exposed by the action of the fingers, leaving a very porous and well-draining surface. The coating provided by the applicator has a much lower material consumption than the coating over the entire surface of the substrate, thereby providing additional material savings that make this surface cheaper.

Application can also be accomplished by methods other than coating the rows of strips in the strips described above. For example, a plurality of nozzles may apply thin lines of coating to the rows of strips, and the spreading knife may press them against the underside of the mat while leaving relatively wide and long portions of the substrate uncoated and hence functional in dewatering. Coating rollers of different diameters can also be used for coating.

According to another embodiment of the invention, lines may be provided for demarcating the playing surface on the playing surface by connecting adjacent edges of the sports surface parts with a specific joint. As shown in Figure 8, a joint strip 5L is inserted below adjacent but spaced apart edges 53 and 55 of adjacent surface portions 57 and 59. Joint strip 51 has stitched strips 63 at its center portion 65 but has no strips on its wide The central panel 65 is located between the edges 53 and 55 of the surface panels 57 and 69, wherein the sewn strips 63 in the central panel 65 may have a different color and / or a different length compared to the strips 7 of the surface panels 57 and 59. to form a line 71 indicating the playing area. The wide side flanges 67 and 69 of the connector 51 may be needled on the crimped pile fabric. Adhesive A is applied to the upper side of the wide side skirts 67 and 69 to adhere the overlying surface parts 57 and 59. The curled pile fabric facilitates the bonding of the joint strip 51 to the surface portions 57 and 59. The joint strip 51 is underneath The central panel 65 can be coated with a coating material M, preferably also under the side flanges 67 and 69. This prevents leakage of the adhesive A used on the joint by the strip 51 and possible sticking to the substrate.

-7EN 292592 B6 (10

After the strip 51 has been attached to the surface parts 57 and 59, as shown in Figure 9, and hence the parts have been joined, the strips 63, due to their different appearance compared to the strips 7 on the surface of the parts 57 and 59, represent a line 71.

In a further embodiment of the invention, a surface with long strips of artificial grass of at least four and a half inches (11.43 cm) is used, the thickness of the bulk material layer corresponding to this stripe length. This surface can be used for growing plants. The loose filler material may be a crop growth material, for example a moisture retention material for the plants and a material that allows the development of a strong root system. The bulk material layer may be comprised of one or more layers of the support material. In some cases, the support material may have a specific gravity less than water, and as the backsheet below the topsheet remains in place and is not carried away by water. These surfaces would be particularly useful in arid areas. The irrigation tubes can be laid directly in the bulk material layer. The backing layer may have a porosity such that it retains moisture in the bulk material and promotes plant growth. The strips would minimize the amount of bulk material that would blow winds in windy areas.

A pitch using long strips and thick layers of loose material containing cryogenically ground rubber could be used as an environment for growing natural grass, with its root systems developing in the loose material.

Claims (17)

An artificial grass surface (1) for a sports field, characterized in that the artificial grass surface (1) comprises a resilient substrate (3), parallel rows (5) of artificial strips (7) representing blades grass pointing upwardly from the substrate (3), the row (5) of the strips (7) spaced from each other, the surface (1) comprising an essentially thick layer of bulk material (9) deposited on the substrate (3) substantially upright with respect to the substrate (3), wherein the relationship of the length (L) of the strips (7) and the gaps (A) between the rows (5) is 2A <L, so that the length (L) of the strips (7) is at least twice as large as the gap (A), and the thickness of the bulk material (T) relative to the length of the strips (L) is substantially 2/3 L is the length of the strips measured from the resilient substrate and T is the thickness of the bulk material layer. Surface according to claim 1, characterized in that the length of the strips is such that the strips (7) overlap the bulk material layer (9) by 0.635 cm to 3.81 cm (1/4 inch to one and a half inches). Surface according to claim 1 or 2, characterized in that the substrate (3) comprises one or more fabric layers (11), (13), (15), wherein at least one of the fabric layers is needled to form curled fibers (15). ) on its surface to increase the permeability of the substrate (3). Surface according to any preceding claim, characterized in that dimension A has a value between 1.588 cm and 5.715 cm (5/8 inches and 2a1 / 4 inches) and an dimension L has a value between 3.175 cm and 12.7 cm (1a / 2). 4 inches and 5 inches). -8EN 292592 B6 Surface according to any preceding claim, characterized in that the relationship between the length of the strips (L), the gaps (A) between the rows (5) and the thickness of the bulk material (9) is: 2A = 3/2T = L. A sports field surface according to any preceding claim, wherein L has a value in the range between 3A and 6A. Surface according to any preceding claim, characterized in that the length of the strips (L) is such that they overlap the bed of bulk material (9) by 0.635 cm to 2.54 cm (1/4 inch and one inch). A surface according to any preceding claim, wherein the strip (7) has a width of about 1.77 cm (half an inch). Surface according to any preceding claim, characterized in that the substrate (3) is a single layer of permeable material. Surface according to any one of claims 1 to 8, characterized in that the substrate (3) comprises a double layer of permeable material. Surface according to any one of claims 1 to 8, characterized in that the substrate (3) comprises a triple layer (11), (13), (15) of permeable material. The surface of any preceding claim, wherein the layer of bulk material (9) is a mixture of sand and cryogenically ground rubber. The surface of claim 12, wherein the ground rubber is in particulate form having a substantially smooth surface. Surface according to claim 12 or 13, characterized in that at least a portion of the bulk material (9) is in the grain size range between 1 mm (15 mesh) and 0.5 mm (30 mesh). Surface according to claim 1, characterized in that the substrate (3) comprises one or more layers (11), (13), (15) of the fabric, at least one of the layers of fabric being needled to form curled fibers on its surface. The surface of any one of claims 10 to 12, wherein at least one of the layers of permeable fabric is needled to form curled fibers on its surface. Surface (1) according to any one of the preceding claims, characterized in that it comprises a strip of coating material (45) at the bottom of the substrate (3), the strip covering from below each row (5) of strips (7) of artificial grass for fastening strips ( 7) to a substrate (3), wherein the substrate (3) is porous and not covered by a coating material between these strips (45).