Artificial grass is generally used in areas where real grass cannot grow and where maintenance is too expensive or tedious. In the past, it was mostly used in sports arenas and stadiums. Today it is used residentially and commercially and has become somewhat of a safety requirement for playgrounds and even smaller applications like shop fronts.
What is artificial grass?
Artificial Grass is a resurfacing material used to emulate grass and is largely manufactured utilizing three materials:
Where does artificial grass come from and how has it evolved over the years?
A brief historical timeline (The history of Artificial Grass)
1st Generation Artificial Grass
In the early 1950s, the tufting process was invented. This process involved a large number of needles which inserted filaments of fibre into a fabric backing. Then a flexible adhesive like polyurethane or polyvinyl chloride was used to bind the fibres to the backing. This procedure is still used for the majority of residential and commercial carpets today but has obviously evolved over the years.
In the early 1960s, the Ford Foundation challenged science and engineering to advance playing surfaces in urban spaces, as a part of its mission to improve human achievement. The idea was to offer urban children year-round access to play areas with better play quality and more uses than the traditional concrete, asphalt, and compacted soil of small city playgrounds and to improve the physical fitness in young children.
From 1962, the Chemstrand Company, a subsidiary of Monsanto Industries, was working on manufacturing synthetic fibres to enhance the toughness of carpet surfaces. The surfaces were tested for foot traction and cushioning, weather drainage, flammability, and wear resistance.
In 1964, Donald L. Elbert, James M. Faria, and Robert T. Wright who worked for Monsanto Industries co-invented the 1st generation synthetic turf which was originally called Chemgrass. Synthetic turf was formerly manufactured by using the same methods used to produce carpets. These nylon synthetic fibres were initially made with short-pile fibres and installed without any infill.
The first-ever artificial grass installation was done on a recreational area in 1964 at Moses Brown School in Providence, Rhode Island.
In 1965, Judge Roy Hofheinz built the Astrodome in Houston, Texas. Hofheinz consulted with Monsanto about replacing the natural grass with a new synthetic playing surface. This was owing to the Astrodome Stadium’s natural grass dying because of insufficient sunlight due to the harsh conditions of the playing field (the harsh sunlight and severe ray of light blinding and preventing players from catching the ball) which required them to paint the dome, and thus inefficient grass-growing conditions in order to maintain the real grass.
In 1966 the year-old Astrodome in Houston Texas, dubbed the 8th wonder of the world, was recovered in synthetic turf. The Astrodome was home to the Houston Astros Baseball Team and thus changed their name from “the Domed Stadium” to the Astrodome. And this is how “Chemgrass” became Astroturf.
In 1967, Astroturf was patented. The patent for a “monofilament ribbon file product” was issued to inventors Wright and Faria, of Monsanto Industries.
Indiana State University Stadium, in Terre Haute, Indiana became the first outdoor stadium to install Astroturf in 1967.
Synthetic grass was later installed in other multi-purpose stadiums such as Pittsburgh’s Three Rivers Stadium (installed in 1983), Philadelphia’s Veterans Stadium, and Cincinnati’s Riverfront Stadium.
2nd Generation Artificial Grass
In early 1970, synthetic turf systems featured longer fibres made of polypropylene which was cheaper and softer than nylon. The tufts were packed more widely apart which proved to be less abrasive and more flattering and grass-like. Sand infills were introduced into the installation systems used between the fibres to form adequate firmness and stability for players using the surface.
Second generation artificial turf fields presented a flatter playing surface than natural grass, providing better ball control and preventing balls from shooting off in unexpected directions.
This was greatly acceptable by Hockey Sports as the shorter fibre structures improved speed significantly. This has not only increased the speed of the game by putting a greater demand on the conditioning of the players but also changed the shape of hockey sticks to allow for different techniques, such as reverse stick trapping and hitting.
3rd Generation Artificial Grass
In the mid-1990s, artificial turfs were manufactured with polyethylene fibres instead of polypropylene which are chemically-treated high-quality constituents making them UV resistant, which protects the colour of the fake grass from fading due to harsh weather conditions, water-resistant, softer, less abrasive, and more durable. 3G surfaces are also manufactured with a “thatch layer” which is typically curly shorter yarn situated in the fibres and backing for better cushioning or support. A mixture of rubber granules in addition to a stabilizing layer of sand is used as an infill to ensure a more durable, stable, comfortable and safer playing surface that looks and performs more like real-grass than ever before.
In the late 1990s, UEFA became heavily involved in the testing of artificial turf in order to meet with FIFA standards.
In 2000, the Tropicana Field, a domed stadium located in St Pietersburg, Florida, United States became the first Major League Baseball Team to use 3rd generation synthetic turf.
In February 2001, FIFA launched its FIFA Quality Concept. FIFA designated a star system for synthetic turf fields that have undergone a series of tests examining quality and performance based on a two-star system.
In August 2005, Heracles Almelo, a Dutch professional football club in Almelo received the first certificate from FIFA.
In 2009, FIFA launched the Preferred Producer Initiative to improve the quality of artificial football turf at each stage of the life cycle (manufacturing, installation and maintenance).
There are currently seven FIFA preferred producers: CC Grass, Limonta Sport, Domo Sports Grass, GreenFields, Edel Grass, Saltex and Field Turf. These firms have made quality guarantees directly to FIFA and have agreed to increased research and development. We are proud to announce our FT Pro football artificial grass at Arturf Africa is supplied by Limonta Sport.
The next generation?
There are some companies referring to 4G or even 5G synthetic turf products, although these are not yet recognized or accepted by any of the sport’s governing bodies, such as FIFA, FIH or World Rugby.
Perhaps the next generation will see non-infill surfaces with the same performance attributes and playing qualities that can be certified for play by the governing bodies.
How is artificial grass made?
Artificial grass is essentially made up of three parts, being:
1. The artificial grass fibre (fibres are also referred to as yarns or blades)
The fibres or blades are made from polypropylene and are either manufactured into monofilament or fibrillated (also known as slit-film) structures.
Monofilament blades are extruded through a spinneret where the die hole of the spinneret regulates the cross-section of the blade whereas fibrillated blades are produced by foil extrusion.
The design of the turf blade plays an important role in the performance characteristics of the synthetic turf pitch. The fibres are responsible for the comfort and safety of the player, durability, soft feel, and natural grass-like appearance.
Ideal fibres should reduce skin friction, skin abrasion, and offer superior durability, high resilience, and temperature stability.
2. Thatch Layer
This is the curly yarn which gives added support and cushioning to the artificial lawn.
Artificial grass backings are comprised of a primary backing and a secondary backing. They work together to provide dimensional stability to the entire system.
The primary backing is comprised of woven polypropylene materials that allow the artificial turf fibres to be tufted into the material in rows and facilitate seaming between artificial turf panels.
The secondary backing is often referred to as the ‘latex coating’ or ‘polyurethane coating’ and is applied to the reverse side of the primary backing in order to permanently lock the tufted fibres in place.
Artificial Grass Manufacturing process:
- High-quality resin pellets are melted down to form the artificial grass yarns. It is in this melting process that UV inhibitors, stabilizers, colours, and other additives.
- The melted plastic is extruded through a steel plate producing long thin strands.
- These strands exit the steel plate into a trough of water which solidifies the synthetic grass mixture. A machine pulls the strands through a large pulley keeping the strands separated.
- Rollers stretch the strands until they become as thin as real grass.
- The strands are wound around spools like cotton. Once a spool has been filled, different colour strands are woven together to form multiple synthetic yarns. The yarn is prevented from slackening by traveling through guides while it is coiled around a giant spool.
- Once artificial grass yarns are completed, they can be tufted into a backing. The backing is a woven fabric/cloth that forms the back of the synthetic grass.
- The yarns are tufted into the backing in loops. Tufting is a process where a needle (like a big sewing needle) is pushed through the backing together with the yarn to form a loop or a pile. The loops are cut to create individual piles so that the yarn appears like grass blades.
- The backing is moved through a coating roller that uses latex or polyurethane, a liquid-adhesive product that is applied to the backside of the backing to fix the yarns.
- The liquid adhesive hardens and merges forces with the woven baking to give rigidity to the carpet and to fix the grass piles.
- During this coating process, small holes are punched into the grass carpet backing for drainage.
- The last step in production is the quality and specification inspection. Some of these tests include measuring the turf fibre length and minor trimming as well as durability tests.
You can also view this video by “How it’s Made” https://youtu.be/b91cXZ1l2uQ
- The area to be installed is measured
- Materials for the installation are procured
- First, the existing grass/soil/sand is removed
- The area is then excavated, levelled, and compacted
- A geotextile membrane is laid down to prevent weeds from growing through.
- A 50mm crusher/quarry dust base, with the largest stone being 6mm in diameter, is built for drainage
- The area is again levelled and compacted using specified equipment
- Cement borders are arranged on the edges of the surface for ease of fastening down the artificial grass carpet. These borders are non-decorative and should be allowed to dry before laying down the synthetic turf.
- The artificial grass is then placed on the ready to lay surface and trimmed to perfectly match the edges of the surface of the installation.
- If there are two carpets to be joined, this will be done first by gluing the carpets to the joining/seaming tape and then gluing down the perimeter to the cement borders.
- Once the glue is dry, the area is then covered in silica sand (which helps the artificial grass blades remain upright, promotes the longevity of the grass, reduces the heat in hot weather and makes the grass appear more natural)
- The silica sand is then brushed in using a mechanical power tool to brush it in evenly.
- For a sports field, rubber granules are added in addition to silica sand for adequate support