FAQs – Backing
Have you ever wondered how synthetic turf has been designed to imitate natural grass? The backing is the final stage in the manufacturing process, that helps to make sure that the fibres are secured in place, in the same way a root would grip the grass. This ensures the finished synthetic turf meets the required sporting quality. We’re often asked about this step, so we’ve compiled this list of FAQs to help out.
What is the primary role of synthetic turf backing?
There are two main functions in synthetic turf backing. The first is simply to provide a medium through which the synthetic grass fibres are tufted. This is known as the backing cloth. Sometimes more than one layer of backing cloth is used, to help with the second function of backing.
This is to secure the fibres and prevent them from falling or being pulled out. When the needle punches the yarn through the backing cloth it leaves a hole. Using two backing cloths helps to restrict the hole and provide a little grip on the yarn. After this the secondary coating is applied. If this is latex or PU material, it is applied in liquid form, with the idea of covering the back of the turf, thereby securing the fibre tufts. To improve the strength (tuft lock) some of the secondary backing will be soaked, either into the primary backing, or through the small hole from tufting.
Once the secondary backing is dried in the ovens, the tuft is now secured. This is checked against the required measurements before the turf is then sent to the roll up unit.
What is the best secondary backing to go with?
In Europe, the most common form of secondary backing is latex. This gives a good tuft lock but can be susceptible to damp or wet conditions. Latex absorbs water and, unless fully dried during production, may cause issues leading to a reduction in tuft lock. If correctly applied, this rarely happens, making latex a lower cost option for synthetic turf backing.
In the US and other parts of the world, PU is a more commonly used material. PU is not affected by moisture and does not weaken. It also provides a stronger bond with the correct adhesive, making for securer roll edge joints. The strength of a PU backed product is normally stronger than latex, but it is also more expensive.
More recently fully recyclable backings have been introduced, including the PRT system from CCGrass. This produces an even stronger seam joint than PU, is up to 5 times more porous and much lighter, making installation easier. PRT can be fully recycled at a local plastic recycling plant, at end of life, but is a more expensive initial backing option.
Why do some products have heavier backing weight than others?
Our industry consists of specialist synthetic turf producers who have backing lines designed specifically for artificial grass, and producers who use their existing carpet ovens to back their turf. These companies have much longer backing lines and therefore require more latex to be applied; achieved through adding additives into the latex, such as water and chalk. This results in heavier backing weights.
It should be noted that this does not mean that the tuft lock is any stronger, only that the extra weight is a production necessity not a product advantage.
Generally more latex is applied to a backing cloth than PU. This is due to the need to achieve a targeted tuft pull result, which is achieved by PU with a lighter coating.