Sports Field - Turf Infill

Sources: Industry and internet research

First of all, sports field turf infill provides shock absorbency and turf stabilization.
Sports field turf particles must be consistent, resilient and able to meet environmental requirements – Rubber helps with shock absorbency, sand helps with vertical deformation or foot stability. Players want a shock absorbent sports field turf that is not too soft. Sand not only adds dimensional stability to the system but will also prevent the system from undergoing excessive surface deformation which can lead to over-stretched ligaments.

Sand and rubber in time will segregate in the sports field turf with the sand dropping to the bottom and the rubber remaining on the top. Obviously the largest contribution to the Gmax is the rubber granules present. Sand with time will compact more quickly than rubber but its contribution to the Gmax value is small. Rubber granules will compact with time but its contribution to the Gmax value being greater will be more significant than the compaction of the sand. The ultimate ability to retain an acceptable Gmax value will therefore depend on the rubber granules. This therefore becomes a reflection on the quality of the rubber granules originally installed in the sports field turf, to a lesser extent the quality of the sand particles initially installed, but ultimately on the quality of the maintenance programme adopted for the sports field turf.

Gmax values can only be maintained if the sports field turf system installed is correct and the maintenance is fully implemented. Gmax values will increase if the rubber granules are allowed to compact due to a lack of maintenance as they would in a partially sand-filled system. The rate of compaction will vary from system to system but is inevitable if the correct maintenance procedures are not in place. Many companies would argue that even an all-rubber system is insufficient and that a shockpad underneath the carpet as well as the rubber infill is necessary to reduce the tendency of the system to compact and consequentially increase the Gmax values. Even such sports field turf systems without maintenance will still compact.

The goals are:
•  Guaranteed durability; excellent strength and protected against ageing
•  Revolutionary contribution towards consistent turf system performance
•  Maximum safety towards environment
•  Maximum safety toward human health;
•  No negative odor; high comfort
•  Infill characteristics should remain consistent throughout the life of the sports field turf product
•  Dust free material
•  No negative interaction between fibre and infill material of the sports field turf.
•  Studs of the shoes can still penetrate into the pitch giving the required grip. For the player this means that he feels a consistent “natural turf pitch"  performance.

EPDM and SBR infill for Sports Field Turf Systems
In some countries for supposed environmental reasons SBR infills are rejected in preference for EPDM. As a general principle Environmental pressure groups regard recycling as the preferred environmental option.

SBR is the rubber in-fill source of the majority of manufacturers of this generation of sports field turf infill systems. Other virgin synthetic rubbers like EPDM granules for example are several times more expensive than reclaimed truck tyre SBR. In fact the term SBR (which is the preferred polymer type in passenger car tyres) is inaccurate as the majority of the compound used in making truck tyres is natural rubber, which is blended with a smaller amount of SBR. Unfortunately the industry has grown accustomed to referring to it as SBR. EPDM stands for Ethylene Propylene Diene Monomer. Rubbers differ from plastics in several ways. One significant aspect is the fact that rubbers are chemically cross-linked. Some rubbers have in-built cross-link sites others have them introduced by copolymerising cross-link sites onto the main backbone. EPDM is of the latter type. The Diene Monomer is the site for cross-linking. Various monomers are used as cross-linking sites for example dicyclopentadiene; ethylidene norbornene and 1,4 hexadiene are typical.

Some countries have adopted so-called environmental legislation, which prevents the use of SBR rubber in sports field turf infill. SBR is cross-linked with various chemicals, some of which contain Zinc compounds, the most usual being Zinc Oxide. Zinc Oxide is not classed as dangerous by the World Health Organisation; in fact on the contrary it is sold at pharmacists as a preventative for the common cold. It is also an ingredient in sun-block lotions and adhesives used in medical tapes. Zinc is an essential mineral for life acting as a coenzyme. In certain countries like Switzerland they have banned recycled SBR (albeit that recycling is supposed to be environmentally friendly). They prefer to use virgin EPDM (the manufacture of virgin rubber uses up depleting oil resources and would therefore be deemed environmentally unfriendly) instead.

There isn't currently the manufacturing capacity to produce the necessary quantities of EPDM to replace SBR around the world.

Other Sports Field Infill Discussion
Both recycled and virgin rubbers have been successfully incorporated as resilient infills in sports field turf infill systems. There have also been notable failures when poor quality recycled materials or poor quality virgin rubber materials have been used. For this reason FIFA has found it necessary to introduce requirements on the performance, environmental resistance and the wear resistance of the rubbers used as in-fill materials. It has been unavoidable to impose these requirements on both recycled and virgin rubber materials because of the failures experienced in some supplies of these products.

ACT Global Sports has always taken attention to this subject by having discussions with the infill industry and the test houses to create awareness in durable solutions for sports field turf infill systems.

ACT Global Sports goal is to provide football fields which meets the norms set by the football organisations. We have obtained three products which has been UEFA certified, four products will meet the lab portion criteria set in the New Quality Concept for Artificial Turf launched by FIFA on March 1, 2005. This newer Quality Concept has been enlarged with additional testing like skin friction and can be classified into One Star and Two Star. Two of our products will meet the criteria in the Two Star classification. In addition, two sports field turf products have also been tested according to the Scandinavian requirements.

The team of ACT Global Sports has a lot of industry experience going back to the days of Astroturf. Our synthetic turf and artificial grass systems can be used for many sports field turf and indoor sports fields needs. The systems are designed to go be more like replicated grass and beyond just fake grass. Sports turf uses include indoor soccer, football turf or soccer turf. You are invited to also inquire more about our synthetic lawn products for environments where simulated grass or waterless lawns is desired.