The manufacturing process for synthetic turf can vary widely. It starts by taking raw materials – namely, the polymer (polyethylene is now used exclusively for long-pile turf) and color – and melting them in an extruder. The melted material is then either formed into a film and cooled or pushed through a spinneret and cooled. The spinneret features an interchangeable die plate in which holes are cut in the shape desired for the finished fiber. Monofilament turf fibers, which have emerged as a popular alternative to slit film only within the past five years, are manufactured in dozens of different shapes. Rectangles, triangles and diamonds are common, as are turf blades exhibiting one or more vertical spines along their length. One fiber introduced this year combines a concave shape with multiple spines, much like a natural grass blade.
Shape can determine how well a fiber resists fraying or how the entire field responds to heat retention. Above all, various shapes have been introduced to enhance fiber memory – the ability of the filament to stand up after being trampled down. The industry at this point is rapidly changing and new shapes are brought to market almost every 6 months!
But shape is only part of the monofilament fiber equation. The other parts involve the production process and are harder to explain, since both are the stuff of proprietary secret. Suffice to say that even though polyethylene is the polymer of choice among all manufacturers of long-pile synthetic turf, polyethylene formulas vary from one manufacturer to the next as each searches for the right chemistry to balance fiber softness and rigidity. Chemistry also plays a role in a field’s ability to maintain color, withstand UV exposure and reflect heat.
Research conducted in 2008 by Dow Chemical Company determined that fibers extruded from octene-based polyethylene resins can last twice as long as those made from butene-based resins, while not significantly adding to the field’s manufacturing cost.
What comes next is anybody’s guess, but it can be guaranteed that manufacturers will continue to tweak yarn formulas and fiber designs in their attempts to stay a step ahead of the competition.