Infill is the loose particles that are brushed into the synthetic turf playing field’s carpet.
The taller fibers used today are usually made of polyethylene (PE), a non-abrasive and relatively durable material. However, PE is, chemically speaking, a lazy fiber — it needs other more resilient materials to hold it up. Otherwise it would just fall down and would not last the full warranty period. This is done with infill particles and/or with more resilient nylon fibers.
Infill is often used to absorb the impact of falls.
Infill is also used to stabilize the turf carpet. By weighing down the turf, infill can help prevent movement and wrinkling.
You Should Know:
Due to recent public controversies about crumb rubber, alternative infills are getting more attention, and clients are demanding more options. But, all too often, we see clients, designers, and other turf companies look at alternative infill options in a vacuum. They say, “Oh, no crumb rubber? Let’s just substitute something else.” Rather, infill should be looked at as one element of an overall system that is comprised of synthetic turf carpet, infill, and pad, with each element interacting and affecting the others.
Dropping a very expensive alternative infill into the same carpet that would have been used with crumb rubber and sand is wasteful. Instead, AstroTurf has designed systems specifically for alternative infills. With a shorter, denser turf carpet and a pad, you can often get the guaranteed shock absorption of a re-usable pad, the performance of a cutting-edge infill, and increased density and durability from the turf carpet… all for about the same price you would spend sinking more alternative infill into a taller system!
We’ll walk you through a variety of commonly used sports grass infills below.
SBR stands for Styrene-Butadiene Rubber. It is by far the most commonly used infill material in synthetic turf fields. It is made of ground up recycled tires.
- Most economical shock absorbing infill
- Most widely studied infill (70+ independent studies)
- No study has ever found ill environmental or human health effects
- Absorbs shock
- Moves with play, requiring more maintenance to preserve safe shock absorption at all areas of the field (when used without a pad)
- Less cutting-edge infill technology (has been around for 20+ years)
- Negative perceptions regarding safety in the general public
- Higher field temperatures
Greenplay Organic Infill
Greenplay organic infill is produced with a proprietary blend of natural ground cork and coconut fibers. The cork is a durable, high density variety. The coconut fibers utilized are taken from the hearty, rich, and robust inner pith of the coconut shell. Importantly, the coconut fibers are taken from coconuts that are completely pesticide and chemical-free.
- VERY natural feel and playability
- Good energy restitution
- Cooler field temperatures
- Excellent aesthetics (organic infill forms around synthetic turf fibers, helping to lift them)
- No “tire store smell” like crumb rubber fields exhibit
- Greater upfront investment than crumb rubber
- Requires use of pad
- Requires more maintenance than traditional crumb rubber fields (but less than natural grass fields)
- Must remain moderately damp to prevent caking. Amount of watering will depend on local climate and weather conditions. Very humid areas that receive ample rain may need as little as 1-2 waterings per year, whereas very arid climates may require watering as often as 1-2 times per week.
- Requires an annual top-off of one to two supersacks, at an annual materials cost of approximately $2500-$3000 per year.
Ethylene Propylene Diene Monomer (EPDM) is a virgin rubber material. It is a high quality, high dollar replacement for crumb rubber.
- Few issues with quality in the marketplace
- Attenuates shock
- Very high melting point
- No negative perceptions in the marketplace
- Very expensive
- Aside from overcoming the perception issue, offers little performance advantage over crumb rubber
ZeoFill is a brand of zeolite. ZeoFill is a very interesting infill. Used for industrial waste cleanup and sold in healthfood stores, zeolites have a honeycomb molecular shape that allows the material to absorb and contain toxins. This molecular shape also allows it to absorb and slowly release water for noticeably cool field temperatures.
- No tire-store smell
- Absorbs and slowly releases water for lasting temperature reduction
- Does not require water
- Does not require additional maintenance
- Inexpensive alternative infill
- Must be obtained from Death Valley mine for optimal purity and hardness (This is why AstroTurf only uses ZeoFill)
- Does not absorb shock on its own, but added pad creates completely consistent impact attenuation.
Silica sand is often used for synthetic turf ballast. It comes from multiple quarries throughout the country, contributing to its low cost. Silica sand is often used in combination with other performance infills.
- Very inexpensive
- Widely used and proven
- No negative market place perceptions
- Good ballast material
- Does not absorb shock (must be used with a pad or shock absorbing infill)
- Compacts. If used in too great a quantity without a pad, will negatively impact shock absorption as it hardens.
- No real benefits aside from ballast
- Can abrade fibers
Nike Grind Infill
Nike Grind has selected AstroTurf as its partner to create cutting-edge turf systems. As such, Nike Grind is ONLY available for AstroTurf systems. Nike Grind infill is a rubber infill material that is derived from the excess materials collected during the manufacturing of Nike shoes. The rubber outsoles are collected, chopped up and sized for optimal field drainage, and encapsulated with a premium green coating that bolsters infill resiliency and creates a more uniform and plush field appearance.
- Nike Grind is engineered for human contact and conforms to Nike’s stringent quality standards and Restricted Substances List (RSL)
- Sustainability (Each Nike Grind field diverts 160,000 pounds of materials into next uses)
- Plush and uniform field appearance
- Temperature reduction (versus black crumb rubber)
- One of the more affordable alternative infill selections
- Absorbs shock
- No negative public perception
- Moves with play
- More expensive than crumb rubber
Thermoplastic Elastomers (TPE) are a class of copolymers or a physical mix of polymers (usually a plastic blended with a rubber). These are virgin materials that are either extruded or molded.
- Varied shapes of TPE are less likely to compact
- No perception issues of crumb rubber
- Attenuates shock
- Very expensive
- Must be very careful to purchase TPE with a very high melting point. The industry has seen field failures from TPE sourced out of China.