Material Breakthroughs Lead to Best Performing Turf

The history of synthetic turf dates back to the 1960’s when Monsanto developed what later became known as Astroturf for the Astrodome in Houston, Texas, home of major league baseball's Houston Astros. The advent of domed, indoor stadiums and their inability to support a natural turf playing field soon caused the use of synthetic turf to spread throughout the major leagues and other professional and collegiate athletics. Back then, the turf fields were made from Nylon 6,6, and the filament was unforgiving and rough to players, causing frictional burns from falling and sliding on the surface.

This early turf soon gave way to the second generation of synthetic fields in the 1970s. This time, the material of choice was polypropylene (PP) and it was European companies that brought it to market in 1976. This shift saw the industry going to a longer, tufted filament plus the addition of sand infills, making the material more forgiving to the players.

In the 1990’s and through the present day, most turf fields around the world are made with linear low density polyethylene (LLDPE). The use of this material was a breakthrough, and for more reasons than one. The LLDPE material was much softer and it “gave” better. It also featured greater traction than the previous generations of turf, which was supplemented by the inclusion of infills made of sand and recycled rubber. Most stadiums and fields in the world today use this third generation turf system. (Source)

The move to LLDPE fields was driven by safety of the players. These were not the “rugburn” inducing fields of previous generations, and players groups from all over professional sports supported these third generation fields. Instead of fighting against artificial surfaces, many of today’s players prefer synthetic turf for safety, aesthetics and duration of play on one field.

But what came along with the switch to LLDPE fields was quite surprising, and further supports the use of the material. When subjected to weathering testing, the LLDPE fields were able to hold their color longer - much longer - than the previous two materials (Nylon 6,6 and PP).

FIFA, the international governing body of soccer, recommends 3,000 hours of accelerated weathering testing on turf in a QUV device to determine color hold. At Americhem, we’ve found the LLDPE fields can sustain 6,000, 9,000 and even up to 12,000 hours of xenon arc weathering testing and still retain their desired colors. Certain colors are better than others (reds are notoriously less colorfast, for example) and not all colors can hold up to the 12,000 hours of testing, but Americhem’s weathering studies go far beyond what FIFA recommends because we want to be able to make sound recommendations to our customers.

Americhem has released a synthetic turf color selector guide which contains cardwrapped samples of various colors of turf yarn, including greens and a number of popular logo colors. All of the colors recommended in the book can stand up to at least twice the FIFA mandated accelerated tests of 3,000 hours. It’s also in these longer tests that you can see the difference in failure mechanism between the LLDPE and the previous materials. So the material was developed to make life better for the players and, in the end, it also proved to be the superior material from a standpoint of longevity and reduced color fade.

Americhem has written a white paper on the subject of today’s turf fields and weathering. Please contact Scott Blanchard at sblanchard@americhem.com to receive a copy of the white paper or to receive a copy of our turf color selector guide.

Larry Campbell
Americhem’s resident synthetic turf expert

We're Always Learning When it Comes to Weathering

One of Americhem’s core competencies has always been weathering. We help customers understand how their products are going to stand up to the elements, whether they’re used outdoors, like wood composite deck boards, or indoors, like commercial or residential carpeting. We’ve been at the forefront of weathering testing technology for polymeric products for decades, and we’re proud that we’ve helped establish some of the standard weathering tests that are used in various polymeric product industries.

When it comes to weathering, Americhem has a deep knowledge base, and we’re always learning. That’s why the results of a recent long-term outdoor weathering study were very interesting to us. We believe the results urge some caution on the part of building products manufacturers when using accelerated testing as a predictor of real world weathering.

Our researchers tested several polymeric compounds used in building products, including PVC, an enhanced PVC compound, some PVC blends and ASA. The samples were brown in color with lightness (L*) values between 35 and 65. Testing was performed by QUV accelerated testing devices with water spray capabilities (to simulated outdoor moisture/condensation exposure) in accordance with the ASTM D4329 standard. The length of the accelerated testing was 2,500 hours, which is a period determined to be most closely associated with a two-year outdoor exposure period. The outdoor testing was completed after two years at three sites representing three different climates: humid continental Ohio, humid sub-tropical Florida and arid Arizona. The exposed materials, both to accelerated and outdoor testing, were then compared to one another for each material.

For PVC, with typically poor weathering performance, the samples weathered equally poorly in accelerated and outdoor exposure. Enhanced PVC weathered well in outdoor trials at all three locations, but accelerated tests showed much more color fade than the real world trials. So if accelerated QUV testing results were given significant weight, the material which performed very well in the real world might never have been produced.

In PVC blends containing PVC and varying amounts ASA or acrylic, the correlation between accelerated and outdoor weathering was also quite weak. Additionally, the weathering performance was inconsistent between the three outdoor sites. We drew the conclusion that the materials in blends might not be fully compatible, forming two separate weathering phases. Finally, ASA was tested and found to be highly weatherable and well correlated between accelerated QUV testing and real world outdoor weathering.

What did we learn? We considered these to be the major takeaways:

• Enhanced PVC and ASA are good performers and superior to PVC and PVC blends in weatherability.
• Outdoor testing in end-use environments is vital, because accelerated weathering’s ability to predict performance is at least somewhat inaccurate.
• QUV testing results are more apt to be accurate with single polymer compounds.

So, Americhem’s weathering experts are learning every day. The results of their work can have a big impact on the producers of polymeric building products, and we hope this insight can be of assistance to our customers. Americhem is working on a white paper which will be available soon that contains much more detail on this important study. In the meantime, to learn more about Americhem’s weathering capabilities visit our website.

Scott Blanchard

Senior Corporate Marketing Specialist