Polyolefin materials and technology in artificial turf I: Yarn developments

Abstract

Artificial turf surfaces with “soft” yarns are increasingly used because of haptic attractiveness and player-friendliness. Linear low density polyethylene (LLDPE) with low density is preferred to achieve the desired softness. The choice of LLDPE material is guided by the performance requirements outlined in the FIFA Quality Concept for football turf. Different LLDPE materials were extruded into monofilament yarns on production scale machinery. Yarn tenacity, elongation and shrinkage were characterized and built into a statistical model to relate processing conditions and material properties to yarn performance. Processing conditions and choice of particular LLDPE greatly influence yarn performance. Shrinkage is identified as an important measure to characterize residual stress in low density LLDPE yarns and can be related to performance in the Lisport test used to determine the durability of an artificial turf yarn. The model results are used to optimize properties of yarn made with a given low density LLDPE. Improved durability and softness is shown to be synergistic with superior elastic recovery (resiliency) of low density LLDPE. With use of the processing model the performance of artificial turf yarns can be optimized for the best possible playing conditions.

Keywords:

• Artificial turf
• durability
• resiliency
• polyethylene