The material of choice in the foam industry for many years was Ethylene-Vinyl Acetate copolymers (EVA). This dominance was based on its flexibility, adhesion performance, and foaming window. In the last ten years, ethylene-a-olefin inter-polymers (or Polyolefin Elastomers (POE)) have been integrated in foam formulations as a means to increase processability and cost efficiency. In recent years, the discovery of INFUSE™ Olefin Block Copolymers (OBC's) has increased the benefits of using ethylene-a-olefin inter-polymers in foam applications. This paper shows that the characteristics that make INFUSE™ OBC's of interest in Crosslinked (XL) foam systems are increased softness, improved shrinkage, and compression set resistance at elevated temperatures. The paper also shows that OBC foams long- term fatigue behavior departs from that of EVA and POE foams with the same cure state. The room temperature data allowed one to draw the following conclusions: (ⅰ) OBC foams showed a more elastic response than EVA and POE as demonstrated by lower final strain and faster recovery after dynamic testing; the elastic response of OBC foams was attributed to its block architecture, and (ⅱ) materials based on short-chain branching (OBC and POE) seemed to recover faster than the foam based on highly branched EVA.
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