Study of Compression Set of Ethylene Vinyl Acetate (EVA) Foams

Ethylene vinyl acetate (EVA) foams were used to measure the change in compression set with test temperature variations. In particular, the compression set is expected to increase as the temperature increases. However, for practical studies, diameter shrinkage occurs at high temperatures, and the compression set decreases. It is because the existing compression set only reflects the height change due to compression, and the current compression set has difficulty in explaining the compression set at high temperature with diameter shrinkage. In this study, the concept of volume compression set reflecting both diameter and height was introduced. The new volume compression set explained very well the compression behavior of EVA foams at high temperatures. In addition, the concept of volume compression set is expected to help set the standard for judging the heat resistance and durability of foams at elevated temperatures.