Ethylene vinyl acetate (EVA) is a plastic made by combining ethylene and vinyl acetate. It’s very soft and elastic and it can be made into a plastic that’s like rubber, yet extremely tough. It’s considered to be a safe alternative to PVC. EVA can also be made into EVA foam, with the use of a plasticizer.
EVA is a thermoplastic polymer. EVA materials have been widely used in shoe materials for a long time. Its blended foamed shoe materials have the properties of softness, good elasticity, shock absorption, chemical resistance, etc., and are widely used in medium and high-end tourist shoes, The soles of hiking shoes, slippers, sandals, etc.
In terms of shoe materials, EVA foaming process generally has three processes: traditional large flat foaming, small in-mold foaming and injection cross-linking foaming. Among them, molded foaming and injection cross-linking foaming are more used. In recent years, with the development of supercritical foaming technology, EVA materials can also realize the foaming application of this technology.
Traditional flat foam ，Small factories generally use this because the cost of machinery and equipment is relatively low. This process is made of plates, which are then made into products through processes such as punching and edging, but the production efficiency is low and there are many leftovers.
In-mold small foaming, which is also called molded foaming, is to pelletize the material prepared according to the formula, weigh it and put it into the opened mold, and the foam will look like a shoe. This process presents higher quality in details and higher dimensional accuracy.