The English name of polyethylene: polyethylene, abbreviated as PE, is a thermoplastic resin polymerized from ethylene. In industry, it also includes copolymers of ethylene and a small amount of α-olefins. Polyethylene is odorless and nontoxic, feels like wax, and has excellent low temperature resistance (the lowest service temperature can reach -70 ~- 100℃), good chemical stability, resistance to most acids and bases (not oxidative acids), insolubility in general solvents at room temperature, low water absorption and excellent electrical insulation performance.

Ethylene-vinyl acetate copolymer (EVA)

The ethylene-vinyl acetate copolymer is an ethylene-vinyl acetate copolymer. Generally, the content of vinyl acetate (VA) is 5% ~ 40%. Compared with polyethylene, EVA is widely used in foam shoes, functional shed films, packaging films, hot melt adhesives, wires and cables, toys and other fields because of the introduction of vinyl acetate monomer in the molecular chain, which reduces the high crystallinity and improves the flexibility, impact resistance, filler compatibility and heat sealing performance.

It is a common midsole material, usually called primary foaming, which has a certain cushioning effect, but this material is slippery, so it is usually mixed with hard rubber. EVA is a common material, which is found in many sports shoes, but it is difficult to compare with air in effect.