The material used for EVA soles is ethylene/vinyl acetate * * * polymer (also known as ethylene-vinyl acetate * * * polymer), which is polymerized from ethylene (E) and vinyl acetate (VA)***, and the English full name is: EthyleneVinylAcetate. EVA for short, the content 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.

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EVA sole features:

EVA soles are characterized by good flexibility, rubber-like elasticity, good flexibility below 0℃, good transparency and surface gloss, good chemical stability, good anti-aging and ozone resistance, and no toxicity. Good miscibility with filler, good coloring and molding processability.

It has a great relationship with vinyl acetate content, molecular weight and melting index. When the melt index (MI) is fixed and the content of vinyl acetate (VA) is increased, its elasticity, flexibility, compatibility and transparency are also improved. When the content of VA decreases, its properties are close to those of polyethylene, its rigidity increases, and its wear resistance and electrical insulation improve.

If the content of VA remains unchanged, the melt index will increase, the softening point will decrease, the processability and surface gloss will improve but the strength will decrease. Otherwise, with the decrease of MI, the molecular weight will increase, and the impact resistance and environmental stress cracking resistance will improve. The polarity of acetate increases elasticity and viscosity, but decreases crystallinity and electrical properties. It is soluble in hydrocarbon solvents and oils.

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