As we all know, more and more people now pay attention to the comfort of shoes, and shoes with EVA soles meet the needs of modern people today. High toughness, EVA sole resilience and resistance to tension, has a good shockproof, buffer performance, heat insulation, excellent insulation cold and low temperature resistance, resistant to cold and exposure, airtight bubble hole, sound insulation effect is good, airtight bubble pore structure, non-absorbent, moisture-proof, good water resistance, resistance to sea water, oil, acid, alkali and other chemical corrosion, antibacterial, non-toxic, tasteless, no pollution.

The material used in EVA sole is ethylene/vinyl acetate copolymer (also known as EthyleneVinylAcetate copolymer), which is prepared by the copolymerization of ethylene (E) and vinyl acetate (VA). EVA for short, content in 5% ~ 40%. Compared with polyethylene, EVA, due to the introduction of vinyl acetate monomer in the molecular chain, thereby reducing the high crystallinity, improve the flexibility, impact resistance, filler solubility and thermal sealing performance, is widely used in the foamy shoe material, functional shed film, packaging film, hot melt adhesive, wire and cable and toys and other fields.

EVA soles are characterized by good softness, rubber-like elasticity, good flexibility, transparency and surface gloss under 0℃, good chemical stability, good anti-aging and ozone resistance, non-toxic. It has good mixing with filler, good coloring and forming processability.

It is closely related to the content of ethylene acetate, molecular weight and melt index. When the melt index (MI) is constant and the content of vinyl acetate (VA) is increased, its elasticity, softness, solubility and transparency are also improved. When the VA content is reduced, the performance is close to polyethylene, rigidity is increased, wear resistance, electrical insulation is improved. If the VA content of EVA sole is constant, the melt index will increase, the softening point will decrease, the workability and surface gloss will improve, but the strength will decrease. Otherwise, with the decrease of MI, the molecular weight will increase, and the impact performance and environmental stress cracking resistance will improve. The polarity of acetic acid increases the elasticity and viscosity, decreases the crystallinity and electrical properties, and is soluble in hydrocarbon solvents and oils.