Specific Gravity (Density) of EVA
EVA (Ethylene-Vinyl Acetate Copolymer) is a thermoplastic resin copolymerized from ethylene and vinyl acetate, with excellent flexibility, toughness and low temperature resistance.
Its density varies in a clear range with VA content, hardness and foaming / filling modification, and density differences among different grades are mainly determined by copolymer components and modification methods, with obvious differences among different grades and modified types, as detailed below:
General-Purpose Injection / Extrusion Grade EVA (VA Content 10%～28%): 0.92～0.95 g/cm³, typical value 0.93 g/cm³, the higher the VA content, the slight increase in density, with simultaneous improvement of hand feel and toughness
High VA Content EVA (VA Content 30%～40%): 0.95～0.97 g/cm³, typical value 0.96 g/cm³, stronger polarity, outstanding adhesion and flexibility, higher density than general-purpose grades
Hot Melt Adhesive Grade EVA: 0.93～0.96 g/cm³, typical value 0.94 g/cm³, suitable for low-temperature melting and bonding requirements, density matching VA content
General Closed-Cell Foamed EVA (Shoe Materials / Packaging): 0.10～0.30 g/cm³, typical value 0.20 g/cm³, the higher the foaming ratio, the lower the density, with excellent lightweight and cushioning performance
High Elasticity / High Ratio Foamed EVA: 0.05～0.15 g/cm³, typical value 0.10 g/cm³, mostly used in high-end shoe materials and sports protectors, with extremely low density and good resilience
Mineral Filled EVA (Calcium Carbonate / Talc Filled): 0.95～1.20 g/cm³, the higher the filler content, the higher the density, used to enhance rigidity, reduce cost and improve processability
Flame Retardant EVA: 0.94～1.05 g/cm³, typical value 0.98 g/cm³, flame retardant addition makes density slightly higher than general-purpose EVA of the same VA content
This density parameter is a core basis for the design of shoe midsoles, packaging cushioning materials, hot melt adhesives, photovoltaic encapsulation films, wire and cable sheaths, children's toys and other products. The adjustability of density with VA content and foaming degree makes it suitable for different softness, lightweight and cushioning requirements. Density calculation is also key data for product weight control, mold cavity design and extrusion / injection / foaming parameter setting, while supporting its core properties of high toughness, low temperature resistance and easy processability.
