The Secret To EVA Foam Expansion

EVA foam typically expands 3-40 times, much like the fermentation process of bread. When ethylene-vinyl acetate copolymer encounters a foaming agent:

Basic Expansion: Ordinary foaming processes achieve 3-15 times expansion.

High-Pressure Foaming: Special processes can achieve 20-40 times expansion.

Height Conversion: A 1cm thick raw material with 10 times expansion can be increased to approximately 10cm.

Thickness Performance in Practical Applications: EVA foam in different scenarios is like deformable clay:

Sports Insoles: Typically uses 8-12 times foaming, resulting in a finished thickness of approximately 5-8mm.

Packaging Materials: Commonly uses 15-25 times foaming, achieving a cushioning layer of 3-5cm.

Yoga Mats: Choose 6-8 times foaming to balance elasticity and support.

Key Variables Affecting Thickness: These factors cause the expansion effect of EVA foam to fluctuate dramatically:

Temperature Control: A 5℃ deviation in foaming temperature can lead to a 10% change in thickness.

Raw Material Ratio: Increasing the foaming agent by 1% may increase the expansion ratio by 15%.

Cooling Rate: Rapid cooling may reduce the finished product thickness by 20%.

Mold Design: Closed molds have 30% higher thickness uniformity than open molds.