Three EVA foaming processes for shoes
EVA is an abbreviation of ethylene-vinyl acetate copolymer, which is a random copolymer composed of a non-polar, crystalline ethylene monomer and a highly polar, amorphous vinyl acetate monomer (also known as VA).
Compared with PE, EVA introduces vinyl acetate monomer into the molecular chain, which reduces crystallinity, improves flexibility, impact resistance, improves filler mixing and heat sealing, and generally has a density between 0.91 and 0.93. , transparency and gloss are good.
EVA is a thermoplastic polymer, so it can be used in injection molding, extrusion, blow molding, calendering, rotational molding, vacuum thermoforming, foaming, coating, heat sealing, welding and other processing processes.
EVA materials have been widely used in shoe materials. The blended foam shoes have softness, good elasticity, shock absorption and chemical resistance. They are widely used in medium and high-grade sneakers, hiking shoes, slippers and sandals. Sole and other aspects.
In terms of shoe materials, the EVA foaming process generally has three processes: traditional flat plate large foaming, in-mold small foaming and injection cross-linked foaming, in which molded foaming and injection cross-linking foaming are used more.
1. Traditional flat large foam
Small factories generally use this because the cost of machinery and equipment is relatively low. This process is made of sheet metal, and then made into products by punching, edging and other proc