Publish Time: 2022-02-03 Origin: Site
EVA is a random copolymer composed of ethylene and vinyl acetate. Vinyl acetate (VA) is used as a flexible segment in the EVA molecular chain, and ethylene is used as a crystalline segment, which shows a certain degree of softness and high elasticity as a whole.
In terms of technology, EVA generally adopts chemical in-mold foaming in the shoemaking industry. The EVA pellets are put into the foaming mold, and high temperature and high pressure are applied to make it foam. By foaming EVA, the sole can be made lighter. The EVA resin with a certain elasticity can make the sole have a proper cushioning function so that the EVA foam shoe material can meet the needs of most casual shoes and jogging shoes. After foaming, the resilience of EVA can generally be increased to 50-55%, or even higher.
EVA blended foam products are widely used in the soles and interior materials of middle and high-end travel shoes, hiking shoes, slippers, and sandals. And because of the price advantage of EVA foam material, it will still be the leading material choice for mass sports shoes for a long time in the future.
TPU is a thermoplastic polyurethane elastomer, a block copolymer composed of diisocyanate, chain extender, and polyol. The soft segment composed of polyols exhibits flexibility and toughness. At the same time, diisocyanate acts as a hard segment to impart hardness and rigidity to the material, and the hard segment acts as a physical cross-linking point after crystallization, making TPU exhibit high elasticity. Therefore, TPU has significant advantages such as high tensile strength, elongation, and low long-term compression set.
In terms of technology, the ETPU midsole adopts physical foaming. Compared with the chemical foaming of EVA, it has no taste and is environmentally friendly and recyclable. The wet slip performance is also far superior to the traditional EVA material. The foamed TPU is ETPU, and the rebound value of the foam falling ball can reach 60%, which is significantly higher than that of EVA. It is equivalent to the rebound of the shoe when the shoe hits the ground, which can effectively reduce muscle fatigue, reduce muscle shaking, and allow you to run farther with full power.
However, the price of ETPU is higher than that of EVA, which discourages some manufacturers, and there are specific difficulties in process innovation. But these are all temporary. Many manufacturers have tried to bring ETPU materials to a broader range of downstream applications. For example, the successful commercial application is ETPU plastic track. More commercial applications have appeared in our In the field of vision in recent years, such as ETPU bicycle seat pads, sports protective pads, ETPU children's crawling pads, bicycle helmet padding, car seat padding, etc.
In general, the price of ETPU is higher than that of EVA. Still, ETPU is much better than EVA in terms of resilience, deformation recovery, abrasion resistance, and wet skid resistance.
Dongguan Changying Sponge Products Co., Ltd. is a professional EVA shoe manufacturer. We offer professional OEM ODM service. Welcome to contact us.
DONGGUAN CHANGYING SPONGE PRODUCTS CO., LTD.
Sophia Chen
Email: sophia@evafoamproducts.com
Whatsapp/Wechat/Cellphone: +86 13717157339