Views: 114 Author: Site Editor Publish Time: 2024-04-19 Origin: Site
What's the role of the EVA midsole in sneakers?
Huadong Sole, the EVA midsole manufacturer, will make it easy for you to understand.
We'll walk you through this question by clarifying the following 4 points:
What Is Sneaker Midsole?
What Is Eva?
What Is Eva Midsole? Why Use It? Are EVA Midsole Good?
Eva Midsoles In Various Brand Sneakers (Nike, Air Jordan & New Balance)
Imagine a shoe as a car: the outsole is like the wheel, the midsole acts as the suspension system, and the upper is akin to the body of the car. If the suspension system of a vehicle doesn't function well, driving on rough or uneven terrain will be uncomfortable and difficult. A shoe's comfort relies mostly on its midesole. If the midsole lacks quality and cushioning, it could harm your body. Hence, the midsole is the key to a comfortable and supportive pair of athletic shoes, packed with advanced technology.
The EVA material is copolymerized by ethylene (ET) and vinyl acetate (VA) through a high-pressure bulk polymerization process. EVA is regarded as another great ethylene polymer after high-density polyethylene (HDPE), low-density polyethylene (LDPE) and linear low-density polyethylene (LLDPE) due to its excellent performance and wide application range.
The performance of different grades of EVA materials varies, contributing to a wide range of applications. To produce different grades of EVA materials, various conditions and parameters during the polymerization process need to be adjusted, such as the reaction temperature, pressure and the dosage of modifiers and vinyl acetate (VA) which is used to regulate the melt index (MI) and VA content.
During the production of EVA, maintaining a constant melt index (MI) while appropriately increasing the vinyl acetate (VA) content enhances the product's elasticity, flexibility, transparency, resistance to environmental stress cracking, and compatibility with fillers. Conversely, reducing the VA content results in properties resembling polyethylene, with increased rigidity, tensile strength, abrasion resistance, chemical resistance, heat resistance, and electrical insulation.
Similarly, keeping the VA content constant while increasing the MI lowers the softening point and improves processability and surface smoothness. Conversely, decreasing the MI increases the molecular weight, thereby enhancing impact resistance and resistance to environmental stress cracking.
Therefore, manufacturers can select the suitable grade of EVA based on product requirements, market demand, and design concepts.
Simply, Eva midsole is shoe midsole made of EVA foam, a lightweight foam made of thousands of compressed bubbles. EVA midsole is a staple in footwear, offering lightweight, cushioning, and durability.
Compared to other material midsoles, EVA midsole is better in performance thanks to EVA's stable chemical properties and easy modification.
Source: Aibang
EVA is part of the ethylene polymer, known for its stable chemical properties. Its molecular structure includes vinyl acetate (VA) groups, which offer resistance to oxidation and chemical corrosion, making EVA chemically stable overall. This stability allows EVA to withstand exposure to corrosion by seawater, oils, acids, and alkalis. That's why EVA is considered a long-lasting material with antibacterial, non-toxic, odorless, and environmentally friendly features.
The addition of vinyl acetate monomers to EVA's molecular chain reduces its crystallinity, leading to improved elasticity, flexibility, impact resistance, compatibility with fillers, heat sealing ability, and transparency.
As a result, EVA outperforms other ethylene-based materials, particularly in footwear applications. It has become a vital component in the midsoles of athletic shoes, providing comfort, durability, and performance.
Due to its unique molecular structure, EVA possesses superior compounding capabilities compared to other high-quality polymer materials. By using EVA as the primary component and incorporating other polymers as additive modifiers, a new type of modified material can be created, which is often referred to as a "polymer alloy". This results in a material that combines the advantageous features of various polymer materials, enhancing the already excellent properties of EVA.
The compounded derivatives of EVA excel in thermoplastic elastomer materials, offering characteristics such as elasticity, flexibility, shock resistance, abrasion resistance, corrosion resistance, environmental stress crack resistance, and water resistance. As a result, it has become the preferred choice for trendy brand athletic, training, and casual footwear soles.
Shoe sole manufacturers usually customize different functional shoe sole products based on the modified EVA materials, utilizing various injection molding techniques to meet specific requirements and provide a variety of footwear shoe midsole options.
Nike Lunar uses the copolymer of EVA and nitrile rubber. This mixture is 30% lighter compared to EVA and Phylon.
Souce: Nike
The classic Air Jordan 10 midsole is made of Phylon, a type of secondary EVA foaming material. Compared to EVA, phylon is lighter, more elastic, and offers excellent cushioning properties. Currently, most of Nike's basketball shoes also feature Phylon midsoles.
Source: Air Jordan
Phylite is composed of 60% Phylon and 40% rubber. It is lighter than rubber but heavier than Phylon. Footwear made with this material, such as the Nike FREE RUN series, is characterized by lightweight and flexibility.
Source：NIKE
New Balance Casual Shoes EVA-based Midsole (Fresh Foam)
Fresh Foam, derived from modified EVA, is more precise, softer, lighter, and offers better cushioning compared to EVA. Currently, the majority of New Balance casual shoes feature Fresh Foam midsoles.
Source: New Balance
Huadong Sole, a professional shoe sole manufacturer & supplier, operates our own shoe sole manufacturing factory in China. We can provide high quality eva shoe soles that meet your shoe making requirements at an affordable price! Get a quote now!
