What material is used for sports shoe soles?

For shoe soles, the materials used in sports shoes are mainly EVA, TPR, and rubber. Among these, EVA is the lightest and offers good flexibility; most sports shoes use EVA soles. However, EVA has little friction, which can lead to slipping on smooth surfaces, so it is common to add some rigid material to the bottom layer of EVA soles. TPR and rubber are both heavier materials with moderate flexibility but high friction; they are often used in leather shoes and children’s sports shoes. Unlike EVA, TPR and rubber do not deform easily. High-end brands like ADIDAS use a combination of TPU and EVA. TPU is wear-resistant

For the sole, the materials used in sports shoes are mainly EVA, as well as TPR and rubber. Among these, EVA is the lightest material and possesses good flexibility; most sports shoes use EVA soles. However, EVA has little friction, which can make it easy to slip on smooth surfaces. That’s why a hard material is usually added to the bottom layer of the EVA sole. TPR and rubber are both heavier materials with average flexibility, but they offer good friction. In children’s sports shoes, TPR and rubber are preferred over EVA because they are less likely to deform. 1. The materials used for the sole can be simply described as natural rubber or synthetic rubber. (1) Natural rubber: The advantage of natural rubber is its great softness and excellent elasticity, which make it suitable for various sports. However, its obvious drawback is its poor wear resistance. Indoor sports shoes often use natural rubber. 2. Synthetic rubber is further divided into wear-resistant rubber, environmentally friendly rubber, air rubber, sticky rubber, rigid rubber, and carbon-added rubber. (1) Wear-resistant rubber: Wear-resistant rubber has excellent wear resistance and toughness, which makes it very durable; this type of rubber material is generally used in the soles of tennis shoes. (2) Environmentally friendly rubber: Also known as recycled rubber, this type of rubber sole contains up to 10% recycled rubber, with the main purpose being to protect the environment. (3) Air rubber: It contains air within the rubber, which provides some shock absorption capability; however, it is not very wear-resistant and its applications are limited. (4) Sticky rubber: Sticky rubber is characterized by its good flexibility and high anti-slip properties; it is generally used in indoor sports shoes. (5) Rigid rubber: Rigid rubber is the most versatile type of rubber used in sole materials; it is tough, non-slipping, and highly wear-resistant, which naturally leads to its wide range of applications. This type of rubber is commonly used for the soles of multi-functional shoes and basketball shoes. (6) Carbon-enhanced rubber: Carbon elements are added to ordinary rubber materials, making the rubber more tough and wear-resistant. This type of rubber is used in most running shoes, and the letters BRS can be found on the rear part of the shoe sole to indicate that carbon-enhanced rubber has been used in the sole. 3. Rubber-based outsole: This type of outsole is not common; its raw material is industrial glue, which is mixed using a mixer and then poured into molds to be heated and shaped. Its characteristics are softness and excellent slip resistance. II. Midsole 1. As for the midsoles used in sneakers, I think many people already know what they are; they are PHYLON midsoles, which are the most common alongside EVA midsoles. In fact, both types of midsoles belong to the same category, namely engineering plastics; then why are there different names for them? PHYLON originated in the United States; the earliest insoles were all called PHYLON, with no distinction between EVA insoles and PHYLON insoles. As shoe products continued to develop, research and development facilities for major brand shoes in Taiwan and South Korea introduced a more systematic classification for insoles, which led to the emergence of what we know today as EVA insoles. Next, I will explain in simple terms the differences between the EVA midsole and the PHYLON midsole. The most commonly used midsole material in shoes today is PHYLON. The main advantages of PHYLON are its light weight, good elasticity, and excellent shock-absorbing properties; it is referred to as a second-stage foaming material. The EVA midsole is also lightweight, but its shock-absorbing capabilities and elasticity are far inferior to those of the PHYLON midsole; moreover, its cost is much lower than that of PHYLON. The EVA midsole is known as a one-shot foam midsole. The reason why they have the same properties but different names and performance levels is that PHYLON undergoes secondary foaming, while EVA undergoes primary foaming. (1) Single-shot foaming: A shoe midsole that is formed in one step by injecting material into a mold and then heating it at high temperatures is called a single-shot foamed midsole, or EVA shoe midsole. (2) Secondary foaming: After the material is injected into the mold, the midsole is formed through two rounds of high-temperature heating; such a midsole is known as a secondary-foamed midsole, which is what we commonly refer to as PHYLON midsole. The hardness of PHYLON is also controlled by temperature; during the firing process of the PHYLON midsole, the higher the temperature, the greater the density of the resulting PHYLON, and thus the harder it becomes. The lower the heating temperature, the lighter and softer the PHYLON that is produced. Therefore, the quality of a shoe’s midsole cannot be assessed based on its weight or degree of softness. (3) Lined midsole: The lined midsole is also a PHYLON midsole; it is simply a shoe-making technique used by designers to achieve a cohesive overall design. The best example of this is when the same material is used for both the midsole and the upper of the shoe, which contributes to a seamless integration between the upper and the sole – and this is also one of the highlights of this shoe’s manufacturing process. To achieve this process, the already formed PHYLON midsole is wrapped in selected fabric, and then heated in a mold, resulting in a shoe midsole with a fabric-like texture, just like the LB1 we see. 2. PU midsole: In addition to PHYLON and EVA midsoles, PU midsoles are also very common. The greatest advantage of PU midsoles is their good elasticity and toughness. 3. Encased midsole: Many sneakers these days use an internal midsole structure, also known as an encased midsole. Series like the well-known T-MAC series, as well as Nike’s Air series, all feature a wrapped midsole structure. From the outside, the midsole appears to consist of two main parts: the outsole and the upper, but in reality it is made up of three parts – the outsole, the midsole, and the upper – with the midsole being wrapped inside the upper. III. Insole and Integrated Sole 1. Insole: The insole can also be used as a type of midsole. Unlike a regular midsole, the insole is a layer that is enclosed within the outer sole of the shoe. For example, the FORCE1 features an insole structure; it is not a single rubber sole as it might appear on the outside. In fact, inside the rubber sole, there is a midsole, which is also known as an MD midsole and is produced through EVA one-shot foaming. 2. Monolithic sole: (1) The most common type of monolithic sole is the EVA one-shot molded sole; such soles are inexpensive, but they offer poor traction – when wet, they make walking feel like skating on roller skates. REEBOK’s 3D soles are the best representation of such EVA one-shot molded soles. (3) PU overall sole: ADI and Nike use this type of sole not very often; PU soles are those that are molded at low temperatures. The advantage of PU soles is their light weight, but they should not be exposed to water, as contact with water triggers a chemical reaction that causes them to corrode layer by layer. (4) Pure rubber soles: Pure rubber soles are commonly used in outdoor hiking shoes, as well as in work shoes and electrician’s shoes. The entire sole is made entirely of rubber; the advantage is that it is wear-resistant and non-slip, while the disadvantage is that it is too heavy. This type of sole is generally used in CAT’s work shoes, and it is also known as an insulating sole.

Generally, polyurethanes that are not very hard are the most common

There are quite a few EVA options; you can tell just by looking at the packaging

Most sports shoes are made of polyurethane.

I agree with what was said on the 2nd floor; there are quite a few Evas. Since many sports shoe soles are foamed, EVA is suitable for foaming. The dense part should be made of polyurethane, as it is highly wear-resistant.

If it’s a low-end sports shoe, I guess the foam part is likely made of PVC.

Now, many shoe soles are starting to use carbon fiber! It mainly involves adding carbon plates, such as in some hiking shoes, running shoes, and so on!

Basically, EVA, TPR, and rubber are used; among these, EVA is the lightest material and possesses good flexibility. Most sports shoes use EVA soles. However, EVA has little friction, which makes it easy to slip on smooth surfaces. That’s why a hard material is usually added to the bottom layer of EVA-based soles. TPR and rubber are both heavier materials with moderate flexibility but high friction; they are often used in leather shoes and children’s sports shoes. The difference between TPR and rubber and EVA is that TPR and rubber are less likely to deform

It is made of polyurethane elastomer.

There are many types: soft, low-quality ones include EVA and PVC, while high-quality ones include PU

TPE insoles for shoes made from SBS and SEBS are currently the most widely used.