The material of the sole (二)

2. Midsole

1. Now I don’t think many people will know the midsole of sneakers, that is, the PHYLON midsole, and the most common EVA midsole. In fact, both midsoles belong to the same attribute category (engineering plastics), but why are there different names? PHYLON originated in the United States. The earliest shoe midsoles were called PHYLON, and there was no distinction between EVA midsole and PHYLON midsole. Later, with the continuous development of footwear products, some big brand footwear product R&D factories in Taiwan and South Korea were used as the basis. At the source, the name of the midsole is more systematic, and there is what we now call the EVA midsole. Next, I will talk about the difference between the EVA midsole and the PHYLON midsole.

Now the most used midsole in shoes is PHYLON midsole. The biggest feature of PHYLON is lightness, good elasticity, and good cushioning performance. PHYLON is called secondary foaming. The EVA midsole is also very light, but the cushioning performance and elasticity are far inferior to the PHYLON midsole, and the cost is much lower than that of the PHYLON. The EVA midsole is called primary foaming. The reason why they have the same properties, but different names and different performances is that PHYLON is secondary foaming, while EVA is primary foaming.

(1) One-time foaming: The shoe midsole formed once after the material is injected into the mold and heated at a high temperature is called a one-time foaming midsole, that is, the EVA shoe midsole.

(2) Secondary foaming: After the material is injected into the mold, the shoe midsole is fired after two high-temperature heating, which is called the secondary foaming midsole, which is what we often call PHYLON midsole. The hardness of PHYLON is also controlled by temperature. In the process of firing PHYLON midsole, the higher the temperature, the denser and harder the fired PHYLON will be. The lower the heat, the lighter and softer the naturally burned PHYLON, so the evaluation of the quality of the midsole of the shoe cannot be measured by the weight or the degree of softness and hardness.

(3) Baobu burning midsole: Baobu burning midsole is also a PHYLON midsole, but it is just a shoemaking technology used by designers to pursue the overall design feeling. The best example is the shoe midsole and shoe body The same kind of fabric is used to make the overall combination of the shoe body and the sole, which is also a highlight in the craftsmanship of this shoe. To achieve this process is to wrap the formed PHYLON midsole with the selected fabric, and burn it at high temperature in the mold to become a cloth midsole like the LB1 we saw.

2. PU midsole: In addition to PHYLON midsole and EVA midsole, PU midsole is also very common. The biggest advantage of PU midsole is its good elasticity and toughness.

3. Packed midsole: Many sneakers now use a built-in midsole structure, also called a packed midsole. Like the T-MAC series that everyone is familiar with, NIKE’s style series all belong to the midsole structure of the bag. The midsole of the bag is composed of two parts, the outsole and the upper, but the structure is still the outsole, the midsole and the shoe. The upper is composed of three parts, but the midsole is wrapped on the inside of the upper.