Sole material, PU,TPU,TPR, sole process requirements: double density (pu+ rubber), flat, brightness, matte light requirements for the surface.
The soles in the production, the mold is divided into the upper and lower mold, when making, mold, the production of the sole is above, the mold made out of the bottom of the soles;
The underside or bottom of the sole is required on the surface because it is exposed outside, and the general process requires surface, flat, light, Matt.
On the other hand, the upper surface of the sole has not much to ask for, because it is in the shoe and is usually bonded to a piece of cloth, or other material, to act as the bottom of the shoe. Therefore: the production of sole mold, the upper and lower molds need the sole release agent, but the mold required follow-up spray painting, the next mold to be sticky cloth.