There are many types of sole materials available in the current market, with different patterns. Sole or shoe manufacturers must determine what performance their products should meet and what standards they must meet, and they must also choose the materials of manufacture: rubber (RU), thermoplastic rubber (TR), polyurethane (PU), or thermoplastic polyurethane (TPU). As an integral part of shoe production, the upper must cooperate closely with the sole material. Therefore, the manufacturer should make the correct choice for the upper material. There are also laser equipment for design and processing ( laser engraving machine , laser cutting machine), all of these parts must be selected properly to ensure the final product has good quality.
Of course, it cannot be generalized. The requirements for different shoes, as far as the mainstream is concerned, the upper requirements are more individual and beautiful without losing elegance; the production process is more demanding to save costs and produce faster, which is difficult to complete with traditional machinery Only laser engraving machines with high technology can do this; the requirements for soles are not the same. The requirements for soles include light weight, low abrasion, strong grip, even the stability of leather, a wide range of operating temperatures, resistance to chemicals and grease, etc. In general, the market's requirements for shoes are usually a combination of several of the above-mentioned requirements.
In view of the current situation, the combination of materials, such as double-layer soles, has become the best and most convenient solution to protect the feet by using a resistant outsole, while walking through the use of a softer midsole Comfort. For this purpose, the current best combination of materials is made of rubber (artificial rubber) for the outsole and polyurethane for the midsole. The manufacturing process of the outsole and midsole of the sole can be performed in steps, and finally they are bonded together with an adhesive. In most cases, pretreatment is required, such as halogenating and / or sanding the rubber surface. Another bonding method is to use an automatic adhesive spray process between the two materials, using the chemical bonding function of rubber and the bonding function of PU to achieve the purpose of bonding.
There is also a simpler way to combine shoe materials, which is thermoplastic polyurethane and polyurethane. Among them, the outsole of the shoe is made of a thin layer of thermoplastic polyurethane, and the midsole is made of polyurethane. In addition to their outstanding physical characteristics, outsoles made of thermoplastic polyurethane can meet the needs of modern design. When the direct molding process is performed, transparent soles or bright soles can be produced.
In addition, in terms of engraving style, almost no restraint is imposed on the designer's head. Even the multi-colored soles with sports shoes features can be quite economical in the production process. You can use a laser engraving machine to sculpt them. And marking to make the sole more beautiful.
Last but not least, the double-layer sole began to use polyurethane / polyurethane material combinations to make double-layer soles, of which both soles were made of polyurethane. For the outsole, a particularly dense polyurethane material must be selected, and for the midsole, for the sake of comfort, foamed polyurethane must be selected.
Polyurethane (PU) The simplest shoe is made from a single density polyurethane outsole. Polyurethane soles must have two tasks: first, they must be comfortable and light, and second, they are also very important, that is, safety issues, such as non-slip. In fact, it is difficult to combine these two functions, and in most cases, only one of them can perform correctly.