There are various types of sole materials available in the current market. Sole or shoes manufacturer must determine to what performance, its products should accord with what standard, and must also choose materials: rubber (RU), thermoplastic rubber (TR), polyurethane (PU)/thermoplastic polyurethane (TPU). As an integral part of shoe making, the shoe company must cooperate closely with the sole material. Therefore, the manufacturer should make the correct choice for the shoe material. And design and performance, all of which must be chosen properly to ensure that the final product has good quality.
Of course, shoes and shoes can't be the same, and the requirements for different shoes, especially the soles, are not the same. The requirements for the sole include light weight, low friction, strong grip, even leather stability, greater use of temperature range, resistance to chemicals and grease, etc. In general, the demand for shoes is usually a combination of several items mentioned above. All kinds of shoes have important and basic common features, such as the comfort of walking and the protection of feet. Ironically, nowadays, these basic features of shoes are gradually replaced by popular fashion, and more and more buyers regard fashion as the most important factor in buying shoes.
Against the status quo, the combination of materials, such as double soles, be the best, the most convenient solution, through the use of resistant outsole to implement protective on foot, at the same time by using the soft bottom to achieve walking in comfort. For this purpose, the best combination of materials at the moment is using rubber (artificial rubber) to make the outer base and using polyurethane to make the bottom. Sole outsole and the bottom of the production process can be divided into steps, and finally use adhesive bonding together with them, in most cases, the need for pretreatment, such as halogenation and/or the rubber surface with grinding processing. Another kind of adhesion is to use the automatic adhesive spray process between the two materials, using the chemical bonding function of rubber and PU adhesion function to achieve the purpose of bonding.
There is also a more simple way of making shoe materials, namely thermoplastic polyurethane and polyurethane, in which the outer sole is made of thermoplastic polyurethane thin layer and polyurethane is used in the bottom.
Besides they have outstanding physical properties of the thermoplastic polyurethane shoe outsole can satisfy the need of modern design, when the direct molding process, can produce transparent soles or soles of bright colours.
In addition, in the style of carve patterns or designs on woodwork, almost without any bondage imposed on the head of the designer, and even more color characteristic of sports shoes sole in the production process can also be an economy.
Last but not least, the double sole begins to apply the polyurethane/polyurethane mix to make a double sole, in which two soles are made of polyurethane. To the bottom of the outside, must choose the special compacted polyurethane material, and for the sole interlayer, for the comfort of the consideration, must choose the foaming polyurethane.
With the new DESMA technology, the shoe equipment can ensure the industrial use of rubber, thermoplastic polyurethane and the active polyurethane (PUR) process in a single mechanical system with the most economic benefits.
Whenever possible, once the production engineering, materials, mold design and process parameters with the expected shoes type and the current production of the structure of the consistent sexual problems, DESMA can provide comprehensive professional knowledge, qualified professional advice and take the customer as the center of the project.
The simplest shoes are made from a single density polyurethane. Polyurethane sole must have two tasks: first, must feel comfortable, and the sole is light, second, also is very important point, namely safety aspect problem, if prevent slippery. In fact, it's hard to combine these two functions, and in most cases, only one of them can perform the right performance.
The density of polyurethane sole is mostly around 0.8g/cm3, which is usually used in leisure shoe industry. The production of single density shoes is very simple and effective, but the products produced are still high-grade commercial shoes.
For more than 20 years, the footwear industry has been producing dual-density polyurethane shoes with a machine that can be injected directly into the machine.
The combination of dense polyurethane outsoles and light and comfortable midsole makes it possible to combine the two features of the shoe collection. It is possible to use materials with very dense structure to make the outer bottom, which will make it more resistant to wear and wear, as well as good anti-skid and grease resistance. You can use a foaming polyurethane system to make the bottom, so the shoes will be more comfortable and even lighter.
The production of shoes is different from that of single density shoes. The first step is to inject the tight outer bottom into the closed mould. After a certain period of reaction, the upper part of the bottom and the outer bottom of the injection molding, through the sole and the shoe help adhesion, a simple shoe sample is successful.
Most of the time, this kind of material is used in the safety shoe industry, because in this industry, it is necessary to look for a comfortable appearance, but also to have good features. But in the casual shoe category, you can also find many interesting designs using polyurethane/polyurethane mix. The density of the outer base was mainly 0.9g/cm3, while the density in the middle ground was mostly 0.45g/cm3.
For safety shoes, the two layers of glue exceed the required standard, and the bottom can be made from a thinner layer.
Thermoplastic polyurethane (TPU)
Of such materials as propaganda, this is because the single density thermoplastic polyurethane outsole will not make the shoes how much would be comfortable to wear, at about 1 g/cm3 density of thermoplastic polyurethane, which means that this kind of shoes is unlikely to have good sound insulation effect of footsteps. In addition, it is often very difficult to glue thermoplastic polyurethane into the upper shoe, so thermoplastic polyurethane is not used very often.
Thermoplastic polyurethane/thermoplastic polyurethane (TPU/TPU)
This type of shoe has become more interesting because of new developments in material suppliers. The bottom of the thin thermoplastic polyurethane and blown thermoplastic polyurethane shoes will become a new material combination in the future. More or less, its principle has something in common with the combination of polyurethane/polyurethane production materials. Thermoplastic polyurethane hardness range is larger, in shoemaking, shaw from 55 a to nearly 85 a hardness values, in fact, it's excellent antiwear and skid resistance, thermoplastic polyurethane soles, fine carve patterns or designs on woodwork process. Blown can thermoplastic polyurethane perfusion technology now, that means manufacturers can skip over the short term from thermoplastic polyurethane to combinations of thermoplastic polyurethane (pu)/thermoplastic polyurethane materials.
Compared with polyurethane, thermoplastic polyurethane has a great advantage in processing. The thermoplastic polyurethane can be packed in bags when feeding. It does not involve any professional knowledge related to chemical properties, and operators do not have to adjust a large number of parameters to different machines when operating the machine.
Thermoplastic polyurethane/polyurethane (TPU/PU)
Perhaps this is the most common combination of materials today. Thermoplastic polyurethane/polyurethane has many advantages. First, you can complete the shoe making process through one-stop process. In this process, thermoplastic polyurethane is used to make shoes out of the bottom, while polyurethane is used to make soles in shoes. For the bottom direct forming process, it is extremely interesting to use the combination of the bottom and bottom of the shoe with the low weight of the self-reactive polyurethane foam with compact thermoplastic polyurethane. The result of the combination is a composite sole with a very durable outer bottom and a bottom for comfortable shoes.
Besides they have outstanding physical properties of thermoplastic polyurethane shoe outsole can satisfy the need of modern design, when the direct molding process, using transparent soles or sole bright colours.
Multi-functional thermoplastic polyurethane/polyurethane (MTPU/PU)
Using thermoplastic polyurethane injection molding process, the new DESMA process can produce the sole of three colors, which makes designers and manufacturers extremely excited. This can implement a process, three colors or functions. The colored material is injected into the mold structure by a pair of injection molding equipment and is filled with the sole area, and the amount of injection is determined by the user. After hardening, the perfusion material forms the outer bottom. And then the bottom of the shoe, which is done. All the operation steps are completed on the same machine as an integral part of the same entire process. No sale without treatment. It not only saves the processing, distribution and material steps, but also improves the quality and economy of the products. A process, multiple features, DESMA process quickly take advantage of the new products may not sure, now, not only can distinguish according to color sole category, can also according to the different hardness, function, strength and characteristic to distinguish.
These advantages, for example, allow the makers of safe shoes to offer special categories of support or shoes that allow users to walk easily.
So far, one of the best material combinations has been made of rubber, made of polyurethane in the soles of shoes. Sole outsole and the bottom of the production process can be divided into steps, and finally use adhesive bonding together with them, in most cases, the need for pretreatment, such as halogenation and/or the rubber surface with grinding processing. Another kind of adhesion is to use non-woven wool between the two materials, using the mechanical bonding function of rubber and the adhesive function of polyurethane to achieve the purpose of bonding.
However, all these process involves a considerable number of auxiliary equipment and a large number of logistics, many footwear manufacturers try to avoid this kind of cost intensive investment, to switch to other easy to processing of materials. Normally, rubber and polyurethane do not bond because of their physical and chemical properties. In addition, it is usually not processed with polyurethane under the expected conditions in this process. DESMA thus evolved into a process, do not use the above process steps now, it can use rubber/polyurethane material combination, produced by one-stop process does not need to use any harmful glue shoes. Subsequently, polyurethane injection molding equipment can be injected polyurethane on the rubber outsole, filling water-based adhesives, two different materials reached a perfect adhesion, and accord with the requirement of related standard of safety shoes.
One of the most common techniques used in military footwear is the use of a rubber/rubber material combination process, in which the soles and soles of shoes are made of rubber. The outer sole and the process of using thermoplastic polyurethane/thermoplastic polyurethane materials are the same as the outer sole, and the bottom of the shoe is made of foam rubber. Such shoes have excellent performance, such as high temperature resistance, or grease and fuel. These materials, like polyurethane, do not support hydrolysis, but in the military-industrial sector, rubber/rubber military shoes are used in the military industry. The same is true in athletic shoes. This material combination has many important advantages, such as true, good anti-skid performance.