Leather is a durable and flexible material created by tanning animal raw hide and skins. The most common raw material is cattle hide. It can be produced at manufacturing scales ranging from artisan to modern industrial scale
Leather is used to make a variety of articles, including footwear, automobile seats, clothing, bags, fashion accessories, and furniture. It is produced in a wide variety of types and styles and decorated by a wide range of techniques. The earliest record of leather artefacts dates back to 2200 BC.
Majority of the footwear soles ,Be it lifestyle, fashion ,sports or industrial footwear are made from POLYURETHANE which is more commonly known as PU.
Polyurethane Elastomers are used in application where toughness, flexibility, strength, abrasion resistance and shock absorbing qualities are required ,Which is why Polyurethane is the most preferred & popular sole making material in the footwear industry
Polyurethane is obtained by mixing ingredient chemical isocyanate and polyols, in predetermined proportion, which further react to form the polymer.
Otto Bayer in Germany discovered and patented the chemistry of polyurethane in 1937.
Some of the leading manufacturers of polyurethane globally are Basf ,Huntsman and Dow Chemicals.
The simplest PU is linear in which the hydroxyl compound and the nitrogen compound each have a functionality of two. This can be represented by the following
Isocyanate + Polyol = Polyurethane
This is a exothermic reaction, as liquid isocyanate and polyol react to form PU, the mixture becomes increasingly viscous eventually forming a solid mass.
The important processing characteristics of the system will include viscosity, pot life, reactive mix ratio control, time and process temperature.
Polyurethane is any polymer consisting of chains of organic units joined by urethanes links
Polyurethane can be made in a variety of textures and hardness by varying the particular monomer used and adding other substances.
They are best known to us in the form of flexible foams, mattresses, earplugs, chemical resistant coating, specialty adhesives, sealants ,furniture, automotive seating and footwear soles.