THE OUTSOLE: The outsole is the bottom part of the shoe which has direct contact with the ground. We can classify the Outsoles depending on the materials in which they are made. We have the Leather outsoles and Man Made outsoles. The leather usually is more expensive and is sold by weight while man made is sold by pair.
LEATHER OUTSOLES: These are made of adult cattle and tanned with vegetable tanning making them harder but very classical and beautiful to wear and look.
MAN MADE OUTSOLES: Is made out of different components like PU (POLYURETHAN – very versatile since it can be finished to look like Leather, Cork or other materials), TPU (Thermo Plastic Polyurethan), TPR (Thermoplastic Rubber), PVC( Poly Vinyl Chloride ), TR (Thermo Rubber). The difference in materials gives the outsoles its different flexibility, weight and function and the choice will depend on the final result we need to obtain.
On the other hand, latex soles are natural and come from Rubber Tree.
The rubber material will give a stronger grip while usually being heavier while other materials like PU will be very light weight with less traction.
If we want a very light shoe (example running shoes), we can use EVA ( Ethylene-Vinyl- Acetate ) Midsole with a Rubber Outsole for Grip or TPU. Today even though more costly, many casual shoes are also made with eva outsoles.
Thunit on the other hand is a specialized material which copies the look of leather and is made of vulcanized Rubber which is sold in sheets and is a very a high-quality material.
There is a second Classification for outsoles: OUTSOLES CUT OUT & OUTSOLES MOLDED
OUTSOLES CUT OUT: In this case, the various materials come in sheets which could be made of leather, thunit, rubber and crepe and are cut by a metal blade called a DIE CUTTER placed on the sheet which is pressed by a hydraulic press. A laser printer can reproduce the NESTING with designs of all the pieces of material to be cut out.
OUTSOLE MOLDED: The Mold, which has the shape of the outsole, is usually made of Metal and the material making the outsole is poured inside which can be Solid, Semi-Solid or Liquid, then the mold is closed until the final product is dried. The Mold is Machine made at first and then will be manually finished by Hand.
The quality of this mold is essential since it needs to make an outsole which will fit perfectly to the upper fitted over the last of the shoe.
OPENING A NEW MOLD; means investing in the series, since each shoe size represents one mold size. The cost of each mold is very expensive.
It is very important to take note that once the Soles come out of the Molds, they can expand (EVA) or reduce (PU) in volume and these considerations should be taken into account during the production of these SOLES by putting more or LESS material into the Molds.
Some Outsoles are bult directly onto the upper of the shoe (Vulcanized or Injected ). In both cases, the upper is first lasted and then inserted in the mold which closes and the liquid or melted material is injected into the mold which will take its shape around the bottom part of the upper making them one single bonding unit. You can easily identify these constructions since they leave a small thin line of junction piece of outsole in the front and back called “ Flash “ made by the closing of the mold. A more widely used kind of vulcanization is first placing a initial outer sole to the lasted upper, then spreading a special heat activated glue around it and then wrapping a stipe of rubber all around the bottom part of the shoe, then putting the entire shoe into a autoclave with high temperature and pressure which will react the rubber making it bond directly to the upper.
FUNCTION: The outsoles are the tires of the shoe by protecting the bottom part of the foot, giving them traction, flexibility and adding to the shape and stability.
Italian Footwear Solution will only use outsoles which are made of world’s best components ensuring not only durability but a shoe which is light in weight, flexible and bouncy comfort during each step.
Always trust the high quality of our materials and our specialized experts assembling each part of the shoe for the best experience in look and comfort walk.