HIROAN INSTITUTE

Different type of leather for different application

You need to use different types of leather depending on applications.
Let us explain why you need to use different types of leather.

Leather generally means animal skins. However, it is skin the same as a human being has.
The skin naturally decays without treatment after it is removed from the body. Therefore, a treatment technique called tanning was developed and has a long history.
As a result of the success of tanning, leather was produced to make products.

There are basically 2 methods of tanning.
The first one is tanning using astringent persimmon, which is familiar to us.
However, it is not so convenient to use actual persimmon.
Tanning using quebracho, mimosa or chestnut is a more common tanning method. In this method, the sap of the tree is used.

Lizard by Gaudi

Lizard by Gaudi

What are the characteristics of leather tanned with tannin?

What characteristics does the leather have after tanning?
It might be difficult to understand only by mentioning leather. Let us compare it to textiles.
Because tannin is a natural material, the leather becomes like textiles made of natural fibers, such as cotton, linen or silk.
It absorbs a lot of water; so it becomes weak when damp and strong when dry. When you make it crimpy, it stays that way, but it becomes taut again when you steam-iron it. The texture gains a natural feel as time goes by.
It is very convenient to use the leather tanned with tannin to polish a cut edge.

The leather becomes easier to make into a shape when it is damp.
Because animal protein remains in the leather tissue, when you polish damp leather, the edge will get crumpled and be round with the aid of friction heat, gain a glaze, and will then be solidified. This is the mechanism for polishing leather tanned with tannin.

Sword of Damascus steel

Sword of Damascus steel

Tanning with chrome

What about the leather tanned with chrome?
Chrome is a well-known metal with Cr as the atomic symbol and 24 as the atomic number. Tanning with chrome solution makes leather tanned with chrome.
Following the comparison to the textile above, it is like a textile made of chemical fiber.
Because it (fiber) doesn't absorb water, the strength won't change whether it is damp or not.
Even when you try to make it crimpy, it will soon recover.

Yet, a wrinkle made by folding cannot be erased easily even with an iron after one year has passed.
Thus, the leather tanned with chrome has good restoring force, while it is difficult to make a shape.
As for a cut edge, it shows no change by polishing it because protein in the leather tissue has been altered.
Therefore, it is not suitable for edge polishing at all.

Mille fiori from Venice

Mille fiori from Venice

Polishing method developed by HIROAN

As a matter of fact, HIROAN has already developed a way of polishing even for leather tanned with chrome.
Some people consider tanning with chrome is of little value, but it is effective because of its strong waterproofing property. For example, it can be used for industrial-use gascket, and as a more familiar application, for the belt loops on the back of jeans. It won't degrade after repeated washing. The leather tanned with tannin will soon be fragile under such usage.
Tanning with chrome is very advantageous to manufacture products with stable quality.

However, comparing tanning with tannin and tanning with chrome, there is one contradiction about the strength.
Although the leather tanned with tannin is a completely natural fiber, it is weak against heat, while the leather tanned with chrome is artificial fiber, but strong against heat.
However, it is about a temperature at 100℃ or higher, so you don't have to worry about it as long as you use a leather product in normal conditions.
Then, you may not be able to tell which is tanned with tannin and which is tanned with chrome. There are too many differences to describe them all. Let us show you some typical examples:

Blue and white ceramic with dragon pattern

Blue and white ceramic with dragon pattern

Typical examples of leathers tanned with tannin and chrome

Leather tanned with tannin

  • Cordovan leather
  • Bridle leather
  • Vachetta leather

(Specialty of the town of Santa Croce in the suburbs of Florence, Italy)

Vachetta refers to the manufacturing method. Brand names include Minerva Liscio and Buttero, etc.

Leather tanned with chrome

  • Waprolux(by Weinheimer)
  • Tcherkess(by Du Puy)
  • Kenya calf(by Weinheimer)
  • Box calf(by Weinheimer)

All of the above are adopted by prestigious European brands.

As you can guess by referring to the description above, Cordovan and Bridle leathers are not so strong. To solve this problem, they need to be thicker and many of their products are thick and solid.
Then, HIROAN came up with a unique solution to manufacture thin and flexible products. The surface layer (body) is made very thin (0.4 to 0.6mm) and has a strong but very thin underlayer tanned with a solution mixing a little chrome instead of genuine tannin and is attached to the entire surface (full bonding).
There are almost no products in the world that uses Cordovan or Bridle and adopts full bonding.

Imari oil pot

Imari oil pot

Teapot of Yixing

Teapot of Yixing

About coloring

There are basically 2 methods for coloring leather. One is dyeing and the other is painting.
As the word suggests, painting means applying color paint to the surface of the leather. Applying is usually done by blowing. This makes a coating layer on the surface of the leather and the texture of the leather cannot be felt by touching the finished product.
However, it may be reasonable to mass-produce products with a constant color. And, it is strong against moisture.

Dyeing is a general word to color a material with dye (dyestuff).

The dyeing agent soaks into the leather, and it doesn't make a coating layer on the surface. Degreasing is done before dyeing for the purpose of obtaining a constant finish, but it is difficult to attain a uniform finish and it always has unevenness.

However, that unevenness brings natural sensibility with the indescribable sense of transparency.
Many of the typical dyed leathers are those tanned with tannin. Bridle and Vachetta leathers are among them.
99% of HIROAN products are dyed leathers.
However, most Cordovan leathers have a top coat finish (treated with lacquer) or spray painting. Then, we use Cordovan without surface treatment; we use the leather only with a dyeing finish.
The leather with a genuine dyeing finish is rarely found around the world.

Nose medicine bottle

Nose medicine bottle

HIROAN: 3-generation special men's accessories manufacturer

HIROAN has been a special men's accessories manufacturer for three generations.

Therefore, instead of pursuing eccentricity, we like to focus on orthodoxy with texture, prefer tanning with tannin, choose dyeing instead of coating, and pursue perfection of a cut edge finish.

Coin purse of Lux

Coin purse of Lux

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