By tanning agent to hide into the water with a leather (i.e. semi-finished leather), after finishing the leather cutting split into multiple layers, then retanning, giving differently finished PU purse leather full, soft and tough properties. Different tanning agents are used, and the finished leather is different from black pleather couch.
Generally, grasp the following characteristics of tanning leather
1. Vegetable tanned leather
Usually measured by weight, so called "heavy leather", but also because of its tannin taste bitter, commonly known as "bitter skin". Tanning method is the first method for leather tanning, the use of plant extract from tannin (mainly tannin) to tanning, it is environmentally friendly only tanning leather in PU leather material, even if the burning does not release toxic substances. Some of the present pet food is made from this kind of leather. This leather texture is thick, leathery, easily absorb liquid, easy to mold the shape after absorbing water, the color is black PU leather extract itself, after oxidation, using factors of sunshine and the absorption of body fluids will gradually become darker (long time sunshine will put the bag material PU tanned black and brown), application of basic dyes (the basic dye staining). Because of vegetable tanned leather texture and tough, thick, used for military, machinery accessories, belts, shoes, basketball, PU
purse, leather box, PU leather bag and leather carving.
The following categories are usually measured by area, so they are collectively called "light leather":
2. Chrome tanned leather
Invented in 1858 using sulfuric acid chromium as a chromium tanning agent tanning method for the leather tanning, the time and cost than vegetable tanned pu bag material tanning save a lot, this method is called "wet blue leather". Chrome tanned leather is soft and flexible, with little fading and shrinkage, and is easy to dye and sew. It is used for making clothing, handbags, shoes and so on. But this kind of leather burns to produce harmful substance "valence chromium".
The main oil wax, namely oil tanned leather, the surface of rich oil wax, high-grade leather, the only disadvantage is not particularly resistant to water, oil, the oil skin (also known as crazy horse leather, two kinds of matte and glossy), mainly used for high-end shoes, shoe material PU
, cool package.
4. Brain tanning
Using emulsified fat (such as cod fish oil, animal brains after air oxidation) for the tanning of leather, the fake leather boots texture of the soft, breathable, washable. Previously used only for tanning suede, now more than sheep skin, leather suede leather (suede), for the lens and other fine tools to wipe.
5. Aldehyde tanning
Tanning agents are mostly formaldehyde (formalin) or glutaraldehyde aqueous solution. Aldehyde tanning water resistance for PU shoe material
6. Aluminum tanning
Using aluminum sulfate as tanning agent for leather tanning, aluminum is white, it is called "wet white leather", its soft, grain close and meticulous, but after washing will detanning. The white wet skin becomes thin and hard after drying, so the aluminum tanning agent is seldom used alone. Wet white leather faux leather for shoes for a long time, can be further processed into different types of finished leather is a substitute for wet blue leather.
7. Combination Tannage
Leather that has been tanned in the same or at the same time with two or more tanning agents. For chrome vegetable combination tanning, fullness, elasticity, wear resistance than vegetable tanned PU synthetic leather
is greatly improved, mainly used for making semi pu leather
for shoes. combination tannage is stable, good water resistance. Commercially available now is combined with tanned leather.
8. Raw and cooked leather
Raw 100 PU materia
l and cooked leather are rare now. Leather tanning is to hide away the remnants of the soft tissue after soaked in lime water, then open air into hard and brittle leather, mainly used without bending parts such as drum skin leather is tanned leather; cooked by hot water or hot wax treated liquid to solid, traditional used to do on the armor, faux leather material to cover chairs and book cover.