The history of leather. - Everybody know that?
Release time:
2023-01-31 16:53
Source:
One: The history of leather
More than 5,000 years ago, people began to use leather to protect against wind and cold, and then used leather as a noble gift. By the Zhou Dynasty (more than 1,000 BC), people had initially mastered the technology of leather making and fur making in long-term practice, forming the primitive leather industry. In the mid-19th century, the discovery and application of chrome leather softening method greatly accelerated the development of leather industry. In the early 20th century, with the successful development of various tanning chemicals, the tanning industry has been rapidly developed, and many countries have gradually formed a larger tanning industrial system, the leather industry from the original pure manual operation transition to semi-mechanized and mechanized production.
Two: leather classification and processing technology:
1. Natural leather. 2. Synthetic leather. 3. Textile materials)
Leather is generally divided into: 1. Natural leather. 2. Synthetic leather. 3. Textile materials
1, artificial leather is divided into artificial foam leather and synthetic leather,
(1), artificial bubble mainly JuAnYiXi leather, wool, poly (amino resin as coating, such as cloth as the base, characteristic is airtight, mainly used in the manufacture of handbags, belts, etc.,
②, synthetic leather surface is mainly polyurethane, base material is polyester, cotton, polypropylene and other synthetic fibers made of non-woven fabric, has a certain air permeability, is characterized by beautiful luster, not easy to mold and moth.
(1) synthetic leather.
Smooth surface, through the thickness, color, strength is equal, waterproof, acid and alkali resistance, microbial better than natural skin. But not resistant to high temperature, high cold, easy to aging.
(2) artificial leather.
The base is made of plain cloth, canvas, rat cloth, recycled cloth, fiber knitted cloth, etc., and then finished with different finishing materials.
Commonly used are: PVC artificial leather, PVC foam leather, etc
(3) Textile materials.
There are fine canvas, cotton - woven cloth, Velen cloth, plain cloth, imitation cashmere, etc.
2, animal leather is a kind of natural leather, that is, we often say derma. It is made of animal (raw skin) after a series of physical and chemical processing into a fixed, durable material, it has soft, tough, water is not easy to deformation, dry is not easy to shrink, heat resistance, chemical resistance and other properties, with good air permeability and anti-aging and other special advantages.
The processing process of animal leather is very complicated, and dozens of processes are needed to make the finished leather: Raw hides, flooding, fleshing, degreasing, hair removal - alkali leaching - inflation - deliming, softening, pickling, tanning, split, shaving, retanning, neutralizing, dyeing gas filling -- -- -- -- -- -- - finishing - finishing - drying - Finished leather.
Animal leather types are also very many, according to the material is generally common sheep leather, cow leather, horse leather, snake leather, pig leather crocodile leather, according to the performance can be divided into two layers of leather, full grain leather, suede leather, modified leather, film leather, composite leather, coated layer leather.
Two layer leather refers to the grinding leather in leather processing by chemical and physical pressing. This kind of leather is hard, easy to break, not enough extension.
Full-grain leather: Leather that retains and uses the original surface of animal skin (the growing or scaly side), called front leather. Full grain surface without coating less direct use, most of them are decorated after beautification, such as embossing, etc., full grain leather raw material requirements of high grade raw material leather, and processing requirements are high, belongs to high-grade leather, and the surface of the leather is completely retained in the skin and, its firm performance is good, full grain leather surface without coating or coating and very thin, It maintains the soft elasticity and good air permeability of leather, and its finished products are comfortable, durable and beautiful.
Suede leather: Refers to the surface of the velvet leather, the use of leather front (growth hair or scale side) by grinding into called velvet, the use of leather back (flesh) by grinding called velvet, the use of two layers of leather made of linen is called two layers of velvet, because suede has no coating layer, its breathable performance is better, the softness is more changed, but its waterproof, dustproof and maintenance become poor, The firmness of suede without grain is reduced. Suede products are comfortable to wear and have good health performance. However, except suede made by oil tanning, suede is easy to be dirty, not easy to clean and maintain. It is mainly used for leather shoes, leather clothes, leather bags and gloves.
Finishing leather: It refers to the leather that partially or completely removes the original surface of animal skin and then applies artificial film on it. There are first layer modified surface leather and two layer modified surface leather. The surface film is mostly made of finishing liquid made of various chemical materials after many times coating and pressing some patterns. Modified leather is mainly to make up for the lack of material surface, its poor air permeability, low fastness, folding resistance and aging resistance is reduced, wear as comfortable as full grain leather, but its water resistance is good, easy to clean and maintain.
Composite leather refers to a layer of rubber film on the split skin, has good chemical resistance, durability, suitable for footwear.
Finishing split leather is the addition of a colored resin layer to the split skin