Properties of Leather
The physical properties which make leather a unique and valuable material for upholstery purposes include:
High tensile strength
The tensile strength of leather is the tensile strain of leather until it tears.
The tensile strength is very different in the longitudinal and transverse direction of the leather skin. Leather with higher fat content has a higher tear strength. But there are many other parameters that influence the tear strength: the tanning method, the finish, the stiffness or the age of the leather. Since leather is a natural product, every skin behaves differently, and even within the same skin, the properties are very different.
The tensile strength of cow leather is between 8 – 25 N / mm². The car industry requires at least 200 N per 5 cm.
Resistance to tear
Good leather is stable and resistant to tearing, whereas suede, nubuck or extremely soft lambskin will not have the same stability as, for example, a belted leather. But within the types of leather very different qualities exist. So, an inferior quality leather within the same type of leather will always tear more easily than that of a higher quality. Also sanded leather is usually less stable than full-grain leather.
High resistance to flexing
The term flex resistance does not mean resistance to flexing or bending, rather, the ability to withstand numerous flexing cycles without damage or deterioration. Flex-crack resistance is the ability to withstand a number of flexing cycles without experiencing the occurrence of surface cracks as a result of stress. Most commonly, leather products and components are damaged by repeated flexing cycles in the form of surface cracks.
High resistance to puncture
Puncture resistance denotes the relative ability of leather to inhibit the intrusion of a foreign object. Puncture resistant leather protects from punctures, cuts, tearing and abrasions
Good heat insulation
It is a measure of the rate at which heat passes through a material or through a series of layers of different materials. High thermal insulation means that heat travels very slowly through the material, causing the temperature to build up on the side of the heat source. Leather contains a great deal of air, which is a poor conductor of heat. It is a good heat barrier and provides excellent heat insulation. This makes leather a very comfortable item for the human skin.
It is able to hold large quantities of water vapor such as human perspiration and then dissipate it later.
Permeability to water vapor
Water vapor permeability is related to materials breathability, in other words, its capacity in the passage and absorption of water vapor. Leather fibers will hold large quantities of water vapor. This property enables leather to absorb perspiration, which is later dissipated. A significant factor in comfort.
The leather is warm in winter and cool in summer. It is resistant to heat and fire
Leather can be molded and will retain its new shape. It has both elastic and plastic properties in wear. It can be made to stiffen or can be made to be flexible. It can be molded into a certain shape and then remolded into another shape later.
Resistance to wet and dry abrasion
The leather is resistant to abrasion in both wet and dry environments. This makes leather an excellent protector of human skin. These properties, concerned with wear and maintenance, are controlled by the tannage and surface finish.
Resistance to fire
The properties of materials and products when subjected to fire can be evaluated through contact with the flame to assess the combustion rate, extension, and combustion time.T he leather is inherently resistant to heat and flame.
Resistance to fungi
The leather is resistant to mildew and mold.
Resistance to chemical attack
The atmosphere of modern cities is polluted from the burning of carbon fuels with sulfur dioxide gas, which can accelerate the deterioration of leather. Modern leathers are tanned and dressed to resist these harmful chemicals.