How-Leather-is-Made

Leather interiors are expensive for one reason: the leather itself is expensive. It doesn't take any more time to upholster a leather seat than a vinyl seat, it's just that leather material is far more expensive than other upholstery materials. Why? Because it takes a lot of resources to process animal skins into leather. Here's the story, starting at the beginning.

The original clothing material

The history of leather goes back thousands of years. Primitive humans needed some sort of clothing and there weren't any fabrics back then, so they looked at what other animals were wearing: their pelts. Unfortunately, these pelts probably didn't last very long when humans wore them. After all, this is a natural product that would eventually decompose. However, somewhere along the line, someone discovered that when pelts were soaked with certain plants, they would be preserved. Thus, began the first leather tanning operations.

Leather curing

Today, most leather comes from the skins of cattle, sheep and calves.The harvesting process starts with the careful removal of the hides after the animal is killed. After the hide has been removed, it is "fleshed" removing any remaining meat, tissue or fat. Freshly fleshed hides are then shipped in refrigerated trucks to tanneries for processing into leather. In some cases, the fleshed hides are cured by immersion in brine for 12 hours. After curing, the hides can be stored for several months without damage and can be shipped to tanneries without needing refrigeration.

Chemical processing

At the leather tannery, the final processing begins. First, the hair is removed by using a solution of lime and sodium sulphide. The hides are then neutralized with acids and treated with special enzymes to increase softness.

The last step in turning hides and skins into leather is the tanning process. There are several methods of tanning but the most common is chrome tanning. The process begins in rotating drums with a bath containing trivalent chrome. Once this has finished the chrome is fixed in the leather by adding sodium carbonate or bicarbonate.

Coatings

Finalfinishing consists of placing a series of coatings on the surface of the leather. These coatings are designed to protect the leather and make it look pleasing. Some finishing processes apply urethane resins to the surface of the leather. Others coat it with vinyl, wax, or nitrocellulose. To make the surface look good, leather is often embossed with a pattern. For example, our technical consultant at Selma Chrysler, Selma, CA says that the leather in the Chrysler 300s is embossed with "European, milled pebble."

Upholstery

The last step, of course, is upholstery.After the leather sheets are finished, they are shipped to upholstery companies that use the leather to construct automotive seats and other leather products.