Hair removal

Dehairing of Cashmere, Camel Hair, and Yak

Dehairing refers to the separation of fine undercoat from coarse guard hair. It is a mechanical process carried out after washing the raw material to achieve a higher fineness.

The animals' fur contains a very soft and fine undercoat that warms the animals but also protects them from heat. The coarse guard and kemp hairs serve to repel rain, snow, and wind, making it bead off.

The shorn, combed out, or collected hair is subjected to a mechanical processing (dehairing) after washing.

This dehairing process is still a closely guarded secret, originally operated by England until the mid-20th century. Raw material traders developed their own machines, had them custom-built, and adapted them to their needs and experience. Some of these machines are over 100 years old and are still partly in operation today. With globalization, dehairing now primarily takes place in the countries of origin, i.e., Mongolia or China.

In this process, the coarse guard hairs and kemp are separated from the soft down, so that ideally only the high-quality and fine undercoat is obtained.

The process begins with a carding machine that first loosens and opens the material. This then feeds the first perforated rotating hollow drum.

The Dehairing Process

is primarily carried out using these rotating hollow drums. The material is inside the drum. Due to the different specific densities of the lighter (undercoat, down) and the heavier guard hairs, the heavier guard hairs are more readily propelled outwards than the fine undercoat. Through the perforations, the coarser guard hairs gradually fall through with the aid of suction and are collected in a receptacle under the drum. In the airflow from drum to drum, the lighter undercoat is simultaneously transported to the next drum in greater quantities.

7-10 drums are used in sequence. At the end, a carding process is performed on a cotton card to orient the material and improve its style.

The fewer guard hairs remaining at the end, the finer and softer the hair, and the more valuable it is.

Cashmere can be dehaired to a residual guard hair content of approx. 0.5%.

Camel hair can be economically dehaired to a guard hair content of approx. 1-2%.

The coarse guard hairs are essentially a waste product. They can be sold cheaply to the felt industry, which, for example, produces insoles.

Furthermore, guard hairs are also used as an admixture for hand-knitting yarns when protruding hairs on the yarn are desired as an effect.