BADER Polska, based in Bolesławiec and Nowa Sól, produces premium leather for the automotive industry. To maintain its durability, leather for use undergoes treatments such as cleaning, drying and polishing. Currently, production at BADER Polska covers leather from the wet-blue and wet-white stages, through the crust stage, to finished leather

The Structure of Leather and Its Properties

Leather—obtained from both wild and farmed animals—is a raw material widely used in industry. It consists of three layers:

  • Epidermis—the outermost protective layer, on which hair, feathers or scales are found,
  • Dermis—a layer made of connective tissue, used in industry,
  • Subcutaneous layer.

The quality of leather for use is mainly affected by two factors—temperature and humidity. Reduced humidity causes leather to shrink, while increased humidity positively affects its elasticity and stretchability. However, at high temperatures and humidity, leather may develop mould; when exposed to excessive sunlight, it oxidises and ages more quickly. That is why it is so important to preserve it properly before putting it into use—cleaning, drying and polishing it.

The Company’s Beginnings—the 1990s

“In 1991, BADER began producing leather intended for car upholstery at the tannery in Leszno Górne. The first stage was producing leather to the wet-blue stage, followed by crust, which, after finishing, became a high-quality upholstery product for Mercedes. It was made from the best raw material—bull hides from southern Germany,” recalls Janusz Dudkiewicz, an employee of BADER Polska. Later, the finishing plant, and subsequently the production of crust leather, were moved to Bolesławiec. Here, work is already carried out on partially processed leather.

Leather Processing Stages

In the leather industry, the object of leather dressing is the collagen tissue of the dermis.

Before leather is put into use, it is properly prepared in the leather processing department—https://pracabader.pl/oferty-pracy/pracownik-czka-obrobki-skory-boleslawiec/. Leather dressing consists of three basic stages:

  • Preparation stage
  • Tanning—a technological process that protects leather against decay
  • Finishing the tanned leather

The preparation stage includes operations such as soaking fresh or salted hides, liming, deliming, bating and pickling. Tanned leather (wet-blue, wet-white) is then retanned, fatliquored, dyed and dried. At this stage, it is called crust. The final stage involves applying suitable finishing coatings to the grain side of the crust leather to obtain a finished product, which then goes to the sewing department—https://pracabader.pl/oferty-pracy/szwacz-ka-boleslawiec/. The basic indicators determining the correct course of leather dressing processes in liquor are the number of baths and chemicals used, temperature and process duration.

“It is usually believed that the hides of cows and bulls undergo tanning, but this is not true—hides from various animals can be tanned, even kangaroo hides. Because of their resistance to abrasion and tearing, kangaroo leather is used to produce sports footwear,” says Janusz Dudkiewicz.

Wet Blue or Crust—What Does It Mean?

Wet-blue leather, wet-blue, as the name suggests, is moist leather with a blue colour. Chromium salts, a natural and mineral tanning agent, are used in its processing. In turn, tanning leather using the wet-white method is synthetic processing with glutaraldehyde and vegetable tanning agents. The leather then turns white. Crust is leather that has been retanned, fatliquored, dyed, dried and prepared for finishing

Leather—a By-Product

Producing leather for automotive purposes is—mainly because it is not seasonal—economically beneficial. The situation is completely different in companies producing footwear or clothing, where the season determines increases or decreases in production. Producing leather for automotive purposes is also beneficial from an ecological perspective, because leather is a by-product—cattle are not raised for their hides, but for their meat. In this case, the hide is waste and, if it were not used, it would be sent for disposal.

Leather Testing

Leather is tested visually and organoleptically, that is, by touch. The denser, softer and fuller it feels in the hand, the better. At various stages of production, leather undergoes many tests, intended to ensure the highest quality in use.

For example:

  • Shrinkage temperature—the shrinkage of leather kept at boiling temperature is checked
  • Tear strength
  • Light reflection—most often used for leather intended for convertibles, which should not heat up quickly
  • Dry and wet rubbing—the degree of leather discolouration is tested
  • Adhesion—the degree to which the finishing coating adheres to the leather grain
  • Flexing
  • Softness
  • Odour
  • Flammability

So far, no one has managed to create a leather substitute possessing all its properties. Natural leather is a unique and extremely valuable product. Its quality depends on how the cattle are fed, the thickness of the hair coat, as well as proper processing and care.

Leather is a natural product, which means that it can sometimes be difficult to predict exactly how it will behave in all physicochemical processes. That is why the knowledge and experience of those supervising leather production are so important here.