Newsletter 7/2020 from Cotance, The European Leather Association

Tanning involves performing successive, interconnected chemical and mechanical operations. Water and various chemicals are used in precise quantities, at exact temperatures. Imposed treatment times, and mechanical operations have strict settings. Leather quality requires monitoring, control, and human intervention. These processes impart the qualities that are desired in the finished leather.

In short, leather quality is a set of characteristics: resistance to physical-mechanical stress; comfort and safety during use/wear; durability and repair possibilities; aesthetics.

Let us go a little more into details:

Restricted substances

Restricted substances are chemicals which are strictly controlled.
Restrictions are stipulated by laws and regulations (such as the EU REACh Directive) and are complemented by lists of unwanted chemicals set by global brands, ecolabels, and NGOs, e.g. Restricted Substance Lists, Product Restricted Substance List or Manufacturer Restricted Substance List). In all cases, limit values are specified and test methods recommended.

Look, Touch & Smell

The look of leather is determined by the raw material and the tanning process. When leather is left as natural as possible, the original grain, the pattern of the  dermis (hair follicles, fish or reptile scales) as well as any scars from the animal’s life can be observed with the naked eye. If sanded with abrasive paper, you get nubuck or suede. By embossing with various patterns, you can mimic a different natural grain or create a totally new design. When covered with finishing films or coatings, you get coated leather and, if it has a mirror-like appearance, it becomes patent leather.

Touch and smell are sensations felt by the user. The touch can be dry, waxy, oily. The smell is the trace of a range of chemicals used to process the hides and skins. Some of them impart  to the leather their own specific aroma. This is the case of vegetable tannins as well as oils. It is a specific odour, peculiar, but not at all unpleasant.

Resistance to physical and mechanical stress or to environmental and use conditions

Resistance is the property derived from the original fibrous structure of the material and what gives durability to the leather. It refers to tensile strength and tearing load. The surface doesn’t crack with bending and elongation, and elasticity gives comfort when worn.
Leather resists water, sunlight, temperature, wet and dry rubbing, abrasions, repeated flexing, as required by the intended use.

Comfort

Leather provides thermal insulation, elasto-plasticity, which allows the product to keep its shape and not feel rigid the next time it is worn. Leather absorbs perspiration and releases it in the interval between uses. This is particularly relevant in footwear.

To conclude:

Since leather talks to your senses, it better keeps its promises!
All the above quality characteristics are routinely assessed by tanners and their customers, with test methods that the leather industry has developed over time and which are standardised in IULTCS, ISO and CEN.

European leather assures consumers of its unequalled quality credentials.