A Technician's Perspective: Understanding the Difference Between Leather and its Imitations

The differences between genuine leather and imitations of leather are not apparent, even for professionals. Due to the lack of well-defined legislation, consumers don't understand the difference.  Companies that opt for leather imitations exploit this confusion through inaccurate claims in marketing campaigns. Further, brands don't rely on real experts regarding the technology of the materials they use.

In Italy, the ministers' council approved the provisions concerning words such as leather, skins, and fur. After a battle lasting several years by UNIC (National Union of Tanning Industries), the terms can only apply when referring to products that utilise real leather. The over-arching goal is to end using 'Vegan leather', 'PU leather', 'PVC leather', and 'synthetic leather' in advertising campaigns. The regulation proved to be a milestone in the leather industry; however, it is yet to occur in many other production areas worldwide.

Below, I explain the differences between leather and its imitations.

What is Leather?

Leather is of animal origin and is called leather once the rawhide undergoes tanning. The term "tanning" refers to several operations that make the leather resistant over time. The teas have three broad categories: mineral teas, white teas and vegetable teas and all three produce skin.

Tanning is a preliminary operation and, often, it is not sufficient to make the leather usable. To make the leathers functional: re-tanning, drying and finishing operations are essential in making commercial leather goods. Therefore, with the following phases, the tanneries start from a generic material (tanned leather) to obtain specific characteristics that can produce footwear, furnishings, and automotive products.


The term eco-leather implies that the production cycles have a less severe environmental impact. Further, the product itself must have specific eco-friendly characteristics. These characteristics are not to be confused with biodegradability, which is much debated in the industry. When leathers are certified as eco-leather, it merely implies that their production cycles have complied with environmental sustainability standards.

For the products of a tannery to be defined as eco-leather, they must have obtained certification from an appropriate certifying body. The UNI 11427: 2011 Leather standard – Criteria for determining the performance characteristics of leather with reduced environmental impact establishes the requirements minimum that an article and the respective production cycle must meet to be certified as eco-leather.

Minimum product (i.e. article) requirements:

  • Compliance with consumer health and safety needs;
  • Performance of hides and skins in compliance with specific product technical standards for the intended use

Minimum requirements of the production process of that particular article:

  • Compliance with the limits of chemical substances subject to legislative restrictions for use in tanning processing;
  • Compliance with the limitations of chemicals subject to legislative regulation in finished leathers;
  • Compliance with current environmental legislation and any other relevant topic;
  • Compliance with the limit values of specific predefined environmental indicators (consumption of water, chemicals, and waste produced)

How can we have the guarantee that the production of a company classifies as eco-leather?

The items produced to comply with the UNI 11427: 2011 standards should be certified with a logo issued by the nation's certifying body, where the tannery is. In Italy, this institute is the ICEC.

In recent years, some companies have started to use the term eco-leather to indicate plastic materials such as PU and PVC exploit the ambiguity generated by the name and consumers' confusion. Be wary of those companies that offer you plastic, calling it by the name of eco-leather, because they are using an unfair marketing tactic. Eco-leathers are more eco-friendly leathers than other leathers. Also, pay attention to the fact that the label 'eco-leather' does not indicate that these leathers are biodegradable and compostable.

PU and PVC materials – PU and PVC imitations

The plastic imitations of the skin can be of two types:

  • based on polyurethane, PU;
  • based on polyvinyl chloride, PVC.

In both cases, they are products of petrochemical derivation that have nothing natural in them.

Leather imitations are a product of many layers of PU or PVC coupled together. The base of the material, which is a non-woven fabric functions to give the material its finishing.

Fig. 1: The a mixture is spread as a base-coat around the cylinder. The supporting paper roll has a slightly pigmented fixative layer

Fig. 2: (overly simplified) diagram of a three-blade coating line (three application layers). The sequence begins with the temporary backing paper's unrolling, continues with the three applications, and ends with the separation of paper and material.

PUs are liquid products, and the preparation of mixtures is simple. PU blends consist of 60-65% PU (different depending on the layer), 25-30% plasticiser solvent and 10-15% pigments. Variable amounts of auxiliaries can determine the level of plasticity in a solvent. The solvent used in PU materials is DMF, di-methyl-formamide, a highly toxic solvent that is highly harmful to the human reproductive system.

The PVC blends contain about 50-60% of PVC granules, 30-40% of plasticiser solvent, 5-10% of pigments and a variable quantity of auxiliaries and expanding agents. The plasticiser solvent used in PVC blends is DOTP, Dioctylterephthalate, which is not considered a dangerous solvent. In PVC imitations, it is possible to adjust the materials' final thickness by adjusting the quantities of blowing agents, which are activated at high temperatures (200-220 ° C). With additional auxiliaries, it is possible to reduce their activation temperature.

The difference herein lies in the thickness, with PU, the thicknesses is low (0.7-0.9 mm), whereas with PVC the thickness in considerable (1.2-1.4 cm).

Further, PU and PVC have different bases to support the materials. For PU they are known as coagulated bases, which are rolls of non-woven fabrics treated at very high temperatures 180-220 ° C). For PVC materials, the bases are different and cheaper like cotton, as it does not need thermal treatment. Cotton is a non-allergenic material; therefore, PVC's support bases are safer than those of PU.

PU materials are not long-lasting and the material deteriorates after only 24 months from the date of production. On the other hand, PVC materials are more resistant, which makes disposal a significant problem. Both are plastic materials, derived from petroleum and therefore highly polluting. They are neither biodegradable nor recyclable, the only factor that makes them commercially viable are their prices and a short production time.

Such imitations do not posses any form of craftsmanship and their application in a wide range of products simply comes from the type of base material used.

Vegan leather – plant-based imitations of genuine leather

Vegan leather is another form of imitation that has some organic matter that may be derived from plants. You could call it a plant-based imitation. Plant-based products when treated may imitate the look of leather, for example, raw materials such as cotton, coconut, wood, apples, cacti, pineapple, agave, mushrooms and many others.

The way such imitations are produced, falls under two broad categories:

  • Fibre based, and (examples: pineapple and mushrooms)
  • Non-fibre based (apple leather)

For the latter, the plant-based material is grounded and pulverised before it be used commercially to make goods.

What's the difference?

The pulverised plants become an inert material and cannot give rise to any material. For it to be usable, the inert powder is mixed with a poly-based material that gives it support. Subsequently, the mixture transforms into rolls of materials using the same processes as PU and PVC based imitations.

What does this mean?

Pulverisation implies that the material has lost its eco-friendly properties and is nothing more than vegetable powder mixed in with plastic. Advertisements promoting vegan leather often show symbols of nature and large farms or a walk in the forest, and not the actual production process, which is an industrial process with its fair share of chemical utilisation.

Coming to fibre-based materials, for example, Pinatex - a new generation material produced from pineapple leaves, may seem industry altering on the surface, but it is far from being truly sustainable. While you may see brands like H&M, Hugo Boss, and Paul Smith supporting the material, unlike leather, the finished products are neither long lasting, nor heat or abrasion resistant. And while Pinatex claims to be biodegradable, strangely there isn't a lot of transparency around it.

Another example of mycelium based imitations, which vaguely resemble suede. As promising as it seems, mushroom leather, too isn't a solution that presents itself as a mature alternative to some of the imitations currently on the market.

We can conclude that fibrous based imitations are more biodegradable than some of the other imitations available in the market; however we need more transparency around the conversation. Particularly around biodegradability and compostability, which aren't publicly available at the moment.

For genuine leather to regain it's reputation as a durable, long-lasting and truly organic material, the leather industry needs to stand up and raise the bar of transparency.

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