The study concludes, with scientific data, that leather degrades far more than the synthetic and artificial alternatives that imitate it

One of the most relevant conclusions is that, during the composting processes, while the different samples of natural leather analysed show total or partial degradation within a period of 21 to 35 days depending on the type of leather, the samples of alternative materials show no sign of degradation 90 days after the start of the compostability test.

At a session organised at Adoberia Bella, the headquarters of Leather Cluster Barcelona, the cluster, together with A3 Leather Innovation Center UdL, presented the results of the biodegradability project based on compostability. This project is supported by Acció (Generalitat de Catalunya).

The project, carried out over recent months by the team of researchers of A3 Leather Innovation Center UdL on behalf of Leather Cluster Barcelona, consisted of a scientific study to analyse the compostability of leather and other materials.

The purpose of this study is to determine the physical and chemical differences, as well as other thermometric properties, of seven different types of finished leather and of three leather imitations: a material of synthetic origin (commercially known as imitation leather) and two alternatives based on raw materials of biological origin (pineapple and cactus) that attempt to imitate leather in the fashion industry (commercially known as vegan leather).

This project has received the support of ACCIÓ, the public agency for the competitiveness of Catalan companies, attached to the Department of Enterprise and Labour of the Generalitat de Catalunya, under the competitiveness-strengthening initiative grants for the entities that make up the Catalunya Clústers Programme, related, among other things, to the implementation of strategic changes, innovations and new trends in the cluster or in the companies of the sector.

During the session presenting the results, Anna Bacardit, director of A3 Leather Innovation Center UdL, gave details of how this research study on the compostability of leather and the other materials was carried out.

The study used the composting standard for plastic materials UNE-EN ISO 20200:2015 – Determination of the degree of disintegration of plastic materials under simulated composting conditions in a laboratory-scale test -. The test method described in the international standard determines the degree of disintegration of plastic materials when they are exposed to a composting environment. It is a method that can be reproduced in any laboratory.

The work includes a complete physical and chemical characterisation of the different materials under study, applying the standardised methods of the leather sector at international level. It also includes a study of the accelerated ageing of the materials in a climatic chamber and their subsequent characterisation, in order to determine what effect these extreme conditions have had on the materials under study.

Once the composting process was completed, a leaching study of the different composts was included with the aim of identifying the substances released by the composts after the experiment. Standard UNE-EN 12457-4:2002 is used for the preparation and analysis of the leachates, in order to determine their composition.

Finally, a study of the volatile organic compound content of the 10 samples under study is included. The objective is to determine whether the different substrates contain volatile organic compounds (VOCs) of greater or lesser volatility, or of greater or lesser hazard to the user. The analysis methodology indicated in standard ISO 12219-3 is followed for the capture of the analytes and the subsequent determination of total VOCs at a qualitative and semi-quantitative level by TD-GC-MSD in accordance with standard ISO 16000-6.

Having set out the scientific method developed to carry out this biodegradability and compostability project, Anna Bacardit went on to explain its main results.

As regards physical properties, the alternatives to leather that were studied show lower strength and lower permeability, which places these materials at a lower level of durability and well below the intrinsic qualities and properties of leather and of the uses for which it is intended.

The results of this project provide information and value for establishing with scientific rigour that leather of natural origin has far higher degradation rates than the synthetic and artificial alternatives that seek to imitate it.

In order to continue providing further data that confirm these conclusions, Leather Cluster Barcelona and A3 Leather Innovation Center UdL want to scale up this project, from the tests now carried out in a laboratory to an industrial composting facility such as the one in Jorba.

With the scientific arguments arising from this project, Leather Cluster Barcelona wishes to champion leather as an example of the circular economy, and to demand the correct use of the term leather only for those articles of natural origin. The term leather is used in many cases, but not always respecting the nature of its origin. Leather of animal origin, used as a raw material to make consumer products, is a sustainable material with long durability and the capacity to be composted. The leather tanning and finishing industry, as an agent of the circular economy, gives value to this resource, preventing it from becoming waste.

Leather imitations, both the synthetic materials mostly made of polyvinyl chloride (PVC) or polyurethane (PU) and the new fashionable alternatives based on raw materials of organic origin from various industries but produced with petroleum-derived polymers (so-called vegan leather), are neither biodegradable nor recyclable nor sustainable and will remain for centuries in landfills.

Leather Cluster Barcelona is an environment of competitive cooperation for promoting cross-cutting, transformative strategic projects with the aim of driving the ecosystem of the Catalan leather sector. The cluster is an entity accredited under the Catalonia Clusters programme and is supported by Acció.