Leather production is a complex and vital component in the footwear manufacturing process. The processes used in the manufacturing of leather will not only affect the sustainability of the product, but also affect the cost. Global legislation and environmental concerns will affect the type of leather processing that can be used. General purpose chemicals such as sodium, sulphide, lime and sulphuric acid, chemicals used for performance qualities such as syntans, dyes and fat liquors and tanning agents including vegetable and chrome tanning extracts all play a vital role in producing finished leather. The questions to ask are how are these chemicals used and where and when are they used? How aware is the footwear industry, with regards to the production procedures used in tanning leather? What quality standards are available and how does the general makeup and the chemicals used impact on the environment?

Thorough testing is needed

Over the past 30 years, the footwear industry saw the finished leather merely as a component needed to produce the final product. This meant they did not have to know the technical aspect of leather tanning. The knowledge of the technical processes and the chemicals needed in tanning was mostly left to the experts in that particular field. This drew a clear divide in the two areas of expertise of footwear manufacturing and leather tanning.

An important part of footwear manufacturing is determining if the final product meets the quality and finesse expected by the retailer and consumer. Testing of raw materials, chemicals, leather auxiliaries and performance testing of the footwear itself are necessary to make such a determination. In order to be competitive in today’s environmentally conscience market, effective physical and chemical testing is needed to assure that the chemicals used are not only the most appropriate and effective, but also that they are not a hazard to the consumer and the environment. Physical and chemical tests such as tensile and tear strength, abrasion, flexing, grain crack/distension, colourfastness, water vapour permeability, water absorption, heavy metals chromium VI and azo dyes should all be performed before the leather leaves the tannery. This will help to ensure that the leather is made to the highest standards before being shipped to the manufacturers.

The key lies in effective supply chain management

Increased global environmental awareness and regulations banning certain substances used in leather manufacture have made it necessary for technologists to understand more about the developments and chemicals used in turning the raw materials into the final side of finished leather. Footwear manufacturers also need to be aware of what chemicals and processes are used in the production of footwear and other leather goods. Footwear manufacturers and retailers have now also begun to look more closely at ways to manage the leather supply chain from raw materials to components to final products. This will result in more eco-friendly products that meet current regulations and consumers’ environmental and quality expectations.

Tier systems have largely been the response to such issues, looking at not only the components involved in footwear, but also the materials and chemicals used to make the components. To achieve this, the workflow must be monitored from the very first raw materials used, to the final finished product. As a result, general chemicals such as wetting agents, lime, ammonium chloride and formic acid are now being analysed for their purity to ensure these chemicals can be used.

To open up the fibre structure of skins during different processes of tanning, microscopical and bacteriological tests can be used to evaluate the sufficiency of curing, to manage or avoid possibilities of future bacterial damage.

With the current environmental and regulatory awareness, the importance of examining the chemicals used in tanning leather will put more emphasis on finding which chemicals and practices best suit modern footwear and to ensure that the quality of such chemicals are high enough to produce the best possible grade of leather in an eco friendly manner.

Find more information on SGS Services for the Footwear Industry.

For more information, please contact:

Karen E. Kyllo, Ph.D.
Deputy Vice President, Global Softlines
SGS North America Inc.
t+ 1 973 461 7934

Ian Leybourne
Global Footwear Manager, Global Softlines
SGS United Kingdom Limited
t+ 44 2030087860