Green Shoes 4.0
Maria José Ferreira and Green Shoes 4.0 consortium
The world is facing challenges that are causing the footwear sector to accelerate its efforts to be sustainable by developing and adopting green and digital solutions and business models. Fashion businesses need to help minimise depletion of the planet’s resources and greenhouse gas (GHG) emissions, solve complex problems such as those posed by climate change. As has already happened in Europe, global fashion also needs to tackle environmental issues including recycling, water and land usage, and GHG. They also need to adopt responsible business models that help prevent and compensate for ‘loss and damage’ caused by climate breakdown. These include promotion at production level of good health and safe workplaces, renewable energy, heat and flood mitigation if applicable, salaries and social protection systems. At consumption level, it calls for durable long lasting goods, repair, reuse and circularity.
There are, however, many potential areas of intervention and a number of variables still remain, so significant research and innovation needs to be done. Firm steps are being accomplished within Green Shoes 4.0, a Portugal 2020 R&D collaborative project. It is promoted by a group of 15 companies covering the whole footwear value chain and includes leather, soles, software, production equipment, leather goods and footwear, representation and leadership, plus eight R&D bodies with complementary capabilities. As explained by Maria José Ferreira, Director at CTCP (Centro Tecnológico do Calçado de Portugal) and Green Shoes 4.0 coordinator, it aims to develop new leathers, soling materials, software, production systems, footwear concepts and business models (Figure 1).
Functionalised circular leathers
Leather is a renewable biomaterial that presents excellent physical and comfort properties for use in leather goods and footwear. It has high resistance to repeated flexion, tearing and abrasion, resistance to water penetration, good sweat absorption and desorption, and even resistance to heat and fire. From a sustainability point of view, it deserves to be highlighted that leather is very durable, repairable and that its use contributes to recycling animal hides, an organic waste from the meat industry, even though leather production also results in waste. Important product features appreciated by footwear brands and consumers include materials having high physical resistance, lightweight and are recycled and/or recyclable, thus increasing footwear comfort and overall sustainability.
In this context, Green Shoes 4.0, CTCP and partners IPB, CTIC, Boaventura and Fontevelha teams work included the modification of leather’s internal structure to increase mouldability, reduce density (weight), increase the area usable in final products and the use of leather production waste. Leather functionalisation was promoted by hydrolysed by-products obtained from solid leather residues and commercial microparticles of low density that are hollow and rigid or elastic and expandable, which allow modifying and filling of the leather’s structure.
Preliminary tests indicated that the microparticles are best positioned on the surface and not penetrating the interstices of the skin. Reinforcements based on leather hydrolysate (water resistance) from wet white and wet blue leather waste, composed of mixtures of proteins with different molecular weights, as well as different levels of functional groups (NH2), and transglutaminase (fillers) were tested and incorporated by chemical anchoring into the leather’s structure. The samples were subjected to light microscopy and SEM (electron) microscopy. The SEM results showed that wet white hydrolysate led to better filling of the leather’s structure than the wet blue. Analysing the physical and flexion test results shows that the best percentages to employ are between 25% and 50% hydrolysate.
Recycled soling materials
Green Shoes 4.0, CTCP and partners IPB, UMinho, Atlanta and Procalçado are developing materials for use in flexible, durable, lightweight and recyclable soles. New formulations, processes and advanced additives have been studied with the aim of developing high quality thermoplastics and materials incorporating up to 90% recycled content have been developed. Test results confirm the optimised materials have properties ´like virgin materials´ and soles meet the specifications required by fashion and more demanding casual footwear. Additionally, the teams have worked hard on the development of materials incorporating soles and footwear production waste (ground and devulcanised) and post-consumer footwear including rubber, fabrics, glues and paperboard (Figure 2). Soles developed by Atlanta and Procalçado using these materials were tested in regard to density, hardness, resistance to abrasion and fatigue, tearing, traction and elongation at break. The results indicate they are ready to enter the market immediately.
Digitisation of the value chain
Green Shoes 4.0 has several new concepts in terms of digitisation, with company CEI by ZIPOR developing software and tools to digitally connect leather suppliers and their clients to shorten the processes of leather digitalisation, nesting and cutting. AMF and INESCTEC have been working on a consumer profile, trends and ‘forecast’ system, that extracts relevant indicators for analysing customer purchases and preferences to define more efficient production planning with faster overall response times to boost sales. An innovative footwear soles injection planning system has also been studied with regard to tactical planning (lot-sizing) and operational planning (scheduling). Work carried out included the development of a mathematical model that would solve the problem of tactical planning. The result is an aggregated production plan that indicates which production orders to produce each week for the chosen time span (normally between two and six months) and forecasts stock needs and delays in deliveries to the client. Practical usage by shoe manufacturer AMF indicates up to 15% greater production efficiency.
New product concepts
Green Shoes 4.0 partners are actively deploying new products and concepts. One example is LeatherGoods by Belcinto. The new brand set itself the difficult objective of producing items only using surplus materials from previous collections and production, reusing them and using them fully, without generating new ‘leftovers’ in the process. This forced them to think the design through rigorously looking at a piece in every respect to fully satisfy functionality issues without failing to please and even surprise consumers, and keeping up to date without compromising on sustainability. A work that both amuses and rewards. The result is a deeply original line, with roots planted in the company’s DNA, producing prestigious leathergoods made with exceptional world-class quality for international markets, while preserving the environment with eco-friendly providers.
The Green Shoes 4.0 project is due to run until the end of June this year.
LeatherGoods by Belcinto.
Credit: BELCINTO IN GREEN SHOES 4.0
