Shanghai, China -- Bayer MaterialScience's global footwear competence centre says it has developed a unique concept for a 'green' shoe that uses a host of sustainable materials and technologies.
These include renewable polyurethane feedstocks, raw materials for solvent-free coatings and adhesives, and a polycarbonate blend and thermoplastic polyurethane (TPU) based on renewable resources, according to a 13 Sept press release from BMS. Up to 90 percent of all components in the 'Ecotrekker' concept shoe can be given eco-friendly properties by using the company's products, the release adds.
"Footwear manufacturers, end consumers and, not least, the environment can all benefit equally from this development," suggests John Zhang, head of the Shanghai unit where the shoe was developed, in close collaboration with the Simple Factory Group, whose many years of experience in shoe design and production helped to successfully create the concept, the release added.
The concept also offers health and safety benefits for employees of shoe makers as well as the environment. "The aqueous coating and adhesive products are completely solvent-free and ... the polyurethane products used do not contain any heavy metals. This is also important for disposal, once a shoe has reached the end of its service life," Zhang explained.
Use of these coatings and adhesives alone would cut global emissions of organic solvents by about 150 kilotonnes, the release added.
Turning to the main components of the shoe, Bayer claims the microcellular polyurethane elastomer systems for outer soles and midsoles alone use raw materials with the proportion of renewable as high as 70 percent. It also has a shoe cap made from a polycarbonate blend with PLA (polylactic acid) which gives it a high proportion of biobased raw materials, the firm says,
In addition, the concept shoe's heel counter, shoelace eyelets and, even, the manufacturer's logo on the sole, are made from thermoplastic polyurethanes which are also based on a high level of renewable raw materials. Due to its outstanding mechanical properties, the highly abrasion- and wear-resistant TPU, sold under the Desmopan tradename, can also be used for traditional TPU shoe components such as outsoles or decorative upper parts.
TPU films from BMS' Dureflex range form a vapour-permeable membrane to reinforce the inner sole, without using plasticisers. And, in a final remark, Bayer points out that the concept shoe incorporates a counterfeit-proof label made by high-contrast laser engraving of a polycarbonate film from its Makrofol ID range. In addition, different security features like holograms can be incorporated, the firm adds.
The global footwear competence centre was established by BMS in 2007.
"China accounts for more than 60 percent of global footwear production. In 2005, more than 7000 million pairs of shoes were made in China," said Peter Vanacker, head of the Polyurethanes Business Unit of Bayer MaterialScience, in a 19 Dec 2007 company statement."