Bioplastics and recycled plastics. A more sustainable future for shoe sole molding.
From raw materials to recycling: how bioplastics and recycled plastics are revolutionizing sole molding for a greener future.
In recent years, the footwear industry and the fashion industry as a whole have seen a growing interest in innovative and sustainable materials, as well as the recycling of end-of-life shoes, with the goal of creating increasingly green footwear. This trend stems from the need to reduce the environmental impact of industrial production and meet the demands of an increasingly sustainability-conscious consumer base. But what exactly are bioplastics, and how can they be used in shoe sole molding?
What are bioplastics?
Bioplastics are polymeric materials that can be renewable, biodegradable, or both. They are divided into two main categories:
Renewable bioplastics: derived from plant biomass such as corn starch, sugar cane, cellulose, or vegetable oils. They may have similar characteristics to traditional plastics without necessarily being biodegradable.
Biodegradable bioplastics: they degrade naturally thanks to the action of microorganisms present in the environment. Among the best-known examples are PLA (polylactic acid), PBAT (polybutylene adipate-co-terephthalate), and PHA (polyhydroxyalkanoates).
Bioplastic vs. Recycled Plastic: What’s the Difference?
The terms bioplastic and recycled plastic are often confused. However, there are substantial differences:
Bioplastic: A material produced from renewable sources or with biodegradable capabilities. It is not necessarily derived from pre-existing plastic, but rather from plant biomass or innovative biochemical processes.
Recycled plastic: A traditional plastic (of fossil origin) recovered from post-industrial or post-consumer waste and subjected to a mechanical or chemical recycling process for reuse in new products.
Both solutions contribute to environmental sustainability, but in different ways: bioplastics reduce dependence on fossil fuels, while recycled plastic minimizes waste and extends the material’s life cycle.
New materials for molding shoe soles
The use of biopolymers and secondary raw materials in the footwear industry is becoming an increasingly widespread option, representing an ecological breakthrough that meets sustainability demands without compromising quality and performance. Injecting these materials into molding presses allows for the creation of soles with characteristics similar to conventional plastics, but with a lower environmental impact. Bioplastics can also be modified to achieve different hardnesses, colors, and textures, meeting the needs of luxury and fashion brands. Some innovative solutions include:
Biobased TPU: Thermoplastic polyurethane is a widely used material for molding shoe soles due to its high abrasion resistance, elasticity, and lightness. Biobased versions, derived from vegetable oils such as soybean or castor, offer the same performance while reducing the use of fossil-based materials.
Recycled TPU: An increasingly popular sustainable alternative is recycled TPU, obtained by granulating industrial waste. This material maintains the same mechanical properties as virgin TPU and contributes to a more circular production model.
Biobased or recyclable polyurethanes: Used for the production of lightweight and comfortable soles, especially in high-end and athletic footwear. They can be formulated with biobased components or designed for easy recycling.
Biobased EVA: Ethylene Vinyl Acetate is a material known for its lightness and shock absorption. Formulations containing a percentage of biobased EVA, derived from sugarcane, reduce the use of fossil-based polymers without compromising the sole’s flexibility and durability.
Natural and recycled rubber: Used to produce various footwear styles, including elegant ones, it can be blended with recycled materials to improve sustainability.
Towards a more sustainable future for the footwear sector
Sustainability has become a key factor for the footwear industry in today’s market, as highlighted by the 21st International Conference of the UITIC (International Union of Footwear Industry Technicians), which in 2023 addressed the theme “Towards Sustainability Through Innovation.” More and more brands and manufacturers are rethinking their production processes to reduce energy consumption, use secondary or biobased raw materials, and monitor greenhouse gas emissions.
With the growing demand for eco-friendly materials from fashion brands and consumers, the adoption of biopolymers or recycled plastics, as well as innovative and eco-friendly fabrics for uppers, is becoming increasingly widespread, contributing to a greener future for the fashion industry.
Our commitment to sustainable innovation
We also believe that the future of the footwear industry is green. We use biobased or recycled TPU certified by the Global Recycle Standard (GRS) and recover our industrial waste through the in-house granulation of production waste and its reuse in the production cycle. We design the sole mold to minimize manufacturing waste. We are optimizing our processes to minimize resource consumption and the environmental impact of our production, introducing water-based glues, which are harmless to the environment and humans, in our assembly and gluing processes.
We are also committed to research and development for end-of-life shoe recycling, providing alternative and more sustainable solutions for the disposal of end-of-life footwear. We collaborate with brands to develop customized solutions for the production of more sustainable shoe soles, maintaining high quality and performance standards.
If your company is looking for innovative solutions for sustainable sole molding, contact us to discover our latest technologies and materials!
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