Walk On Air with XL EXTRALIGHT: Closed-cell Structure for Footwear

Key Points

1. Closed-cell foam engineered via a proprietary injection process; early hurdle, shrinkage, was solved with a patented method (1997), enabling high strength at very low weight.
2. SUSTAINABLE+ formulation uses ~51% pre-consumer industrial scraps, preserving XL EXTRALIGHT®’s mechanical properties while cutting virgin inputs; each pair has a unique surface from recycled particulates.
3. Proven in fashion collaborations (RAL7000STUDIO × Bershka; Adidas Originals ZX Mutant): maxi-outsoles and shells deliver extreme lightness with durable rebound and wear resistance.
4. Comfort comes from ultra-low density and tuned compounds: lab-customised blends allow soft-foam injection tailored to use case (clogs, frames, outsoles, accessories).
5. Beyond footwear: the material’s strength-to-weight and longevity support bags, eyewear, furniture components and medical devices; operations backed by ISO 9001/14001/45001, ISCC-PLUS and GRS certifications.

Full interview with XL EXTRALIGHT

The closed-cell structure is a key feature of your material. What were the major hurdles in perfecting this technology, and how did you address potential trade-offs between flexibility and durability?

XL EXTRALIGHT® is the result of an exclusive production process that begins with the formulation of the material and ends with the injection moulding of the product, progressing through mould engineering. When XL EXTRALIGHT® was first developed, one of the major hurdles was controlling the material’s shrinkage, which the company successfully managed using patented technology registered in 1997.

XL EXTRALIGHT® stands out due to its closed-cell structure in every formulation. This structure gives the material high strength and resistance to various factors, allowing it to be used in a wide range of products, including footwear, fashion accessories, pool and bicycle accessories, and medical devices. Its flexibility largely depends on the application and on the formulation of the compound according to customers' requests.

In the RAL7000STUDIO and Bershka project, digital barriers were overcome to make the product tangible. What role did XL EXTRALIGHT® play in this process, and how did your material enhance the physical experience of a previously digital-only design?

RAL7000STUDIO x BERSHKA began with a careful observation of reality, translating into an inclusive vision that aims to make accessible design for an innovation-conscious audience within the fashion industry. The result was a clog with sculptural volume, defined by organic lines derived from natural elements that could be seen as an oxymoron. What appeared to be a hand-carved block of stone turned out to be an extremely lightweight and comfortable creation, thanks to the collaboration with XL EXTRALIGHT®.

The product features a unique compound called SUSTAINABLE+, one of the latest technologies developed by XL EXTRALIGHT® and composed of 51% pre-consumer industrial scraps. This makes each pair unique due to the uneven surface and the random distribution of the recycled parts throughout the product.

In your collaboration with Adidas Originals for the ZX Mutant adidas model, what were the specific material challenges you faced, and how did XL EXTRALIGHT®'s SUSTAINABLE+ formulation meet Adidas's stringent performance and sustainability requirements?

XL EXTRALIGHT® was selected by RAL7000STUDIO for an experimental project with Adidas Originals. The protagonist of this special project was the MUTANT ZX 2K Boost, released in 2020 and inspired by the iconic ZX model from 1989.

The creative studio RAL7000 was called upon to reimagine and rework the new ZX series through a concept based on genetic mutation and a real alteration of the product’s DNA. The result was a super-light maxi-outsole combined with a shell entirely made from XL EXTRALIGHT® technology in its special formulation, SUSTAINABLE+, with a recycled neoprene sock inside.

XL EXTRALIGHT® Sustainable+ retains the incredible physical and mechanical properties characteristic of XL EXTRALIGHT®; however, it requires a highly engineered technique that entails the recovery and mixing of the scraps and by-products resulting from the processing rejects of the group’s plants. More than 50% of the material in the formula comes from the recovery and recycling of these industrial scraps from the manufacturing cycle, resulting in significant savings of mineral resources and preventing the scraps and residues of a large industrial group from becoming waste, thus avoiding landfill disposal.

Your materials are used to create footwear with unprecedented comfort. What specific material properties of XL EXTRALIGHT® contribute to this comfort, and how do you optimise these for different types of footwear?

XL EXTRALIGHT® is a special blend of polyolefin compounds that our ‘artists’ in the chemical lab develop daily to achieve better performance across every product. As a result, it can vary significantly between different applications.

Thanks to its extraordinary features and the company’s ability to support customers from the initial idea to implementation, while ensuring privacy throughout the process, which is particularly valued in the fashion industry: XL EXTRALIGHT® enables us to enhance any product in a new and surprising way.

Comfort is primarily guaranteed by the lightness of this ingredient, as well as by the ability of our laboratories, as mentioned above, to create tailor-made formulas for injecting soft foam products according to the requests of customers and designers.

Looking ahead, what new industries or applications do you believe will benefit most from the unique properties of XL EXTRALIGHT® materials, and how might these collaborations shape the future of those industries?

What sets XL EXTRALIGHT® apart is its focus on developing lightweight, flexible, and durable foam materials. These materials are crucial not only for the footwear industry, where comfort and performance are paramount, but also for a wide range of products, from fashion accessories to medical devices. The foam produced by XL EXTRALIGHT® is renowned for its exceptional performance, featuring a closed-cell structure that enhances strength, resistance, and longevity. Given the brand’s reputation for excellence in design, durability, and an appealing array of vibrant colours, it has become the go-to choice for many top brands.

XL EXTRALIGHT® foam can be utilised across various sectors, including fashion accessories (such as bags, sandals, watches, sunglasses, light shoes, and shoe soles), functional elements (like furniture, bus seats, headrest cushions, and shower mats), and design objects (including chairs and furnishing accessories).