Decathlon, a French sportswear manufacturer, has patented a unique knitting technique for the creation of their new Negombo fabric after conducting extensive testing. The fabric is now available in Decathlon Nabaiji swimwear, which is recyclable and mostly made from recycled feedstocks.
For swimwear, however, materials that mould to the body are a must, and to ensure the necessary elasticity, elastane fibres are commonly employed in blends with polyamide or polyster. The elastanes provide the necessary level of elastic return and morphological adaptability, but in the quantity required in fibre blends for swimwear garments are non-recyclable by conventional routes.
Negombo fabric eliminates elastane and is based on a combination of Lycra’s T400eco fibre and recycled PET, which Decathlon reports is effectively stretchy and retains its shape over time as a result of the special knitting technique it has developed – hence the patent protection. The fabric also contains 76% recycled fibres.
A recycling process for the material is currently being developed with various partners with the aim of establishing a fabric-to-fabric circular reprocessing route. Elastane can also deteriorate when exposed to chlorine, but laboratory tests demonstrate a chlorine resistance of over 500 hours for Negombo.
This significantly enhances durability, while another advantage of polyester-based fabrics is that they can be printed by sublimation techniques, with 60% lower CO2 emissions than conventional dyeing. In addition, Negombo has 210 grams of opacity, eliminating the need for a liner in the swimwear, saving fabric and ensuring faster drying. It also has a UV protection factor of over 50.
Smart Stitch and Disassembly
Decathlon has futher teamed up with Resortecs, in the development of the new Nabaiji apparel based on Negombo fabric. This Brussels-based company is making recycling easier and more actionable through two simple but highly effective design-for-disassembly technologies.
The company’s Smart Stitch is a range of is a range of 16 heat-dissolvable sewing threads suitable for a variety of applications that have been exhaustively tested on various production line configurations. They are also compatible with every stitching machine available on the market and supplied in different colours and tenacities to enable full creativity in design and high quality in manufacturing.
“Smart Stitch sewing threads are engineered to dissolve at various temperatures between 150 and 190 degrees depending on fibre type,” explains Resortecs CTO Acerina Trejo-Machin. “When employed at the design stage, they are highly advantageous for disassembling fabrics, so especially useful in dealing with unsold inventory. During their lifetime, garments using these threads can be washed, ironed and laundered without problem.”
Smart Disassembly is the company’s complementary technology – a patented industrial-scale thermal disassembly system with a flexible capacity of from 1-13 tons per day and a processing speed five times faster than manual disassembly. It is based on low-oxygen chambers with no risk of oxidation damage in a closed-loop heating system that maximises energy recovery and minimises CO₂ emissions.
