The ultimate recycled knitting yarn
Companies in the fashion industry are looking for recycled textile products, which are not (yet) on the makt. The complexity of textile products makes recycling very difficult. Sorting and recycling textiles consisting of various fibre compositions -which is the case for almost all textiles in the fashion industry- is a technical challenge. In addition, mechanical recycling leads to loss of fibre quality. This means that in production processes such as spinning, weaving and knitting, the maximum range of equipment has to be explored in order to make high-quality products. The variations in fibres, especially recycled fibres, require a thorough investigation of interdependent production options.
Wolkat Fibre BV is a Dutch company that specializes in textile recycling. Used textile products such as clothing are mechanically recycled into new raw materials, especially for the interior design sector and products such as bags and tea towels. Wolkat is experiencing an increasing demand from the fashion industry for recycled yarns, specifically for knits, in order to actually recycle clothing into clothing. However, producing this knitting yarn brings new challenges. In order to produce mechanically recycled knitting yarn of market-conform quality, it is spun with relatively high twist settings. However, this high twist leads to problems in the knit, called spirituality. In this case, the knit, and therefore also the garment, tends to twist.
Project objective
This project is about optimizing the properties of a sustainable knitting yarn, with a focus on reducing twist and thus spirality problems in knitted fabrics. Various fiber ratios are included in this research, with the aim of creating the ultimate recycled knitting yarn. Of course, scaling up and commercial feasibility of the yarn are also important. Since factories are optimized for mass production, it is not feasible to carry out the research in factory environments. In addition, various production facilities and test equipment are necessary for thorough research. These resources are available in the circular textile laboratory of the Lectorate S&FT.
In order to define the project, it was decided not to vary in yarn number or the thickness of the yarn. This has been set at 12Nm, a yarn number that is common in the fashion industry for commercial knitted structures. In addition, we are investigating one spinning method: rotor spinning. Wolkat uses this spinning method and that makes the research directly translatable to the spinning machines in the factory. The fibers used in this research are mechanically recycled fibers from Wolkat and virgin polyester fibers.
The knitting structures used in this research are single jersey knitting structures. According to previous research by Wolkat, most spirality problems occur in these knitting structures compared to double jersey knitting structures (eg rib, pearl and double face jacquard knitting structures). These knitting structures are often used in the fashion industry for e.g. T-shirts, pullovers, sweaters, scarves and hats because they are relatively lighter and cheaper.
Partners
The project is subsidized by KIEM GoChem of Regieorgaan Sia.