Nonwovens from Mechanically Recycled Fibres for Medical Applications

This report summarizes VTT’s work carried out in Circular Nordic Bio Nonwoven in MedTech Applications (NordicBio) project - a bilateral Swedish Finnish co-operation funded by Vinnova and Business Finland. NordicBio aimed for development and pilot scale demonstration of a cost effective, bio and circular material based materials suitable for medical applications. VTT work focused on two processes: 1) cleaning of mechanically recycled fibres, and 2) production of nonwoven materials from recycled fibres. Targeted applications were laminated nonwoven products suitable, for example, for bed sheet and absorptive products in hospitals. Disinfection of textiles can be carried out either in high temperatures with alkaline chemicals and laundry detergents without oxidative chemicals, or in lower temperature together with oxidative chemicals and laundry detergents. It was found that the most effective treatments decreased fibre strength properties, but with certain chemical compositions also removal of some colours was possible. Microbial tests showed that the use of high temperature (80°C) at alkaline conditions is the most effective way to disinfect microbes, even bacterium pores. Lower temperatures (60°C and 40°C) with oxidative detergent reduce the content of other microbes effectively, except bacterium pores. Nonwovens were prepared from recycled fibres in combination with pulp, regenerated cellulosic fibres and bi-component binder fibres, and using spunlacing, latex treatment and thermally activated bico fibres as binding methods. It was observed that mechanical properties, strength and strain, of nonwovens can be varied widely by fibre content and binding method. We concluded that high recycled cotton content can be achieved with optimized formulation and binding. Slushable materials suitable for recycling were obtained using spunlacing as binding method. Nonwovens were also prepared in pilot scale for lamination trials. Tensile strength of piloted materials was comparable to commercial references, but their strain was lower and grammages higher than references. Lamination trials were successfully carried out for rolled materials, and lamination improved the mechanical properties.