Samenvatting

At the Swedish School of Textiles, previous research showed that the fiber length loss during shredding could be decreased by pre-treatment of the textile. A lubricant pre-treatment reduced friction in the process which made the shredding process gentler and longer fibers was obtained. The research at hand focuses on the possibility to ring spin the untreated and treated mechanically recycled cotton fibers. 
The untreated and treated recycled cotton fibers were blended with virgin cotton, flax and hemp fibers. The yarn prototypes were evaluated on mechanical properties, tensile strength, elongation, twist number and a visual analysis was performed. To evaluate the yarns in a fabric, plain weft knit textiles were produced with the spun yarns. The knitted fabrics were tested on their mechanical properties, tensile strength, elongation, abrasion and pilling resistance as well as flexibility.
After optimizing the ring spinning process for short staple fibers, a spinnable blend was achieved with 60% untreated or treated recycled cotton fibers. However it was not possible to spin this with 40% hemp or flax fibers, in all yarns at least 10% virgin cotton need to be added for spinnability. During the spinning it was noticed that the spinnability of the treated recycled cotton fibers compared to the untreated recycled cotton fibers was equally. There was also no significant difference between the tensile strength of the yarns spun with untreated and treated recycled cotton fiber. The twist number of the yarns was very high, which was necessary to be able to create the yarns. 
This research shows that friction and rigidity are the main factors that influence the spinnability of the recycled fibers. The blend also influences the spinnability of the recycled cotton fibers. By adding virgin cotton the recycled cotton fibers became more spinnable and by adding flax fibers the yarn gives a higher tensile strength.