The felting of wool is very specific to this fibre only. It is positive for the production of felted products. It is negative for garments which have to be washed by the consumer.
The felt free property is achieved by the treatment of wool. This finish prevents woollen textiles from extended shrinkage and deformation by felting during washing.
The felting of Wool
Felting happens during a mechanical treatment of the fibre in water.
Even though it is wanted for the manufacture of felts or fabrics having specific surface appearances, it is one of the major problems during the washing of woollen garments when the non reversible felting happens.
Reason for this is the structural surface of the wool, all scales are in one direction from the roots to the top, resulting in an individual value for friction depending on the direction.
During any agitation in water the one directional fibre moves (toward the root) continues and leads to a higher density of the fabric.