Subclass 1/073: Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres having existing or potential cohesive properties, e.g. natural fibres, prestretched or fibrillated artificial fibres (felting apparatus D04H 17/00 ) by treatment to produce shrinking, swelling, crimping or curling of fibres Acrylonitrile series