Process for the production of piece-dyed pile fabrics

A process for producing piece-dyed pile fabric having in the pile warp polyacrylonitrile fibre spun yarns shrinkable above 100 DEG C. comprises heating the untreated material to above 100 DEG C. in the dry state, dyeing said material in a closed winch beck having a roller and lateral spreader and finally raising and shearing the material. The polyacrylonitrile fibres are preferably of high molecular weight linear polymer of acrylonitrile containing more than 80% arcylonitrile. Before raising the material above 100 DEG C. it may be given a preliminary napping treatment. Then the heat treatment may be carried out on a strenter. After the dyeing and final nap raising the material is preferably dried on a stenter at aboue 100 DEG C. before being shorn. An example is given of the treatment of a particular material.