Self-extinguishing polyacrylonitrile fibre prodn. - by adding organic halogen-contg. flame-retardant before dry-spinning to controlled residual solvent content

摘要

Difficultly inflammable self-extinguishing polyacrylonitrile filaments or fibres are dry-spun after adding an organic halogen cpd. to the acrylonitrile polymer to be spun. The halogen cpds. are soluble in the spinning solvent used and insoluble in water. The residual solvent content of the polyacrylonitrile filaments in the spun material is max. 12 wt.%. The halogen content introduced by the flame-retardant is at least 19 wt.% for halogen-free polyacrylonitrile filaments and at least 5 wt.% for modacrylic filaments. (The %-ages refer to the polymer solids and flame-retardant sum). Dry-spun filaments having LOI-index over 30 are obtd. The flame-retardant is evenly distributed and is not washed out from spun material in after-treatment steps.