Flame retarded, reinforced polypropylene technical fibres

A new simple method has been elaborated for increasing the strength of oriented polypropylene fibres by additives. The principle of the process is the incorporation of inorganic fillers (such as talc or CaCO3) into polypropylene matrix material in a manner that allows maintaining the stretch ability of the fibre formed in this way. A new halogen free additive system has been developed which contains reactive P, N, Si and Zn derivatives that react with each other in the production line forming a flame retarded polypropylene fibre by reactive extrusion. The influence of the additive system under combustion is based on the formation of a closed intumescent surface layer, that hinders the heat and flammable material transport.