17 Electrical insulating materials; chemical fiber, not for textile use; chemical fiber yarn and thread, not for textile use; threads of rubber or plastic, not for textile use; plastic sheeting for agricultural purposes; plastic films for agricultural purposes; plastic semi-worked products in the form of pellets, rods, foils, foams, fibers, films and sheets; semi-processed plastics containing more than 50 % calcium carbonate and consisting principally of polyolefin resin, including those in sheet form; plastic semi-worked products consisting principally of calcium carbonate and polyolefin resin in the form of pellets, rods, foils, foams, fibers, films and sheets; semi-processed plastics containing more than 50 % inorganic filler and consisting principally of thermoplastic resin, including those in sheet form; plastic semi-worked products consisting principally of inorganic filler and thermoplastic resin in the form of pellets, rods, foils, foams, fibers, films and sheets; plastic semi-worked products in sheet, film, foil or tape-shaped form; semi-processed plastics; plastic film for packing and stuffing; plastic sheets for packaging