METHOD OF MANUFACTURING POLYOXYMETHYLENE FILAMENTS

摘要

A method of manufacturing polymethylene filaments, wherein polyoxymethylene having the molecular weight from 30,000 to 100,000 and containing stabilizing additives in a quantity from 0.1 to 3.0 per cent of the weight of the polyoxymethylene is subjected to thermal treatment at a temperature from 100.degree.C to 150.degree.C and pressure from 1 to 100 mm mercury to attain constant weight. The thermally treated polyoxymethylene is melted at a temperature from 170.degree.C to 230.degree.C, whereafter the melt is forced through the orifices of an extrusion nozzle. The jets of the melt, leaving the orifices of the extrusion nozzle, are cooled to a temperature from 70.degree.C to 169.degree.C. After the cooling the obtained filaments are drawn at a temperature from 120.degree.C to 165.degree.C to a length exceeding from 7 to 14 times the initial length. The disclosed method offers a simple technology of producing filaments as strong as 100 grams per tex. To produce low-shrinkage fibre (i.e. with a shrinkage rate from 0 to 5 per cent at 150.degree.C) the drawn filaments are thermally treated at a temperature exceeding that of the drawing by 2.degree.C to 50.degree.C, the filaments being maintained under tension. Alternatively, the drawn filaments may be first tensioned and then thermally treated.