GB708173A - Process and apparatus for melt spinning - Google Patents

Abstract

Poly-e -caprolactam is melt-spun by feeding it in solid form to an initial heating device and delivering it therefrom in molten form to a sump or reservoir and thence to the spinning pump, the initial heating device and the sump being kept at a temperature not more than 15 DEG C. above the melting point of the polymer and p below the spinning temperature, and the source of heat for the spinning pump and spinneret being separate from the source of heat for the initial heating device and for the sump respectively, whereby the melt is heated to the spinning temperature immediately before the spinning. The capacity of the sump is sufficiently great to allow the heated material completely to melt before reaching the spinning pump. In the example poly-e - caprolactam having a melting point of 214 DEG C. and containing 1 per cent. of water-soluble monomers is melted in a heating chamber and flows by gravity into a sump of such capacity that the average time required for a particle of the melt to travel from the initial heating chamber to the spinning pump is 90 minutes. The chamber and the sump are surrounded by heating jackets and the temperature of the jackets and of the melt in the sump is 225 DEG C. The melt flows from the sump to a block containing the spinning pump and spinneret and heated by a third jacket so that the spinning temperature is about 254 DEG C. The content of monomers in the melt reaching the spinneret is 3 per cent. as compared with 5.9 per cent. in the usual melt-spinning process.