MANUFACTURE OF THERMOPLASTICS FIBRIDS

摘要

A process for the manufacture of thermoplastic fibrids by shredding a solution of a polymeric thermoplastic in a field of shearing forces, said shredding being performed by passing a homogeneous solution of the thermoplastic in an organic solvent, which is a solvent for said thermoplastic only at elevated temperature, through a nozzle having one or more orifices in the form of an annular die into a zone having the form of an impulse exchange chamber which has a mean inlet diameter of from 2 to 20 times that of the circular area equal to the total cross-sectional area of the nozzle orifices through which the homogeneous solution is extruded and a length of from 2 to 30 times its hydraulic diameter, in which chamber the homogeneous solution is cooled such that the thermoplastics material precipitates and in which a turbulent field of shear forces exists, this being produced by the introduction of one or more jets of a gaseous or liquid medium, which jets are located centrally to the annular orifice, into said impulse exchange chamber at a velocity of from 5 to 500 m/s.