Spinning oil for synthetic fiber

摘要

It is an object of the invention to provide a spin finish generating neither tar nor scum in false twisting treatment either of the hot plate contact heating type or of the non-contact heating type using a radiation type high temperature heater and thus enabling long term stable false twisting treatment. This invention provides a spin finish for synthetic fibers which satisfies the following relations (1) and (2): 10<=T<=22 (1) 0<=Re<=0.25 (2) where T is the surface tension (mN/m) of the oil after allowing the same to stand at 220° C. for 1 hour and Re is the percent residue (% by weight) on heating of the oil after allowing the same to stand at 400° C. for 24 hours.