Patent ID: 7056461

Claim:
A method of producing a polyester multifilament yarn for rubber reinforcement, comprising; A) melt-spinning polyester, containing 95 mole % or greater ethylene terephthalate as a repeating unit, passing the spun polyester through a hot zone (heating or non-heating zone) and a quenching zone to enable the spun polyester to be solidified to produce an undrawn yarn having an intrinsic viscosity (I.V.) of 0.83 or more and a density of 1.338 g/cm 3 or more, and oiling the undrawn yarn; and B) multi-stage drawing the oiled undrawn yarn using a draw roller at 80° C. or less, and heat-setting a resulting yarn using a heat-set roller at 210° C. or less to produce a drawn yarn having a density from 1.38 to 1.3865 g/cm 3 and a tenacity of 7.2 g/d or more.