Patent ID: 6967058

Claim:
A polyester multifilament yarn for rubber reinforcement, produced according to the method comprising: A) melt-spinning polyester, containing 95 mole % or more ethylene terephthalate as a repeating unit, passing the spun polyester through a retarded cooling zone (heating or non-heating zone) and a cooling zone to enable the spun polyester to be solidified to produce an undrawn yarn with an intrinsic viscosity of 0.83 or more and a density of 1.338 g/cm 3 or more; and B) multi-stage drawing the undrawn yarn such that a draw ratio is 1.5 to 2.5, and heat-setting a resulting yarn to produce a drawn yarn with a density of 1.38 to 1.3865 g/cm 3 and a tenacity of 7.2 g/d or more and having a density of 1.38 to 1.3865 g/cm 3 , a shrinkage of 4.5% or more, an intrinsic viscosity of 0.83 or more, a tenacity of 7.2 g/d or more, and a carboxyl end group of 20 microequivalents/g or less.