The invention relates to a porous soft
polyester fiber FDY
yarn and a preparing method thereof. According to the invention, modified
polyester employs a porous spinneret for
spinning to prepare the porous soft
polyester fiber FDY
yarn; an arrangement mode of the spinneret holes on the porous spinneret is in an elliptical shape, the aperture center of the spinneret holes is positioned on concentric ellipses, the concentric ellipses are a series of ellipses, the long shafts of all ellipses are collinear, and the short shafts are collinear. the porous soft polyester
fiber FDY
yarn is prepared by metering modified polyester slices, extruding, cooling, oiling, stretching,
thermoforming and reeling the material. A preparation method of the modified polyester comprises the following steps:
terephthalic acid and glycol are subjected to a reaction to prepare
ethylene glycol terephthalate,
terephthalic acid and branched chain-containing hexanediol are subjected to a reaction to obtain the
terephthalic acid glycol ester, and continuous reacting is carried out on the material to obtain the product. The yarn has excellent fiber performance, the
linear density deviation ratio is less than or equal to 0.5%, the breaking tenacity CV value is less than or equal to 4.0%, breaking elongation CV value is less than or equal to 8.0%, and a yarn unevenness CV value is less than or equal to 2.0.