MANUFACTURING METHOD OF POLYESTER FIBER FOR AIR-LAID NONWOVEN FABRIC

PROBLEM TO BE SOLVED: To provide a manufacturing method of a polyester fiber for air-laid nonwoven fabric, capable of producing a nonwoven fabric having excellent uniformity and bulkiness, with extremely excellent airlaying formability especially in spinning from a screen.SOLUTION: A manufacturing method of a polyester fiber for an air-laid nonwoven fabric comprises a step of preparing an undrawn yarn of polyester containing 80 mol% or more of alkylene terephthalate repeating units, having a fineness of 10 dtex or less or a fiber length of 8 mm or more, an elongation of 130 to 600%, a crimp number of 8.5 peaks/25 mm or more, a crimp percentage/crimp number of 0.65 or less, a crimp modulus of elasticity of 70% or more, and a dry heat shrinkage ratio at 180°C of -20 to 2%, at a spinning rate of 1500 m/min or less; a step of drawing the undrawn yarn at a temperature lower than the glass transition point of the polyester; and a subsequent step of overfeeding the drawn yarn at a ratio of 0.50 to 0.9 for heat treatment at a temperature at least 10°C higher than the glass transition point of the polyester.