Abstract: This process for manufacturing a carbon-fiber precursor acrylic fiber bundle and this steam drawing apparatus are characterized in that the drawing of an acrylic fiber bundle with a pressured-steam drawing apparatus is conducted by: opening an acrylic fiber bundle by blowing a fluid thereto; supplying humidifying steam to the opened acrylic fiber bundle at a fiber temperature of 80 to 130° C. to adjust the water content of the fiber bundle to 3 to 7%; and thereafter drawing the resulting acrylic fiber bundle in a pressurized-steam atmosphere. Thus, the present invention can prevent the breaking of a single fiber, the fluffing of the fiber bundle, and the breaking of the whole of the fiber bundle, though such defects are susceptible to occurring in a case where an acrylic fiber bundle is drawn by steam drawing at a high draw ratio, at a higher speed, or into a fiber having a small denier.

Abstract: A steam-drawing apparatus has supply roll 1 that transfers carbon-fiber-precursor acrylic fiber bundle (T) in a transfer direction of fiber bundle (T); fiber-opening device 2 for opening fiber bundle (T); width control device 3 for controlling the width of fiber bundle (T); steam box 4 to provide steam for heating fiber bundle (T) to a temperature that allows fiber bundle (T) to be drawn; and haul-off roll 5 that transfers fiber bundle (T) at a speed faster than that of supply roll 1. Using width control device 3 provided at a position between supply roll 1 and steam box 4, the width of fiber bundle (T) after passing through width control device 3 is set to be 65˜110% of the width of fiber bundle (T) before entering the supply roll. The present invention proposes a method for producing a carbon-fiber-precursor acrylic fiber bundle using such a steam-drawing apparatus capable of conducting a high-speed drawing process of carbon-fiber-precursor acrylic fiber bundles at a high draw rate with stable results.

Abstract: This process for manufacturing a carbon-fiber precursor acrylic fiber bundle and this steam drawing apparatus are characterized in that the drawing of an acrylic fiber bundle with a pressured-steam drawing apparatus is conducted by: opening an acrylic fiber bundle by blowing a fluid thereto; supplying humidifying steam to the opened acrylic fiber bundle at a fiber temperature of 80 to 130° C. to adjust the water content of the fiber bundle to 3 to 7%; and thereafter drawing the resulting acrylic fiber bundle in a pressurized-steam atmosphere. Thus, the present invention can prevent the breaking of a single fiber, the fluffing of the fiber bundle, and the breaking of the whole of the fiber bundle, though such defects are susceptible to occurring in a case where an acrylic fiber bundle is drawn by steam drawing at a high draw ratio, at a higher speed, or into a fiber having a small denier.

Abstract: A steam drawing apparatus for providing pressurized steam on running yarn to draw the yarn, comprising a steam chamber; first seal chamber adjacent to a yarn entrance of the steam chamber; and second seal chamber adjacent to a yarn exit of the steam chamber, first seal chamber and second seal chamber are each provided with a labyrinth seal section having a plurality of plate pieces, first yarn-position regulating bar is provided to prevent the running yarn from touching the plate pieces, first yarn-position regulating bar extends horizontally intersecting the running direction of the yarn at right angles, and a horizontal plane passing through the point of the first yarn-position regulating bar closest to the yarn is set at least 0.1 mm closer to the yarn than a horizontal plane passing through the tip of the plate piece closest to the yarn.

Abstract: A steam drawing apparatus for providing pressurized steam on running yarn to draw the yarn, comprising a steam chamber; first seal chamber adjacent to a yarn entrance of the steam chamber; and second seal chamber adjacent to a yarn exit of the steam chamber, first seal chamber and second seal chamber are each provided with a labyrinth seal section having a plurality of plate pieces, first yarn-position regulating bar is provided to prevent the running yarn from touching the plate pieces, first yarn-position regulating bar extends horizontally intersecting the running direction of the yarn at right angles, and a horizontal plane passing through the point of the first yarn-position regulating bar closest to the yarn is set at least 0.1 mm closer to the yarn than a horizontal plane passing through the tip of the plate piece closest to the yarn.

Abstract: A steam-drawing apparatus has supply roll 1 that transfers carbon-fiber-precursor acrylic fiber bundle (T) in a transfer direction of fiber bundle (T); fiber-opening device 2 for opening fiber bundle (T); width control device 3 for controlling the width of fiber bundle (T); steam box 4 to provide steam for heating fiber bundle (T) to a temperature that allows fiber bundle (T) to be drawn; and haul-off roll 5 that transfers fiber bundle (T) at a speed faster than that of supply roll 1. Using width control device 3 provided at a position between supply roll 1 and steam box 4, the width of fiber bundle (T) after passing through width control device 3 is set to be 65˜110% of the width of fiber bundle (T) before entering the supply roll. The present invention proposes a method for producing a carbon-fiber-precursor acrylic fiber bundle using such a steam-drawing apparatus capable of conducting a high-speed drawing process of carbon-fiber-precursor acrylic fiber bundles at a high draw rate with stable results.