Method of manufacturing stabilized fiber bundle, and method of manufacturing carbon fiber bundle

Abstract

A method of manufacturing a stabilized fiber bundle, including travelling an acrylic fiber bundle in an oxidation oven, with the acrylic fiber bundle being conveyed by guide rollers placed on both sides outside the oxidation oven, to subject the acrylic fiber bundle to a heat treatment in an oxidizing atmosphere, wherein a direction of hot air in the oxidation oven is horizontal to a travelling direction of the fiber bundle, and a contact probability P between adjacent fiber bundles, defined by expression (1), is 2 to 18%:P=[1−p(x){−t<x<t}]×100  (1)wherein P represents the contact probability (%) between adjacent fiber bundles, t represents an interspace (mm) between adjacent fiber bundles, p(x) represents a probability density function of a normal distribution N(0, σ2), σ represents a standard deviation of an amplitude of vibration, and x represents a random variable under the assumption that a median amplitude of vibration is zero.

1 .- 9 . (canceled) 
     
     
         10 . A method of manufacturing a stabilized fiber bundle, comprising travelling an acrylic fiber bundle obtained by adjacently aligning a plurality of bundles, in a hot air heating-type oxidation oven, with the acrylic fiber bundle being conveyed by a guide roller placed on each of both sides outside the oxidation oven, to thereby subject the acrylic fiber bundle to a heat treatment in an oxidizing atmosphere, wherein a direction of hot air in the oxidation oven is horizontal to a travelling direction of the fiber bundle, and a contact probability P between adjacent fiber bundles, defined by expression (1), is 2 to 18%:
     P =[1− p ( x ){− t<x<t }]×100  (1)
   wherein P represents the contact probability (%) between adjacent fiber bundles, t represents an interspace (mm) between adjacent fiber bundles, p(x) represents a probability density function of a normal distribution N(0, σ 2 ), σ represents a standard deviation of an amplitude of vibration, and x represents a random variable under the assumption that a median amplitude of vibration is zero.   
     
     
         11 . The method according to  claim 10 , wherein a lateral length between the guide rollers is 14.5 m or more. 
     
     
         12 . The method according to  claim 10 , wherein an air velocity of hot air flowing in the oxidation oven is 1.0 to 6.0 m/sec. 
     
     
         13 . The method according to  claim 10 , wherein the guide roller has a control mechanism of a width of fiber bundle. 
     
     
         14 . The method according to  claim 10 , wherein a surface of a single fiber of the acrylic fiber bundle has a surface asperity structure extending for 2.0 μm or more in a longitudinal direction of the fiber in a square range of 2.0 μm in a circumferential direction and 2.0 μm in a fiber axis direction, and a longer diameter/shorter diameter ratio in a cross section of the single fiber is 1.01 to 1.10. 
     
     
         15 . The method according to  claim 10 , wherein the acrylic fiber bundle has a length of hook drop of 300 mm or less. 
     
     
         16 . The method according to  claim 10 , wherein an amount of attachment of a silicon based oil agent to the acrylic fiber bundle is 0.1 to 3.0% by mass. 
     
     
         17 . The method according to  claim 10 , wherein a single fiber fineness in the acrylic fiber bundle is 0.05 to 0.22 tex. 
     
     
         18 . A method of manufacturing a carbon fiber bundle, comprising subjecting a stabilized fiber bundle manufactured by the method of manufacturing a stabilized fiber bundle according to  claim 10 , to a precarbonization treatment at a maximum temperature of 300 to 1,000° C. in an inert gas, to thereby manufacture a precarbonized fiber bundle, and subjecting the precarbonized fiber bundle to a carbonization treatment at a maximum temperature of 1000 to 2000° C. in an inert gas.