Patent ID: 7155893

Claim:
A method for producing a heat-resistant crimped yarn, comprising: providing twisted yarn by twisting yarn of a heat-resistant high functional fiber such that said heat-resistant high functional fiber is twisted to a twist parameter K of from 5,000 to 11,000, wherein K is represented by the formula K=t×D 1/2 with t indicating a count of twist of the fiber in terms of turns/m, and D indicating a fineness of the fiber in terms of tex; making yarn cheese or yarn corn having a thickness of at least 15 mm and having a winding density of at least 0.5 g/cm 3 by winding said twisted yarn around a heat-resistant bobbin having through holes in a surface of a cylinder and/or a flange of said bobbin, with a diameter of each of said through holes being from 2 mm to 9 mm, and with a hole area rate defined by said through holes being 1% to 20%; loading said yarn cheese or yarn corn into an autoclave; reducing pressure in said autoclave so as to be within a range of from 5.0×10 3 Pa to 5.0×10 4 Pa; bringing said yarn cheese or yarn corn, while in said autoclave, into contact with steam having a high pressure and a high temperature within a range of from 130° C. to 250° C. or water having a high pressure and a high temperature within a range of from 130° C. to 250° C., thereby providing twist-set yarn having a snarl value of at most 6.5; and untwisting said twist-set yarn.