| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a fine-size optically interfering fiber exhibiting excellent optically interfering effects even by a fine size, and suitable for the development in a commodity field requiring more aesthetic appearance; and to provide a method for stably producing the fiber. <P>SOLUTION: The optically interfering fiber having a protection layer with 0.1-5.0μm thickness, and≤4.0 dtex single fiber fineness is obtained by forming an undrawn fiber composed of an alternate laminate part obtained by alternately laminating polymer layers having mutually different refractive indexes so as to be parallel in the major axis direction of the cross section, and the protective layer covering the alternate laminate part, subjecting the undrawn fiber to flow drawing of 5.0-20.0 times at≤10 min<SP>-1</SP>strain rate in a heating bath at a temperature not lower than the glass transition temperatures and not higher than the crystallization temperatures of both of the polymers, and subjecting the flow-drawn fiber to neck drawing. The polymers forming the polymer layers are regulated so that the ratio (SP ratio) of a solubility parameter value (SP1) of the high refractive index side polymer to a solubility parameter value (SP2) of the low refractive index side polymer may satisfy the formula: 0.8≤SP1/SP2≤1.1. <P>COPYRIGHT: (C)2005,JPO&NCIPI</p> |
