| 摘要 |
PURPOSE:To obtain a para-oriented aromatic polyamide sheet effective in distinguishing a high temperature by contacting an undried para-oriented aromatic polyamide sheet with a liquid containing a dye or a pigment and having specific pH and temperature. CONSTITUTION:The objective colored sheet varying the color at a definite temperature and enabling the distinguishment of temperature especially in a high temperature range is produced by contacting (A) a sheet containing >=50wt.% (preferably >=80wt.%) of water and produced by dissolving a para- oriented aromatic polyamide (e.g. poly-p-phenylene phthalamide) in sulfuric acid having a concentration of >=96wt.% at a polymer concentration of >=10wt.%, extruding the dope in the form of a sheet on a supporting face, converting the sheet from optically anisotropic state into optically isotropic state and subjecting the product to coagulation, washing, etc., with (B) a liquid adjusted to pH7-9 and >=90 deg.C (preferably >=95 deg.C) and containing a dye (preferably acid dye) or a pigment and washing the treated sheet A. |
