| abstract |
A polyethylene naphthalate fiber formed from a naphthalate-based copolyester in which at least 85 mol% of all repeating units are accounted for by ethylene 2,6-naphthalate units and 1 to 15 mol% dihydric phenol/alkylene oxide adduct represented by the following general formula (I) H-(OA)m-O-Ar-O-(AO)n-H has been copolymerized with a diol ingredient, wherein A represents a C2-4 alkylene; m and n are the same or different and each represents an integer of 1 to 5; and Ar represents p-phenylene, m-phenylene, or a group represented by the following general formula (II) -Ph-X-Ph-, wherein Ph represents p-phenylene and X represents a 2,2-propylene, sulfone, or methylene group or an oxygen or sulfur atom. The fiber has high retentions of tensile strength and knot strength, has excellent durability, and is especially suitable for use in applications such as a dryer canvas for papermaking which is used under such severe conditions that it is repeatedly exposed to wet heat and dry heat. |