| 摘要 |
<p>It is a problem of the present invention to provide a normal pressure cationic dyeable polyester being cationic dyeable under normal pressure, and having high strength. The problem can be solved by a normal pressure cationic dyeable polyester, characterized by being a copolymerized polyester having a main repeating unit including ethylene terephthalate, and including in an acid component forming the copolymerized polyester, a metal salt or sulfoisophthalic acid (A) and a compound (B) which is a phosphonium salt of sulfoisophthalic acid or the like in such a state as to simultaneously satisfy the two mathematical expressions. Preferably, the glass transition temperature of the copolymerized polyester is within the range of 70 to 85°C, and the intrinsic viscosity of the copolymerized polyester is within the range of 0.55 to 1.00 dL/g. Further, by melt spinning the copolymerized polyester, it is possible to provide a polyester fiber.</p> |
