| abstract |
PURPOSE:To obtain the titled fiber having high dyeability with cationic dye and excellent alkali resistance and heat-resistance, by clocking at least a part of terminal with residue of a specific sulfonic acid metal salt compound and setting an alkali solubility constant within a specific range. CONSTITUTION:At least a part of the terminal of a polyester is blocked with a residue of a sulfonic acid metal salt compound of formula I, II and III (A, A<1>, A<2> and A<3> are ester-forming functional group; R, R<1>, R<2> and R<3> are H, OH, alkyl or halogen; M, M<1>, M<2> and M<3> are metal; k and l are 1 or 2; m and n are 0, 1 or 2; 1<=m+n<=4; p and q are 0 or 1; p+q=1, a and b are positive integers satisfying the formulas m+n+p=5 and n+b+q=5). The amount of the blocked terminal is 1.3-4.0mol% based on the dicarboxylic acid component constituting the polyester and the alkali solubility constant of the polyester is adjusted to 3.3X10<-9>-6.5X10<-9>cm/sec. |