Polyester different-contraction commingled yarn

Polyester different-contraction commingled yarn comprising two different types of filaments with different boiling water shrinkage ratios, comprising polyester polymer as the principal component individually,

• wherein
• the polyester polymer is one produced by polycondensation of an aromatic dicarboxylate ester in the presence of a catalyst,
• the catalyst comprises at least one ingredient selected from among mixture (1) and reaction product (2) below,
• the mixture (1) is a mixture of the following components (A) and (B):
• (A) a titanium compound component comprising at least one compound selected from the group consisting of:
• (a) titanium alkoxides represented by the following general formula (I):
• [wherein R1, R2, R3 and R4 each independently represent one species selected from alkyl groups having 1 to 20 carbon atoms and phenyl group, m represents an integer of 1-4, and when m is an integer of 2, 3 or 4, the two, three or four R2 and R3 groups may be the same or different], and
• (b) reaction products of titanium alkoxides of general formula (I) above with aromatic polyvalent carboxylic acids represented by the following general formula (II):
• [wherein n represents an integer of 2-4] or their anhydrides, and
• (B) a phosphorus compound component comprising at least one compound represented by the following general formula (III):
• [wherein R5, R6 and R7 each independently represent alkyl groups having 1 to 4 carbon atoms, and X represents at least one species selected from among —CH2— group and —CH2(Y) group (where Y represents phenyl group)],
• the catalyst mixture (1) is used with a mixing ratio such that the ratio (%) MTi of the millimoles of titanium element in the titanium compound component (A) with respect to the number of moles of the aromatic dicarboxylate ester and the ratio (%) Mp of the millimoles of phosphorus element in the phosphorus compound component (B) with respect to the number of moles of the aromatic dicarboxylate ester satisfy the following expressions (i) and (ii):
• 1≦Mp/MTi≦15 (i)
• 10≦Mp+MTi≦100 (ii),
• and the reaction product (2) is the reaction product of the following components (C) and (D):
• (C) a titanium compound component comprising at least one compound selected from the group consisting of:
• (c) titanium alkoxides represented by formula (I) above and
• (d) reaction products of titanium alkoxides of general formula (I) above with aromatic polyvalent carboxylic acids represented by general formula (II) above or their anhydrides, and
• (D) a phosphorus compound component comprising at least one phosphorus compound represented by the following general formula (IV):
• [wherein R8 represents alkyl group having 1 to 20 carbon atoms or aryl group having 6 to 20 carbon atoms, and p represents an integer of 1 or 2].