Elastic fiber, process for the same and polyester elastomer used thereof

A process for preparing an elastic fiber of polyester elastomer, comprising the steps of;

• melt-spinning said polyester elastomer,
• drawing the obtained fiber at the draw ratio of 1.3 or more,
• and then heat-treating at the temperature of 40 degrees Celsius or more;
• wherein said polyester elastomer mainly comprises the repeating unit expressed by the formula (1):
• ##STR17## in said formula (1), "Ar" represents an arylene group having 6 to 20 carbon atoms where part or all of hydrogen in the aromatic ring can be replaced by an alkyl group and/or a halogen atom, and "R" is at least one of constitutional units selected from the group consisting of the following formulae (A), (B) and (C):
• (A) Formula (1)-1 ##STR18## where "p" is an integer of 2 to 4, "R.sup.1 " and "R.sup.2 " are independently an alkyl group having 1 to 4 carbon atoms or a halogen atom, "m" and "n" are independently integers of 0 to 4;
• (B) Formula (1)-2 ##STR19## where "q" is an integer of 2 to 4;
• "R.sup.3 " and "R.sup.4 " are independently an alkyl group having 1 to 4 carbon atoms or a halogen atom;
• "k" and "l" are independently integers of 0 to 4;
• and
• (C) Formulae (1)-3 and (1)-4 ##STR20## where "R.sup.5 " is an alkyl group having 1 to 4 carbon atoms or a halogen atom;
• "j" is an integer of 0 to 4;
• "R.sup.6 " is an alkylene group having 2 to 20 carbon atoms which may contain an ether linkage in the molecular chain;
• said "a" and "b" denote the numbers of moles for the constitutional units represented in said formulae (1)-3 and (1)-4, respectively, and the formula (1)-5 is satisfied:
• 0.01<b/a<1.0 (1)-5.

An polyester elastomer suitable for use in preparing an elastic fiber of polyester elastomer, said polyester elastomer comprising a hard segment of an aromatic polyester component mainly comprising repeating units expressed in the formula (1), and a soft segment of a poly(alkyleneoxide)glycol component having a number-average molecular weight of 500 to 5000;

• wherein the content of poly(alkyleneoxide)glycol is within the range from 30 to 95 weight percent of the polyester elastomer;
• and the inherent viscosity of the polyester elastomer (IV) (with measuring solvent of phenol/1,1,2,2-tetrachloroethane=4/6 (in weight percentage) at the measuring temperature of 35 degrees Celsius) is within the range from 0.5 to 13.0;
• ##STR21## in said formula (1), "Ar" represents an arylene group having 6 to 20 carbon atoms where part or all of hydrogen in the aromatic ring can be replaced by an alkyl group and/or a halogen atom, and "R" is at least a constitutional unit expressed in the following (A),
• (A) Formula (1)-1 ##STR22## where "p" is an integer of 2 to 4, "R.sup.1 " and "R.sup.2 " are independently an alkyl group having 1 to 4 carbon atoms or a halogen atom, "m" and "n" are independently integers of 0 to 4.

A polyester elastomer suitable for use in preparing an elastic fiber of polyester elastomer,

• said polyester elastomer comprising the hard segment of aromatic polyester component mainly comprising the repeating units expressed in the formula (1), and the soft segment of poly(alkyleneoxide) glycol component having a number-average molecular weight of 500 to 5000;
• wherein the content of poly(alkyleneoxide) glycol is within the range from 30 to 95 weight percent of the polyester elastomer;
• and the inherent viscosity of the polyester elastomer (IV) (with measuring solvent of phenol/1,1,2,2-tetrachloroethane=4/6 (in weight percentage) at the measuring temperature of 35 degrees Celsius) is within the range from 0.5 to 13.0;
• ##STR23## in said formula (1), "Ar" represents an arylene group having 6 to 20 carbon atoms where part or whole of hydrogen in the aromatic ring can be replaced by alkyl group and/or halogen atom, and "R" is a constitutional unit expressed in the following (B):
• (B) Formula (1)-2 ##STR24## where "q" is an integer of 2 to 4;
• "R.sup.3 " and "R.sup.4 " are independently an alkyl group having 1 to 4 carbon atoms or a halogen atom;
• "k" and "l" are independently integers of 0 to 4.

A polyester elastomer suitable for use in preparing an elastic fiber of a polyester elastomer, said polyester elastomer comprising an aromatic polyester component as a hard segment, and poly(alkyleneoxide)glycol component having a number-average molecular weight of 500 to 5000 as a soft segment;

• said polyester elastomer mainly comprising the repeating unit expressed in the formula (1);
• ##STR25## where "Ar" represents an arylene group having 6 to 20 carbon atoms where part or all of hydrogen in the aromatic ring can be replaced by an alkyl group and/or a halogen atom, and "R" is the constitutional unit expressed in the formula (C):
• (C) Formulae (1)-3 and (1)-4 ##STR26## where "R.sup.5 " is an alkyl group having 1 to 4 carbon atoms or a halogen atom;
• "j" is an integer of 0 to 4;
• "R.sup.6 " is an alkylene group having 2 to 20 carbon atoms which may contain an ether linkage in the molecular chain;
• said "a" and "b" denote the numbers of moles for the constitutional units represented in said formulae (1)-3 and (1)-4, respectively, and the formula (1)-5 is satisfied:
• 0.01<b/a<1.0 . . . (1)-5.