Polyester type conjugate fiber package

Polyester type pre-oriented conjugate fiber of either a side-by-side type or an eccentric sheath/core type in which two kinds of polyester components are adhered to each other to form a single filament, wherein at least one of the components consisting of the single filament is polytrimethylene terephthalate containing repeating units of trimethylene terephthalate of 90 mol % or more, and wherein the pre-oriented conjugate fiber is wound to form a package and satisfies the following items (1) to (4):

• (1) a stretching elongation Vc prior to being treated with boiling water is less than 20%,
• (2) an elongation at break is in a range from 60 to 120%,
• (3) a dry heat shrinkage stress value is in a range from 0.01 to 0.15 cN/dtex, and
• (4) a yarn fineness variation value U% is 1.5% or less and a variation coefficient of a yarn fineness variation period is 0.4 or less.

Polyester type drawn conjugate fiber of either a side-by-side type or an eccentric sheath/core type in which two kinds of polyester components are adhered to each other to form a single filament, wherein at least one of the components consisting of the single filament is polytrimethylene terephthalate containing repeating units of trimethylene terephthalate of 90 mol % or more, and wherein the drawn conjugate fiber is wound to form a package and satisfies the following items (5) to (8):

• (5) a stretching elongation CE2 measured after the conjugate fiber has been treated with boiling water under a load of 2×10−3 cN/dtex is in a range from 5 to 100%,
• (6) an elongation at break is in a range from 25 to 80%,
• (7) a dry heat shrinkage stress value is in a range from 0.02 to 0.24 cN/dtex, and
• (8) a yarn fineness variation value U% is 1.5% or less and a variation coefficient of a yarn fineness variation period is 0.4 or less.

A method for producing a package of polyester type pre-oriented conjugate fiber of either a side-by-side type or an eccentric sheath/core type in which two kinds of polyester components are adhered to each other to form a single filament;

• at least one of the components consisting of the single filament being polytrimethylene terephthalate containing repeating units of trimethylene terephthalate of 90 mol % or more;
• and the conjugate fiber being spun by a melt-spinning method and wound in the package without drawing the conjugate fiber after being cooled and solidified by a cooling air, wherein the winding is carried out under the condition satisfying the following items (a) to (e):
• (a) a spinneret is used to ensure the spinning condition after the two kinds of polyester components join together, having a dimensional ratio L/D of 2 or more wherein L is a hole length and D is a hole diameter and an orifice slanted at an angle from 10 to 40 degrees relative to the vertical direction,
• (b) the spinning tension is in a range from 0.10 to 0.30 cN/dtex,
• (c) the heat treatment temperature is in a range from 70 to 120° C. and the heat treatment tension is in a range from 0.02 to 0.10 cN/dtex,
• (d) the package temperature is 30° C. or lower when the conjugate fiber is wound onto the winder, and
• (e) the winding speed is in a range from 1,500 to 4,000 m/min.

A method for producing a package of polyester type drawn conjugate fiber of either a side-by-side type or an eccentric sheath/core type in which two kinds of polyester components are adhered to each other to form a single filament;

• at least one of the components consisting of the single filament being polytrimethylene terephthalate containing repeating units of trimethylene terephthalate of 90 mol % or more;
• and the conjugate fiber being spun by a melt-spinning method and wound in the package as drawn conjugate fiber obtained by directly drawing the conjugate fiber without being once wound in the package after being cooled and solidified by cooling air, wherein the winding is carried out under the condition satisfying the following items (a) and (f) to (h):
• (a) a spinneret is used to ensure the spinning condition after the two kinds of polyester components join together, having a dimensional ratio L/D of 2 or more wherein L is a hole length and D is a hole diameter and an orifice slanted at an angle from 10 to 40 degrees relative to the vertical direction,
• (f) the drawing tension is in a range from 0.05 to 0.40 cN/dtex,
• (g) a speed V R of a heated second godet roll is in a range from 2000 to 4000 m/min,
• (h) a ratio VW/VR of a winding speed VW m/min) to the speed VR (m/min) of the heated second godet roll satisfies the following formula (2):
• 0.85≦VW/VR≦1 (2)
• and
• (i) the package temperature when the conjugate fiber is wound onto the winder is 30° C. or lower.