Method for producing polypropylene elastic fiber and polypropylene elastic fiber
AssigneeIdemitsu Kosan Co., Ltd.
InventorsTomoaki Takebe, Yutaka Minami, Toshitaka Kanai
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Abstract
Provided are a method of producing an elastic fiber, including the steps of: subjecting a raw material to melt extrusion with a spinning nozzle at 100 to 300° C.; cooling the fiber after the melt extrusion in a water bath at 0 to 50° C.; and winding the cooled fiber, in which a specific low-crystalline polypropylene is used as the raw material, and an elastic fiber having a core-sheath bicomponent structure, which is obtained by using a specific low-crystalline polypropylene.
Claims18
A method of producing an elastic fiber, the method comprising:
- melt extruding a raw material with a spinning nozzle at 100 to 300° C., to obtain a fiber;
- cooling the fiber, after the melt extruding, in a water bath at 0 to 50° C., to obtain a cooled fiber;
- and
- winding the cooled fiber, to obtain a wound fiber
- wherein a low-crystalline polypropylene satisfying characteristics (a) to (g) or a crystalline resin composition comprising the low-crystalline polypropylene, the low-crystalline polypropylene or the crystalline resin composition satisfying characteristics (A) and (B), is the raw material:
- (a) [mmmm]=20 to 60 mol %;
- (b) [m]=50 to 90 mol %;
- (c) [rrrr]/(1−[mmmm])≦0.1;
- (d) [rmrm]>2.5 mol %;
- (e) [mm]×[rr]/[mr]2≦2.0;
- (f) weight-average molecular weight (Mw)=10,000 to 200,000;
- (g) molecular weight distribution (Mw/Mn)<4;
- (A) a crystallization temperature (Tc), which is measured with a differential scanning calorimeter (DSC), is 20 to 100° C.;
- and
- (B) a melting point (Tm-D), which is defined as a peak top of a peak observed at a highest temperature of a melting endothermic curve obtained with a differential scanning calorimeter (DSC) by retaining the raw material under a nitrogen atmosphere at −10° C. for 5 minutes and then increasing the temperature at 10° C./min, is 0 to 120° C.
A core-sheath bicomponent elastic fiber, obtained by sheathing a low-crystalline polypropylene satisfying characteristics (a) to (g) or a crystalline resin composition comprising the low-crystalline polypropylene, the low-crystalline polypropylene or the crystalline resin composition satisfying characteristics (A) and (B), at least as a core component:
- (a) [mmmm]=20 to 60 mol %;
- (b) [m]=50 to 90 mol %;
- (c) [rrrr]/(1−[mmmm])≦0.1;
- (d) [rmrm]>2.5 mol %;
- (e) [mm]×[rr]/[mr]2≦2.0;
- (f) weight-average molecular weight (Mw)=10,000 to 200,000;
- (g) molecular weight distribution (Mw/Mn)<4;
- (A) a crystallization temperature (Tc), which is measured with a differential scanning calorimeter (DSC), is 20 to 100° C.;
- and
- (B) a melting point (Tm-D), which is defined as a peak top of a peak observed at a highest temperature of a melting endothermic curve obtained with a differential scanning calorimeter (DSC) by retaining the raw material under a nitrogen atmosphere at −10° C. for 5 minutes and then increasing the temperature at 10° C./min, is 0 to 120° C.
- wherein the fiber has a total low-crystalline polypropylene fraction, which is calculated from the following equation (I), of 80 to 99 mass %
- Total low-crystalline polypropylene fraction=(Ws×Xs+Wc×Xc)/100 (I),
- wherein
- Ws represents a mass fraction of a sheath component,
- Wc represents a mass fraction of the core component,
- Xs represents a mass fraction of the low-crystalline polypropylene in the sheath component, and
- Xc represents a mass fraction of the low-crystalline polypropylene in the core component.
Dependencies are inferred from the claim text.