Core-sheath composite fiber, production method therefor, and fiber structure
AssigneeKuraray Co., Ltd.
InventorsKota TOGII, Shunichi HASEGAWA, Yuji OGINO
Life of this patent
Estimating the term…
Abstract
Provided are a core-sheath composite fiber, a production method therefor, and a fiber structure. The core-sheath composite fiber includes: a core component (12) including a melt-anisotropic aromatic polyester (a polymer A); and a sheath component having an islands-in-the-sea structure and including a flexible thermoplastic polymer (a polymer B) and a melt-anisotropic aromatic polyester (a polymer C). The polymer B and the polymer C constitute a sea component and an island component of the islands-in-the-sea structure, respectively. The island component includes a plurality of islands (18) dispersed in a sea (14) that is formed of the sea component.
Claims10
A core-sheath composite fiber comprising:
- a core component including a melt-anisotropic aromatic polyester (a polymer A);
- and
- a sheath component having an islands-in-the-sea structure and including a flexible thermoplastic polymer (a polymer B) as a sea component and a melt-anisotropic aromatic polyester (a polymer C) as an island component, the islands-in-the-sea structure being provided with a plurality of islands formed of the island component dispersed in a sea formed of the sea component, wherein
- the sheath component has a proportion of the island component of more than wt %;
- among the islands in a cross section cut along a longitudinal direction of the core-sheath composite fiber, an island represented by having a largest width along a direction perpendicular to the fiber has a maximum width W of 0.65 μm or shorter;
- the island having the maximum width W has a maximum diagonal length L1 which is a longest length in the island overlapped with a diagonal line drawn in the sheath component at a fixed angle of 10° relative to the longitudinal direction of the fiber along one end to another end thereof, and has a ratio L1/W of the maximum diagonal length L1 to the maximum width W of said island being 5.0 or more.
A method for producing a core-sheath composite fiber, the core-sheath composite fiber comprising:
- a core component including a melt-anisotropic aromatic polyester (a polymer A);
- and a sheath component having an islands-in-the-sea structure and including a flexible thermoplastic polymer (a polymer B) as a sea component and a melt-anisotropic aromatic polyester (a polymer C) as an island component, the islands-in-the-sea structure being provided with a plurality of islands formed of the island component dispersed in a sea formed of the sea component, the method at least comprising:
- kneading the polymer B and the polymer C for the sheath component in a twin-screw extruder at a temperature which is equal to Mb° C. or higher, is equal to (Mc−20°) C. or higher, and is lower than Mc° C., where Mb is a melting point of the polymer B and Mc is a melting point of the polymer C, and melt-kneading the polymer A for the core component in an extruder different from the twin-screw extruder used for the sheath component;
- discharging an as-spun composite fiber of the kneaded sheath component and the kneaded core component;
- and
- taking up the discharged as-spun fiber at a draft value of from 13 to 50, the draft value being a ratio of a winding speed to a discharging speed.
Dependencies are inferred from the claim text.