Abstract: The present invention provides a chargeable sheath/core-structured fiber that contains a polypropylene-based resin as a main resin, wherein the sheath part contains (a) a carboxylic anhydride-modified polyolefin and (b) at least one antioxidant selected from the group consisting of a combined antioxidant a phenolic antioxidant and a phosphorus-based antioxidant, and sulfur-based antioxidants; and (c) an oil containing a polyoxyalkylene alkyl ether represented by the general formula (I) as a finishing oil is deposited on the outer surface of the sheath part, and that can satisfy heat resistance and charge retainability. (In the formula, R1 represents a saturated or unsaturated aliphatic hydrocarbon group having 10 to 30 carbon atoms; R2 represents a hydrogen atom or a methyl group; and k is an integer of 1 to 4.

Abstract: The present invention provides a chargeable sheath/core-structured fiber that contains a polypropylene-based resin as a main resin, wherein the sheath part contains (a) a carboxylic anhydride-modified polyolefin and (b) at least one antioxidant selected from the group consisting of a combined antioxidant a phenolic antioxidant and a phosphorus-based antioxidant, and sulfur-based antioxidants; and (c) an oil containing a polyoxyalkylene alkyl ether represented by the general formula (I) as a finishing oil is deposited on the outer surface of the sheath part, and that can satisfy heat resistance and charge retainability. (In the formula, R1 represents a saturated or unsaturated aliphatic hydrocarbon group having 10 to 30 carbon atoms; R2 represents a hydrogen atom or a methyl group; and k is an integer of 1 to 4.

Abstract: Provided are a method for producing a drawn conjugated fiber, capable of producing a conjugated fiber having a high strength and a thin fineness, and a drawn conjugated fiber. A drawn conjugated fiber is produced by performing a spinning step of obtaining an undrawn fiber having a core-sheath structure in which a core material is a resin containing, as a main component, a crystalline propylene polymer and a sheath material is a resin containing, as a main component, an olefin polymer having a melting point lower than that of the core material, by means of melt-spinning (step S1); and a drawing step of drawing the undrawn fiber (step S2).

Abstract: Provided are a method for producing a drawn conjugated fiber, capable of producing a conjugated fiber having a high strength and a thin fineness, and a drawn conjugated fiber. A drawn conjugated fiber is produced by performing a spinning step of obtaining an undrawn fiber having a core-sheath structure in which a core material is a resin containing, as a main component, a crystalline propylene polymer and a sheath material is a resin containing, as a main component, an olefin polymer having a melting point lower than that of the core material, by means of melt-spinning (step S1); and a drawing step of drawing the undrawn fiber (step S2). During the production, a fineness of the undrawn fiber is adjusted to 1.5 dTex or less, and, in the spinning step, a melt flow rate of the core material discharged from the spinneret is adjusted to 70 to 170 g/10 minutes at 230° C. and a load of 21.