US 12,264,418 B2
Method for producing drawn conjugated fiber, and drawn conjugated fiber
Hirohumi Yashiro, Tokyo (JP); Kouki Endou, Tokyo (JP); and Tatsunori Tsukahara, Tokyo (JP)
Assigned to UBE EXSYMO CO., LTD., Tokyo (JP)
Filed by UBE EXSYMO CO., LTD., Tokyo (JP)
Filed on Sep. 2, 2022, as Appl. No. 17/902,461.
Application 17/902,461 is a division of application No. 14/905,499, abandoned, previously published as PCT/JP2014/069370, filed on Jul. 22, 2014.
Claims priority of application No. 2013-152703 (JP), filed on Jul. 23, 2013.
Prior Publication US 2023/0002936 A1, Jan. 5, 2023
Int. Cl. C08K 5/1575 (2006.01); B29C 48/05 (2019.01); C08K 5/00 (2006.01); C08K 5/52 (2006.01); C08K 5/521 (2006.01); D01D 5/08 (2006.01); D01D 5/098 (2006.01); D01D 5/12 (2006.01); D01D 5/34 (2006.01); D01F 1/10 (2006.01); D01F 8/06 (2006.01); D02J 1/22 (2006.01); D04H 1/4291 (2012.01); D04H 1/4382 (2012.01); D04H 1/541 (2012.01); B29K 23/00 (2006.01); D01F 6/46 (2006.01)
CPC D01F 8/06 (2013.01) [B29C 48/05 (2019.02); C08K 5/0083 (2013.01); C08K 5/0091 (2013.01); D01D 5/12 (2013.01); D01D 5/34 (2013.01); D01F 1/10 (2013.01); D02J 1/222 (2013.01); D04H 1/4291 (2013.01); D04H 1/43828 (2020.05); D04H 1/5412 (2020.05); B29K 2023/10 (2013.01); D01F 6/46 (2013.01); D10B 2321/021 (2013.01); D10B 2321/022 (2013.01)] 10 Claims
OG exemplary drawing
 
1. A method for producing a drawn conjugated fiber comprising:
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; and
a drawing step of drawing the undrawn fiber, wherein the undrawn fiber has a fineness of 1.5 dTex or less, and
in the spinning step, the core material discharged from a spinneret has a melt flow rate of 70 to 170 g/10 minutes at 230° C. and a load of 21.18 N, and a ratio of the melt flow rate of the core material discharged from the spinneret at 230° C. and a load of 21.18 N to a melt flow rate of the sheath material discharged from the spinneret at 230° C. and a load of 21.18 N is from 1 to 2.2, wherein at least one of a hydroxyamine ester, an isotactic polypropylene having a melt flow rate of 700 to 1550 g/10 minutes at 230° C. and a load of 21.18 N, and a metallocene polypropylene is added to the resin containing, as the main component, the crystalline propylene polymer, thereby adjusting the melt flow rate of the core material to be the melt flow rate of 70 to 170 g/10 minutes.