US 11,702,779 B2
Spunbonded non-woven fabric, sanitary material, and method of manufacturing spunbonded non-woven fabric
Taiichiro Ichikawa, Tokyo (JP); Akio Matsubara, Ichihara (JP); Koichi Shimada, Chiba (JP); and Shigeyuki Motomura, Chiba (JP)
Assigned to MITSUI CHEMICALS, INC., Tokyo (JP)
Appl. No. 17/424,577
Filed by MITSUI CHEMICALS, INC., Tokyo (JP)
PCT Filed Jan. 30, 2020, PCT No. PCT/JP2020/003483
§ 371(c)(1), (2) Date Jul. 21, 2021,
PCT Pub. No. WO2020/158875, PCT Pub. Date Aug. 6, 2020.
Claims priority of application No. 2019-014680 (JP), filed on Jan. 30, 2019.
Prior Publication US 2022/0081814 A1, Mar. 17, 2022
Int. Cl. D04H 1/541 (2012.01); D04H 1/56 (2006.01); D04H 1/4291 (2012.01); D04H 3/007 (2012.01); D04H 3/16 (2006.01)
CPC D04H 1/5416 (2020.05) [D04H 1/4291 (2013.01); D04H 1/56 (2013.01); D04H 3/007 (2013.01); D04H 3/16 (2013.01)] 11 Claims
OG exemplary drawing
 
1. A spunbonded non-woven fabric, comprising a fiber comprising: a propylene homopolymer having a melting point of 140° C. or more; a polyethylene having a density of from 0.941 g/cm3 to 0.970 g/cm3; and at least one polymer selected from the group consisting of a polymer specified in the following (I) and a polymer specified in the following (II),
wherein the fiber comprises a sea-island structure, and a percentage of an island phase having a diameter of from 0.12 μm to less than 0.63 μm with respect to an entire island phase in a cross section orthogonal to an axis direction of the fiber on a number basis is 30% or more:
(I) a random copolymer of propylene and at least one selected from ethylene or an α-olefin having a carbon number of from 4 to 20, and
(II) a propylene homopolymer with a melting point of less than 120° C., satisfying the following (a) to (f):
(a) [mmmm]=from 20% by mol to 60% by mol,
(b) [rrrr]/(1−[mmmm])≤0.1,
(c) [rmrm]>2.5% by mol,
(d) [mm]×[rr]/[mr]2≤2.0,
(e) weight-average molecular weight (Mw)=from 10,000 to 200,000, and
(f) molecular weight distribution (Mw/Mn)<4,
wherein, in (a) to (d), [mmmm] represents a meso-pentad fraction, [rrrr] represents a racemic pentad fraction, [rmrm] represents a racemic meso-racemic meso-pentad fraction, each of [mm], [rr], and [mr] represents a triad fraction, and Mn represents a number-average molecular weight.