A hollow fiber that extending along at least a portion of the fiber along a longitudinal axis thereof and is defined by an interior wall is provided. Through selective control over the manner in which it is formed, the present inventors have discovered that the hollow fiber can exhibit a unique combination of a high void fraction and small fiber size that makes it particularly suitable for use in certain applications, such as in nonwoven webs for absorbent articles.

A polyolefin composition for preparing fibers, made from or containing: A) 60-95% by weight of a propylene homo- or copolymer; and B) 5-40% by weight of a copolymer of butene-1 or a butene-1 polymer composition having: a Melt Flow Rate value of from 5 to 100 g/10 min., measured according to ISO 1133 at 190° C. with a load of 2.16 kg; a copolymerized comonomer content from 4% to 15% by mole, referred to the total weight of B); a Mw/Mn value equal to or lower than 4; and flexural modulus of 80 MPa or higher.

A polyolefin composition for preparing fibers, made from or containing: A) 60-95% by weight of a propylene homo- or copolymer; and B) 5-40% by weight of a copolymer of butene-1 or a butene-1 polymer composition having: a Melt Flow Rate value of from 5 to 100 g/10 min., measured according to ISO 1133 at 190° C. with a load of 2.16 kg; a copolymerized comonomer content from 4% to 15% by mole, referred to the total weight of B); a Mw/Mn value equal to or lower than 4; and flexural modulus of 80 MPa or higher.

A disposable absorbent article is described. The disposable absorbent article has a topsheet, a backsheet, and an absorbent core disposed between the topsheet and the backsheet. A carded staple fiber nonwoven having a basis weight of between about 50 grams per square meter (gsm) and about 100 gsm, includes a blend of absorbing fibers, stiffening fibers and filler fibers. The carded staple fiber nonwoven has a pore volume radius mode of between about 60 μm and about 120 μm.

A disposable absorbent article is described. The disposable absorbent article has a topsheet, a backsheet, and an absorbent core disposed between the topsheet and the backsheet. A carded staple fiber nonwoven having a basis weight of between about 50 grams per square meter (gsm) and about 100 gsm, includes a blend of absorbing fibers, stiffening fibers and filler fibers. The carded staple fiber nonwoven has a pore volume radius mode of between about 60 μm and about 120 μm.

A fiber sheet (1) according to the present invention includes a plurality of stem fibers (2) containing a thermoplastic resin and extending in one direction and includes a fibril fiber (3) containing substantially the same thermoplastic resin as the above thermoplastic resin, extending between the stem fibers (2), and having a smaller diameter than that of the stem fibers (2). The plurality of stem fibers (2) include one stem fiber (2) and another stem fiber (2) branching from the one stem fiber and have a void between the stem fibers. The stem fibers (2) hold a plurality of inorganic particles (5). The fiber sheet preferably has a pore volume fraction of 50% or more and 98% or less. In the fiber sheet, the number of fibers having a diameter of 500 nm or less is preferably 50% or more of the total number of the constituent fibers. The inorganic particles preferably include zinc oxide. The fiber sheet is preferably produced by uniaxially drawing a resin sheet containing a thermoplastic resin and inorganic particles.

A spunbonded non-woven fabric includes a fiber including a propylene homopolymer having a melting point of 140° C. or more, a polyethylene having a density of from 0.941 g/cm.sup.3 to 0.970 g/cm.sup.3, and at least one polymer selected from the group consisting of a polymer represented in (I) and a polymer represented in (II). In the spunbonded non-woven fabric, the fiber includes a sea-island structure, and the percentage of an island phase having a diameter of from 0.12 μm to less than 0.63 μm with respect to an island phase in a cross section orthogonal to the axis direction of the fiber on a number basis is 30% or more. (I) represents 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. (II) represents a propylene homopolymer with a melting point of less than 120° C.

A spunbonded non-woven fabric includes a fiber including a propylene homopolymer having a melting point of 140° C. or more, a polyethylene having a density of from 0.941 g/cm.sup.3 to 0.970 g/cm.sup.3, and at least one polymer selected from the group consisting of a polymer represented in (I) and a polymer represented in (II). In the spunbonded non-woven fabric, the fiber includes a sea-island structure, and the percentage of an island phase having a diameter of from 0.12 μm to less than 0.63 μm with respect to an island phase in a cross section orthogonal to the axis direction of the fiber on a number basis is 30% or more. (I) represents 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. (II) represents a propylene homopolymer with a melting point of less than 120° C.

The present disclosure provides a polyolefin film including a fibrous polyolefin having an average diameter of 0.1 μm or more and less than 1.0 μm, wherein the polyolefin film has a connected-void structure, has a void ratio a of 50% to 90%, has a thickness d in μm, which satisfies, together with the void ratio a, a relation of 40≤(d×(100−a)/100)≤200, and is used as a radiative cooling film, and a radiative cooling structure body including the polyolefin film.

The present disclosure provides a polyolefin film including a fibrous polyolefin having an average diameter of 0.1 μm or more and less than 1.0 μm, wherein the polyolefin film has a connected-void structure, has a void ratio a of 50% to 90%, has a thickness d in μm, which satisfies, together with the void ratio a, a relation of 40≤(d×(100−a)/100)≤200, and is used as a radiative cooling film, and a radiative cooling structure body including the polyolefin film.