Absorbent cores for disposable absorbent articles
The present invention is an absorbent core that may be incorporated into absorbent hygiene articles, such as baby diapers, adult incontinence or feminine hygiene articles. It is particularly suited for articles which are intended to receive more than one liquid gush load, as the absorbent core comprises a fluid distribution layer that comprises sub-layers comprising particular ratios of multicomponent binder fibers, cross-linked cellulose fiber and/or treated or untreated cellulosic fibers.
1 . An absorbent core for an absorbent article, the absorbent core comprising:
a) a fluid distribution layer in the form of a unitary, heterogenous structure and comprising:
i) a first sub-layer, wherein the first sub-layer comprises a first amount of multicomponent binder fibers or cross-linked cellulose fibers, or a combination thereof, and the first sub-layer is between 20% and 60% by weight of the fluid distribution layer;
ii) a second sub-layer, wherein the second sub-layer comprises treated or untreated pulp and a second amount of multicomponent binder fibers, cross linked cellulose fibers, or a combination thereof, wherein the % by weight of the first amount of the multicomponent binder fibers, the cross-linked cellulose fibers, or the combination thereof of the first sub-layer is greater than the % by weight of the second amount of the multicomponent binder fibers, the cross-linked cellulose fibers, or the combination thereof of the second sub-layer; and
iii) one or more additional sub-layers positioned adjacent to the second sub-layer and away from the first sub-layer, wherein the one or more additional sub-layers comprise multicomponent binder fibers, cross-linked cellulose fibers, or a combination thereof in an amount, in % by weight, that is the same or less than the second amount of the multicomponent binder fibers, the cross-linked cellulose fibers, or the combination thereof of the second sub-layer; and
b) a fluid storage layer, wherein the fluid storage layer comprises at least 50% by weight of a super absorbent polymer and a surface area of the fluid storage layer is less than a surface area of the fluid distribution layer, wherein
the first sub-layer is positioned to be oriented towards a user of the absorbent core,
the second sub-layer is positioned to be oriented further away from the user than the first sub-layer,
the second sub-layer is sandwiched between the first sub-layer and the one or more additional sub-layers,
the fluid distribution layer is formed as an airlaid material,
the fluid distribution layer is embossed and does not include any adhesives, and
the fluid storage layer is positioned to be oriented further away from the user than the fluid distribution layer.
2 . The absorbent core of claim 1 , wherein the first sub-layer further comprises treated or untreated pulp.
3 . The absorbent core of claim 1 , wherein the fluid distribution layer comprises between 2% and 30% by weight of the first amount of the multicomponent binder fibers, the cross-linked cellulose fibers, or the combination thereof.
4 . The absorbent core of claim 1 , wherein the first sub-layer of the fluid distribution layer further comprises a non-woven layer that forms a first surface of the fluid distribution layer.
5 . The absorbent core of claim 4 , wherein the non-woven layer comprises fibers have an average length of 25 mm to 200 mm.
6 . The absorbent core of claim 5 , wherein the fibers of the non-woven layer comprise non-cellulosic fibers.
7 . The absorbent core of claim 1 , wherein the fluid distribution layer further comprises a dispersion binder.
8 . The absorbent core of claim 1 , wherein the first sub-layer of the fluid distribution layer comprises untreated or treated pulp fibers, the cross-linked cellulose fibers and the multicomponent binder fibers.
9 . The absorbent core of claim 1 , wherein the fluid distribution layer is substantially free of super absorbent polymers.
10 . The absorbent core of claim 1 , wherein the super absorbent polymer of the fluid storage layer is selected from the group consisting of Absorbent Gelling Materials and absorbent foams.
11 . The absorbent core of claim 1 , wherein the fluid distribution layer has a thickness ranging from 0.2 mm to 5.0 mm.
12 . The absorbent core of claim 1 , wherein the fluid distribution layer has a thickness ranging from 1.8 mm to 4.0 mm.
13 . The absorbent core of claim 1 , wherein the multicomponent binder fibers are made of polyethylene and polypropylene.
14 . The absorbent core of claim 13 , wherein the multicomponent binder fibers have a polypropylene core and a polyethylene coating on the polypropylene core.
15 . The absorbent core of claim 1 , wherein the multicomponent binder fibers are made of polyethylene and polyethylene terephthalate.
16 . The absorbent core of claim 1 , wherein the first sub-layer comprises from 50% to 70% by weight of multicomponent binder fibers and from 30% to 50% by weight of cross-linked cellulose fibers or pulp fibers.
17 . The absorbent core of claim 1 , wherein the second sub-layer comprises less than 20% by weight of multicomponent binder fibers and/or cross-linked cellulose fibers.
18 . The absorbent core of claim 1 , wherein the fluid storage layer comprises 50% to 90% by weight of superabsorbent polymers.
19 . The absorbent core of claim 1 , wherein the second amount of multicomponent binder fibers, cross-linked cellulose fibers, or a combination thereof of the second sub-layer is no more than 50% by weight of the total fluid distribution layer.
20 . The absorbent core of claim 1 , wherein
a cross direction width of the fluid storage layer is not more than 90% of a width of the fluid distribution layer, and
a machine direction length of the fluid storage layer is not more than 90% of a length of the fluid distribution layer.