ABSORBENT STRUCTURE
The present invention relates to an absorbent structure, preferably for use in absorbent products, such as used in the food, consumer, household, building and construction, beauty and medical industry, and as used in the personal hygiene industry. The substantially cellulose free absorbent structures continuously immobilise absorbent polymer material via initial smaller pockets and subsequently larger compartments allowing excellent fluid management of the absorbent polymer material in dry, partially and fully liquid loaded state. Preferably such absorbent structure volume increases are result of temporary secondary attachment patterns made in combination with substantially permanent primary attachment grids allowing the release of bigger volumes from the initial smaller volumes by detachment of the secondary attachments. Furthermore the absorbent structure according to an embodiment of the invention non-homogeneously swells to form a liquid-managing surface structure as a result of exposing the absorbent structure to liquid. The present invention foresees in the need for improved flexible, thin, lightweight absorbent structures which overcome the absorbency problems of the prior art during absorption, distribution and retention of liquids with optimal fit.
1 . A substantially cellulose free absorbent structure comprising a carrier layer, an auxiliary layer and an absorbent polymer material there between, the carrier layer and auxiliary layer being at least partially joined together by attachments made up of substantially permanent primary attachment grids and/or substantially temporary secondary attachment patterns, so as to form a sandwich-like composite structure containing patterned absorbent particulate polymer materials provided in at least some of the unattached regions between the carrier layer and auxiliary layer forming an absorbent polymer material area, the plurality of smaller-sized pockets made up by at least substantially temporary secondary attachments define spaces which immobilize the available dry volume absorbent polymer material, the substantially temporary secondary attachment being gradually releasable as a result of exposing the surrounding absorbent polymer material to liquid so as phase in an intermediate volume increase to fewer and medium-sized compartments immobilising the partially wetted absorbent polymer material, and resulting in still fewer maximum-sized compartments immobilising the wetted absorbent polymer material to obtain continuous fluid management.
2 . An absorbent structure according to claim 1 characterized in that its substantially permanent primary attachments are provided, in combination with the substantially temporary secondary attachment to make up the initial small-sized pockets, which remain substantially intact.
3 . An absorbent structure according to claim 1 , characterized in that the substantially permanent primary attachment grid and/or substantially temporary secondary attachment pattern is distributed over substantially the majority of the surface area of the absorbent polymer material area.
4 . An absorbent structure according to claim 1 , characterized in that the absorbent structure non-homogeneously swells to form a liquid management surface structure due to release of the substantially temporary secondary attachments.
5 . An absorbent structure according to claim 1 , characterized in that the absorbent structure non-homogeneously swells to form a liquid management surface structure due to phased swelling of the absorbent polymer material area.
6 . An absorbent structure according to claim 1 , wherein the attachments are at least partially formed via a mechanical, thermal, physical, chemical, thermo-mechanical and/or most preferably an ultrasonic process.
7 . An absorbent structure according to claim 1 , wherein at least some or all of the substantially permanent primary attachments and/or substantially temporary secondary attachments are formed with at least an adhesive or binder as an attachment medium.
8 . An absorbent structure according to claim 1 , wherein the substantially permanent primary attachments and/or substantially temporary secondary attachments have different locations, sizes and/or shapes.
9 . An absorbent structure according claim 1 , wherein at least 80% of the absorbent material is absorbent polymer material.
10 . An absorbent structure according to claim 1 , wherein the absorbent structure has on average within the absorbent polymer material area at least one pocket per about 0.10 cm 2 , preferably 1 per about 0.50 cm 2 , preferably 1 per about 1 cm 2 ; preferably 1 per about 2.5 cm 2 , preferably 1 per about 5 cm 2 and/or at least 1 compartment per about 5 cm 2 , preferably 1 per about 10 cm 2 , preferably 1 per about 20 cm 2 , preferably 1 per about 30 cm 2 , preferably 1 per about 45 cm 2
11 . An absorbent structure according to claim 1 , wherein at least some or all of the substantially permanent primary attachments and/or substantially temporary secondary attachments have an average surface size of at least 0.3 mm 2 , preferably at least 0.5 mm 2 , preferably at least 1.0 mm 2 and more preferably at least 3.0 mm 2 .
12 . Absorbent structure according to claim 1 , wherein the absorbent structure has a flexure-resistance of less than 500.0 grams, more preferably less than 250.0 grams, and still more preferably less than about 175.0 grams and most preferably less than 130.0 grams or 100.0 grams.
13 . Absorbent structure according to claim 1 , with a wet immobilization of more than 50 wt %, preferably more than 60 wt %, preferably more than 7 wt %, more preferably more than 80 wt %.
14 . An absorbent article comprising an absorbent structure according to claim 1 , wherein said absorbent article is a feminine hygiene garment, baby diaper, baby pants or adult incontinence garment.
15 . An absorbent article according to claim 1 , comprising a liquid pervious topsheet, a liquid impervious backsheet and a liquid absorbing absorbent structure situated in between the liquid pervious topsheet and liquid impervious backsheet.
16 . A method for the manufacturing of an absorbent structure according to claim 1 which comprises: providing a carrier layer, covering the carrier layer with an absorbent material, covering the absorbent material with an auxiliary layer which is joinable to the carrier layer; and in at least one position substantially temporary and/or substantially permanently attaching the auxiliary layer to the carrier layer, and by means of at least substantially temporary secondary attachments defining small-sized pocket wherein dry absorbent material is immobilized, such that by means of gradual release of substantially temporary secondary attachment patterns bigger-sized intermediate and final compartments are provided, thereby continuously immobilising the absorbent material from dry to wetted state.