Absorbent articles for absorption of body fluids such as menses or blood or vaginal discharges are well known in the art, and comprise for example feminine hygiene articles such as sanitary napkins, panty liners, tampons, interlabial devices, as well as wound dressings, and the like. When considering for example sanitary napkins, these articles typically comprise a liquid-pervious topsheet as wearer-facing layer, a backsheet as garment-facing layer and an absorbent structure, also referred to as core, between topsheet and backsheet. The body fluids are acquired through the topsheet and subsequently stored in the absorbent core structure. The backsheet typically prevents the absorbed fluids from wetting the wearer's garment.
An absorbent core structure can typically comprise one or more fibrous absorbent materials, which in turn can comprise natural fibres, such as for example cellulose fibres, typically wood pulp fibres, synthetic fibres, or combinations thereof.
Absorbent articles can further comprise, typically in the absorbent core, superabsorbent materials, such as absorbent gelling materials (AGM), usually in finely dispersed form, e.g. typically in particulate form, in order to improve their absorption and retention characteristics. Superabsorbent materials for use in absorbent articles typically comprise water-insoluble, water-swellable, hydrogel-forming crosslinked absorbent polymers which are capable of absorbing large quantities of liquids and of retaining such absorbed liquids under moderate pressure. Absorbent gelling materials can be incorporated in absorbent articles, typically in the core structure, in different ways; for example, absorbent gelling materials in particulate form can be dispersed among the fibres of fibrous layers comprised in the core, or rather localized in a more concentrated arrangement between fibrous layers.
Absorbent cores for absorbent articles having a thin structure can further provide an improved immobilization of absorbent gelling materials, particularly when the article is fully or partially loaded with liquid, and an increased wearing comfort. Such thinner structures provide absorbent articles combining better comfort, discreetness and adaptability, such as for example, thin absorbent structures where the absorbent gelling material is located and somehow kept in selected, e.g. patterned regions of the structure itself.
EP 1447067, assigned to the Procter & Gamble Company, describes an absorbent article, typically a disposable absorbent article, such as a diaper, having an absorbent core which imparts increased wearing comfort to the article and makes it thin and dry. The absorbent core comprises a substrate layer, the substrate layer comprising a first surface and a second surface, the absorbent core further comprising a discontinuous layer of absorbent material, the absorbent material comprising an absorbent polymer material, the absorbent material optionally comprising an absorbent fibrous material which does not represent more than 20 weight percent of the total weight of the absorbent polymer material. The discontinuous layer of absorbent material comprises a first surface and a second surface, the absorbent core further comprising a layer of thermoplastic material, the layer of thermoplastic material comprising a first surface and a second surface and wherein the second surface of the discontinuous layer of absorbent material is in at least partial contact with the first surface of the substrate layer and wherein portions of the second surface of the layer of thermoplastic material are in direct contact with the first surface of the substrate layer and portions of the second surface of the layer of thermoplastic material are in direct contact with the first surface of the discontinuous layer of absorbent material.
Absorbent articles according to EP 1447067 and comprising thin absorbent cores with relatively high amounts of absorbent gelling materials and rather low content of fibrous materials commonly have good absorption and retention characteristics to body fluids. However there still remains room for improvement for fluid handling, and particularly in order to better control rewet, e.g. due to gushing, and fluid acquisition effectiveness, in a core structure which is thin and comfortable, yet highly absorbent.
Low rewet, i.e. the capability of an absorbent structure of effectively and stably entrapping fluid within the structure itself, even after e.g. sudden gushes, with low tendency to give it back upon compression, for example upon squeezing of the absorbent structure which may occur during wear, is typically a characteristic which is in contrast with fast fluid acquisition, particularly in a thin absorbent structure. In other words, in order to have a thin absorbent structure which is also highly absorbent it is typically necessary to compromise between these two apparently contrasting features. In fact a thin absorbent structure, in order to rapidly acquire fluid, can typically have a rather “open” structure, which may in turn not provide for an optimal low rewet.
Thus, an absorbent core structure is desired exhibiting thinness for comfort combined with high absorbent capacity, while at the same time providing low rewet and fast fluid acquisition.