Patent Description:
The present invention also relates to a method for producing such absorbent sanitary articles.

Absorbent articles such as disposable diapers, adult incontinent pads, and the like are manufactured in many different sizes and shapes. Incontinent pads are disposable absorbent articles worn by incontinent persons between the legs and fastened around the waist of the wearer.

An absorbent sanitary article typically has a structure that comprises a central body or chassis having a front section and a rear section. The chassis normally includes a permeable topsheet intended to come into contact with the user's skin when the article is worn, an impermeable backsheet and an absorbent core sandwiched between the topsheet and the backsheet. The front and rear sections of the chassis are normally closed around the user's waist by means of hook-and-loop fasteners, better known as Velcro© fastening devices.

There is a constant effort to make such absorbent articles more comfortable and discrete and less obtrusive for the wearer. This is particularly true in the case of adult incontinent pads. Adult incontinent pads, by their nature, are quite thick so they can handle the relatively large quantities of urine they receive.

The desire for less bulky incontinent pads is particularly great among incontinent persons, many of whom are elderly adults, because it can be embarrassing to wear diaper-like articles. In addition, most individuals would rather use some type of article that could be worn with the undergarments they normally wear.

One key component of an absorbent article that contributes to its size and bulk is the absorbent structure used therein.

The absorbent core of the absorbent sanitary article ideally should be such that the absorbent article absorbs liquid exudates immediately when they are discharged so that such exudates will not pool or otherwise remain on top of the core.

The absorbent core ideally should also be constructed so exudates initially absorbed will be immediately transported to a place within the absorbent core where they can be stored.

The absorbent core should also provide a system of distribution and storage for exudates that efficiently uses the entire capacity of the absorbent core. One problem that often arises in absorbent articles without such a system (particularly those absorbent articles that use the same layer or batt of material to serve the different functions of acquiring, distributing, and storing exudates) is that the storage capacity of the absorbent article is exhausted prematurely. This can occur in several different ways. In many absorbent articles, the saturation of the absorbent material in the region where exudates are initially deposited reduces the ability of the absorbent material to transport additional exudates to other parts of the core. This phenomenon can also lead to the undesirable pooling of exudates on top of the core discussed above.

<CIT> discloses an absorbent core wherein a first core layer comprises a channel having a first shape and a second core layer comprises a further channel having a second shape and wherein the first and second core layers are disposed one on top of the other such that a third channel shape is formed along the core length and width.

<CIT> discloses a method for producing an absorbent structure, comprising advancing a first non-woven layer, distributing superabsorbent granular material on the first non-woven layer, volumizing said first non-woven layer by means of a toothed portion that penetrates into the first non-woven layer.

<CIT> disclose an absorbent core including a first absorbent core construction having multiple spaced-apart sections of a fibrous construction having a fibre structure. A first non-woven sheet is positioned above the fibrous construction. A second nonwoven sheet is positioned below the fibrous construction. The first non-woven sheet is coupled with the second non-woven sheet at locations between adjacent sections of the multiple spaced-apart sections of the fibrous construction. Absorbent material is disposed within the fibre structure, between the first and second non-woven sheets.

<CIT> discloses an absorbent core comprising at least one absorbent structure comprising a substrate layer and an absorbent layer with channels. The channels are formed by bonding of the first substrate layer to a second substrate layer through the channels so that the channels are at least partially maintained both in the dry state and in the wet state.

The object of the present invention is to provide an absorbent sanitary article with an improved shape that has an absorbent structure that quickly acquires and distributes exudates throughout the absorbent core where they can be stored.

An object of the present invention is to provide an absorbent article, such as an adult incontinent pad, having a rapid acquiring, multiple layer absorbent structure having an improved shape that can be worn in the wearer's usual undergarments.

Another object of the present invention is to provide an absorbent structure for an absorbent sanitary article which is especially efficient in acquiring, distributing, and storing liquid exudates as they are deposited on the absorbent article.

In particular, an object of the present invention is to provide an absorbent structure in which the functions of acquiring and distributing exudates are handled by layers that are separate from the layers used for storing exudates.

According to the present invention, these objects are achieved by an absorbent sanitary article having the features of claim <NUM>.

According to another aspect, the invention relates to a method for manufacturing absorbent sanitary articles having the features of claim <NUM>.

The claims form an integral part of the technical disclosure provided here in relation to the invention.

The present invention will now be described with reference to the attached drawings, provided purely by way of non-limiting example, wherein:.

It should be appreciated that the attached drawings are schematic and not to scale with respect to real products. Various figures may not be represented in the same scale. Also, in various figures some elements may not be shown to better show other elements.

With reference to <FIG>, numeral <NUM> indicates an absorbent sanitary article according to an embodiment of the present invention.

The absorbent sanitary article <NUM> comprises a chassis <NUM> elongated along a longitudinal axis X. The chassis <NUM> has two side edges <NUM>, a front section <NUM> and a rear section <NUM>. The front section <NUM> and the rear section <NUM> in use are closed around the user's waist. A crotch section <NUM> extends between the front section <NUM> and the rear section <NUM>. In use, the crotch section <NUM> is arranged between the legs of the user.

The absorbent sanitary article <NUM> comprises a fastening device configured for fastening the front section <NUM> and the rear section <NUM> to each other. The fastening device may comprise two back side panels <NUM> attached to the rear section <NUM> of the chassis <NUM> and two front side panels <NUM> attached to the front section <NUM>, extending laterally beyond respective side edges <NUM>. The back side panels <NUM> and/or the front side panels <NUM> may be elastically stretchable in a transverse direction. The back side panels <NUM> may have distal portions provided with micro-hook elements <NUM> which form a releasable surface connection with a micro-loop layer provided on the front side panels <NUM>.

With reference to <FIG>, the chassis <NUM> comprises a topsheet <NUM> made of a permeable material which, in use, is in contact with the user's skin, an impermeable backsheet <NUM> which, in use, is in contact with the user's undergarments, and an absorbent structure <NUM> arranged between the topsheet <NUM> and the backsheet <NUM>. The topsheet <NUM> and the backsheet <NUM> are joined to each other, e.g. by welding or by glue, around the absorbent structure <NUM> along the side edges <NUM> and transverse edges of the chassis <NUM>.

The absorbent structure <NUM> comprises a fluff absorbent core <NUM> adjacent to the topsheet <NUM> and comprising a mix of cellulose fluff and superabsorbent granular material dispersed in the cellulose fluff.

The fluff absorbent core <NUM> is a soft pad having a generally flat shape elongated in the longitudinal direction X with two opposite first and second surfaces <NUM>, <NUM>. The first surface <NUM> may be in contact with the topsheet <NUM>. The fluff absorbent core <NUM> has at least one through aperture <NUM> which extends through the mix of cellulose fluff and superabsorbent granular material between the two opposite surfaces <NUM>, <NUM>. In a possible embodiment the through aperture <NUM> is shaped as a channel (see <FIG>) elongated along the longitudinal axis X. The fluff absorbent core <NUM> may be enclosed in a thin permeable non-woven layer which contains the mix of cellulose fluff and superabsorbent granular material.

The absorbent structure <NUM> comprises a fluff-free absorbent core <NUM> adjacent to the backsheet <NUM>. The fluff-free absorbent core <NUM> comprises a plate-shaped non-woven web containing high quantity of superabsorbent granular material dispersed in the non-woven web.

The fluff-free absorbent core <NUM> has two opposite third and fourth surfaces <NUM>, <NUM>, generally parallel to the first and second surfaces <NUM>, <NUM> of the fluff absorbent core <NUM>. The fourth surface <NUM> may be in contact with the backsheet <NUM>.

The fluff-free absorbent core <NUM> has a thickness which is considerably less than the thickness of the fluff absorbent core <NUM>. In a possible embodiment, the thickness of the fluff-free absorbent core <NUM> is comprised between <NUM> and <NUM>, preferably between <NUM> and <NUM>.

The fluff-free absorbent core <NUM> comprises a non-woven material formed by processes such as spunbonding, meltblowing, carding, and the like. Non-limiting examples of suitable fibers include spunbond, spunlaid, meltblown, spunmelt, solvent-spun, electrospun, carded, film fibrillated, melt-film fibrillated, air-laid, dry-laid, wet-laid staple fibers, and other non-woven web materials formed in part or in whole of polymer fibres as known in the art, and workable combinations thereof. Nonwovens do not have a woven or knitted filament pattern. It is to be appreciated that non-wovens having various basis weights can be used. For example, some nonwovens may have a basis weight from about <NUM> gsm to about <NUM> gsm, preferably between <NUM> and <NUM> gsm.

In a possible embodiment, the fluff-free absorbent core <NUM> may comprise at least one layer of high loft non-woven material. An high loft non-woven is an ATB (air through bond) in two-component fibres, with high apparent thickness and large gaps between the fibers to accommodate the SAP. The weight range of high loft non-woven webs is comprised between <NUM> to <NUM> gsm, preferably between <NUM> to <NUM> gsm.

In a possible embodiment, the fluff-free absorbent core <NUM> comprises super-absorbent granular material dispersed in the non-woven fibres in an amount comprised between <NUM> to <NUM> gsm, preferably between <NUM> and <NUM> gsm. The fluff-free absorbent core <NUM> may be manufactured as disclosed in <CIT> by the same Applicant.

In a possible embodiment, the fluff-free absorbent core <NUM> may be enclosed in a liquid permeable wrapping layer. In a possible embodiment, the fluff-free absorbent core <NUM> may comprise upper and lower non-woven layers. In a possible embodiment, both upper and lower non-woven layers contain super-absorbent granular material. In a possible embodiment, only the lower non-woven layer contains super-absorbent granular material. In both cases, the fluff-free absorbent core <NUM> may be enclosed in a liquid permeable wrapping layer.

The absorbent structure <NUM> comprises an acquisition and diffusion layer (ADL) <NUM> set between the fluff absorbent core <NUM> and fluff-free absorbent core <NUM> and overlapping the at least one through aperture <NUM> of the fluff absorbent core <NUM>. The acquisition and diffusion layer <NUM> may be formed by a high loft non-woven material, which does not contain neither cellulose fluff nor superabsorbent polymers. The acquisition and diffusion layer <NUM> has the shape of a thin plate having opposite fifth and sixth surfaces <NUM>, <NUM> generally parallel to the surfaces <NUM>, <NUM> and <NUM>, <NUM> of the fluff absorbent core <NUM> and fluff-free absorbent core <NUM>. The fifth and sixth surfaces <NUM>, <NUM> of the acquisition and diffusion layer <NUM> are in contact, respectively, with the second surface <NUM> of the fluff absorbent core <NUM> and with the third surface <NUM> of the fluff-free absorbent core <NUM>.

The fifth surface <NUM> of the acquisition and diffusion layer <NUM> covers at least the portion of the second surface <NUM> of the fluff absorbent core <NUM> on which the at least one aperture <NUM> extends. The sixth surface of the acquisition and diffusion layer <NUM> is <NUM>% or more of the third surface <NUM> of the fluff-free absorbent core <NUM>. The acquisition and diffusion layer <NUM> may have a mono-layer or a multi-layer structure.

Normally a fluff-free absorbent core has liquid acquisition times longer than a fluff absorbent core. In the arrangement according to the invention, the acquisition and diffusion layer <NUM> acquires rapidly a surge of liquid, such as urine, passing through the through aperture <NUM> of the fluff absorbent core <NUM> and serves as a temporary reservoir for the liquid until the fluff-free absorbent core <NUM> can absorb the liquid. Also, the acquisition and diffusion layer <NUM> receives the liquid concentrated mainly in the area facing the through aperture <NUM> and distributes the liquid over a larger surface to facilitate absorption of the liquid by the fluff-free absorbent core <NUM>. The acquisition and diffusion layer <NUM> forms a spacer between the fluff absorbent core <NUM> and the fluff-free absorbent core <NUM> and allows the liquid passing through the aperture <NUM> to be distributed over most of the surface of the fluff-free absorbent core <NUM>.

Traditional dual-core absorbent sanitary articles have a very high absorbing capacity but are bulky and obtrusive for the wearer.

The absorbent sanitary article according to the present invention retains the same very high absorbing capacity of prior art dual-core absorbent sanitary articles in a structure which is more comfortable and discrete and less obtrusive for the wearer and that can be worn in the wearer's usual undergarments.

The absorbent sanitary article according to the present invention is particularly rapid in acquiring a liquid surge, typical of incontinent adults, and has a multiple layer absorbent structure which is especially efficient in acquiring, distributing, and storing liquid exudates as they are deposited on the absorbent article.

The functions of acquiring and distributing exudates are handled by the acquisition and diffusion layer <NUM> which is separate from the fluff absorbent core <NUM> and the fluff-free absorbent core <NUM> which are used for storing the exudates.

The absorbent sanitary articles <NUM> according to the present invention may be manufactured by a machine schematically shown in <FIG> and indicated by the reference numeral <NUM>.

The machine <NUM> comprises a forming unit <NUM> comprising a stationary forming chamber <NUM> and a rotating forming wheel <NUM>. The forming chamber <NUM> contains a mix of cellulose fluff and superabsorbent granular material dispersed in the cellulose fluff. On the outer surface of the forming wheel <NUM> a plurality of fluff absorbent cores <NUM> are formed, each comprising a mix of cellulose fluff and superabsorbent granular material and each having at least one through aperture, e.g. a channel shaped through aperture. A compacting conveyor <NUM> compacts and transports the fluff absorbent cores <NUM> in a machine direction MD. The fluff absorbent cores <NUM> are spaced apart from each other in the machine direction MD.

A first web feeding device <NUM> feeds a continuous topsheet web <NUM> in the machine direction MD. A first glue dispenser <NUM> applies a first glue layer on an upper surface of the continuous topsheet web <NUM>.

The individual absorbent cores <NUM> moving in the machine direction MD are applied on the upper surface of the continuous topsheet web <NUM> and are attached thereto by the first glue layer.

A second web feeding device <NUM> feeds a continuous fluff-free absorbent non-woven web <NUM>, comprising superabsorbent granular material dispersed in the non-woven web. The continuous fluff-free absorbent non-woven web <NUM> may be unwound from a reel <NUM>.

In a possible embodiment, the continuous fluff-free absorbent non-woven web <NUM> may be manufactured in-line with the machine <NUM> by a method comprising:.

A third web feeding device <NUM> feeds a continuous acquisition and diffusion web <NUM>. The continuous acquisition and diffusion web <NUM> may be unwound from a reel <NUM>. A second glue dispenser <NUM> applies a second glue layer on an upper surface of the continuous acquisition and diffusion web <NUM>.

A first cut-and-slip unit <NUM> transversally cuts the continuous acquisition and diffusion web <NUM> to form individual acquisition and diffusion layers <NUM>. The individual acquisition and diffusion layers <NUM> are spaced apart from each other in the direction of movement and are applied on the upper surface of the continuous fluff-free absorbent non-woven web <NUM> and are attached thereto by the second glue layer.

A third glue dispenser <NUM> applies a third glue layer on an upper surface of the continuous fluff-free absorbent non-woven web <NUM>.

A second cut-and-slip unit <NUM> transversally cuts the continuous fluff-free absorbent non-woven web <NUM> along transverse cutting lines set between each pair of adjacent acquisition and diffusion layers <NUM>, so as to form individual fluff-free absorbent cores <NUM> each having a respective acquisition and diffusion layer <NUM> applied thereon. The individual fluff-free absorbent cores <NUM> are spaced apart from each other in the machine direction MD and are applied over respective fluff absorbent cores <NUM> attached on the upper surface of the continuous topsheet web <NUM>, as they move in the machine direction MD, so as to form an array of absorbent structures <NUM> each comprising an acquisition and diffusion layer <NUM> sandwiched between a respective fluff-free absorbent core <NUM> and a fluff absorbent core <NUM>. The fluff-free absorbent cores <NUM> are attached to the respective fluff absorbent cores <NUM> by the third glue layer.

A compression unit <NUM> compresses the array of absorbent structures <NUM>. The compression unit <NUM> may carry out an embossing of the continuous topsheet web <NUM> and press portions of the continuous topsheet web <NUM> inside the through apertures <NUM> of the fluff absorbent cores <NUM>.

Pairs of side panels <NUM>, <NUM> may be attached to the continuous topsheet web <NUM>.

A fourth web feeding device <NUM> feeds a continuous backsheet web <NUM>. A fourth glue dispenser <NUM> applies a fourth glue layer on an upper surface of the continuous backsheet web <NUM>. The continuous backsheet web <NUM> is then overlapped to the continuous topsheet web <NUM>. The array of absorbent structures <NUM> is sandwiched between the continuous topsheet web <NUM> and the continuous backsheet web <NUM>, so as to form a continuous chassis chain <NUM>.

A cutting unit <NUM> cuts the continuous chassis chain <NUM> so as to form individual absorbent sanitary articles <NUM>.

A method for producing absorbent sanitary articles according to the present invention comprises:.

Claim 1:
An absorbent sanitary article comprising a chassis (<NUM>) including a liquid permeable topsheet (<NUM>), a liquid impermeable backsheet (<NUM>), and an absorbent structure (<NUM>) arranged between the topsheet (<NUM>) and the backsheet (<NUM>), wherein the absorbent structure (<NUM>) comprises:
- a fluff absorbent core (<NUM>) comprising a mix of cellulose fluff and superabsorbent granular material dispersed in the cellulose fluff, the fluff absorbent core (<NUM>) being adjacent to the topsheet (<NUM>) and having at least one through aperture (<NUM>),
- a fluff-free absorbent core (<NUM>) adjacent to the backsheet (<NUM>), comprising a non-woven web and superabsorbent granular material dispersed in the non-woven web, and
- an acquisition and diffusion layer (<NUM>) set between the fluff absorbent core (<NUM>) and the fluff-free absorbent core (<NUM>) and overlapping said at least one through aperture (<NUM>).