WO2011150955A1

WO2011150955A1 - Disposable absorbent article and set for forming an absorbent article

Info

Publication number: WO2011150955A1
Application number: PCT/EP2010/057536
Authority: WO
Inventors: Rozalia Bitis
Original assignee: Sca Hygiene Products Ab
Priority date: 2010-05-31
Filing date: 2010-05-31
Publication date: 2011-12-08

Abstract

Disposable absorbent article comprising: a chassis (10) being divided into a front panel (11) and a back panel (12); wherein the chassis has at least one pocket (32) arranged at least in the front panel or the back panel, a longitudinal absorbent body (14) extending between the front panel and the back panel and having a crotch portion inbetween the front and the back panel, one end (14a, 14b) of the absorbent body in the longitudinal direction being inserted into the at least one pocket; characterized in that the end (14a, 14b) of the absorbent body (14) inserted into the at least one pocket (32) is only held relative to the chassis (10) by means of the at least one pocket; and a side of the absorbent body (14) facing the chassis (10) is fixed to the chassis only in the crotch portion of the absorbent body at a fixing portion (30). Further, the present invention also relates to a set for forming an absorbent article having a reusable chassis and a disposable absorbent body which are both configured similar and to the use of an absorbent body in such a set or an absorbent body of such a set, respectively.

Description

Disposable Absorbent Article and Set for Forming an Absorbent

Article

Technical Field

The present invention relates to an absorbent article and particularly to diapers. In this context, the present invention relates to both disposable absorbent articles intended for one use only as well as reusable articles being constituted by a set preferably composed of a reusable part and a disposable part intended for one use only. The present invention in this regard relates to absorbent articles for both adults and children.

Background of the Invention

Disposable diapers conventionally include a chassis being divided into a front panel configured to in use face the stomach of a user, a back panel configured to in use face the back of a user and a crotch portion inbetween the front and the back panel and configured to in use be positioned in the crotch of a user. In general, both the front and the back panel have a waist portion such that, when the diaper is worn around the waist of the user, the waist portions provide a continuous encirclement of the user. In order to fasten the diaper around the waist of a user, either a fastening system comprising fastening tabs or a fastening belt is commonly employed. The fastening tabs may be provided on side panels which extend from lateral side edges of the diaper chassis. Alternatively, the diaper may have the shape of panties so that no particular fastening system is required and the diaper may be put on in the same way as panties. As the user of a diaper moves about, the circumference of the user's waist expands and contracts, which consequently results in the waist portions of the diaper being stretched and relaxed. In order to prevent the waist portions from being permanently deformed maintaining a good fit of the diaper, it is known to provide the chassis with a certain degree of elasticity. The elasticity may be provided by elastic waist bands and/or the use of an elastic material in at least a portion of the chassis such as described in

WO-A-2008/143560.

In addition, conventional diapers comprise a longitudinal absorbent body extending between the front panel and the back panel. It is known to fix the absorbent body with a side facing the chassis to the chassis by means of welding or adhesive. It has been known to fix the side of the

absorbent body over a substantial part of its surface area to the chassis. This fixation of the absorbent body leads to a decreasing elasticity of the chassis at least in the fixing portion. Such an absorbent article is for example known from JP-A-2008-023116. Although, the absorbent body is fixed with a substantial portion to the chassis, JP-A-2008-023116 teaches that the respective ends of the absorbent body may be accommodated in and securely fixed to pockets arranged in the front and back panel. A similar disclosure may be found in WO-A-2009-/240400.

Alternatively, US-A-4, 615, 695 suggests a reusable diaper having a reusable chassis and a single use absorbent body, wherein the absorbent body at opposite ends in a longitudinal direction is inserted into respective pockets of the chassis. However, the absorbent body is only held by the pockets and is freely movable in the crotch portion. Hence, when the user moves about, the absorbent body may be displaced

relative to the user as well as the chassis. In other words, the absorbent body may not be maintained in its intended place. Both decreasing the elasticity of the chassis in a remarkable area as with a diaper suggested by e.g. WO-A-2009/240400 leading to a decreased fit of the diaper, as well as the movability of the absorbent core relative to the chassis as in US-A-4 , 615, 695 result in an increased risk of leakage.

Summary

Hence, it is the object of the present invention to provide an absorbent article or a set for forming such an absorbent article which is improved concerning the risk of leakage.

This object is solved by a disposable absorbent article as defined in claim 1 as well as a set for forming an absorbent article as defined in claim 3. Embodiments of the present invention are defined in the dependent claims.

The basic idea of the present invention is to hold at least one end of the absorbent body and preferably both ends only by means of pockets and fix the absorbent body only in its crotch position to the chassis. That is, no glue or weld is required in the end portions of the absorbent body, whereby the elasticity of the front panel and the back panel of the chassis is maintained. This has the additional advantage that between a traverse edge of the chassis, in the vicinity of which "che pocket is located, and a fixing portion, where the absorbent body is securely fixed to the chassis, a softer textile feeling may be perceived at the outside as the absorbent core may to a certain extent move relative to the chassis in this section. An additional advantage of a pocket particularly when extending over a certain width of the chassis in a transverse direction is that the pocket may form a feces barrxer in that feces may enter into and be retained by the pocket. At the same time, the absorbent body is securely fixed to the chassis in the crotch portion of the absorbent body whereby the absorbent body is immovable relative to the chassis in the crotch portion. In this connection, the crotch portion of the absorbent body is the central part of the absorbent body. The length of the crotch portion in the longitudinal direction of the absorbent body is 40% of the length of the absorbent body, i.e. starting at the center of the absorbent body in the longitudinal

direction 20% towards the front panel and 20% towards the back panel. The crotch portion of the absorbent body is disposed between a front portion and a back portion, both having a length of 30% of the length of the absorbent body in the longitudinal direction. In this context, the front portion will be located in the front panel, whereas the back portion will be positioned in the back panel. Because the absorbent body is securely fixed to the chassis in the crotch portion, the relative position of the absorbent core

particularly in the crotch portion where it is assumed that urine and feces are discharged is held in place. Thus, the present invention enables that the relative position of the absorbent body to the chassis and the user may be maintained in use of the article. The present invention, therefore, provides for an absorbent article that is improved with regard to both form fit and relative positioning of the absorbent core, thereby reducing the risk of leakage.

In view of the aforesaid, the present invention suggests a disposable absorbent article, such as a diaper. That is, the absorbent article is intended for one use only. The present invention may be implemented in diapers having fastening means or a belt for closing the diaper in use or in diapers having the form of panties. In addition, the present invention may also be implemented in similar incontinence guards .

The absorbent article of the present invention comprises a chassis. The chassis may be of any conventional type and may comprise a liquid impermeable or a liquid permeable back sheet forming the outer side of the chassis in use facing away from a user. Further, a liquid permeable or liquid impermeable top sheet may be provided as an inner side of the chassis. The back sheet may be formed by a thin plastic film, e.g. a polyethylene or polypropylene film, a non-woven material coated with a liquid impermeable material, a

hydrophobic non-woven material which resists liquid

penetration or a laminate of a plastic film and a non-woven material. The back sheet may be breathable so as to allow vapor to escape from the absorbent body, while still

preventing liquid from passing therethrough. Examples of breathable outer back sheets are porous polymeric films, non- woven laminates of spunbond and meltblown layers and

laminates of porous polymeric films and non-woven materials. Preferably, the back sheet comprises a non-woven material on at least the outer side thereof to provide for a textile feeling. In addition, it is preferred that the back sheet has a certain elasticity at least in some portions thereof. The chassis has a certain elasticity all over or at least in the front and/or back panels. The top sheet can comprise a non-woven material, e.g. spundbond, meltblown, carded, hydro- entangled, wet-laid, etc. Suitable non-woven materials can be composed of man-made fibers, such as polyester, polyethylene, polypropylene, viscose, rayon, etc. or natural fibers such as wood, pulp or cotton fibers or from a mixture thereof. The top sheet may further be composed of tow fibers which may be bonded to each other in a bonding pattern as e.g. disclosed in EP-A-l 035 818. Further examples of the top sheet

material are porous foams, plastic films, apertured plastic films, laminates of non-woven materials and apertured plastic films, etc. The materials suited as the top sheet should be soft and non-irritating to the skin. In principle, only one layer is sufficient to form the chassis, e.g. a back sheet layer. Nevertheless, a top sheet may be desirable

especially, if the inner side of the back sheet is a plastic film. In this instance, the top sheet should provide

softness to the inner side of the chassis. The top sheet as the back sheet may have a certain elasticity at least in some portions thereof as described above with respect to the back sheet. If the chassis only consists of a partly or fully elastic back sheet or of a partly or fully elastic top sheet and back sheet, the chassis is partly or fully elastic in itself. In most cases, when a top sheet and the back sheet are provided, the top sheet and the back sheet of the chassis may be joined at least along the outer circumferential edge of the chassis, but also ail over or substantially all over the surface area of the chassis.

The chassis of the present invention is divided into a front panel configured to in use face the stomach of a user, a back panel configured to in use face the back of the user and a crotch portion inbetween the front and the back panel and configured to in use be positioned in the crotch of a user, that is between the legs. A front edge defining the end of the chassis at the front panel and a back edge defined at the end of the back panel of the chassis in use constitute at least part of the waist portion circumscribing the waist of a user. The chassis may at least in the front and/or back panel comprise an elastic, such as a waist elastic. The elastics may be configured by prestretched threads or bands attached to the top sheet and/or the back sheet, that is to the chassis. Alternatively, foamed elastics are conceivable as well. The elastic properties may be provided

alternatively or additionally in that the chassis material is elastic by itself or in combination with added elastic material and an elastic chassis material.

According to the present invention, the chassis has at least one pocket arranged at least at the front panel or the back panel. The pocket is configured so as to be at least open in a direction toward the opposite back panel or front panel, respectively. If one pocket is provided, it is preferred that the opening of the one pocket extends transverse to a direction from the front to the back panel, that is

transverse to a longitudinal direction extending from the front panel to the back panel of the chassis. Alternatively, two pockets may be provided on either side of a longitudinal center axis of the chassis extending from the front to the back panel. Those pockets which are comparable to photo corners will have an opening that extends in an angle to the longitudinal center axis and/or a direction transverse thereto .

The absorbent article further comprises a longitudinal absorbent body. That is, the absorbent body has a dimension which is largest compared to the other dimensions. This largest dimension is referred to as the longitudinal

direction. The absorbent body extends with its longitudinal direction between the front panel and the back panel of the chassis and has a crotch portion in the center (see above) . Hence, the absorbent body is disposed with its crotch portion in the crotch portion of the chassis and extends into the front panel and the back panel of the chassis. At least one end of the absorbent body in the longitudinal direction is inserted into the at least one pocket. If two pockets similar to photo corners are provided the end of the

absorbent body is inserted into both these pockets. Further and according to an embodiment, at least one pocket is provided in both the front panel and the back panel and both ends of the absorbent body in the longitudinal direction are respectively inserted into one of these pockets. According to the present invention, the end or the ends of the

absorbent body inserted into the at least one pocket or the pockets at both ends is only held relative to the chassis by means of this pocket/these pockets. In other words, the ends of the absorbent body Inserted into the pocket or pockets are not additionally fixed or attached to the chassis by any other means than the pocket/-s. Even other forms of the pockets than the ones mentioned above are conceivable and encompassed by the present invention as long as the ends of the absorbent body may be received within such pockets or at least parts of the ends may be received therein. The pockets may be formed by an opening {cut or slit) in the top sheet of the chassis in an area where the top sheet is not fastened (freely movable relative) to the back sheet. This is

particularly advantageous regarding ease of manufacture. It may even be conceivable that the pockets have two opposite openings. In this instance, the pockets have the form of strips connected at both their opposite longitudinal ends (in the transverse direction) to the chassis, wherein the ends of the absorbent body or parts thereof may be inserted below the strips, that is between the strips and the inside of the chassis. In this instance, a part of the absorbent body may even extend beyond those pockets. Particularly, such an embodiment may lead to less material needed for the pockets and, therefore, to reduced costs. In addition, the portions of the pockets fixed (attached) to the sheet, if provided separately, may be minimized thereby minimizing the

stiffening of the article in these portions.

Additionally, a side of the absorbent body facing the chassis is fixed to the chassis. In this context, the absorbent body is only fixed to the chassis in the crotch portion of the absorbent body. In other words, the absorbent body has only one fixing portion and this fixing portion is located in the crotch portion of the absorbent body. By this configuration, the crotch portion of the absorbent body is inseparably fixed to the chassis and thereby held in place relative to the chassis, which in turn leads to a maintenance of the position of absorbent body relative to the wearer in use. In

addition, the ends of the absorbent body are free where the absorbent body is inserted into the pocket/-s so that a relative movability between the absorbent body and the chassis is permitted in the front and/or back panel.

Thereby, the elasticity provided by either elastic means and/or the elasticity of the material used for the chassis is not compromised in the front and/or back panel. Thereby, an improved form fit may be obtained with an improved comfort while at the same time maintaining the relative position of the crotch portion of the absorbent body relative to the chassis. Thereby the position of the absorbent body relative to the body of a user may be maintained in use. In addition and compared to prior art entirely adhering the absorbent body to the chassis less adhesive is required which provides for reduced costs when manufacturing the absorbent article of the present invention. In addition, the relative movability of the absorbent body to the chassis except at the fixing portion provides for a softer textile feeling which provides for a buying incentive.

The absorbent body may comprise any known absorbent

structure. Examples of commonly occurring absorbent

materials are cellulosic fluff pulp, tissue layers, highly absorbent polymers (so called superabsorbents) , absorbent foam materials, absorbent non-woven materials or the like. It is common to combine cellulosic fluff pulp with

superabsorbent polymers in an absorbent core. Superabsorbent polymers are water soluble, water insoluble, organic or inorganic materials capable of absorbing at least about 20 times their own weight of an aqueous solution containing 0.9 wt-% of sodium chloride. Organic materials suitable for use as superabsorbent materials can include natural materials such as polysaccharides, polypeptides and the like, as well as synthetic materials such as synthetic hydrogen polymers. Such hydrogen polymers include for example alkali metal salts of polyacrylic acids, polyacrylamides , polyvinyl alcohol, polyacrylates , polyvinyl pyridines and the like. Other suitable polymers include hydrolyzed acrylonitrile grafted starch, acrylic acid grafted starch and isobutylene maleic hydride copolymers and mixtures thereof. The hydrogen polymers are preferably likely cross-linked to render the materials substantially water insoluble. Preferred

superabsorbent materials are further surface cross-linked so that the outer surface or shell of the superabsorbent, particles, fibers, flakes, spheres, etc. posses a higher cross-linked density than the inner portion of the superabsorbent . The superabsorbent materials may be in any form which is suitable for use in absorbent composites including particles, fibers, flakes, spheres and the like.

A high liquid storage capacity is provided by the use of higher amounts of superabsorbent material. For an absorbent body comprising a matrix of hydrophilic fibers such as cellulosic fibers and superabsorbent material, the proportion of superabsorbent materials is preferably between 10 and 90% by weight, more preferably between 30 and 70% by weight. It is conventional for absorbent articles to have absorbent bodies comprising layers of different properties with respect to liquid receiving capacity, liquid distribution capacity and storage capacity. The absorbent bodies which are common in for example baby diapers and incontinence guards, often comprise a compressed, mixed or layered structure of

cellulosic fluff pulp and superabsorbent polymers. The size and absorbent capacity of the absorbent body may be varied to suit different uses such as infants or adult incontinent persons .

The absorbent body may further include an acquisition and distribution layer placed on top of the primary absorbent core which is adapted to quickly receive and temporarily store discharged liquid before it is absorbed by the primary absorbent core. Such acquisition and distribution layers are well known in the art and may be composed of highly porous fibrous non-woven or foam materials.

The absorbent body is constituted by the absorbent structure and may further comprise additional layers such as the mentioned acquisition and distribution layers. In addition, the absorbent body has an enclosure to maintain the integrity of the absorbent structure as well as of possible additional layers. The enclosure of the absorbent body may be

constituted by an exterior sheet and a surface layer. The exterior sheet and the surface layer may be made of the same material being wrapped about the absorbent structure and possible additional layers. The exterior sheet is provided at the side of the absorbent body facing the chassis, whereas the surface layer is provided at the side of the absorbent body which in use is placed in direct contact with the skin of a user. The exterior sheet of the enclosure of the absorbent body may be made of the same or similar materials as the back sheet of the chassis as described above. In the same manner, the surface layer of the enclosure of the absorbent body may be constituted by the same or similar materials as the top sheet of the chassis. If the exterior sheet and the surface layer are made of different materials, they may extend beyond the circumference of the absorbent structure and possible additional layers and be connected to each other outside the absorbent structure and the possible additional layers to form an integral absorbent body. The material selected for the exterior layer and the surface layer of the enclosure of the absorbent body is mainly determined based on the selection of material of the back sheet and/or the top sheet of the chassis. In particular, if the enclosure of the absorbent body has a liquid permeable exterior sheet, the chassis ought to be liquid impermeable, e.g. by having a liquid impermeable back sheet. If the absorbent body in contrast has a liquid impermeable exterior sheet, the chassis may be both liquid impermeable or liquid permeable depending on the desired degree of security. An impermeable chassis will provide for improved leakage proof, whereas a permeable chassis may be more airy and comfortable to wear.

According to a preferred embodiment of the present invention, the absorbent body is fixed to the chassis by material closure preferably by means of an adhesive bond or a weld.

Further, it is known to provide channels in the absorbent body in which the absorbent is more compressed than in other regions {refer to WO-A-2005/032145) . The channels may also be substantially free of absorbent material as disclosed in WO-A-2006/059922. It may be preferred that the fixing portion is located within areas that correspond to the channels. Particularly, if the absorbent body comprises a supporting material and a superabsorbent material dispersed in the supporting material (e.g. cellulosic fluff pulp} as mentioned above, it is preferred that the fixing portion is located within longitudinal portions of the absorbent body that are substantially free of superabsorbent material.

These portions could coincide with the channels with

compressed absorbent or being substantially free of absorbent material. Within these channels, no or at least a very small amount of less than 1.5 g of superabsorbent material is contained. Preferably, if the part of the chassis which is to be fixed to the absorbent body is made of a non-woven and if the supporting material is made of a non-woven as well, it may be advantageous to use an ultrasonic welding process to fix the absorbent body to the chassis within the longitudinal portions. This has the advantage of better fit in the crotch portion, because of stronger fixation within the channel areas, which will facilitate the anatomical shape {bowl shape) even after swelling of the absorbent body. Core crumpling of the center part of the core between the two fixation areas should be prevented and the gain will be better comfort and minimized risk of leakage.

Beside the disposable absorbent article described above, the present invention also suggests a set for forming an

absorbent article. The set comprises a reusable chassis having a configuration as described above as well as a longitudinal absorbent body that is intended for one use only. The remainder of this configuration is the same as that described above.

Yet, in this embodiment it is preferred that a fastener is applied to the side of the absorbent body in use facing the chassis in the crotch portion. The fastener may either be adhesive or a mechanical fastener such as a hook and loop fastener or pressure buttons. In case of a mechanical fastener, a first part, e.g. a hook material or a first button part, may be fastened to either the chassis or to the absorbent body and the second part, e.g. a loop material or a second button part, may be fastened to the other of the absorbent body and the chassis. If the inner side of the chassis or the outer side of the exterior sheet of the absorbent body is of a non-woven material, this non-woven material may suffice as a loop material and, thus, no extra loop material need to be added. In case the fastener is an adhesive, the adhesive may be covered by a release paper that may be removed before use when the absorbent body is to be attached or fixed to the chassis. Further, the chassis may have an indication mark in the crotch portion indicating where the absorbent body is to be attached. Yet, if two pockets are provided the orientation of the absorbent body may as well be defined when the absorbent body being inserted into the pockets. In addition, the mark may be provided by a pattern and the adhesive applied to the absorbent body may be a colored adhesive applied in the same pattern or in a pattern supplementing the pattern of the chassis so that an aesthetical pattern is visible from the outside of the chassis .

Further, the present invention also relates to an absorbent body of such a set. Additionally, the present invention relates to the use of such an absorbent body with a chassis of a set as described above.

According to a preferred embodiment of the present invention, the absorbent body is discontinuously fixed within the fixing portion. That is, the absorbent body is fixed or to be fixed to the chassis not in the entire crotch portion but only to a certain discrete section (area) of the crotch portion. The fixing may be obtained by one or more linear or curved portions. Alternatively, a plurality of discrete punctiform fixing portions may be provided. The discontinuous fixing portion may provide for a pattern which is visible on the outer side of the chassis in use facing away from a user. For this purpose, a colored adhesive may be used, the color of which being visible from the outside of the chassis. In this context, it is preferred that a material for the chassis at least in this area is selected so as to be at least partially transparent.

The fixing portion within the crotch portion of the absorbent body is preferably less than 16.5%, more preferred less than 15% and most preferred less than 13,5% of the total area of the absorbent body facing the chassis in size. Yet, it is preferred that the fixing portion is at least 7% and more preferred at least 8.25% and most preferred at least 8.9% of the total area of the absorbent body facing the chassis in size. In addition, it is preferred that the absorbent body is fixed to the chassis or to be fixed to the chassis within the fixing portion by at least 5%, preferably at least 8% and most preferred at least 16% of the area of the fixing

portion. Preferably, the fixing is less than 55%, preferably less than 45% and most preferred less than 35% within the fixing portion.

According to one embodiment, the length of the fixing portion of the absorbent body in the longitudinal direction is 13% to 32%, preferably 15.8% and 30% and even most preferred 17% to 26% of the longitudinal direction of the absorbent body. In this context, the absorbent body may be fixed or to be fixed to the chassis along the entire length of the fixing portion in the longitudinal direction. That is, it is preferred that the last fixing position of the absorbent body to the chassis is at one end of the fixing portion in the longitudinal direction and another last fixing point is disposed at the opposite end thereof. The width of the pocket may be selected corresponding to the width of the absorbent body having at least the same width but preferably a slightly larger width than the absorbent body at the respective end to be inserted into the pocket. Yet, from the view of ease of manufacture, it may be

preferred that at least one pocket is formed by a folded portion of the chassis. That is, at least part of the chassis is at an edge (front edge/back edge) folded in the longitudinal direction along a transverse folding line over itself inside against inside, whereby the material of the chassis is double-layered. Then, at positions distant in the direction transverse to the longitudinal direction of the chassis, the material is connected to each other along the longitudinal direction forming the pocket. The materials could be connected at or in the vicinity of the longitudinal edges of the chassis, i.e. at opposed edges of the chassis in the transverse direction. In this case, the width of the pocket would be the same as that of the front/back edge where the pocket is located. The material could also be connected inward of the longitudinal edges, e.g. by two joints formed at a transverse distance that is somewhat larger than the transverse width of the end of the absorbent body to be inserted into the pocket, but smaller than the transverse width of the chassis at the corresponding longitudinal location. Yet, it is also conceivable to separately

manufacture the pocket and attach it to the chassis. This may even save material and thereby decrease the costs.

Further features and advantages of the present invention will become apparent from the following description of a preferred embodiment. These features may be implemented as such in combination with one or more of the aforesaid features unless the features contradict each other. Brief Description of the Drawings

The following description makes reference to the accompanying drawings in which:

Figure 1 shows a plan view of a flattened diaper viewed upon the inner side in use directed to the skin of a user;

Figure 2 shows a schematic view of an alternative pocket configuration in a cross-section of the flattened diaper corresponding to a cross-section of Figure 1 along the line 2-2;

Figure 3 shows a cross-section of the flattened diaper of Figure 1 along the line 3-3;

Figure 4 shows the fixing portion of Figure 1 in an enlarged view with different fixing patterns in a) to c) .

Figure 5 shows a schematic plan view of a flattened diaper viewed upon the inner side in use directed to the skin of the user in an alternative embodiment in which the absorbent body comprises channels; and

Figure 6 shows a cross-sectional view of the flattened diaper of Figure 5 along the line 6-6.

Detailed Description

Although the following description has been made on a conventional diaper to be closed by means of a fastening means, the present invention may as well be implemented in diapers having a belt or panty-like diapers. In addition, the present invention may as well be incorporated in

incontinence guards. Figure 1 of the drawings shows an embodiment of an absorbent article in the form of a diaper. The diaper is intended to be worn around the waist of the wearer like a pair of pants. The absorbent article comprises a chassis 10 having a front panel 11 (length A) which in the embodiment shown in the drawings in use is intended to extend over the stomach of the wearer. The chassis also comprises a back panel 12 {length B) , which in the shown embodiment is the part of the chassis that in use is intended to extend over the back of the wearer. Each of the front and back panel 11 and 12 has a waist portion 11a and 12a, respectively. The article has a longitudinal direction y and a lateral transverse direction x. The absorbent article as shown in Figure 1 may further be symmetric about a longitudinal center axis L.

A crotch portion 13 {length C) of the chassis is the part of the article that in use is intended to extend through the wearer's crotch area between the legs. An absorbent body 14 is disposed in the crotch portion 13 and extends into the front and back panels 11, 12. The chassis 10 comprises an inner top sheet 15 and an outer back sheet 16.

The top sheet 15 and the back sheet 16 of the chassis 10 may be of any kind as known in the art and as described earlier.

On each side of the waist portion 12a of the front panel 12, side panels 17, 18 may be provided. The side panels 17, 18 are preferably substantially identical. The side panels 17, 18 have a length L in the lateral direction x and a height H in the longitudinal direction y, wherein the height may vary along the length of the side panels as shown in Figure 1.

Each side panel 17, 18 may have a fastening means for example a mechanical fastening means in the form of a hook or loop member, intended to cooperate with a complementary mechanical fastening means on the outside of the front panel 11, the so called landing zone. The entire external surface of the back sheet 16 of the front panel may comprise a non-woven

material, which functions as a loop material or a separate strip of loop material may be attached to the external surface of the front panel forming the landing zone. Further examples of mechanical fasteners are button and holes or button loops, snap fasteners and the like. The buttons can either be fastened to the side panels or to the absorbent article. Alternatively, adhesive fastening means may be used such as a tape tab, wherein at least part of the external surface of the back sheet 16 of the front panel 11 is of a material to which the tape can adhere.

Further, a waist elastic member 25 may be provided that extends in the transverse direction x along at least a part of the waist portion 12a of the back panel 12. The waist elastic member may be an elastic web material as described below. The elastic members are preferably contractibly attached between the top and the back sheet 15, 16, to the external side of the back sheet or to the wearer facing side of the top sheet. Alternatively, it may comprise two or more elastic threads or strips contractibly affixed in a similar manner. Another waist elastic member 26 extending in the transverse direction x may also be provided along at least part of the waist portion 11a of the front panel 11.

If separate elastics are provided, these may be provided in the form of an elastic web material, such as an elastic film, an elastic non-woven, an elastic laminate or the like. The elastic laminate may be a laminate between two or more non- woven layers, two or more film layers or a combination of film and non-woven layers.

The waist elastic members 25, 26, were present, allow an extension of the waist area to follow the users movements, when standing and sitting for example to be taken into account while still providing a comfortable and well fitting waist portion. The waist elastics are preferably located outside the longitudinal limits of the absorbent body 14.

The leg openings may be elastified, said elastification being usually accomplished by a plurality of elastic members 27 such as elastic threads, which are contractibiy fixed as aforesaid. The article may also be provided by a so called raised barrier cuffs (not shown} in order to provide an improved security against leakage. These raised barrier cuffs may in some instance replace leg elastics.

To support the form fit, it is preferred that the chassis 10 comprising the top sheet 15 and the back sheet 16 is made from a material preferably a non-woven that has a certain elasticity to assist other elastic members such as the elastics or elastified side panels and the waist bands 25, 26 as well as the leg elastics 27. The term "elastic" in this respect refers to a material having an elastic elongation of at least 20% as measured in the elasticity test a described below.

The absorbent body 14 may, as shown in Figures 2 and 3, be comprised of an absorbent structure 37 disposed in an

enclosure. The enclosure may be formed by an exterior sheet 35 facing the chassis 10 and a surface layer 36 in use facing the wearer and to be placed in contact with the skin of the wearer. The exterior sheet 35 and the surface layer 36 of the enclosure of the absorbent body which enclose the

absorbent structure 37, that may comprise an absorbent material as well as additional layers, may be constituted as described earlier.

In the past, the absorbent body 14 was attached to the chassis over a substantial amount of its surface area.

Thereby, the elasticity of the product in this area had been compromised and the product was stiffened. This stiffness may lead to a decrease in the form fit and, hence, to leakage in use.

According to the present invention, the fixation of the absorbent body 14 to the chassis 10 is limited to a certain fixing portion 30. This fixing portion 30 is only located in the crotch portion of the absorbent body which in the present embodiment coincides with the crotch portion 13 of the chassis 10. That is, the fixing portion extends along the longitudinal direction y with the portion C. The fixing portion 30 is preferably centered on the longitudinal center line L of the article. Further, it is preferred that the fixing portion 30 only extends over a part of the absorbent body 14 in the lateral direction x. That is, the width of the fixing portion 30 is preferably less than the width of the absorbent body in the lateral direction x. The length of the fixing portion in the longitudinal direction y is in case of baby diapers preferably less than 12 cm, more preferably less than 11cm and most preferred less than 10 cm. The minimum length is preferably more than 5 cm, more preferred more than 6 cm and most preferred more than 6.5 cm.

Furthermore, it is preferred that the absorbent body 14 is only fixed to the chassis 10 and particularly to its back sheet 16 in part of the area of the fixing portion 30. The fixing portion 30 for a baby diaper has preferably an area of 6175 mm². In this context, it is preferred that the

absorbent body 14 is only fixed within 16%, preferably 8% and most preferred 5% of the area of the fixing portion 30. Even more preferred, the absorbent body 14 is fixed to the chassis 10 in less than 55%, preferably less than 45% and most preferred less than 35% of the fixing portion 30.

Further and as shown in Figure 1, the fixation of the absorbent body 14 to the chassis 10 in the fixing portion 30 is discontinuous, wherein different discontinuous patterns may be used as examplified in Figures 4a to 4c. As for example shown in Figure 3, the fixations 31 fix the exterior sheet 35 of the enclosure of the absorbent body 14 to the chassis particularly its inner side (here the top sheet 15). The fixations 31 are as well shown in the cross-section of Figure 3. In the examples of Figures 4a to 4c linear and straight elements crossing each other may be used as shown in Figure 4b. However, punctiform fixations 31 between the absorbent body 14 and the chassis 10 may be used as shown in Figures.4a and 4c. In this connection, the punctiform elements may be squares as shown. Yet, circles ovals, triangles or other geometrical forms are conceivable.

Further and as shown in Figures 4a to 4c, the absorbent body 14 is fixed to the chassis 10 in a fixation pattern. This pattern may be visible from the external side (outside) of the chassis 10 and, hence, the back sheet 16. This may enhance the outer visual appearance of the absorbent article. For this purpose, it may be preferred to use colored adhesive for fixing the absorbent body 14 to the chassis 10. Thereby, the fixed part of the absorbent body 14 may become visible on the outside.

Yet, also other material closure means, such as welding, or even other fixing means may be used. For example and as shown in Figures 5 and 6, it can be preferred to use an absorbent body 14 having at least one longitudinal channel 38 primarily extending in the longitudinal direction y of the article, wherein the absorbent body 14 comprises a non-woven and a non-woven material is also used for the chassis 10. In this instance, the absorbent body 14 in the longitudinal channel may be compressed so that only a very small amount or no amount of absorbent material is contained within the channel (see earlier) . Therefore, it is possible to use an ultrasonic welding process to combine the exterior sheet 35 and possible also the surface layer 36 of the absorbent body 14 and the material of the chassis 10 in a very effective and advantageous manner. This is particularly beneficial, if the chassis and the absorbent body comprise a non-woven material. Yet, other welding or adhesive processes are conceivable as well .

The absorbent body 14 is only fixed to the chassis 10 within the fixing portion 30. The remainder of the absorbent body 14 is not fixed to the chassis at all. It may, therefore, to a certain extend move relative to the chassis. Yet, to hold the absorbent body 14 in a relative position, it is suggested to provide pockets 32 in the chassis. The absorbent body 14 has two opposite ends 14a and 14b in the longitudinal

direction y of the article. These ends 14a, 14b are located within the front panel 11 and the back panel 12,

respectively. Particularly, the front panel 11 and the back panel 12 can be elastic to provide for a satisfying form fit, particularly around the waist of a wearer. As no large fixation area of the absorbent body 14 is present within the front panel 11 and the back panel 12, no stiffening in this area results so that the elasticity in these areas may be maintained. Yet, because the ends 14a, 14b of the absorbent body 14 are inserted into the pockets 32, the ends are securely held in place relative to the chassis 10, though they may to a certain extent move relative to the chassis 10. As, however, the crotch portion of the absorbent body 14 is securely fixed to the chassis, particularly the crotch portion and more particularly the fixing portion 30 can be securely maintained in place during use preventing a shift of the absorbent body 14 relative to the chassis 10 and/or the user .

In addition, the relative movablility of the absorbent body 14 outside the fixing portion 30 provides for a more textile and softer feeling of the product as the particular layers of the chassis and the absorbent core may move relative to each other. This may be a buying incentive for the customers perceiving the product as being more comfortable and softer. The pockets 32 may be formed by one pocket only as shown in the back panel 12 in Figure 1, The pocket 32 is preferably rectangular in shape and may have a width in the lateral direction X slightly exceeding the width of the end 14a of the absorbent body 14 to be inserted into the pocket 32. The height of the pocket 32 may be selected depending on the amount of material to be used for the pocket in view of a secure accommodation of the end 14a of the absorbent body 14 and costs. This pocket 32 and as shown in the alternative embodiment of Figure 2 may be formed by a cut through the top sheet 15 constituting the opening 33, when the top sheet 15 and the back sheet 16 are not fastened to each other within the area of the pocket 32. That is, fastening of the top sheet 15 and the back sheet 16 of the chassis 10 may be omitted in the rectangular area of the pocket 32 and a cut may be formed in only the top sheet thereby forming the opening 33 shown in the back panel 12 of Figure 1. Figure 2 in this regard shows the end 14a of the absorbent body inserted in such a pocket 32, namely inbetween the top sheet 15 and the back sheet 16.

Yet, also two pockets may be provided similar to photo corners as shown in the front panel 11 in Figure 1. These pockets 32 are triangularly formed and only receive parts of the end 14b, particularly corner parts of the end 14b of the absorbent body 14. As is visible as well, the opening 33 of the pocket 32 in the back panel 12 of Figure 1 is directed in the lateral direction, whereas the opening 33 of the pocket 32 in the front panel 11 of Figure 1 are directed in angle to the longitudinal y as well as the lateral x direction.

In the embodiment shown in Figure 1, the pockets 32 are depicted as separate elements attached to the chassis 10 either by welding or the use of adhesive. Yet, only very thin linear or punctiform fixation points are preferably used. Alternatively, it may be preferred to form the pockets 32 by a folded portion 32^f of the chassis 10. Such a pocket is shown in Figure 1 by the reference numerals 32' ' . In this context, the back sheet and/or the top sheet 15, 16 of the chassis 10 have an extension extending beyond the waist edge 12a before folding. This extension portion is folded back so as to form a double layered portion. Connecting the edges 32' ' of the folded portion 32' of the double layered portion by means of adhesive or welding along the longitudinal direction y, a pocket 32''' similar to the pocket 32 in the back panel 12 of Figure 1 may be obtained which, however, is larger in width than the inserted end of absorbent body 14 and larger in height than the pocket 32. This may require more material which, however, may be compensated by ease of manufacture. Furthermore, to reduce the width of the pocket, it is conceivable to fasten the folded portion to the chassis corresponding to a smaller width of the opening related to the width of the inserted end of the absorbent body.

Elasticity Test

The method measures the behavior of an elastic material at repeated load and unload cycles. The sample is tested in the x-direction according to Figure 1. The sample is stretched to a predetermined elongation and a cyclic movement between 0 and said predetermined elongation is performed. Desired load and unload forces are recorded. The permanent, i.e.

remaining, elongation of the relaxed material is measured. The permanent elongation after relaxation should be less than 10% and is measured by the method below. Thus an elastic elongation of 20% is defined as that the laminate should have a permanent relaxation after elongation of less than 10% after being exerted to an elongation of 20% in the tensile tester below. An elongation of 20% means an elongation to a length that is 30% longer than the initial length of the sample. A tensile tester, e.g. Lloyd LRX(TM), able to perform cyclic movements and equipped with a printer/plotter or software presentation is used. The sample is prepared by cutting .it to a width of 25 mm. The length and width of the sample may vary according to the available amount of

material. If the material to be tested has a width higher than 25 mm the sample should be cut so that the width is 25 mm. If, however, the material to be tested, e.g. the elastic material, has a width that is smaller than 25 mm the sample should have the width of the available material piece. The forces then have to be adjusted to the width of the sample according to the values given in brackets in the test method. The tensile tester is calibrated according to the apparatus instructions. The parameters needed for the test (load and unload forces) are adjusted to:

Crosshead speed: 500 mm/min

Clamp distance: adapted to the length of the test sample Preload: 0.05 N (0.02 N/10mm width)

The sample is placed in the clamps and it is made sure that the sample is centered and fastened perpendicularly in the clamps. Depending on the length of the sample the distance between the clamps may vary. If a sample is longer than 100 mm it should be cut to a length of 100 mm. A suitable distance between the clamps is in this case 50 mm. For shorter samples the distance between the clamps can be shorter then 50 mm but as long as possible. For very short samples, less than 20 mm, the elastic sample should at both ends still be attached to inelastic material, wherein the inelastic material is fastened in the clamps with the elastic part of the sample extending between the clamps. It is in this case important that the entire elastic part of such a sample is located between the clamps.

The tensile tester is started and two cycles between 0 and the predetermined elongation are performed. The crosshead should return immediately and not be held in the stretched position. There should not be any delay between the two cycles of the test method. After the last cycle, the sample is relaxed for one minute, then the permanent elongation is measured by stretching the sample until a force of 0.1 N (0.04 N/10mm width) is detected and the elongation is read.

Although only one particular embodiment of the present invention has been described in detail above, it is clear to the skilled person that various modifications can be made. Further, it is understood that the present invention may net only be implemented in an open diaper to be closed by means of a fastening means such as the side panels or a belt, but also to panty-like diapers which are already closed in the manufacturing process. The present invention may further be implemented in incontinence guards. In addition, it is clear that only one end of the absorbent body needs to be

accommodated in the pocket so that only one pocket needs to be present, whereas the above embodiment is a preferred one accommodating both ends of the absorbent body 14 in pockets. Further, even other forms of the pockets than the ones mentioned above are conceivable and encompassed by the present invention as long as the ends of the absorbent body 14 may be received within such pockets or at least parts of the ends may be received therein. It may even be conceivable that the pockets have two opposite openings. In this instance, the pockets have the form of strips connected at both opposite ends to the chassis, wherein the ends of the absorbent body 14 or parts thereof may be inserted below the strips, that is between the strips and the inside of the chassis 10 or the inside of the back sheet 16 of the chassis 10. In this instance, a part of the absorbent body 14 may even extend beyond those pockets. Particularly, such an embodiment may lead to less material needed for the pockets and therefore to reduced costs. In addition, the fixing portions of the pockets to the sheet 10 if provided

separately may be minimized thereby minimizing the stiffening of the article by these connecting portions.

Further, the present invention may even be implemented in a set for forming an absorbent article comprising a reusable chassis and a disposable absorbent body. In this instance, it is preferred to use a fastener so as to enable the user to attach the absorbent body 14 to the chassis as described above. The adhesive used as the fastener which equals the fixation of the absorbent body 14 to the chassis 10 could before use be covered by a release paper. This release paper is to be removed by a user before applying the absorbent body 14 to the chassis 10. In this context, it may be preferred to provide a mark, preferably similar as the pattern 31 on the inside of the chassis 10 to make it easier for the user to apply the absorbent body 14 at the correct position. Yet, if the pockets 32 are provided with closed ends in the

longitudinal direction y, these closed ends at both ends in the longitudinal direction y could clearly indicate the correct position of the absorbent body 14 in the longitudinal direction y to a user. In addition the pockets are limited at opposite sides in a transverse direction x, i.e. the opening 33 of the pockets is generally limited in the transverse direction. This limitation in the transverse direction x could clearly indicate the correct position of the absorbent body 14 in the transverse direction x to a user. Otherwise, such a set would be similarly configured as described with respect to Figure 1 above.

In view of the aforesaid, the present invention is, hence, defined by the following claims.

Claims

1. Disposable absorbent article comprising:

a chassis (10) being divided into a front panel (11) and a back panel (12); wherein the chassis has at least one pocket (32) arranged at least in the front panel or the back panel

a longitudinal absorbent body (14) extending between the front panel and the back panel and having a crotch portion inbetween the front and the back panel, one end (14a, 14b) of the absorbent body in the longitudinal direction being inserted into the at least one pocket;

characterized in that

the end (14a, 14b) of the absorbent body (14) inserted into the at least one pocket (32) is only held relative to the chassis (10) by means of the at least one pocket; and a side of the absorbent body (14) facing the chassis (10) is fixed to the chassis only in the crotch portion of the absorbent body at a fixing portion (30) .

2. Absorbent article according to claim 1, wherein the absorbent body (14) is fixed to the chassis (10) by material closure, preferably an adhesive bond or a weld.

3. Set for forming an absorbent article, the set

comprising :

a reusable chassis {10} being divided into a front panel (11) and a back panel (12) and; wherein the chassis has at least one pocket arranged at least in the front panel or the back panel

a longitudinal absorbent body (14) to be disposed so as to extend between the front panel and the back panel and having a crotch portion inbetween the front and the back panel, wherein one end (14a, 14b) of the absorbent body in the longitudinal direction is to be inserted into the at least one pocket

characterized in that the end (14a, 14b) of the absorbent body (14) is to be inserted into the at least one pocket (32) so as to be only held relative to the chassis (10) by means of the at least one pocket; and in that a side of the absorbent body (14) facing the chassis (10) is to be fixed to the chassis only in the crotch portion of the absorbent body at a fixing portion (30) .

4. Set according to claim 3, wherein an adhesive (31), preferably covered by a removable release paper, is applied to a side of the absorbent body (14) in use facing the chassis ( 10) .

5. Set according to claim 3, wherein a mechanical fastener is provided on a side of the absorbent body (14) in use facing the chassis (10) .

6. Use of an absorbent body (14) of a set according to claim 4 or 5 together with a chassis of the set.

7. The subject matter according to any one of the preceding claims, wherein the absorbent body (14) comprises an

absorbent structure with absorbent material, the absorbent structure having at least one channel with compressed

absorbent material or substantially free of absorbent

material and the absorbent body (14) is fixed or to be fixed to the chassis (10) at least within a portion corresponding to the channel.

8. The subject matter according to any one of the preceding claims, wherein the chassis (10) has at least one pocket (32) arranged at the front panel (11) and at the back panel (12) for receiving both ends {14a, 14b) of the absorbent body (14) in the longitudinal direction (4) respectively.

9. The subject matter according to any one of the preceding claims, wherein the absorbent body (14) is discontinuously fixed to the chassis (10) within the fixing portion (30).

10. The subject matter according to any one of the preceding claims, wherein the fixing portion (30) has an area of less than 16.5%, preferably 15% and most preferred 13.5% of the area of the absorbent body and preferably at least 7%, preferably 8.25% and most preferred 8.9% of the area of the absorbent body.

11. The subject matter according to claim 9, wherein the absorbent body (14) is fixed to the chassis (10) within at least 5%, preferably at least 8% and most preferred at least 16% and less than 55%, preferably 45% and even most preferred 35% of the area of the fixing portion.

12. The subject matter according to any one of the preceding claims, wherein the absorbent body (14) is fixed to the chassis along a longitudinal direction extending along 13% to 32%, preferably 15.8% and 30% and even most preferred 17% to 26% of the longitudinal extension of the absorbent body (14).

13. The subject matter according to any one of the preceding claims, wherein the absorbent body (14) is fixed to the chassis (10) in the form of a pattern (31) visible on an outer side of the chassis (10).

14. The subject matter according to any one of the preceding claims, wherein the at least one pocket (32) is formed by a folded portion of the chassis (10) .

15. The subject matter according to any one of claims 1 to 14, wherein the at least one pocket is formed by a strip attached at opposite ends to the chassis and defining to opposed openings.