Abstract:
An absorbent article has a belt and an absorbent structure. The absorbent structure is fastened to the belt via an article fastener having a form such that the article fastening means does not fold or bend upwards under the forces present when the diaper is assembled.

Description:
TECHNICAL FIELD 
       [0001]    The present invention provides an absorbent article comprising a belt and an absorbent structure. The absorbent structure is fastened to the belt via an article fastening means having a form and orientation such that the article fastening means does not fold or turn up under the forces present when the diaper is being worn. 
       BACKGROUND OF THE INVENTION 
       [0002]    Absorbent articles such as diapers and incontinence guards are worn by incontinent persons to manage body waste such as urine or faeces. They generally comprise two important features: an absorbent structure which absorbs and manages the body waste, and components which keep the absorbent structure in place on the body of the wearer under a range of activities (e.g. walking, sitting or lying down). 
         [0003]    Diapers and incontinence guards can be classified according to their structure. Pant diapers resemble normal underwear, and are applied to a wearer by being pulled up the wearer&#39;s legs, in the same way as regular underwear. Traditional diapers have front and rear portions which are fastened to one another around the waist of the wearer. 
         [0004]    Belted absorbent articles, such as belt diapers, have a belt which is first fastened around the waist of a wearer. Belted absorbent articles are popular with incontinent adults as they can be changed by the wearer themselves while standing up. After fastening the belt, the absorbent structure is then brought between the legs of the wearer and fastened by article fastening means to the belt. In such articles, at least a portion of the waistband of the article only comprises the belt (i.e. the front and rear portions of the absorbent structure are not directly fastened to one another around the waist of the wearer). The present invention concerns belted absorbent articles. 
         [0005]    Examples of belted articles are provided in WO 02/05739, WO 06/065177, WO 03/017904 and WO 03/017903. GB 2 080 093 discloses a traditional diaper (i.e. not a belt diaper) which has strips of tape aligned in the direction of the leg elastics. 
         [0006]    Typically, little attention has been paid to the form and/or placement of the article fastening means used to fasten the absorbent structure of a belted absorbent article to the belt. In the interests of simplicity and manufacturing efficiency, article fastening means to date have usually comprised a square or rectangle of material which is applied to the absorbent structure such that one edge is parallel to the front (longitudinal) edge or the transverse edge in the front region of the absorbent structure. 
         [0007]    However, the primary forces in the waist and hip region of such belted absorbent articles when being worn are directed from the hip region of the belt inwards and downwards towards the crotch of the wearer (see arrow X in  FIG. 2 ). The article fastening means of the prior art are by no means ideal in such situations, and—under such forces—tend to fold upwards or be uncovered at their lower edges (see  FIG. 5 ). This can lead to problems with poor fastening ability, as the entire article fastening means is not in full contact with the corresponding reception surface. Poor fastening in turn leads to poor fit and the risk of leakage. Furthermore, article fastening means which is exposed can fasten undesirably to the wearer&#39;s clothes or bedclothes. 
         [0008]    There thus remains a need for a belted absorbent article in which the above problems are addressed in a simple and effective manner. 
       SUMMARY OF THE INVENTION 
       [0009]    The present invention is based on the realisation that the form and alignment of the article fastening means are important for obtaining a belted absorbent article which poor fit, risk of leakage and undesirable fastening to other articles are reduced. 
         [0010]    The invention therefore provides an absorbent article, such as a diaper or an incontinence guard. The article comprises a belt and an absorbent structure, said belt comprises an article reception surface. The absorbent structure extends in the longitudinal (L) and transverse (T) directions and has a longitudinal centre line (L 1 ) and opposing first and second longitudinal end regions. 
         [0011]    Each of said longitudinal end regions has a perimeter constituted by a transversely extending end edge and a pair of opposed longitudinal edges. The first longitudinal end region of said absorbent structure is attached to the belt. 
         [0012]    The absorbent structure comprises at least one article fastening means at the second longitudinal end region thereof, said article fastening means adapted to fasten to the article reception surface on the belt such that the absorbent article adopts a pant-like shape in use. The article fastening means has a shape such that it is accommodated within an imaginary rectangle, the rectangle having opposed upper and lower first edges extending parallel to said transversely extending end edge of said second longitudinal end region and opposed distal and proximal second edges extending parallel to said pair of opposed longitudinal edges of said second longitudinal end region. A rectangle is thereby defined having an upper distal corner, an upper proximal corner, a lower distal corner and a lower proximal corner. 
         [0013]    At least a continuous region, which is located adjacent the lower distal corner and defined by a portion of the distal second edge and a portion of the lower first edge of the imaginary rectangle, is free of article fastening means. The article fastening means contacts the imaginary rectangle at least on the lower first edge and the distal second edge thereof. 
         [0014]    In one embodiment, an imaginary straight line drawn along at least one edge of the article fastening means towards the first longitudinal end of the absorbent structure meets the longitudinal centre line (L 1 ) of the absorbent structure at an acute angle (α) which lies between 5° and 85°, preferably between 10° and 80°, more preferably between 15° and 45°. 
         [0015]    Suitably, the article fastening means has a rectangular shape, a square shape, a parallelogram shape, a rhombus shape or a triangular shape in the L-T plane. 
         [0016]    The first longitudinal end of said absorbent structure may be attached to the belt via at least one article fastening means located at the first longitudinal end of the absorbent structure, said article fastening means having the shape and alignment as described above. The first longitudinal end of the absorbent structure may be permanently attached to the belt, e.g. via glue or welding. 
         [0017]    Suitably, the maximum extension of the article fastening means in a direction perpendicular to a force line (X) which passes through the centre of the article fastening means and which makes an angle with the longitudinal centre line (L 1 ) of the absorbent structure of between 5° and 85°, preferably between 10° and 80°, more preferably between 15° and 45° is less than 3 cm, preferably less than 2 cm, more preferably less than 1 cm. 
         [0018]    Preferably the belt consists of article reception surface on the garment-facing side thereof. 
       DEFINITIONS 
       [0019]    The term “absorbent article” refers to products that are placed against the skin of the wearer to absorb and contain body exudates, like urine, faeces and menstrual fluid. The invention mainly concerns disposable absorbent articles, which means articles that are not intended to be laundered or otherwise restored or reused as an absorbent article after the first use. 
         [0020]    The “absorbent structure” of the absorbent article is that component of the absorbent article which receives and stores exuded bodily fluids. As such, it comprises at least an absorbent core. The absorbent structure may be permanently attached to the belt of a belted absorbent article, or may be removably attached. Typically, the absorbent structure is manufactured before being joined to the belt of a belted absorbent article. It therefore comprises a separate component of the absorbent article to the belt. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0021]    The invention may be more readily understood by reference to the attached drawings which, by way of example only, schematically illustrate various embodiments of the invention: 
           [0022]      FIG. 1  shows an open belt-diaper according to the invention, seen from the wearer-facing side and with all elastic components of the absorbent structure  30  fully extended; 
           [0023]      FIG. 2  shows the belt-diaper of  FIG. 1  in assembled form; 
           [0024]      FIG. 3  shows a close-up of the second longitudinal end region of the article; 
           [0025]      FIGS. 4   a - e  show alternatives for the article fastening means  40 ; 
           [0026]      FIG. 5  is an illustration of an absorbent fastening means of the invention; and 
           [0027]      FIG. 6  is an illustration of an absorbent fastening means of the prior art. 
       
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0028]      FIG. 1  shows an absorbent article  10  according to the invention, seen from the wearer-facing side (inside) and with all elastic components of the absorbent structure  30  fully extended. The article comprises a belt  20  and an absorbent structure  30 . In  FIG. 1 , the belt  20  is open. 
         [0029]    In use, the belt  20  is fastened about the wearer&#39;s waist, where it acts to hold the absorbent structure  30  in place. The belt  20  of  FIG. 1  comprises two belt halves,  21 ,  22 , although it is conceivable that a single belt is present, which wraps completely around the waist of the wearer. The belt  20  of  FIG. 1  also comprises belt attachment means  23  which fastens to belt reception surface  25 , so that the belt can be fastened around the waist of the wearer. If the belt attachment means  23  comprises hook material of a hook-and-loop (e.g. Velcro®) fastener, belt reception surface  25  suitably comprises loop material. Likewise, if the belt attachment means  23  comprises adhesive material, the belt reception surface  25  suitably comprises a plastic film material to which the adhesive material can fasten, preferably in a releasable manner. The belt  20  may comprise a single length of belt material, to which the absorbent structure  30  is attached, or may comprise two separate lengths of belt material, each of which is attached to the absorbent structure  30 . 
         [0030]    The width of the belt  20  should be between circa 50 mm and 250 mm. The belt  20  may comprise nonwoven material or plastic film, or laminates thereof. In a preferred embodiment, the belt  20  comprises a laminate of at least one nonwoven material and at least one plastic film. The belt  20  may have elastic properties in at least one region thereof, and in at least one direction, preferably in the length direction of the belt. Elastic properties may be provided by the use of one or more elastic components, such as e.g. elastic threads, elastic nonwoven materials or elastic films. Belts  20  having elastic properties are particularly useful. The belt  20  is desirably breathable, and the material constituting the belt  20  may be perforated or porous or the belt  20  may be spaced from the skin of the wearer by spacer fabric or spacer elements. 
         [0031]    The belt  20  comprises an article reception surface  24 , which is preferably the same material as belt reception surface  25 . Indeed, a single reception surface (e.g. of nonwoven material) may constitute both the article reception surface  24  and the belt reception surface  25 . The article reception surface  24  is located on the outside (garment-facing) surface of the belt  20  when worn. Article reception surface  24  and belt reception surface  25  may each comprise separate pieces of material which are joined to the belt  20  during manufacture, or the wearer-facing surface of the belt  20  may itself consist of one or both of these reception surfaces  24 ,  25  (as shown in  FIG. 1 ). 
         [0032]    The absorbent structure  30  is the component of the absorbent article  10  which receives and stores exuded bodily fluids. It extends in the longitudinal (L) and transverse (T) directions as shown in  FIG. 1 , and may have any suitable shape, e.g. rectangular, hourglass or T-shaped. In use, the absorbent structure  30  is located between the legs of the wearer so as to cover the wearer&#39;s genitals and anal region, and is held in place on the wearer by the belt  20 . The absorbent structure  30  has a longitudinal centre line (L 1 ) about which it is symmetrical, and opposing first  31  and second  32  longitudinal end regions. Each of said longitudinal end regions  31 ,  32  has a perimeter constituted by a transversely extending end edge  33 ,  34  and a pair of opposed longitudinal edges  35 ,  36 . 
         [0033]    Traditionally, belt diapers are applied to a wearer by fastening the belt  20  around the wearer&#39;s waist, with the absorbent structure  30  hanging downwards at the wearer&#39;s rear. The absorbent structure  30  is then brought between the wearer&#39;s legs and fastened to the belt  20  at the wearer&#39;s front. In this case, the first longitudinal end region  31  of the absorbent structure  30  will comprise the rear portion of the absorbent article  10 , while the second longitudinal end region  32  of the absorbent structure  30  will comprise the front portion of the absorbent article  10 . However, the reverse situation is also possible. 
         [0034]    In cross-section, the absorbent structure  30  usually comprises a liquid-permeable topsheet  38 , a liquid-impermeable backsheet  39  and an absorbent core  37  located between said topsheet  38  and said backsheet  39 . However, in certain absorbent structures  30 , it may be sufficient to include only an absorbent core  37  and a liquid-impermeable backsheet  39 . 
         [0035]    The topsheet  38  of the absorbent structure  30  is the layer which lies in contact with the wearer&#39;s body when the absorbent article is in use. As such, it should be soft, non-irritating and comfortable against the skin, and bodily fluid should be able to pass through it without hindrance. The topsheet  38  can consist of a nonwoven material, e.g. spunbond, meltblown, carded, hydroentangled, wetlaid etc. Suitable nonwoven materials can be composed of natural fibers, such as woodpulp or cotton fibres, manmade fibres, such as polyester, polyethylene, polypropylene, viscose etc. or from a mixture of natural and manmade fibres. The topsheet may further be composed of tow fibres, which may be bonded to each other in a bonding pattern, as e.g. disclosed in EP-A-1 035 818. Further examples of materials suitable for topsheets are porous foams, apertured plastic films etc. The topsheet  38  may be different in different parts of the absorbent structure  30 . 
         [0036]    The backsheet  39  of the absorbent structure  30  is the layer which lies furthest from the wearer&#39;s body when the article is in use. To protect the wearer&#39;s garments from soiling, it should be liquid-impermeable, but is desirably gas-permeable to allow air and vapour to pass in and out of the article so that the warm, damp conditions which can arise in a diaper are reduced. Typically, the backsheet  39  is of a liquid impervious material, such as a thin plastic film, e.g. a polyethylene or polypropylene film, a nonwoven material coated with a liquid impervious material, a hydrophobic nonwoven material, which resists liquid penetration or a laminate comprising plastic films and nonwoven materials. Examples of breathable backsheet materials are porous polymeric films, nonwoven laminates of spunbond and meltblown layers and laminates of porous polymeric films and nonwoven materials. The backsheet  39  may be different in different parts of the absorbent structure  30 . 
         [0037]    The absorbent core  37  of the absorbent structure  30  acts to receive and contain liquid and other bodily exudates and can be of any conventional kind. As such, it typically comprises absorbent material. Examples of commonly-occurring absorbent materials are cellulosic fluff pulp, tissue layers, highly-absorbent polymers (so called superabsorbents), absorbent foam materials, absorbent nonwoven materials or the like. It is common to combine cellulosic fluff pulp with superabsorbents in an absorbent body. It is also common to have absorbent cores comprising layers of different material with different properties with respect to liquid receiving capacity, liquid distribution capacity and storage capacity. The thin absorbent cores, 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 material. The size and absorbent capacity of the absorbent core  16  may be varied to be suited for different uses such as for infants or for incontinent adults. The absorbent core  37  may comprise one or more layers which are designed to improve the handling of bodily waste. Such layers are designed to receive a large amount of liquid in a short space of time and distribute it evenly across the absorbent structure  30 . They may include so-called transfer, distribution, surge or acquisition layers, and are usually located between the topsheet  38  and the absorbent core  37 . 
         [0038]    The topsheet  38  and backsheet  39  generally have a similar extension in the plane of the article, while the absorbent core  37  has an extension which is somewhat smaller. The topsheet  38  and backsheet  39  are joined to one another around the periphery of the absorbent core  37 , so that the core  37  is enclosed within the envelope formed by the topsheet  38  and the backsheet  39 . The absorbent core  37  is at least located in the crotch portion of the absorbent article  10 , and may also extend somewhat into the front and rear portions. The topsheet  38 , backsheet  39  and other components of the absorbent article  10  may be joined to one another by any means common in the art, e.g. ultrasonic welding, thermal welding or gluing. 
         [0039]    In addition, the absorbent structure  30  may comprise one or more elastic elements  70 . These help the article  10  fit tightly against the body of the wearer, and are usually present as leg or waist elastic elements (shown as leg elastic elements  70  in  FIG. 1 ). 
         [0040]    The first longitudinal end region  31  of said absorbent structure  30  is attached to the belt  20 . Attachment of the absorbent structure  30  to the belt  20  may occur substantially in the middle of the belt, as shown in  FIG. 1 , or towards one end of the belt  20 . The attachment may be permanent—i.e. it is not possible to separate the first longitudinal end region  31  of the belt  20  without tearing or otherwise damaging the article  10 . Alternatively, the first longitudinal end region  31  of the absorbent structure  30  may be removably attached to the belt  20  via at least one article fastening means  40 ′ located at the first longitudinal end region  31  of the absorbent structure  30 , said article fastening means  40 ′ having the shape and alignment of the article fastening means  40  as described herein. 
         [0041]    The absorbent structure  30  comprises at least one (e.g. two) article fastening means  40  at the second longitudinal end region  32  thereof. Preferably, the absorbent structure comprises two article fastening means  40  at the second longitudinal end region  32 , each of which is located towards the transverse edge thereof. The article fastening means  40  is adapted to fasten to the article reception surface  24  on the belt  20  such that the absorbent article  10  adopts a pant-like shape in use ( FIG. 2 ). As such, it may comprise a hook portion of a hook-and-loop type fastener (e.g. Velcro®), or an adhesive tab. 
         [0042]    The present invention is based on the discovery that the form and alignment of the article fastening means  40  are significant for obtaining a secure fit and for minimizing the risk of the fastening means being undesirably uncovered or turned up. As mentioned above, the primary forces in the waist and hip region of belted absorbent articles when being worn are directed from the hip region of the belt inwards and downwards towards the crotch of the wearer (see arrow X in  FIG. 2 ). The angle α made between the longitudinal centre line of the article and the force arrow X typically lies between 5° and 85°, preferably between 10° and 80°, more preferably between 15° and 45°. 
         [0043]    The article fastening means  40  of the invention has a shape such that it is accommodated within an imaginary rectangle  50 . The imaginary rectangle comprises a rectangular area located towards the transverse edge of the second longitudinal end region  32 ; i.e. in that region where the article fastening means  40  is located. The article fastening means  40  is totally enclosed within the imaginary rectangle. The maximum extension of the article fastening means  40  in the transverse and longitudinal directions corresponds to the maximum extension of the imaginary rectangle  50  in the transverse and longitudinal directions. 
         [0044]    As shown in  FIG. 3 , the rectangle  50  has opposed upper and lower first edges  51 ,  52  extending parallel to said transversely extending end edge  34  of the second longitudinal end region  32 . It also has opposed distal and proximal second edges  53 ,  54  extending parallel to said pair of opposed longitudinal edges  35 ,  36  of said second longitudinal end region  32 . A rectangle  50  is thereby defined which has an upper distal corner  55 , an upper proximal corner  56 , a lower distal corner  57  and a lower proximal corner  58 , the edges of which are aligned with the longitudinal/transverse directions. 
         [0045]    As used herein, the terms “upper” and “lower” are used to refer to a component or an element (such as the edge of the rectangle  50 ) which lies further away from (=upper) or closer to (=lower) the transversely-extending centre line T 1  of the absorbent structure  30 , relative to another component or element. 
         [0046]    Similarly, the term “distal” and “proximal” are used to refer to a component or element which is further from (=distal) or closer to (=proximal) the longitudinal centre line than another component or element. 
         [0047]    The article fastening means  40  contacting said imaginary rectangle  50  at least two places. The article fastening means  40  may contact the imaginary rectangle  50  at two places if the article fastening means has a parallelogram or rhombus shape in the L-T plane. The article fastening means  40  may contact said imaginary rectangle  50  at three places if it has a triangle shape in the L-T plane. The article fastening means  40  may contact said imaginary rectangle  50  at four places if it has a square or rectangular shape in the L-T plane. 
         [0048]    A continuous region  60  is located adjacent the lower distal corner  57  of the imaginary rectangle  50 . The continuous region  60  is defined by a portion of the distal second edge  53  and a portion of the lower first edge  52  of the imaginary rectangle  50 , and the edge of the article fastening means  40  which lies closest to the lower distal corner  57 . By “a portion of” a given edge is meant that the continuous region  60  is not defined by the entire length of said edge. At least this continuous region  60  is free of article fastening means  40 . 
         [0049]    The article fastening means  40  of the invention maximises the extension of the article fastening means  40  which lies along the force line (X), while minimising the extension of the article fastening means  40  in the region outside this line, particularly in the lower distal corner  57  of the imaginary rectangle. In addition, the article fastening means  40  of the invention avoids the presence of sharp (acute) angles in the region outside the force line (X). These features reduce the tendency for the article fastening means  40  to turn up or become uncovered in use. 
         [0050]    Preferably, one place at which the article fastening means  40  contacts the imaginary rectangle  50  is located on the lower first edge  52 . In this way, good alignment of the article fastening means  40  with the force arrow X can be obtained. 
         [0051]    An imaginary straight line drawn along at least one edge of the article fastening means  40  towards the first longitudinal end  31  of the absorbent structure  30  preferably meets the longitudinal centre line L 1  of the absorbent structure at an acute angle α which lies between 5° and 85°, preferably between 10° and 80°, more preferably between 15° and 45° (see  FIGS. 4   a ,  4   b ). 
         [0052]    Alternatively, an imaginary straight line drawn as a continuation of a diagonal of the article fastening means  40  towards the first longitudinal end  31  of the absorbent structure  30  preferably meets the longitudinal centre line L 1  of the absorbent structure at an acute angle α which lies between 5° and 85°, preferably between 10° and 80°, more preferably between 15° and 45° (see e.g.  FIG. 4   c ). 
         [0053]    The article fastening means  40  of the invention may have a rectangular shape ( FIG. 4   a ), a square shape ( FIG. 4   b ), a parallelogram shape, a rhombus shape or a triangular shape ( FIG. 4   d ) in the L-T plane. Of these, rectangular, square, parallelogram and rhombus shapes are most preferred, as they can be easily produced from a strip of fastening means with little or no wasted material.  FIG. 4   e  shows an article fastening means  40  which is based on a square, in which the material in the lower distal corner  57  is absent. Suitably, the article fastening means  40  is not circular or ellipse-shaped. 
         [0054]    Suitably, the maximum extension of the article fastening means  40  in a direction perpendicular to a force line (X) which passes through the centre of the article fastening means  40  and which makes an angle with the longitudinal centre line (L 1 ) of the absorbent structure  30  of between 5° and 85°, preferably between 10° and 80°, more preferably between 15° and 45°, is less than 3 cm, preferably less than 2 cm, more preferably less than 1 cm. 
         [0055]      FIG. 5  is an illustration of an absorbent article  10  according to the invention in the fastened configuration, magnified in the region around the absorbent structure where it fastens to the belt. The article fastening means  40  in this case has a parallelogram shape. As can be seen in  FIG. 5 , the entire article fastening means  40  lies flat against the belt, without being undesirably turned up or exposed. 
         [0056]      FIG. 6  is an illustration of a prior art absorbent article in the fastened configuration, magnified in the region around the absorbent structure where it fastens to the belt. The article fastening means is a simple rectangle, the edges of which are parallel to the edges of the absorbent structure. It is evident how the force line in the absorbent structure causes the article fastening means to turn up at its lower right-hand edge, thus exposing the article fastening means  40 . 
         [0057]    The invention has been described with reference to a number of embodiments and accompanying Figures. However, the full scope of the invention is determined by the appended claims.