DISPOSABLE LIQUID-ABSORBENT ARTICLE

Abstract: The present invention relates to an absorbent article such as a diaper (10) or the like, which has a markedly bowl-shaped absorbent body (12). This shape is achieved by elastic (23) which by means of its location and fastening achieves shear forces which form the absorbent body (12) to the desired shape. Further, the absorbent body may be provided with recesses and/or compression lines which facilitate the formation of the desired shape and the guidance and improved transportation of liquid.

Description: TITLE: Disposable liquid-absorbent article. BACKGROUND: The present invention relates to an absorbent article intended for disposable use according to the preamble of claim 1. TECHNICAL BACKGROUND: Liquid-absorbent articles, for example diapers, provided with elastic in order to impart to the article its shape when in use, are already known. For the majority of articles of this kind, the main purpose of the elastic is to create a raised sealed edge at the crotch portion, against the legs of the wearer. Hitherto known solutions, however, have a limiting capacity in terms of the ability to locally collect and enclose larger volumes of, for example, faeces and urine. A pair of training pants in which the leg elastic forms an encompassing cuff around the legs is known, for example, from US 3,860,003. When the article is in a spread-out condition, the elastic is completely rectilinear and extends principally to the side of the absorbent body, to let the edge of the diaper seal against the legs when in use. US 4,050,462 relates to a diaper with elastic extending rectilinearly in a flat condition of the diaper, the purpose of which is to contract the crotch area of the diaper and, by means of pleating, increase the area and the volume per length unit of the absorbent body in order to achieve an increased absorbent action. WO 88/00010 discloses a diaper with a principally rectilinear elastic, forming a V-shaped configuration. The elastic extends onto the absorbent body of the diaper and demarcates a region which is shaped through the contracting action of the elastic. By means of the extension of the elastic with rectilinear portions a pleating of the article as a whole is principally achieved due to the striving of the elastic to reduce the total length of the article. US 4,801,345 discloses a method for the manufacture of diapers. The method includes application of elastic along the crotch portion of the diaper. Thus, the elastic extends concavely outwards along the longitudinal edges of the diaper and completely to the side of the absorbent body. The purpose of the elastic is principally to achieve a sealed connection of the edge of the diaper against the legs of the wearer. A further effect is also a certain contraction and pleating of the absorbent body across the crotch portion. EP 0,219,326 discloses a diaper with elastic extending completely rectilinearly in a flat condition of the diaper and completely to the side of the absorbent body. Elastic is arranged at the outer edge of the diaper on both sides of the crotch portion and also in a trimming on both sides of the absorbent body. In addition to maintaining an erect, sealing edge by means of the trimming, the elastic ensures a certain pleating and contraction of the absorbent body. GB 2,234,157 relates to a pair of training pants with elastic extending around the cuff of the pants, along the edge of the crotch portion against the legs of the wearer and transversely across the crotch portion. The elastic for connection around the legs reduces the risk of leakage, while the elastic transverse to the crotch portion is merely arranged in order to enable a rational application of continuous elastic threads. The construction and the method is especially adapted to diapers in the form of pants. An absorbent article according to the preamble of claim 1 is further disclosed in the Swedish Patent Application No. 9401680-5. SUMMARY OF THE INVENTION: The object of the present invention is to provide a disposable liquid-absorbent article, which when in use is imparted the highly efficient collecting shape evident from Swedish Patent Application No. 9401680-5 and where the article is designed in such a way that the formation of the desired basin shape is facilitated. According to the invention this has been achieved in the way shown by the subsequent claims. DESCRIPTION OF THE DRAWINGS: Fig. 1 shows a plan view of an article according to the invention in Swedish Patent Application No. 9401680-5 Fig. 2 shows a perspective view of the diaper according to Fig. 1, essentially shaped into position for use Fig. 3 shows a perspective view of the article according to Swedish Patent Application No. 9401680-5 in a second embodiment, shaped into position for use Fig. 4 shows a longitudinal section through the diaper in a flat, stretched condition, along the line IV-IV in Fig. 7. Fig. 5 shows a corresponding longitudinal section through the diaper, shaped into position for use, along the line V-V in Fig. 7. Fig. 6 shows a cross section through the diaper, shaped into position for use, along the line VI-VI in Fig. 2. Figs.7-9 schematically show further embodiments of the diaper according to Swedish Patent Application No.9401680-5. Fig. 10 shows a plan view of an article according to a first embodiment of the invention Fig. 11 shows a corresponding plan view of a second embodiment of the invention. DETAILED DESCRIPTION OF THE INVENTION: An article that is particularly representative of the invention has been chosen as an embodiment. It is an article for the collection of liquid and faeces, namely a diaper for so-called heavy incontinence, i.e. not babies but adults who suffer from severe incontinence due to disease. As is shown in the first embodiment, see primarily Figs. 1, 2 and 4, the diaper is constituted by a cover 11, enclosing a core in the shape of an absorbent body 12. In a flat, out-stretched condition, which is shown in Fig. 4 the core exhibits a relatively flat main form with two main surfaces facing away from each other, namely an inner side 13 intended to be faced towards against the user, and an outer side 14, intended to be faced outwards from the user. Further,the absorbent body 12 exhibits an encompassing, rounded edge portion 15, which gives the absorbent body 12 an appropriate outline, anatomically adapted to the body of the wearer. Even if the absorbent body 12 essentially has an even thickness said absorbent body in practice is preferably provided with a central portion 16 of a somewhat greater thickness (not shown) . In the shown example the cover 11 is formed of two layers 17, 18, with mutually different properties, which are located against the inner side 13 and outer side 14, respectively, of the absorbent body 12 and close the absorbent body since the two layers are interconnected outside the edge portion 15 of the absorbent body and form an encompassing flange-like edge portion 19 for the diaper as a whole. In the edge portion 19 the two layers 17, 18 are placed in close contact to each other and are interconnected. The specific components used for forming the shown diaper may be any components commonly used for such purposes. The layer 17 which is affixed on the inner side 13 may be any soft, flexible, liquid-permeable material, such as nonwoven or a soft perforated plastic film of polyethylene or the like. The layer 18 on the outer side 14 is of a liquid- impermeable material, such as thin (e.g. 20 μ) plastic film of polyethylene, polyvinylchloride or the like. The absorbent body 12 may consist of cellulose fibres, air-laid tissue, various types of superabsorbent materials etc. As is most clearly evident from Fig. 1 the diaper in the shown example has a main form of an asymmetrical hourglass or a peanut shell with a waist or a crotch portion 20, which expands in one direction towards a rear portion 21 and in the opposite direction towards a front portion 22, which portions are intended to connect with the corresponding portions of the wearer when in use. The absorbent body 12 tapers to a greater extent than the outlines of the diaper 10 in the crotch portion 20, which gives a larger width of the edge portion 19 of the diaper 10 on a level with the crotch portion 20. In order to impart to the diaper its appropriate shape when in use, the diaper 10 is provided with a contracting elastic 23, which is arranged with a configuration and location specific for the invention. An appropriate shape is such a shape that the diaper, when in use, may accommodate large amounts of liquid and solid excreta from the body, partly by means of absorption and partly by retaining the products by means of its shape, be they urine, blood or other body fluids or faeces. For this purpose, the elastic 23 is at least partially arranged with arcuately curved portions 24, 25 extending across the absorbent body 12. In the shown example two continuously arcuately curved elastic portions 24, are arranged 25, which via edge elastic (see below) principally meet at their ends at two intersections 26, 27 in the proximity of the longitudinal edge portions 28, 29 of the diaper. The elastic 23 is connected to at least one of the layers 17, 18 in the cover 11 and in the first embodiment is connected to the liquid-permeable layer 17. In the shown example the elastic is arranged on the inner side of the layer 17, i.e. between the absorbent body 12 and the layer, but may of course alternatively be applied on the outer side of the layer. The elastic consists of elongate elastic members having for example a thread- or bandshaped elastic core of a highly elastic material, for example rubber, and a wound thread cover which may be connected by an adhesive and enable anchoring of the elastic core in the layer 17 of the diaper, at the same time as the elastic core permits elastic movement. The elastic strives to contract and for this purpose the elastic threads or bands are pre-stressed, i.e. stretched to a certain degree before anchoring occurs in the layer 17 of the diaper. The anchoring is performed by means of an adhesive 30 which is applied in certain parts of the extension of the elastic or in its full extension. In the shown example each of the arcuately curved portions 24, 25 is arranged with double elastic, i.e. with two adjacently extending elastic members 30, 31, 32, 33, of which one elastic member 33 in one of the curved portions 25 turns into edge elastic 34, 35, i.e. extends along a portion of both longitudinal edges 28, 29 of the diaper to the intersection point 26, 27 with the elastic members 30, 31 in the opposite curved portion 24, In the shown example the edge elastic 34, 35 extends essentially rectilinearly but may also have an arcuate, but weak curvature, i.e. with a large radius of curvature. The diaper is shown in Fig. 1 essentially in a plan view, i.e. out-stretched, but in such a condition that the contracting action of the elastic is visible. Fig. 2 shows the diaper shaped to a condition for use. This shape is formed as soon as handling of the diaper commences, which effect is described more closely below. As long as the diaper is flat essentially no shaping occurs except that the absorbent body is somewhat compressed. The desired shape may also be forcibly initiated during bending of the diaper, by pressing down with the hand the region 38 located inside the elastic, before the diaper is applied into position for use. Due to the striving of the curved elastic to contract and its anchoring in one of the layers 17 of the cover together with the connection of the layer to the absorbent core, the elastic in cooperation with the deformation properties of the cover and the absorbent body 12, creates essentially perpendicular basin walls 39' in relation to the flat interior of the article. The cover portions outside side edges of the absorbent body in the crotch portion of the article form the basin walls 39'' which together with the basin walls 39' enclose a basin- like space. Fig.3 shows a view corresponding to Fig.2 of another embodiment of the diaper, where the elastic, here denoted 23', has the same configuration as in the first embodiment, but is connected to the outer layer 18 of the cover, i.e. the liquid-impermeable layer. Also in this case the elastic threads or bands may preferably be applied by adhesive on the inner side of the layer 18. This in turn must be connected by its inner side to the absorbent body. The corresponding appropriate basin is principally achieved also in this embodiment. Here it is of particular importance that the forces acting by means of the arcuate portions of the elastic on the diaper obtain additional assistance from external forces, before these elastic portions give the required deformation of the diaper for the formation of the vertical basin walls. In both embodiments, , the wider portion of the edge portion 19, located directly opposite the crotch portion is raised due to the striving of the elastic to contract, i.e. to reduce its length. When in position for use the raised longitudinal edges 36, 37 seek to bear on the body of the wearer, in practice the inside of the thighs, thereby forming an extremely liquid-sealed connection against the body. Especially in the first embodiment shown in Fig. 2, pronounced, essentially vertical basin walls arise inside the curved elastic portions. Furthermore a certain pleating also arises laterally by means of the contraction of the layer by the elastic. The arcuate basin walls may, as mentioned above, be essentially perpendicular in relation to a line along the basically flat bottom of the basin. The arcuate basin walls may, through choice of the pre-stressing of the elastic and the deformability of the absorbent body, form an acute or obtuse angle to the said line along the basin bottom. When the angle is acute a pocket-like space is obtained closest to the elastic. The encompassing elastic 23 thus forms an upper edge of the basin 39 serving as an accommodation space for excreted body products, which is especially valuable for more severe cases of incontinence where the volumes may become fairly large. Faeces may be received in this space without risk that they pass outside the collection region of the diaper. The absorbent body 12, especially the part which is located within the elastic 23, has the task of absorbing liquid, while the task of the basin walls is also to prevent leakage of liquid from the diaper, before the absorbent body 12 has been able to completely absorb the total liquid volume. The raised edge portions 19 also retain liquid which is not immediately absorbed by the absorbent body 12 because of the position of the diaper, for example when the wearer is lying sideways. As soon as the wearer changes body position the liquid may be absorbed by the absorbent body. The longitudinal section in Figs. 4 and 5 and the transverse section in Fig. 6 illustrate the shaping influence of the elastic, which will be explained more closely. The shaping influence of the elastic arises since the elastic is contracting and thus is striving to reduce its length. By means of the anchoring of the elastic to the cover, the cover is brought together with the contractive movement of the elastic. The cover layers are connected in their turn to the absorbent body by their surfaces, whereby tensile forces in the plane of the cover layers are transferred to the absorbent body. Since the elastic in the main part of its extension across the absorbent body has been applied in a curved shape, the contracting action leads to the elastic in each point along the curved portion applying a force component 40, 41, see Figs. 1 and 4, which is directed towards the relevant centre of curvature for each specific point. If the curved portions have different radii of curvature, separate centres of curvature exist for each specific point. The absorbent body 12 of the diaper exhibits a certain resistance to compression, which is illustrated in Fig. 4 by reactive force components 42, 43, which thus counteract the contractive forces 40, 41 of the elastic. In a preferred embodiment the resistance to compression is greater than the resistance to deformation transversely to the plane of symmetry 44 of the disc-shaped absorbent body, i.e. transversely to the force direction 42, 43 in the plane of the paper. The absorbent body 12 suitably consists of so-called cellulose fluff pulp and ,together with the cover 11, is relatively pliable, but exhibits a certain resistance to compression. These properties, i.e. that the torsional moments caused by the force pairs 41, 43 and 40, 42, respectively, bring about a deformation of the article in regions with arcuate elastic (which deformation is symbolized by the arc lines 48, 49, 50, 51 which schematically represent the local direction of curvature). By means of the location of the elastic outside the plane of symmetry 44, a bending moment on the absorbent body 12 arises already in a flat condition. The article, however, has such a degree of stiffness that it is not deformed in a flat condition; instead, this deformation is not initiated until the article is handled. Fig. 5 illustrates the basin formed by the elastic, which is limited by the, in relation to the plane of the article, essentially perpendicular basin walls 39' along the arcuate elastic and also the basin walls 39' ' formed by portions of the cover extending outside the absorbent body. These portions are raised by the action of the edge elastic 34, 35 in combination with the arcuate elastic. The cross section according to Fig. 6 shows that the basin is comparatively deep and therefore is able to retain large amounts of excreta. In the embodiments shown in Figs. 1-6 the elastic as a whole forms a closed loop in each ready-made diaper. Fig. 7 schematically shows an embodiment of the diaper where the elastic extends transversely across the crotch portion 20 with a curved elastic portion 60 forming the demarcating transverse wall 61. In this case a demarcation is achieved between the rear portion 21 and the front portion 22 of the diaper, whereby faeces and urine are separated and a larger volume is provided for the collection space for faeces in proportion to the collection space for urine. Fig. 8 shows a further option, where the rear portion 21 and the front portion 22, each have one basin-like space 66,67 with transverse basin edges 68-71 inside each curved portion, which space is formed by two curved elastic portions 62, 63, 64, 65. Fig. 9 shows an alternative design, in which the main form of the diaper in a flat condition may be essentially rectangular. An hourglass-shape with a tapering crotch portion 20 is obtained by means of the contracting action of the elastic. Also in this case, transverse basin edges 72, 73 are formed, providing an effective barrier against edge leakage. The type of elastic shown in Figs. 1-9 is that which is already disclosed in Swedish Patent Application 9401680-5, the contents of which are hereby incorporated by reference. 12 Fig. 10 shows a first embodiment of the invention, in which the diaper is provided with groove-shaped recesses 74 which facilitate the formation of the desired shape. Said recesses both facilitate the deformation work for the contracting elastic, and initiate the deformation on desired sites, thereby forming said basin edges. Said recesses may preferably be formed in the absorbent body during its manufacture, before it is enclosed between the layers 17, 18, or be formed by means of powerful compression at a later stage. In the preferred embodiment said recesses 74 are preferably arranged as longitudinal grooves in the absorbent body 12, preferably placed parallel to the edge portions 15. Fig. 11 illustrates another embodiment of the present invention wherein the absorbent body has been provided with compression lines 75, forming a continuous pattern, preferably designed as deformed circles, ovals etc. Said compression pattern, which is arranged inside the basin mentioned above, i.e. within a region limited by the elastic 23 and the edge portions 15, has the purpose of, on one hand, directing the liquid flow in desired directions and, on the other hand, improving the transportation ability in said directions. On the whole, both a better utilization of the absorbent body and a faster liquid uptake of the product are thus achieved. A further effect of said compression lines is a facilitated forming of the absorbent body, since control of the deformation properties is enabled via these lines, whereby the desired bowl-shape is obtained. The invention is by no means limited to the above mentioned embodiments but is of course applicable for other embodiments within the scope of the basic idea of the invention. The closed loop of elastic may, for example, be replaced by detached curved elastic portions. These may, for example, be arranged with another extension, for example transversely across the crotch region 20 so as to separate faeces and urine from each other. Other articles than diapers for heavy incontinence may be of current interest, such as baby diapers, sanitary napkins or the like. The term "essentially continuously curved portion" primarily refers to an arcuate or arcuately curved portion, but also includes a combination of a plurality of rectilinear portions, preferably at least three rectilinear portions as a substitute for a semi-circular arc or the like. Further, said compression lines may be replaced by other types of lines where an increased density in the absorbent material is obtained, for example by means of heat, ultrasound, laser etc.

Claims: CLAIMS : 1. Disposable liquid-absorbent article, such as a diaper (10), sanitary napkin or the like with an essentially elongate shape and comprising an absorbent body (12) with an inside (13) facing inwards towards the body of the wearer, and an outside (14) facing outwards and a cover (11) enclosing the absorbent body with a liquid-permeable inner layer (17) against the inside of the absorbent body and an outer layer (18) against the outside of the absorbent body and contracting elastic members (23) in connection with at least one of the layers in order to impart to the article its shape when in use, whereby at least the cover layer on which the elastic members are applied is connected to the inside and the outside of the absorbent body, respectively, and that said elastic members (23) extend with at least one essentially continuously curved portion (24, 25) across at least one region of the absorbent body (11) and that said elastic member, by means of its striving to contract and by means of its connection to any one of said layers (17, 18), exerts a tensile force on said layer in a direction towards the centre of curvature of the elastic member, whereby said force is transferred to and absorbed by the absorbent body, whereby the absorbent body is formed of a material which makes it pliable but at the same time at least highly resistant to compression when tensile forces towards the centre of curvature of the curved elastic portion occur, and that the elastic members are applied with such a pre-stressing that when bending of the article is initiated by the user, said tensile forces caused by the pre-stressing and the radius of curvature, deform the article to form, in relation to the plane of the article, a transverse basin wall along the curved elastic portions, characterized in that at least one recess (74), preferably in the shape of longitudinal grooves, and/or compression lines (75) arranged in the absorbent body (12) within a region limited by the elastic (23) and the edge portions (15), thereby constituting both folding guides and liquid transporting members. 2. An article according to claim 1, characterized in that said recess (74) and/or compression lines (75) are arranged at the site, or at those sites, where said deformation is desirable when forming the desired bowl-shaped design in the absorbent body (12). 3. An article according to claim 2, characterized in that said recess (74), preferably arranged as longitudinal grooves in the absorbent body (12), preferably placed essentially in parallel to the edge portions (15), is constituted by compressed grooves. 4. An article according to claim 3, characterized in that said compression lines (75) essentially have a layout similar to the outline of the absorbent body (12) for those compression lines closest to the outer edge of the absorbent body, while the compression lines which are closer to the centre of the absorbent body successively adopt a more circular layout. 5. An article according to claim 4, characterized in that said elastic member (23) extends with said curved portion (24, 25) from one side of the article to the other longitudinal edge portion (28, 29) 6. An article according to claim 5, characterized in that said elastic member (23) forms a closed circumference encompassing a closed basin-shaped space formed by the elastic. 7. An article according to claim 6, characterized in that said closed circumference is formed by two curved portions (24, 25) which turn into edge elastic (34, 35) extending along the longitudinal edge portions (28, 29) of the article at the crotch portion (20). 8. An article according to claim 7, characterized in that the absorbent body (12) is tapering at the crotch portion (20) and that the cover (11) at the crotch portion at said longitudinal edge portions (28, 29) forms a raised portion (19) which is raised when in use and is a part of said basin. 9. An article according to any of the preceding claims, characterized in that the absorbent body is formed of so-called cellulose fluff pulp, possibly with particles or fibres of a so-called superabsorbent material applied in said pulp. 10. An article according to any of claims 1 - 9, characterized in that the absorbent material is formed by synthetic fibres and superabsorbent material. 11. An article according to any of the preceding claims, characterized in that the absorbent material is formed of a foam. 12. An article according to any of the preceding claims, characterized in that the article has a front portion, a rear portion and a crotch portion, that curved elastic portions are applied for the formation of a first closed region, displaced towards the front portion and intended for the reception of urine and for the formation of a second closed region, displaced towards the rear portion and intended for reception of faeces (Fig. 9) 13. An article according to any of claims 1-10, characterized in that the article has a transversely curved elastic member for the formation of , in relation to the plane of the article, a raised barrier wall (Fig. 8).

Inventors: EITERJORD BAARD, EITERJORD, BAARD
Applicants: EITERJORD BAARD, MOELNLYCKE AB, EITERJORD, BAARD, SCA MOELNLYCKE AB
Application year: 1996
Main classification: A61F13
IPC codes: A61F5, A61F13