A METHOD OF PRODUCING AN ABSORBENT ARTICLE, AND AN ARTICLE PRODUCED ACCORDING TO SAID METHOD

Abstract: A method of manufacturing an absorbent article such as a diaper or an incontinence protector comprising an absorbent body surrounded by a casing, as well as an article produced according to said method. The absorbent body included in the inventive article is built up of a bottom layer (1) consisting of at least one stratum and a top layer (2) composed of one stratum or several mutually spaced strata, said top layer (2) being intended to fit closely to the wearer's skin during use of the article and to serve as a spacer means between the wearer's skin and the bottom layer (1) while being designed to define at least laterally a basin-like space (7) around the so-called wetting point which space, due to the article being thicker and thus more rigid within the areas (9, 10) around the basin-like space than within the area below said space, is maintained and expanded when applying the article onto the wearer's body.

Description: A method of producing an absorbent article, and an article produced according to said method The present invention relates primarily to a method of producing an absorbent article such as a diaper or an in¬ continence protector, and secondarily to an article pro¬ duced according to said method. One demand on such a product is that it must be capable of absorbing discharged body fluid without leaking. In certain types of urinary incontinence, emptying of the urinary bladder takes place in a sudden, uncontrollable manner so that a large quantity of body fluid is dis¬ charged within a short period of time. For an adult, this quantity may amount to as much as 15-30 cl. of fluid flow¬ ing out at a time. An example of this type of urinary in- continence is the so-called pressure incontinence. Elderly women are those most frequently suffering from pressure incontinence, the symptoms being an urgent, uncontrollable feeling of pressure appearing quite unexpectedly and most often leading to the bladder being emptied before the suf- ferer has had the time to reach a lavatory. The absorbency of conventional diapers is not sufficient for rapidly taking up the large quantities of fluid common in pressure incontinence, and extreme leakages of urine resulting in wetted clothes are therefore a rule rather than an exception for individuals suffering from this type of incontinence. Great efforts have been made to accomplish diaper con¬ structions for the purpose of solving this problem, which have so far proved unsuccessful, however. One suggestion to a solution can be found, for example, in the European Patent Specification 124 365. An absorbent body designed in accordance with the above publication is said to be capable of absorbing and retain- ing during a short period of time a large quantity of dis¬ charged body fluid. Said absorbent body, which is intended for diapers, sanitary napkins and incontinence protectors, is substantially rectangular and has two receptacles for body fluids, accomplished by means of compression, said receptacles being in communication with a duct which is also formed by compression. Discharged body fluid is passed via the communication duct to the receptacles to be absorbed there by the absorbent body. However, due to the comparatively narrow dimension of the duct and the relatively limited receptacle areas, a diaper having such an absorbent body has to be positioned absolutely correctly in the user's crotch to fulfill its function and to actually collect discharged body fluid. When moving, the user will otherwise be exposed to the imminent risk of the diaper slipping somewhat out of alignment, so that body fluid comes outside the duct and flows over the edge of the diaper thereby wetting the user's clothes. According to said patent specification, the rectangular shape of this prior art absorbent body is justified by a desire to widen the communication duct between the re¬ ceptacles in that the diaper when used is compressed in the crotch region so as to assume a "boat shape" in order presumably to reduce diaper leakage. In fact, however, the known, soft and flexible diaper will instead crumple up into a clumsy package between the user's legs blocking in this way the communication duct so that no body fluid can be led off. As a result, the effi- ciency of this diaper will be just as good or bad as other conventional diapers without any duct system being com¬ pressed thereinto, since body fluid will start to flow out and onto the user's clothes as soon as the absorbent ma¬ terial disposed in the crotch region of the diaper has been saturated. Moreover, a diaper of the soft, flexible type described above will easily give rise to the forma¬ tion of cross-folds as the user moves, these folds then leading fluid sideways out of the diaper. There have been made other attempts as well to overcome the problem of taking up large amounts of fluid for ins¬ tance in cases of pressure incontinence. As an example, there is previously known a method of incorporating a li¬ quid-distributing layer in the absorbent body for trans- porting fluid away from the wetting point, making in this manner the greatest possible part of the absorbent body accessible for absorption. The efficiency of this type of liquid-transport is however insufficient for the large quantities of fluid frequently occurring and therefore, the problem of leakage still remains to a large extent. A similar liquid-distributing effect is obtained to a cer¬ tain degree if the absorbent body is compressed along lines extending in its longitudinal direction. There is further previously known a method of building up the absorbent body of two layers; one upper, porous layer primarily absorbing discharged body fluid, and one lower, more compact layer gradually sucking up fluid from the upper layer. In this manner there is gained a certain, but often insufficient receptacle effect in the upper layer. A still further conventional method of attempting to re¬ duce leakage is signified by a plastic film being folded around the absorbent body so as to cover its underside, the edge margins and a portion extending along each longi¬ tudinal edge of the absorbent body upper side. In this way, however, the liquid-permeable portion of the upper side of the absorbent body will be diminished thereby in¬ creasing the risk of leakage, especially if the diaper is slantingly displaced. Also, attempts have been made to produce a fluid-receiving duct by the application of elastic means across the area of the absorbent body intended to face the crotch region of the user. Such a duct may certainly have a positive effect but has unfortunately proved insufficient for those suffering from heavy incontinence involving the large amounts of fluid occurring in such cases. As appears from the aforesaid, a great deal of trouble has been laid down on attempts to solve the above-described problem of developing absorbent products in the form of diapers and incontinence protectors being capable of, without leaking and within a very short period of time, collecting and absorbing large volumes of liquid. Despite all these efforts, no satisfactory solution to the problem has been attained so far, since the resulting products have either given rise to more leakage than desirable, or they have led to a compromise between the demand on se¬ curity against leakage and the demands on comfort and dis- cretion which must always be placed on articles such as diapers and incontinence protectors. With the present invention however, the problem in ques¬ tion has now been overcome. Primarily, this achievement is the result of the absorbent body being built up of a bot¬ tom layer consisting of at least one stratum and a top layer composed of one stratum or several mutually spaced strata, said top layer being intended for placement next to the user's skin while simultaneously serving as a spacer means between the user's skin and the bottom layer, and being designed to at least laterally define a basin- -like space around the so-called wetting point. Because the article is thicker and thus more rigid in the areas around the basin-like space as compared to its smaller volume in the area below it, said space will be maintained and expanded when the article is applied to the body of the user. There are disclosed in the claims a number of different embodiments in connection both with the method according to the invention and with absorbent articles made accord¬ ing to the inventive method. With the absorbent body consisting of two layers of ab¬ sorbent material in combination with the specific design of the upper one of said layers which is intended to face the user's skin, there is achieved the advantage that a diaper performed in accordance with the invention will be forced during use to assume a predetermined configuration. When in use, this diaper will namely transform to a shape presenting a duct extending along its longitudinal center- line as well as a basin-like zone located at least at one end of said duct. Both the basin-like zone and the cent¬ rally extending duct will be surrounded by portions of the diaper upper layer as a result of this layer forming rid¬ ges alongside the edges of the absorbent body. These ridges, which constitute the diaper portions intended to face the user's skin, act like tight basin walls sealing around the so-called wetting point while also serving as spacer means for the absorbing bottom layer in the absorb¬ ent body. Thereby, only the slightest possible portion of the wet diaper will get in touch with the user's skin, avoiding in this manner any discomfort and skin irritation caused by moisture. With the absorbent body built up in this manner, a diaper performed in accordance with the invention will thus assume an optimal configuration with regard to capability of collecting and retaining large and unexpectedly discharged amounts of fluid. Discharged fluid is collected and initially retained in the basin-like zone and the longitudinally extending duct of the diaper, and is then absorbed by the material in the absorbent body. This utilization of the absorbent body in order to make absorbent articles such as diapers or incontinence pro¬ tectors capable of forcibly conforming during use to a specific shape promoting their intended purpose, is an inventive concept rendering the resulting articles prop¬ erties making them superior to hitherto known articles of similar types. By the excellent liquid-absorbing and leak- age-preventing properties incorporated in the absorbent body itself, this article will be most useful in cases of adult urinary incontinence. An important demand on diapers for adults suffering from urinary incontinence is the discrete use. Such diapers must also provide sufficient security for the user to feel safe without having to worry about leakage occurring at a sudden, unexpected discharge from the bladder. To meet the demand on security against leakage, the diapers used up to now have been made large in size and clumsy as they would otherwise be incapable of momentarily sucking up suf¬ ficient amounts of discharged body fluid. These voluminous and awkward diapers, difficult to hide in ordinary cloth¬ ing, could be experienced by the user as mentally disturb- ing, inhibiting a normal social life involving work and personal relations. An absorbent article performed according to the invention could however, in relation to the amounts of fluid it is momentarily capable of handling in normal cases, be made both small in size and discrete in shape without jeopard¬ izing security against leakage. An article performed in accordance with the invention could to advantage also be used for infant incontinence. Today's conventional diapers are most frequently a combin¬ ation of an absorbent body and a plastic backing, many times in the form of integrally made, so-called all-in-one diapers. To reduce the risk of leakage in diapers of this type, they have to be app-lied onto the baby in tightly sealing contact around the legs. This tight seal is gener¬ ally secured by the use of elastic means disposed in the crotch region along the edges of the backing portion of the diaper unit. Such elastic means often make the diaper unpleasant to wear due to chafing resulting in skin irri¬ tation. The plastic material will further seal tightly to the sensitive skin in the crotch region, which may add to the irritation. A further disadvantage associated with conventional diap¬ ers is the increased costs caused by the use of elastic means, which costs are particularly unfortunate with re¬ gard to disposable articles. With a diaper performed in accordance with the invention, however, the need of tightly sealing elastic means will be eliminated since the sealing function is already initially incorporated in the diaper construction in that the raised portions of the absorbent body facing the baby's skin con- stitute buffering ridges protecting against leakage. There is thus no need for any chafing and cost-increasing el¬ astic means in such a novel diaper. Another advantage is that the favorable configuration of the novel diaper will remain intact even though the diaper may slip somewhat out of alignment due to the baby's move¬ ments, whether this displacement occurs in the forward, backward or sideward direction. Conventional, flat diap¬ ers, on the other hand, are liable to fold together caus- ing thereby discharged urine to flow out to the side thereof. This is, inter alia, the reason why these diapers require specific sealing means around the thighs of the infant. The invention will be described in more detail below with reference to an exemplary embodiment shown in the ac¬ companying drawing, wherein Fig. 1 is a plan view of a diaper made according to the invention, illustrating the side thereof intended to face the user's skin; whereas Fig. 2 is a perspective view of said diaper in its state of use as seen obliquely from one side. The diaper shown in Figs. 1 and 2 comprises an absorbent body built up of a lower, flat layer 1 and a superimposed, substantially X-shaped upper layer 2. This absorbent body is accommodated in a casing consisting of a lower, liquid- -impermeable surface layer 3 and an upper, liquid-perme¬ able surface layer 4 intended to face the user's skin, said two layers being interconnected around the absorbent body beyond its edge 5. When applied for use onto the human body, the diaper will assume the configuration shown in Fig. 2. The X-shaped upper layer 2 of the absorbent body will then act as a shape-controlling means enforcing the formation of two basin-like zones 7, 8 and an inter¬ connecting duct 6 extending therebetween. In the embodi¬ ment shown, the diaper is made symmetrical with regard to a transverse centerline. When applying the diaper onto the user's body, the so-called wetting point, i.e. the spot on the diaper first reached by the user's urine, will be lo¬ cated right in the center of the basin situated at the front of the user. The duct 6 and the two basin-like zones 7, 8 are defined along the diaper long sides by ridges 9, 10 serving to prevent leakage and to keep the more soaked duct and basin portions 6 and 7, 8 spaced away from the user's skin. Discharged body fluid is collected in the duct 6 and the basin-like zones 7, 8 to be subsequently sucked into the absorbent material. Because fluid is allowed to pass bet¬ ween the basins 7, 8 via the duct 6, also the basin 8 lo- cated at the back of the user can be utilized for the ab¬ sorption of fluid. In this manner the entire absorbent mass of the diaper will be accessible for absorption. In prior art diapers however, only a small area around the wetting point is available, whereas large portions of the absorbent body remain unutilized. The diaper shown in Figs. 1 and 2 may be used either in combination with elastic baby pants, or together with or¬ dinary, not too wide underpants keeping the ridges 9, 10 of the diaper in close contact with the user's body. The two layers 1, 2 of the absorbent body may to advantage be composed of so-called cellulose fluff pulp and may then preferably be formed by airlaying and compression of the pulp in molds provided to serve this purpose. The layers can then be individually manufactured for subsequent in¬ terconnection. The liquid-permeable casing material 4 fac¬ ing the skin of the wearer during use is suitably connect¬ ed both to the upper layer 2 of the absorbent body and to freely exposed portions of the liquid-permeable casing material 3 at the underside of the diaper. If the bottom layer in the absorbent body is given a higher degree of compression than the top layer, a liquid- -expelling effect from the top to the bottom layer can be attained by the density gradient in a manner known per se. Alternatively, the two layers of the absorbent body can be made of different material. For example, a non-absorbent synthetic fiber wadding can be used for the top layer. Additional embodiments of articles performed in accordance with the invention are conceivable within the scope of the patent claims. For example, a diaper may be provided at its liquid-im¬ permeable backside with binder beads or a foam-plastic coating for preventing the diaper from being displaced during use in relation to the underpants situated closest thereto. Another example is the possibility of providing the in¬ ventive diaper with resilient means in the form of elastic ribbons or the like, as it would be possible to achieve an increased basin-producing effect by the application of such means along the short sides of the diaper, whereas similar means applied across the crotch region thereof would intensify the duct shape desired in this area. Naturally, the bottom layer of the absorbent body need not 4 6 12 be uniformly thick but may, in order to enhance the stab ility and absorbency of the article, be made somewha thicker in the crotch region, said thickness then to ad vantage gradually decreasing towards the ends. An article according to the invention needs of course no be hourglass-shaped but may have any other suitable con figuration such as T-shape, for example. The inventive article may also be provided with foldin lines in order to facilitate its shaping during use. Suc folding lines are suitably applied along the longitudina center duct and along the ridges defining the basin-lik zones in order for the- article to fold more easily durin use to achieve the formation of said longitudinal cente duct and said basin-like zones.

Claims: CLAIMS 1. A method of producing an absorbent article, such as a diaper or an incontinence protector comprising an absorb¬ ent body accommodated in a casing and having between its two ends a so-called crotch portion which is made narrower in relation to at least one of said absorbent body ends, characterized by building up the absorbent body of a bot¬ tom layer (1) consisting of at least one stratum and a top layer (2) composed of one stratum or several mutually spaced strata, said top layer (2) being intended to fit closely to the wearer's skin during use of the article and to serve as a spacer means between the wearer's skin and the bottom layer (1) while being designed to define at least laterally a basin-like space (7) around the so- -called wetting point which space, due to the article being thicker and thus more rigid within the areas (9, 10) around the basin-like space than within the area below said space, is maintained and expanded when applying the article onto the wearer's body. 2. A method according to Claim 1, characterized by con¬ necting the top layer (2) and the bottom layer (1) to the casing (3, 4) at the side facing the wearer's skin during use of the article. 3- A method according to Claim 1 or 2, characterized by compressing the bottom layer (1) more highly than the top layer (2). 4. A method according to Claim 1, characterized by manu¬ facturing initially the two layers (1, 2) included in the absorbent body and subsequently interconnecting said layers. " 5. A method according to any one of the preceding claims, characterized by manufacturing the two layers (1, 2) in¬ cluded in the absorbent body from different materials. 6. A method according to Claim 5, characterized by making the top layer (2) of synthetic fiber wadding and the bot¬ tom layer (1) of cellulose fluff pulp. 7. A method according to Claim 1, characterized by forming the absorbent body by airlaying and compression of so- -called cellulose fluff pulp, the top layer (2) being formed first and the bottom layer (1) thereafter. 8. An absorbent article such as as diaper or an incon- tinence protector manufactured according to the method of Claim 1 and comprising an absorbent body accommodated in a casing and having between its two ends a so-called crotch portion which is made narrower in relation to at least one of said absorbent body ends, characterized in that the absorbent body is built up of a bottom layer (1) consist¬ ing of at least one stratum and a top layer (2) composed of one stratum or several mutually spaced strata, * said top layer (2) being intended to fit closely to the wearer's skin during use of the article an to serve as a spacer means between the wearer's skin and the bottom layer (1) while being designed to define at least laterally a basin- -like space (7) around the so-called wetting point which space, due to the article being thicker and thus more rigid within the areas (9, 10) around the basin-like space 5 than within the area below said space, is maintained and expanded when applying the article onto the wearer's body. 9. An absorbent article according to Claim 8, character¬ ized in that the top layer (2) extends across the entire O width of the diaper crotch portion, the article thereby having a highly rigid crotch portion making it capable of resisting deformation during use; and that the top layer (2) at least in the direction towards the diaper front end, has two branches (9, 10) diverging from the crotch T5 portion and serving as borders defining the basin-like space (7). 10. An absorbent article according to Claim 9, character¬ ized by its symmetrical shape with regard to a transverse 20 centerline in the crotch portion. 11. An article according to any one of Claims 8 to 10, characterized by a liquid-impermeable outer layer (3) be¬ ing coated on its outside with a binder or with foamed 25 plastic in order for the article to be securely fixed to the underpants of the wearer.

Inventors: HERMANSSON JONAS, HERMANSSON, JONAS
Applicants: MOELNLYCKE AB
Application year: 1986
Main classification: A41B13
IPC codes: A61F5, A61F13