WO1998037845A1

WO1998037845A1 - Absorbent articles that include a liquid barrier comprised of a barrier element

Info

Publication number: WO1998037845A1
Application number: PCT/SE1998/000343
Authority: WO
Inventors: Anders Gustafsson; Peter Rönnberg; Eva Fransson
Original assignee: Sca Hygiene Products Ab
Priority date: 1997-02-26
Filing date: 1998-02-25
Publication date: 1998-09-03
Also published as: SE9700695D0; ZA981453B; SE507829C2; SE9700695L; CO5040049A1; AU6315998A

Abstract

An absorbent article (16), such as a diaper, incontinence guard or like article, which includes longitudinally and transversally extending edges, a bottom liquid-impermeable sheet, an absorbent sheet, and a top liquid-permeable sheet, whereby the article in one embodiment has at least one elongated liquid barrier (21, 22) on each side of the longitudinal centre line of the top liquid-permeable sheet, where the barrier includes a barrier web having a longitudinally extending free edge (23, 24) which is puckered by an elastic device, and an absorbent article which in another embodiment also includes an essentially liquid-impermeable sheet including an elongated aperture intended to fit around the anus and the urethra orifice of the wearer, wherein an elastically puckered sealing edge is provided around said aperture, wherein both embodiments, the free edge (23, 24) and the sealing edge respective include puckered edge-parts (A, A') and essentially smooth or non-puckered edge-parts (B) such that the liquid barrier (21, 22) and the sealing edge respective present a generally smooth contact surface to the wearer within the non-puckered edge-parts (B).

Description

ABSORBENT ARTICLES THAT INCLUDE A LIQUID BARRIER COMPRISED OF A BARRIER ELEMENT

BACKGROUND

The present invention relates to an absorbent article, such as a diaper, incontinence guard or like article, that includes a liquid barrier or a sealing edge.

An absorbent article includes, among other things, a bottom liquid-impermeable sheet, or backing sheet, an absorbent sheet disposed thereon, and a top, surface sheet which is intended to lie proximal to the wearer in use. When the absorbent article concerned is a diaper or an incontinence guard, the article will also include flexible side flaps that extend laterally beyond the absorbent body on both sides thereof and elastic devices that extend longitudinally along the free side-edges of the side-flaps at least within that part of the absorbent body which forms the crotch part of the article in use, said flaps and elastic devices enabling the absorbent article to be fitted to the wearer . These elastic devices function as leg elastic when the article is worn and are intended to seal around the wearer's thighs and also to shape the article. Thus, when the article is donned, the elastic devices will be stretched and hold the side flaps tightly against the wearer. The flexible side-flaps form tightening or sealing edges and have the additional function of preventing liquid, and possibly faeces, from leaking-out at the edges, in other words they form barriers.

As an added safeguard against the leakage of liquid from the side-edges of an article, a number of absorbent articles also include additional, inner liquid-barriers or cuffs fastened in the proximity of the longitudinal edges of the article concerned. The purpose of the liquid barrier is to prevent liquid from leaking out at the edges of the absorbent article, and possibly also to prevent the escape of solids, such as faeces. This second or additional liquid barrier is placed inwardly of the leg elastic, i.e. inwardly of the outer liquid barrier, and is comprised of an essentially liquid- impermeable material, for instance a nonwoven material. The liquid barrier comprises a web of material whose one longitudinally extending edge is attached to the absorbent article and the other, free-edge of which is intended to lie against the wearer's skin. The free edge is elastically puckered or gathered together with the aid of an elastic element, such as a rubber thread, that is folded-in in the edge of the web. When the leg elastic on the absorbent article is stretched and the article fastened on the wearer, the elastic element of the barriers will also be stretched, thereby raising the barriers up. The elastic element of the barriers will hold the barrier edges under tension against the wearer. Examples of diapers that include liquid barriers are found, for instance, in SE-T3-0 264 238 and GB-A-2 188 532.

EP-A1-0 534 488 describes sealing gaskets which are preformed to extend outward from the central part of an absorbent article, which is illustrated by a sanitary napkin in the description of the preferred embodiment. The gaskets may be formed by looping a strip of material, such as a non- woven material, so as to form a compliant cuff which bears against the user's body in a comfortable manner. In one embodiment the gaskets are attached directly to the edges of the absorbent article, one edge of the gasket strip is attached to the upper sheet of the absorbent article and the other edge to the lower sheet. The looping of the material form cavitities for imparting compliancy and stability to the gaskets and the looping may also enclose elastic elements that are placed in tension when applied to the article so as to impart an arcuate shape to the article.

In another embodiment the gasket material is an elastic material which is attached to the longitudinally edges of the sanitary napkin. The material is placed in tension when applied to the sanitary napkin. The purpose of doing so is to impart an arcuate shape to the article.

In another embodiment the curvature is obtained by applying elastic segments only to the end sections of the sanitary napkin. No elastic is applied to the middle section of the napkin. In this embodiment the napkin will get a substantially straight middle section and arcuate end sections.

The sanitary napkin is placed in a panty crotch during use and is pressed against the wearer by the force from the panty. Thus, the force applied from the sanitary napkin against the wearer is indirectly caused by pressure from the panty. The gasket embodiments including elastic elements do not cause the force against the body of the wearer. The purpose of the elastic elements, if they are used, are to impart an arcuate shape. This absorbent article differs from the diaper or incontinence guard according to the invention with a barrier element presenting an essentially smooth edge which is subjeted to the greatest strain by an abrupt discharge of liquid fluid. In the inventive article the barrier element will get stretched against the wearer during use and thereby creating a liquid barrier with a good sealing effect. It is the body of the user which makes the elastic device in the barrier to get tensioned.

In the case of diapers that include liquid barriers or cuffs, the barrier will be positioned so as to lie against the wearer's thighs and buttocks, such as to prevent leakage in these areas. Each urine discharge will deliver a certain volume of liquid to the article. Because of the delay that occurs before this urine is able to penetrate through the upper sheet and be absorbed in the absorbent layer, a certain amount of urine will "float" in the absorbent article, on top of the surface sheet. It is this volume of urine that the barrier is intended to contain at the edges of the absorbent article.

It has been found, however, that this barrier is not completely proof against leakage and that liquid is able to escape at the elastically puckered edge that lies against the wearer's skin. Because the barrier edge that lies against the wearer's skin is puckered, there form at the contact surface between the barrier and the wearer's skin small through-penetrating pores or passageways through which liquid is able to escape. If the barrier is extended, i.e. stretched, to a greater extent, the barrier will be puckered to a lesser degree. The barrier will, however, then be stretched hard against the wearer's thighs, which causes discomfort and reduces flexibility as the wearer moves.

The object of the present invention is to solve this problem.

SUMMARY OF THE INVENTION

The present invention relates to an absorbent article, such as a diaper, incontinence guard or like article, that includes a bottom liquid-impermeable sheet, an absorbent sheet, and an upper liquid-permeable sheet which is intended to lie proximal to the wearer in use, said sheets being delimited by two generally longitudinal and two generally transversal edges, and at least one elongated liquid barrier which is fastened to the bottom and/or the top sheet along the major part of the two longitudinally extending edges on each side of the longitudinal centre line of the top liquid-permeable sheet, wherewith the liquid barrier includes at least one elastic device and a barrier web of essentially liquid-impermeable and essentially inelastic material that has a longitudinally extending free edge which is intended to lie against the wearer in use and which is puckered or gathered together by said elastic device, wherein the inventive article is characterized in that the free edge of the barrier web includes puckered edge-parts and a substantially smooth or non- puckered edge-part such that the liquid barrier presents an essentially smooth contact surface against the wearer's skin within the non-puckered edge-part, which constitutes 20-85% of the length of said free edge and includes at least the centre part of the barrier.

The invention also relates to an absorbent article that includes an essentially liquid- impermeable sheet which is intended to lie proximal to the wearer in use and which is delimited by two generally longitudinal and two generally transversal edges and provided with elastic means functioning to shape the article to the wearer's body, wherewith said sheet includes an elongated aperture which is intended to fit around or register with the anus and the urethra orifice of the user, wherewith an elastically puckered sealing edge is provided in the essentially liquid-impermeable sheet around said aperture, wherewith an absorbent body is provided on that side of the essentially liquid-impermeable sheet that lies distal from the wearer, wherewith the absorbent body is enclosed between a liquid-permeable sheet on the side proximal to the wearer, and a liquid-impermeable sheet, and wherein the inventive article is characterized in that the sealing edge includes puckered edge-parts and substantially smooth or non-puckered edge-parts such that the sealing edge will present a substantially smooth contact surface against the wearer within the non-puckered edge-parts, which constitute 20-85% of the length of said sealing edge and include at least the centre part of said sealing edge as seen in its longitudinal direction.

The non-puckered edge-parts will preferably constitute about 40-65% of the full length of the sealing edge, for instance about 50%.

The present invention thus provides an article which includes a liquid barrier or sealing edge that will present an essentially smooth edge, in the absence of through- penetrating pores or passageways, within that part of the edge which is subjected to the greatest strain by an abrupt discharge of liquid or fluid, i.e. within the crotch part of a diaper or an incontinence guard. The substantially smooth edge may be formed by an edge which is slightly puckered by weak elastic that can be readily stretched when the article is donned.

In order for the barrier to shape to and seal tightly against a wearer and also to enable the barrier to be used by persons of mutually different sizes, it is necessary for the free barrier edge or sealing edge to lie against the wearer at a given pressure and also that the edge can be stretched. This is achieved in a conventional article, by fastening one or more elastic threads in said barrier edge or sealing edge so as to pucker said edge. In the case of the inventive barrier, the centre part of the free edge is not puckered therewith acchieving better abutment with the wearer within this barrier part. So that the smooth part of the barrier edge will shape to and be stretched firmly against the wearer, the outer parts of the barrier edge, or sealing edge, i.e. those parts that lie proximal to respective transverse edges of the article, are heavily puckered.

The inventive article may, alternatively, be constructed so that the free edge or sealing edge of the barrier web is divided into parts that are puckered heavily to different extents. In the centre part, the edge is lightly puckered with the aid of a weak elastic element and heavily puckered in the extremities of said edge with the aid of a stronger and more elastic element. When the article is donned by a user, the centre part of the barrier element with the weak elastic element will stretch and therewith form an essentially smooth or non-puckered edge-part.

When a barrier element according to the invention is used in an absorbent article such as a diaper or an incontinence guard, the body of the wearer directs the tensioning of the elastic device in the barrier element. Thus, the elastic is tensioned during use. This is necessary for the function of the barrier element in the absorbent article. The body of the wearer decides how much the elastic device will be tensioned. The elastic part will direct the barrier uppwards against the body and the body makes the barrier stretched during use. It is the tensioning from the body which makes the barrier sealing against the body. This differs from the sealing gasket described in EP-A1-0 534 488, wherein the elastic part of the gasket remain in the same tension irrespective of the size of the wearer. The elastic part does not raise the barrier, the main purpose for the elastic part in the gasket is to impart an arcuate form to the sanitary napkin. Besides, the elastic part is not necessary in the gasket. The force applied from the sanitary napkin against the wearer is indirectly caused by pressure from the panty, in which the sanitary napkin is placed. Also, the gasket will remain in the same tension irrespective of the size of the wearer.

DETAILED DESCRIPTION OF THE INVENTION The invention will now be described in more detail with reference to chosen exemplifying embodiments thereof and also with reference to the accompanying drawings, in which

Fig. 1 illustrates a diaper that has conventional liquid barriers;

Fig. la is an enlarged, schematic cross-sectional view of a conventionally constructed barrier, said view being taken of the part I in Fig. 1;

Fig. 2 is a principle illustration of the division of a barrier element into different edge-parts when the barrier element is used in an inventive absorbent article;

Fig. 3a shows an inventive absorbent article from above, said article being divided along a centre line and being shown in two different embodiments;

Fig. 3b is a cross-sectional view of the article shown in Fig. 3a, said view being taken on the line III-III;

Fig. 4a shows from above a further absorbent article constructed in accordance with the invention, said article being divided along a centre line and being shown in two different embodiments;

Fig. 4b is a cross-sectional view of the article shown in Fig. 4a, said view being taken on the line IV-IV;

Fig. 5a shows a further embodiment of an inventive absorbent article from above;

Fig. 5b is a cross-sectional view of the article shown in Fig. 5 a, said view being taken on the line V-V; Figs. 6-10 are photographs taken with a scanning electron microscope of a conventional liquid barrier from a diaper manufactured by Kimberly-Clark and designated Huggies, and show the standing gather in stretched abutment with a curved Plexiglas element; and

Fig. 11 is a photograph of one embodiment of a liquid-barrier comprised of an inventive barrier element, said photograph being taken with a scanning electron microscope with the liquid barrier lying against a Plexiglas element. The photographs reproduced in Figs. 6-11 were taken with a 5% inclination to the Plexiglas element.

Shown in Fig. 1 is a diaper 1 which includes longitudinal edges.6, 7, transverse edges 8, 9, a bottom liquid-impermeable sheet 27, an absorbent sheet 28, a top liquid-permeable sheet 29 intended to lie proximal to the wearer in use, leg elastic 4, 5, and conventional liquid barriers or cuffs 2, 3. The liquid barriers 2, 3 are placed in the proximity of the two longitudinally extending edges 6, 7 of the absorbent article 1.

Fig. la is a sectioned view of the barrier and shows the parts separated from one another for the sake of clarity. Each barrier 2, 3 includes a barrier element 10 comprised of an essentially inelastic and essentially liquid-impermeable layer of material and is fastened at one longitudinally extending edge 11 to the top liquid- permeable sheet 29 or to the bottom liquid-impermeable sheet 27, in the proximity of the longitudinally extending edges 6, 7 of the diaper. The other, free edge 12 of the barrier element is intended to lie against the wearer and is elastically puckered with the aid of one or more elastic threads 13 fastened in a stretched state in an inwardly folded part of the barrier web. This is illustrated in Fig. la, which is an enlarged cross-sectional view of the part I in Fig. 1 With the diaper in position on the wearer, the liquid barriers 2, 3 will lie against the wearer's thighs and buttocks and therewith prevent liquid leakage in these areas. The elastic, however, puckers to form in the contact surface between the barrier and the wearer's skin through- penetrating pores or passageways through which liquid can escape.

An absorbent article constructed in accordance with the invention, such as a diaper, incontinence guard or like article, includes generally the same elements as the article shown in Fig. 1. Fig. 2 shows the principle construction of a barrier element used in the inventive absorbent article. The barrier element is adapted to fit and seal against the wearer. The upper free edge 14 is intended to lie against the wearer when the article is used, and the bottom edge 15 is fastened to the top sheet 29 or to the bottom sheet 27 of the absorbent article. Only certain parts A, A' of the edge of the barrier element can be stretched by elastically puckering said parts. Such folds as those formed within the elastically puckered parts A, A' will not be formed within the non-stretchable part, marked B, which is not elastically puckered. The barrier element will present an essentially smooth edge in the contact surface between the liquid barrier and the user within this area, which is preferably the area, or region, that is subjected to the highest liquid pressure in the use of the article.

Figs. 3a, b and 4a, b illustrate four pairs of similar embodiments of an inventive article. The liquid barrier 21, 22 has a longitudinally extending free edge 23, 24 which is intended to lie against the wearer in use. The barrier includes elongated, essentially inelastic material whose free edge 23, 24 includes a non-stretchable, essentially smooth part B that constitutes at least 20% and at most 85% of the full length of the barrier and includes at least the centre part thereof. In Figs. 3a, b, the stretchable parts A, A' are puckered elastically with the aid of elastic bands 25, 26 that are fastened in a stretched state and therewith pucker the barrier element within these parts.

The liquid barrier 2, 3 presents an essentially smooth edge in the contact surface between the wearer and the non-stretchable part B of the free edge. In the stretchable parts A, A', the edge is puckered elastically with the aid of prestretched elastic devices 25, 26, 32, 33. The puckered parts A, A' of the barrier are placed in regions where there is less risk of leakage, e.g. in the front and the rear part of the absorbent article in the case of a diaper for instance, and will thus lie against the wearer's behind and stomach when the article is worn. The risk of leakage is high in the crotch part of the article and it is this region that forms the sealing region B.

Fig. 3b is a cross-sectional view of the article shown in Fig. 3a, taken on the line III- III in Fig. 3a. Fig. 3b also shows the bottom liquid-impermeable sheet 27, the absorbent sheet 28 and the top liquid-permeable sheet 29 of the article. The barrier elements 21, 22 are fastened at their bottom edges 30, 31 to the absorbent article 16. The cross-sectional view taken on line III-III lies within a puckered and stretchable region A, where the elastic bands 25, 26 is fastened to the inelastic material. In one embodiment, shown on the left, the elastic band 25 is fastened to the upper side of the inelastic material, whereas in the other embodiment, on the right, the elastic band 26 is fastened to the lower side of the inelastic material.

Figs. 4a and b show a further two embodiments of an inventive absorbent article. These embodiments differ from those shown in Figs. 3a and b insomuch that the elastic devices comprise elastic threads 32, 33 which are fastened in a stretched state in an inwardly folded part, or channel, of the inelastic material. In the embodiment shown on the left, the barrier element 21 is formed along the outer edge of the absorbent article and is fastened thereto right out to said edge. The embodiments of the absorbent articles shown in Figs. 3a and b and in Figs. 4a and b are constructed in the same manner in other respects.

In the case of another embodiment, further transverse liquid barriers are fastened in the proximity of the transverse edges 8, 9 of the absorbent article.

The sealing region need not be restricted to the crotch region of the article, even though this is a preferred embodiment. In the case of a night diaper for a person who sleeps solely on his/her stomach or back, for instance, should not include a puckered region in the vicinity of the stomach or back respectively. An abutment force against the skin is required within that region of the barrier in which the best sealing effect is required. This abutment force is generated with indirect elastic. The elastic is not found in the region B, which shall be tight above all else, but within the regions outside the region B, in the illustrated case the regions A and A'. The upper edge 14 of the barrier element is bent inwards so as to lie against the crotch. This results in a "surplus" of material at this edge of the barrier element. The purpose of the elastic at A and A' is to deal with this surplus material and to generate an abutment pressure within the sealing region, by gathering together, or puckering, the entire barrier. The barrier will be tensioned to different extents in use, depending on the size of the wearer and on the extent to which the stretchable parts are puckered elastically. The barrier web may conveniently be formed so that the material surplus will not be excessive. This differs from the elastic parts in the gaskets described in EP-A1-0 534 488, where the elastic part is to impart an arcuate form to the sanitary napkin.

Because the liquid barrier lies against the wearer's skin and has a smooth surface along certain parts thereof, i.e. those parts in which the barrier is not puckered elastically, the liquid barrier will have a better "sealing effect" at these parts in the contact surface between the wearer's skin and the liquid barrier. The "sealing effect" is thus best at those regions in which the barrier is not puckered elastically.

Figs. 6-11 are reproductions of photographs taken with a scanning electron microscope and enlarged 130 times. Figs. 6-10 show a conventionally puckered liquid barrier stretched to different extents against a curved Plexiglas surface. The through-penetrating pores formed by the folds are clearly visible in the photographs. Fig. 11 shows a corresponding picture taken of a smooth nonwoven material, such as that present within the part B of the barrier in the inventive article. No through- penetrating pores can be seen. The non-stretchable part comprises at least 20% and at most 85% of the full length of the barrier and includes at least the centre part of said barrier. The part B suitably comprises about 50% of the length of the barrier, e.g. 40-65%.

Figs. 5a and b show a further embodiment of an inventive absorbent article. In the case of this embodiment the barrier element 34 consists of a generally rectangular inelastic material which has two layers 39, 40 and which is fastened at its outer edges to the top sheet 29 of the absorbent article. Even though the inelastic material is shown to comprise two layers, it will be understood that the material is not restricted to this number of layers. The barrier element includes a slot or a hole 35 whose edge 38 forms the free edge of the barrier element 35 intended for abutment with the wearer. The elastic threads 36, 37 are fastened in the barrier element 34 in a stretched state, between the two material layers 39, 40. The elastic is fastened close to the end-parts of the slot, which form the free edge 38 of the barrier element 34, such that these parts will be puckered.

Nonwoven material, e.g. a multi-layer nonwoven material, is an example of the essentially inelastic material used. Such a material may be an SMS material, i.e. spunbond-melt-blown-spunbond. The elastic devices may have the form of elastic threads, ribbons or film.

An important advantage of the inventive absorbent article which includes a liquid barrier comprised of a barrier element is that leakages are prevented in the event of heavy liquid discharges and the same size of diaper can be used by persons of mutually different sizes.

It will be understood that the invention is not restricted to the described and illustrated embodiments thereof and that modifications are conceivable within the scope of the following Claims.

Claims

1. An absorbent article (1, 16), such as a diaper, incontinence guard or like article, which includes a bottom liquid-impermeable sheet (27), an absorbent sheet

(28), and a top liquid-permeable sheet (29) intended to lie proximal to the wearer in use, said sheets being delimited by two generally longitudinal edges (6, 7) and two generally transverse edges (8, 9), and at least one elongated liquid barrier (2, 3, 4, 5) on each side of the longitudinal centre line of the top liquid-permeable sheet, said at least one elongated liquid barrier being fastened to the bottom sheet (27) and/or the top sheet (29) along the major part of the two longitudinal edges (6, 7) and comprising at least one elastic device and a barrier web (10) of essentially liquid- impermeable and essentially inelastic material, said barrier web having a longitudinally extending free edge which is intended to lie against the wearer in use and which is puckered by the elastic device, characterized in that the free edge (23, 24, 38) of the barrier web includes puckered edge-parts (A, A') and an essentially smooth or non-puckered edge-part (B) such that the liquid barrier (2, 3) presents an essentially smooth contact surface against the wearer within the non-puckered edge- part (B), said non-puckered edge-part comprising 20-85%, preferably 40-65%, of the length of said edge and including at least the centre part of the barrier.

2. An absorbent article, such as a diaper, incontinence guard or like article, that includes an essentially liquid-impermeable sheet which lies proximal to the wearer in use and which is delimited by two generally longitudinal edges and two generally transverse edges and is provided with elastic to shape the article to the wearer's body, wherein the sheet includes an elongated aperture intended to fit around the anus and the urethra orifice of the wearer, wherein an elastically gathered sealing edge is provided in the essentially liquid-impermeable sheet around said hole, wherein an absorbent body is disposed on that side of the essentially liquid- impermeable sheet that lies distal from the wearer in use, wherein the absorbent body is enclosed between a liquid-permeable sheet on the side proximal to the wearer and a liquid-impermeable sheet, characterized in that the sealing edge includes puckered edge-parts (A, A') and essentially smooth or non-puckered edge- parts (B) such that the sealing edge presents a generally smooth contact surface to the wearer within the non-puckered edge-parts (B), said non-puckered edge-parts comprising 20-85%, preferably 40-65%, of the length of the sealing edge and including at least the centre part of the sealing edge as seen in its longitudinal direction.

3. An absorbent article according to Claim 1 or 2, characterized in that the free edge or the sealing edge is formed by edge-parts (A, A') that are heavily puckered with strong elastic, and edge-parts (B) that are puckered slightly by an elastic which is considerably weaker than the elastic in the puckered edge-parts. (A, A'), so that primarily the slightly puckered edge-parts will be stretched out when donning the article and thereby form the essentially smooth or non-puckered edge-parts (B).

4. An absorbent article according to any one of the preceding Claims, characterized in that the elastic devices (25, 26, 32, 33) are elastic threads, elastic ribbons or film.

5. An absorbent article according to any one of the preceding Claims, characterized in that the article also includes transverse liquid barriers fastened to the bottom sheet (27) and/or to the top sheet (29) along a part of the two transverse edges (8, 9) of the article.

6. An absorbent article according to any one of the preceding Claims, characterized in that the two liquid barriers are each formed on a respective side of said centre line by a generally rectangular, inelastic barrier element (34) whose outer edges are fastened to the top sheet (29) of the absorbent article (16) and includes an elongated slot or a hole (35) at the longitudinal centre line of said article, wherein the slot edge (38) form said free edge, and wherein elastic is provided at or in the vicinity of the end parts of said slot for puckering the barrier element within these parts.