WO1992014429A1

WO1992014429A1 - An insulating layer which forms part of a liquid-collecting sanitary article

Info

Publication number: WO1992014429A1
Application number: PCT/SE1992/000098
Authority: WO
Inventors: Verner E. Andersen
Original assignee: Mölnlycke AB
Priority date: 1991-02-18
Filing date: 1992-02-17
Publication date: 1992-09-03
Also published as: SE467949B; SE9100477L; ZA92733B; AU1328092A; MX9200653A; SE9100477D0; TNSN92016A1

Abstract

The present invention relates to an insulating layer (2) which forms part of a liquid collecting disposable article (1), such as a diaper, an incontinence guard or the like. The insulating layer is positioned outwardly of a liquid collecting body (3) of the article on that side of the body which is intended to face the wearer's skin in use. In accordance with the invention, the insulating layer (2) is comprised of a thin sheet of liquid-impermeable material which includes at least one bellows-like pleat (a-g) at least within a restricted area of the layer, and is liquid-permeable within this area. The invention provides an insulating layer which is able to collect a large quantity of liquid instantaneously.

Description

An Insulating Layer Which Forms Part of a Liquid-Collecting Sanitary Article

The present invention relates to an insulating layer which forms part of a liquid-collecting sanitary arti¬ cle, such as a diaper, an incontinence guard or the like.

Articles of this kind often include an insulating layer between an absorbent body and the wearer's skin. The object of the insulating layer is to prevent rewetting, that is to prevent liquid that has been collected by the absorbent body from returning to the outer surface of the article, for instance as a result of the pressure exerted on the article when the wearer sits down. An insulating layer of this kind is known from SE-B-449 285. This known insulating layer is comprised of a perforated plastic layer or sheet in which the perforations are formed by the internal volume of cylin- ders which project from the underside of the plastic layer towards the absorbent body and which function to conduct liquid to the absorbent body by capillary action and, at the same time, act as spacers which keep the outer surface of the plastic layer spaced from the absorbent body. An insulating layer of this kind will conduct liquid in generally only one direction. U.S. 3,929,135 teaches a similar insulating layer in which the downwardly-projecting cylinders have conical walls.

The object of the present invention is to provide an insulating layer which when superposed on top of a liquid collecting body will conduct liquid in only one direction, similar to the aforesaid known insulating layers, and which has a high instantaneous liquid- collecting ability, i.e. is able to collect a large quantity of liquid discharged by the wearer of a liquid- collecting sanitary article very quickly.

This object is achieved, in accordance with the inven- tion, with an insulating layer of the aforesaid kind which is characterized in that it is comprised of a thin layer of liquid-impermeable material which includes at least one bellows-like pleat at least within a limited area of said layer and which is liquid-permeable in said area.

Since each of the pleats, or folds, forms a channel in which liquid can be collected instantaneously, an insu¬ lating layer constructed in accordance with the inven- tion will be capable of handling large quantities of liquid.

According to one advantageous embodiment of the inven¬ tion, in which the insulating layer includes a plurality of bellows-like pleats, the edges of each sequential pleat are mutually offset, and that part of each pleat which lies nearest the liquid collecting body is perme¬ able to liquid within that part which is covered by the outwardly lying part of the next following pleat. This results in a plurality of mutually offset liquid col¬ lecting channels which extend over a large area. Conse¬ quently, liquid which is discharged from the wearer will always be deposited close to a channel, irrespective of the location of the liquid discharge, therewith reducing the risk of liquid flowing along the surface of a sani¬ tary article which includes an inventive insulating layer.

According to one variant of this embodiment, the pleats, or folds, extend transversely to the longitudinal axis of the article and are disposed so that, in relation to the liquid collecting body, they lie outside one another in a direction from the forward part of the article towards the rearward part thereof. An insulating layer of this construction favours distribution of liquid in a transverse direction while, at the same time, the mutu¬ ally sequential pleats located longitudinally along the insulating layer will prevent liquid from running longi¬ tudinally along the side of the insulating layer remote from the liquid collecting body.

According to another variant of this embodiment, the pleats extend in the longitudinal direction of the article and, in relation to the liquid collecting body, lie outside one another in a direction from the centre of the article towards respective side edges thereof. This variant favours the distribution of liquid in the longitudinal direction of the article while, at the same time, the pleats will prevent liquid from running later¬ ally along the side of the insulating layer remote from the liquid collecting body. This variant of the inven¬ tion greatly reduces lateral leakage of liquid in the crotch part of the article.

According to a further variant of the main embodiment, the pleats provided in the forward and rearward parts of the article extend transversely, whereas the pleats provided in the crotch part of the article extend longi¬ tudinally. It will be seen that an insulating layer constructed in accordance with this variant will favour the distribution, or spread, of liquid transversely in the forward and rearward parts of the article, whereas the longitudinal distribution of liquid is favoured in the crotch part of the article while counteracting lateral leakage within this part of the article at the same time. An exemplifying embodiment of the invention will now be described with reference to the accompanying drawings, in which

Figure 1 illustrates -a bellows-like pleat or fold; Figure 2 illustrates from above an inventive insulating layer, with the side of the layer that faces the wearer in use being presented to the viewer; Figure 3 is a longitudinal section view taken on the line III-III in Figure 2; Figure 4 is a diaper similar to the diaper shown in

Figure 2 but provided with another variant of an inven¬ tive insulating layer; and

Figure 5 is a cross-sectional view taken on the line V-V in Figure 4.

Figure 1 illustrates what is meant by the term "bellows- like pleat" used in the present document. This term is meant to define a pleat form which is constructed around two mutually separate folding lines such as to obtain a Z-like con-figuration, therewith presenting two mutually opposing pleats A, B in the pleated state of the insu¬ lating layer.

Figures 2 and 3 illustrate a diaper 1 provided with an inventive insulating layer 2, wherein that side of the diaper which lies nearest to the wearer's skin is turned to face the viewer. The diaper includes an hourglass liquid collecting body 3 which is enclosed between two casing layers or sheets, i.e. the insulating layer 2 and an outer casing layer 4 of liquid-impermeable plastic material, these casing layers being joined together in those regions thereof which lie externally of the liquid collecting body 3.

The insulating layer 2 is manufactured from a liquid- impermeable plastic material which is made permeable to liquid by perforating the same. The insulating layer also includes a plurality of bellows-like pleats a-k, of which only the pleats a-g are shown in Figure 3. As will be seen from Figures 2 and 3, the folded edges a -

■A. k K and aB-kB of respective pleats a-k are mutually offset longitudinally on both sides of the insulating layer. In the case of the illustrated embodiment, the pleats are arranged in the forward, rearward and crotch parts of the diaper in a manner such that, when seen in a direction from the forward part of the diaper towards the rear part thereof, the pleat b lies outwardly of the pleat a, the pleat c lies outwardly of the pleat b, and so on, in relation to the liquid collecting body 3. As will be seen from Figure 3, the perforations in the insulating layer 2 are formed in those parts of each pleat which are covered by the next-following, out¬ wardly-lying pleat.

When liquid is discharged by the person wearing the aforedescribed diaper, the liquid will flow along the outside of the insulating layer until it reaches the edge of a pleat, for example the edge a . The liquid will then flow into the transverse channel formed be¬ tween the pleat a and the underlying part of the non- pleated part of the insulating layer 2 in the forward part of the diaper. The liquid will then run through the perforations in that part of this insulating layer part which is covered by the pleat a, and into the absorbent body, whereafter the liquid is quickly trans- ported from this channel into the absorbent body through the action of the capillary forces generated therein. That liquid which is unable to flow immediately through the perforations will be collected in the aforesaid channel and therewith distributed transversely. If the amount of liquid discharged is so great and is dis¬ charged so rapidly that the pleat a becomes filled with liquid, the liquid will then flow over the edge a and X into the channel defined between the pleats a and b, whereafter the same procedure is repeated for pleat b.

The channels formed between mutually sequential pleats thus function as a liquid storage container during the time taken for the absorbent body to collect the liquid. An inventive insulating layer is therefore able to collecting large quantities of liquid instantaneously discharged by the wearer, due to the combined storage volume provided by these channels. A desired storage volume can be actually obtained with one single pleat or fold. A plurality of pleats are preferred, however, as described with reference to the illustrated embodiment of the invention. In certain cases, the distribution or spread of liquid longitudinally is favoured prior to the liquid being absorbed by the liquid collecting body, in that several channels are utilized simultaneously, due to liquid remaining the longest time the bottoms of the channels. This enables better use to be made of the absorbency of the absorbent body. As before mentioned, the embodiment which includes a plurality of pleats will enhance the possibility of liquid being discharged in the proximity of a pleat, which enables the liquid to be taken-up quickly in a channel and to run along the outside of the insulating layer for only a short period of time. Furthermore, the edges of the pleats function as liquid barriers against the flow of liquid along the insulating layer in a direction from the forward part of the diaper towards the rear part thereof.

Since discharged liquid can be quickly taken-up in the channels of the insulating layer, that side of the insulating layer which faces the wearer will be felt to be dry by the wearer. Furthermore, liquid that has been collected by the absorbent body is unable to flow back to the outside of the article, because the perforations in each pleat are covered by an imperforate part of a following pleat.

Figures 4 and 5 illustrate a variant of the embodiment illustrated in Figures 2 and 3. In the case of this variant, the pleats a'-m' extend in the longitudinal direction of the article and, in relation to the liquid collecting body, lie outside one another in a direction from the centre of the diaper towards respective side edges thereof. In this variant, the pleats are held together by two welds 5 and 6. The longitudinally- extending pleats favour liquid distribution in the longitudinal direction of the diaper, and the edges of the pleats form liquid barriers against transverse liquid flow along the upper side of the insulating layer 2' . In other respects, the insulating layer 2' func¬ tions in the same manner as the insulating layer 2 of the embodiment illustrated in Figures 2 and 3.

Although not shown, the pleats of the inventive insula¬ ting layer may extend transversely in the forward and rearward parts of the diaper and longitudinally in its crotch part. This variant is particularly suitable in the case of diapers having a narrow crotch part, where the risk of lateral leakage is relatively high.

As will be understood, the inventive insulating layer may be used with other types of absorbent articles than the hourglass diapers illustrated in Figures 2-5. The insulating layer may also be arranged inwardly of a conventional liquid-permeable casing layer of non-woven fibre or the like for instance, and a liquid distribut- ing or spreading layer may arranged between the insu¬ lating layer and the absorbent body. The insulating layer may also be comprised of a liquid-permeable mate¬ rial, such as a non-woven fabric, which has been made hydrophobic. Neither need the material in the insulat¬ ing layer be completely impermeable to liquid. The important criterion is that the liquid permeability of the insulating layer is sufficiently small to prevent the occurrence of rewetting.

Neither is it necessary for the liquid taken-up body to contain absorbent material, since said body may consist of a container, such as a bag, made of flexible mate¬ rial. Rewetting is prevented because the increase in pressure which occurs in this container when the wearer of such an article sits down is corresponded by a simi- lar increase in pressure on the upper side of the insu¬ lating layer, which causes the pleats to be pressed together and therewith closed. It will therefore be understood that the invention is not restricted to the described and illustrated variants thereof and that the scope of the invention is restricted solely by the disclosures made in the following Claims.

Claims

1. An insulating layer (2, 2') which forms part of a liquid-collecting disposable article (1, 1'), such as a diaper, an incontinence guard or the like, said insula¬ ting layer being positioned outwardly of a liquid col¬ lecting body (3, 3') of the article on that side of said body which faces the wearer's skin in use, c h a r - a c t e r i z e d in that the insulating layer is comprised of a thin sheet of liquid-impermeable material which includes at least one bellows-like pleat (a-k, a'-m') at least within a restricted area, and is liquid- permeable within this area.

2. An insulating layer according to Claim 1 and inclu¬ ding a plurality of bellows-like pleats, c h a r a c ¬ t e r i z e d in that the edges (a -g , a -g ) of each

A A B B mutually following pleat (a-k) are offset from one another; and in that the part of each pleat which lies nearest the liquid collecting body (3) is permeable to liquid within that part which is covered by the outward¬ ly lying part of the next following pleat.

3. An insulating layer according to Claim 2, c a r ¬ a c t e r i z e d in that the pleats (a-k) extend in the transverse direction of the article (1).

4. An insulating layer according to Claim 3, c h a r - a c t e r i z e d in that the pleats (a-k) are disposed so as to lie outwardly of one another in a direction from the forward part of the article to the rearward part thereof, as seen in relation to the liquid collec¬ ting body (3) .

5. An insulating layer according to Claim 2, c a r ¬ a c t e r i z e d in that the pleats (a'-m') extend in the longitudinal direction of the article (1') .

6. An insulating layer according to Claim 5, c h a r ¬ a c t e r i z e d in that, when seen in relation to the liquid collecting body (3'), the pleats (a'-m') lie out¬ side one another in a direction from the centre of the article (1') towards respective side edges thereof.

7. An insulating layer according to Claim 2, c h a r ¬ a c t e r i z e d in that pleats disposed in the for¬ ward and rearward parts of the article extend in the transverse direction of said article, and in that pleats disposed in the intermediate, crotch part of the article extend in the longitudinal direction of said article.

8. An insulating layer according to any one of Claims 1-6, c h a r a c t e r i z e d in that pleats are disposed within a continuous area which includes a part of a forward article part, the whole of the crotch part and a portion of a rear article part.