FR2699813A1 - Disposable and absorbent hygienic pad - Google Patents

Abstract

The pad, e.g. for a baby's nappy or adult incontinence pad, comprises an absorbent layer (3) on a backing layer (2) of an impermeable material, made with a central portion for passing between the legs and front and rear panels with waistband fixings. The pad has lengthwise air circulation channels (14) on each side of the absorbent layer, made from a moisture resistant and gas-permeable material attached on one side to the edge of the absorbent layer and on the other to the outer edge of the backing layer. Each channel (14) contains two lengthwise elastic elements, located on the inside of fold lines spaced some 15-25 mm apart, and the inner surface of each channel's outside wall is lined with a strip (24) of a moisture-resistant and gas-permeable material.

Description

DISPOSABLE ABSORBENT HYGIENE ARTICLE PROVIDED WITH AERATION TUNNELS
The present invention relates to a disposable absorbent hygiene article, in particular a disposable diaper for young children or for adult incontinence, which comprises an absorbent pad placed on an outer support sheet, impermeable to liquids. It relates more particularly to an improved hygiene article allowing a good gas exchange between the interior and the exterior, when said article is positioned on the user.

 Hygiene items of this type are designed to ensure a good seal at the thighs of the user, so as to avoid the risk of leakage of urine along the leg. However, this results in risks of skin irritation for the user where the wet absorbent cushion is continuously in contact with the skin thereof.

 To overcome this drawback, it has already been proposed to use as an outer support sheet a material which is not only impermeable to liquids but also permeable to vapor. Thus, thanks to this permeability, it is possible to obtain a gas exchange between the inside and the outside of the hygiene article and therefore a reduction in the moisture content of the ambient prevailing inside said article.

 However, this radical solution has a major drawback, namely the price of such a material which is both impermeable to liquids and permeable to vapor.

 Document EP 0 109 126 proposes a simplified solution making it possible to ensure the gas exchange between the inside and the outside of the absorbent article. In this solution, only the sealing flaps are more vapor permeable per unit area than the actual support sheet. These sealing flaps consist of the portions of the article which wrap around and are in contact with the wearer's leg normally in the thigh region of the wearer.

 Document US 4,887,602 proposes another simplified solution allowing this gas exchange to be ensured. According to this solution, the article has ventilation openings which are located in the areas between the absorbent pad and the lateral and transverse edges of the article.

 However, according to the applicant, in each of these known solutions, the gas exchange is imperfect, being limited to a specific area of the article.

 The goal that the applicant has set is to provide a disposable absorbent hygiene article, in particular a diaper, which is breathable, that is to say which allows a good gas exchange (water vapor and air) between inside and outside of the article, and which does not have the aforementioned drawback. More specifically, the applicant is looking for an article which further improves user comfort.

 This object is perfectly achieved by the disposable absorbent hygiene article, in particular a diaper, according to the invention.

It is an article which comprises, in a known manner, an absorbent cushion disposed on an outer support sheet which is impermeable to liquids; moreover, said article is made in the longitudinal direction of a central part which corresponds to the crotch area and of two end parts one front and the other rear which correspond to the positioning and fixing zones around the size of the user.

 Characteristically according to the invention, the absorbent pad being of substantially rectangular shape, the article comprises a) two longitudinal bands of air circulation, produced in a hydrophobic and gas permeable material, each band being fixed by its first edge longitudinal to the right of the longitudinal flank of the absorbent pad, by its second longitudinal edge and by its two edges transverse to the external contours of the support sheet, and each strip having a width sufficient to form a longitudinal fold whose fold is situated largely above of the absorbent pad, when said article is flat in the stretched state, b) and, for each longitudinal strip, two elastic elements both placed between the two faces of the fold and above the absorbent cushion. Finally the two elastic elements are fixed, at least in the central part, to the corresponding longitudinal strip, the first along the fold and the second on the upper side of the fold, toward the side edge of the absorbent pad.

 The two elastic elements are in the stretched state when the hygiene article is flat. When said article is placed in position to be placed on the user, the two elastic elements retract, causing a curvature of the article and a deformation of the two longitudinal strips. We then observe not only a displacement in height, relative to the absorbent cushion, of the two elastic elements but also a transverse displacement of the first elastic element relative to the position that said first element had above the absorbent cushion, when the article was flat.

 The transverse displacement of the first elastic element has the effect of moving the two folds away from each other and consequently of releasing the parts of the absorbent pad which were initially covered by the two longitudinal strips.

 The deformation, under the action of the two elastic elements, of the two longitudinal bands causes the formation of two ventilation tunnels, arranged on either side of the absorbent pad. Since the longitudinal strips are made of a material which is permeable to gases, it is understood that the vapors which are released during the use of the hygiene article at the level of the absorbent pad can thus be collected inside the two ventilation tunnels and exhausted to the outside.

 In addition, since the material used for the two longitudinal strips is hydrophobic, the underside of the fold which is between the first elastic element and the first longitudinal edge of said strip, fixed to the right of the lateral flank of the absorbent pad, acts as sealing barrier, obstructing the passage of liquids.

 Preferably the second elastic element has a retraction force which is greater than that of the first elastic element. This makes it possible to have very open ventilation tunnels, as will emerge explicitly on reading the example which will be given below.

 Preferably the two longitudinal strips of air circulation have a width such that the two fold lines are, at least in the central part, distant from 15 to 25 mm for an absorbent cushion having a width of the order of 120 mm . According to this particular arrangement, when the hygiene article is flat, the two elastic elements being stretched, the two longitudinal strips of air circulation cover almost all of the absorbent cushion, except for the middle part over the aforementioned width. from 15 to 25 mm. However, when we position the hygiene article for its adaptation on the user, and the two elastic elements retract, we see that the two longitudinal strips, which were initially flat, deviate from each other while taking a tunnel configuration having a cross section which has substantially the shape of a parallelogram.

The hygiene article then has a curved configuration, the absorbent cushion being framed by the side walls of the two ventilation tunnels, said walls also acting as a sealing barrier.

 Advantageously, the hygiene article according to the invention comprises a strip, in a material impermeable to liquids and permeable to gases, which is disposed inside each longitudinal strip and which is fixed to the latter between the second element elastic and the second longitudinal edge. Thanks to this arrangement, the portion of the aeration tunnel, which successively comprises the outer support sheet and the aforementioned strip, is completely impermeable to liquids. However, the fact that said strip is itself permeable to gases makes it possible to ensure the ventilation tunnel its gas exchange function between the inside and the outside of the hygiene article.

 Preferably the first elastic element is an elastic thread whose titration is of the order of 1000 decitex and which, when placed in the stretched state, the article being flat, has an elongation which is between 140 and 180%; the second elastic element is an elastic thread whose titration is of the order of 2,000 to 4,000 decitex and which, when it is in the stretched state, the article being flat, has an elongation which is between 160 and 200%. When the hygiene article does not include other elastic elements than those mentioned above, it is the second elastic thread which tightens the article around the thigh of the user. It is therefore a wire which has a retraction force and a sufficient strength to exercise this function.

 According to an alternative embodiment, the two longitudinal strips of air circulation are joined by their folded zones in the two end parts of the article. Thus in these two extreme parts, during the positioning of the article, the two longitudinal strips cannot deviate from one another but provide transverse anti-leakage barriers.

 According to another embodiment, the outer support sheet has four ventilation openings, which are four zones impermeable to liquids and permeable to gases, two in the front end part and two in the rear end part, said openings being located from on both sides and at least along the absorbent pad; in addition, each longitudinal strip of air circulation covers the two ventilation openings situated on the same side of the absorbent cushion towards its two ends.

Thanks to this arrangement, the vapors collected in the ventilation tunnel can be discharged through the ventilation openings located in the extreme parts of the article.

 This particular arrangement is of even more interest when the article comprises, placed inside each longitudinal strip and fixed to the latter between the second elastic element and its second longitudinal edge, a strip which is made of a material impermeable to liquids and impermeable to gases. In this case the gas exchange between the inside and the outside of the article is done only using the four ventilation openings.

 Preferably the first elastic elements are fixed along the fold over the entire length of the longitudinal air circulation strip, while the second elastic elements are fixed on the upper face of the fold up to a determined distance from the transverse edges. of the article.

 In the aforementioned case where the two longitudinal strips are joined by their fold zones in the two end parts, the predetermined distance is substantially equal to the distance by which the two fold zones are joined.

 The present invention will be better understood on reading the description which will be given of two exemplary embodiments of a diaper with ventilation tunnels, illustrated by the appended drawings in which - FIG. 1 is a representation of the diaper -pantle with two ventilation tunnels, in the stretched state, in a plan view, - Figure 2 is a half-view in section along the axis Il Il of Figure 1, - Figure 3 is a half -View in section of the article as it appears in Figure 2 when the elastic elements are retracted, - and Figure 4 is a representation according to a plan view and in the stretched state of another variant of creation of a pantyhose with two ventilation tunnels.

 The diaper 1 which is illustrated in Figure 1 consists in known manner of an outer support sheet 2, an absorbent pad 3 and a cover sheet 4, covering the absorbent pad 3 and ensuring its attachment on the backing sheet 2.

 The support sheet 2 is impermeable to liquids. It is for example an impermeable plastic film such as polyethylene. It can also be formed in a composite manner from an impermeable plastic film 5, in particular polyethylene, and from a nonwoven sheet 6. In the example shown in FIG. 2, it is the nonwoven 6 which is turned towards the inside of the diaper 1, but it can just as easily be the reverse arrangement.

 The absorbent pad 3 has a substantially rectangular shape for the reasons which will be explained below. It is composed for example of cellulose fluff pulp, possibly containing a super absorbent polymer.

 The absorbent pad 3 is glued to the support sheet 2 and covered with the cover sheet 4 which is permeable to liquids, being for example a non-woven veil.

 The support sheet 2 has a general hourglass shape, with two notches 7, lateral and opposite, delimiting in the longitudinal direction of the diaper 1 a central part 8 and two end parts 9 and 10. The central part 8 corresponds to the crotch zone, ie the zone of the diaper 1 which will be in direct contact with the user's leg at the level of the thigh; the end portions 9, 10 correspond to the zones of the diaper 1 used for positioning and fixing it around the waist of the user. The extreme part 9, which is located towards the top of FIG. 1, corresponds to the front part of the diaper because it is on the front of the user, while the other extreme part 10, at the bottom of Figure 1 corresponds to the rear part since it is located on the back of the user.

 The central part 8 has a width which is less than that of the two extreme front and rear parts 9, 10.

 The structure of the outer support sheet 2 can have different embodiments when it is formed in a composite manner from an impermeable film 5 and from a nonwoven fabric. For example, the impermeable film 5 can be a rectangular film having the same width as the central part 8. For example the nonwoven sheet 6 can be formed from two strips, each of which is glued by one of its longitudinal edges to the corresponding edge of the plastic film, while that its other edge has a notch 7, as shown in Figure 1. In these two examples the parts of the support sheet 2 which are located towards the four corners of the diaper 1, in the end parts 9 and 10 of these consist only of the nonwoven sheet 6.

 The cover sheet 4 has the same length as the support sheet 2, but has a smaller width, which is slightly greater than that of the absorbent pad 3 so as to cover the top 11 as well as the two longitudinal sides 12 of the absorbent pad 3 and to be glued longitudinally on the support sheet 2 along said absorbent pad 3.

 The support sheet 2 and the cover sheet 4 are joined by gluing at their longitudinal ends, at the end portions 9 and 10 of the diaper 1.

 Two adhesive fasteners are fixed laterally, on either side of the rear end part 10. They are intended to be applied to the front end part 9, once the diaper 1 is placed in position on the user.

 Typically according to the invention, the diaper 1 comprises two ventilation tunnels 13. Each of these tunnels 13 is formed by a longitudinal strip 14 of a hydrophobic and gas permeable material. It is for example a hydrophobic nonwoven veil. Each longitudinal strip 14 called the air circulation strip is fixed on the one hand by its first longitudinal edge 15 to the cover sheet 4 in line with the longitudinal flank 12 of the absorbent pad 3 and on the other hand by its second longitudinal edge 16 and by its two edges transverse to the external contours of the support sheet 2. Furthermore, each longitudinal strip 14 has a width sufficient to form a longitudinal fold 17 whose fold 18, when the diaper 1 is flat in the stretched state, is largely above the absorbent pad 3. In the example shown in the figures, the fold 18 was located at a distance of approximately 50 mm from the longitudinal flank 12 of the absorbent pad 3.

 For each ventilation tunnel 13, two elastic elements 19 and 20 are placed between the two faces 21 and 22 of the fold 17, above the absorbent pad 3. The first elastic element 19 is fixed to the longitudinal strip 14 along the fold 18. The second elastic element 20 is fixed to the upper face 21 of the fold 17, towards the lateral edge of the absorbent pad 3. In the example illustrated, this second elastic element 20 is positioned longitudinally about 15 mm from the longitudinal flank 12 absorbent pad 3, when the article is flat in the stretched state (Figures 1 and 4).

 Examination of FIGS. 2 and 3 makes it possible to understand how the ventilation tunnel 13 is formed by deformation of the longitudinal strip 14 of air circulation under the action of the elastic elements 19 and 20.

 Figure 2 shows the positioning of the various components of the diaper when it is flat and in the stretched state. In this case, each elastic element 19, 20 has a certain elongation. For example, the first elastic element is an elastic thread whose titration is of the order of 1000 decitex, and which, in the state shown in Figures 1 and 2, has an elongation which is between 140 and 180%. For example, the second elastic element 20 is an elastic thread whose titration is of the order of 2000 to 4000 decitex and which, under the same conditions, has an elongation which is between 160 and 200%.

 FIG. 3 shows the deformation of the diaper 1 which occurs when the retraction forces of the elastic threads 19 and 20 are allowed to act freely, in particular when the diaper 1 is placed in position to be placed on the 'user. In this specific case, the second elastic element 20 has a retraction force which is greater than that of the first elastic element-19. The retraction of the two elastic threads 19 and 20 brings the two end portions 9, 10 of the diaper 1 closer together. However, since the second elastic thread 20 has a retraction force greater than that of the first elastic thread 19, c 'is the second elastic thread 20 which causes the greatest approximation. At the level of the central part 8 of the diaper 1, this bringing together of the two end parts 9 and 10 results in a displacement in height, according to arrow F , of the second elastic thread 20 and correspondingly of the longitudinal strip 14 to which the second elastic thread 20 is fixed. As for the first elastic thread 19, the retraction force of which is lower than that of the second elastic thread 20, its displacement has a double component, on the one hand in height according to arrow F and on the other hand a transverse component according to arrow G. This transverse movement according to arrow G, is due to the fact that the first elastic thread 19 is fixed to the longitudinal strip 14 inside the fold 18 and that it is therefore driven by said strip 14 during the displacement in height of the second elastic thread 20.

 As can be clearly seen in FIG. 3, the assembly constituted by the folded longitudinal strip 14 and by the lateral part 23 of the support sheet 2, between the edges of which said longitudinal strip 14 is fixed, is deformed to adopt a configuration which has substantially the shape of a parallelogram at least in the central part 8 of the diaper 1.

 It is this deformation which makes it possible to obtain an aeration tunnel 13 capable of collecting and circulating the vapors released during the use of the diaper at the absorbent pad.

 In addition, the transverse movement of each of the first elastic threads 19 has the effect of separating the two longitudinal strips 14 from one another and consequently of releasing the parts of the absorbent pad 3 which were initially covered by the lower faces 22 folds 17.

 According to a preferred, but non-limiting version of the diaper according to the invention, the two fold lines 18, 18 ′ are spaced 15 to 25 mm apart, while the absorbent pad has a width which is of the order of 120mu. As can be seen on examining FIG. 1, when the diaper 1 is flat, the two longitudinal strips 14, 14 ′ of air circulation cover almost all of the absorbent cushion except for the middle part over the above width from 15 to 25mm. However due to the spacing of the two folds 18,18 'during the retraction of the elastic threads 19,20, the positioning of the layer on the user does not pose any difficulty, in particular as regards the placement of the user on the absorbent pad 3.

 Since the material used for the two longitudinal strips 14 is hydrophobic, the underside 22 of the fold 17 which is between the fold 18 and the first longitudinal edge 15 of said strip 14 acts as a sealing barrier, when the layer - panty 1 is placed on the user. However, when the longitudinal strip 14 is a fleece of hydrophobic nonwoven, the protection provided against the passage of the liquid may not be completely effective. In this case and as illustrated in Figures 2 and 3, it is desirable to place, inside the ventilation tunnel 13 a strip 24 which is impermeable to liquids. This strip 24 is fixed to the longitudinal strip 14 along its second longitudinal edge 16 and at the level of the second elastic thread 20.

 In the variant embodiment illustrated in FIGS. 1, 2 and 3, the second elastic thread 20 has a double function: it makes it possible to deform the longitudinal strip 14 and to create the ventilation tunnel 13; on the other hand it ensures the tightening of the diaper 1 around the thigh of the user. Thus obtaining a perfect seal of the diaper 1 due to the impermeability to liquid of the support sheet 2 and the strip 24 which follows it.

 In this case, the strip 24 must also be permeable to gas so as to allow the evacuation towards the outside of the vapors collected inside the aeration tunnel 13.

 There is shown in Figure 4 a second alternative embodiment in which the material of the two strips 24 is impermeable to both liquids and gases.

In this case, the evacuation of the vapors collected inside the ventilation tunnels 13 is effected by means of four ventilation openings 25, 25 ', 26, 26' respectively. These are four areas of the outer support sheet 2 which are impermeable to liquids and permeable to gases. These four openings are located on either side and at least along the absorbent pad 3, two 25.25 'being in the front end portion 9 and the other two 26.26' being in the rear end portion 10 of the layer panty 1. In addition, each longitudinal strip 14 of air circulation covers, towards its two ends, the two ventilation openings 25, 26 located on the same side of the absorbent pad 3. These four ventilation openings are therefore located in the part 23 of the support sheet 2 constituting the fourth side of the ventilation tunnel 13 (FIG. 3).

 This can be achieved in different ways. In a first way the ventilation opening 15 results from a cut formed in the support sheet 2 and from the covering of said cut with a hydrophobic or liquid impermeable material but permeable to gases such as a hydrophobic foam or a non -woven hydrophobic or a hydrophobic microporous film; it can in particular be a microporous nonwoven based on microfibers, of the melt-blown or spun type. In a second way, the ventilation opening 15 results from a series of perforations of small diameters, made locally in the zone corresponding to said ventilation opening 15. The perforations in question will have a diameter large enough to allow the gas exchange, but weak enough to prevent the passage of liquids.

 The vapors collected in the aeration tunnel 13 all along the absorbent pad 3 can thus be evacuated through the aeration openings 25, 26 located in the end portions 9, 10 of the diaper 1.

 The second exemplary embodiment illustrated in FIG. 4 presents, with respect to the first example, another characteristic which consists in the fact that the two longitudinal strips 14, 14 ′ are interconnected by their fold zone 18, in the two end parts 9, 10, towards the transverse edges 28, 29 of the diaper. Therefore, when the diaper 1 is flat, the absorbent pad 3 only appears through a longitudinal slit which extends at least all along the central part 8 and whose ends 27 have a shape rounded.

This connection between the two longitudinal strips 14, 14 'is possible on the one hand because of the small spacing between the two folds 18, 18' and on the other hand because of the relative extensibility of the nonwoven web constituting the strips 14, 14 '.

 This particular arrangement makes it possible to create two anti-leakage barriers, in the two end portions 9, 10, near the transverse edges 28, 29 of the diaper 1 and therefore all around the waist of the user when said layer -cottle 1 is positioned on the user.

 As shown in Figures 1 and 4, the first elastic threads 19 are fixed along the fold 18 over the entire length of the longitudinal strip 14 of air circulation, while the second elastic threads 20 are fixed on the upper face 21 from the fold 17 to a determined distance from the transverse edges 28, 29 of the diaper 1.

 Preferably when the two longitudinal strips 14 are joined by their fold zone 18 in the two end parts 9, 10, as has just been described, the predetermined distance is substantially equal to the distance d by which the two zones of fold are gathered.

 The invention is not limited to the embodiments which have been described above by way of non-exhaustive examples. In particular it is possible, without departing from the invention, that the diaper 1 comprises, in addition to the two elastic elements 19, 20 other elastic elements located at least in the central part 8 along the second longitudinal edge 16 , so as to tighten the diaper around the thighs of the user.

 In addition, one and / or the other of the two elastic elements 19, 20 may consist of several elastic threads.

Claims (11)

1. Disposable absorbent hygiene article, in particular a diaper, comprising an absorbent cushion (3) disposed on an outer support sheet (2) which is impermeable to liquids and which is formed in the longitudinal direction of a central part (8 ) which corresponds to the crotch zone and two end parts, one front (9) and the other rear (10) which correspond to the positioning and fixing zones around the waist of the user, characterized in that, the absorbent pad (3) being of substantially rectangular shape, it comprises a) two longitudinal bands (14) of air circulation, made of a hydrophobic and gas-permeable material, each band (14) being fixed by its first longitudinal edge (15) in line with the longitudinal side (12) of the absorbent pad (3), by its second longitudinal edge (16) and by its two edges transverse to the external contours of the support sheet (2), and each strip (14) having sufficient width to form a longitudinal fold (17) whose fold (18) is situated largely above the absorbent pad (3), when said article is flat in the stretched state, b) and, for each longitudinal strip (14) , two elastic elements (19,20) both placed between the two faces (21,22) of the fold (17) and above the absorbent pad (3), and in that the two elastic elements (19,20) are fixed at least in the central part (8), to the corresponding longitudinal strip (14), the first (19) along the fold (18) and the second (20) on the upper face (21) of the fold ( 17), towards the lateral edge of the absorbent pad (3).  2. Article according to claim 1 characterized in that the  two longitudinal air circulation strips (14) have a  width such that the two lines (18,18 ') of folds are, at  less in the central part (8), 15 to 25 mir apart  an absorbent pad (3) having a width of the order of 120 mm.  3. Hygiene article according to one of claims 1 or 2  comprising a strip (24), made of a material impermeable to liquids, which is arranged inside each longitudinal strip (14) and which is fixed to the latter between the second elastic element (20) and the second longitudinal edge ( 16). 4. Hygiene article according to claim 3 characterized in that the strips (24) are made of a material which is permeable to gases and in that the second elastic elements (20) act as clamping elements of the article (1) against the user's thighs. 5. Hygiene article according to one of claims 1 to 4 characterized in that the first elastic element (19) is an elastic thread whose titration is of the order of 1000 decitex and which, when placed at the stretched state, the article being flat, has an elongation which is between 140 and 180% and in that the second elastic element (20) is an elastic thread whose titration is of the order of 2000 to 4000 decitex and which, when in the stretched state, the article being flat, has an elongation which is between 160 and 200%. 6. Article according to one of claims 1 to 5 characterized in that the second elastic element (20) has a retraction force greater than that of the first element (19). 7. Article according to claim 1 characterized in that the two longitudinal strips (14) of air circulation are joined by their folds zones (18,18 ') in the two end parts (9,10), towards the edges cross section (28,29) of article (1). 8. Article according to claim 1 characterized in that the outer support sheet (2) has four ventilation openings (25.25 ', 26.26') which are four zones impermeable to liquids and permeable to gases, two ( 25.25 ') in the front end part (9) and two (26.26') in the rear end part (10), said openings being located on either side and at least along the absorbent pad, each longitudinal strip (14) of air circulation covering towards its two ends the two ventilation openings (25, 26) situated on the same side of the absorbent pad (3).  9. Article according to claims 3 and 8 characterized in that the strip (24) is made of a gas-impermeable material. 10. Article according to claim 1 characterized in that the first elastic element (19) is fixed along the fold (18) over the entire length of the longitudinal strip (14) of air circulation, while the second element elastic (20) is fixed on the upper face (21) of the fold (17) up to a determined distance from the transverse edges (28,29) of the article. 11. Article according to claims 7 and 10 characterized in that the predetermined distance is substantially equal to the distance (d) by which the two fold zones (18,18 ') are joined.