CA1282906C - Double fastening system with a slit - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
A disposable diaper comprising an absorbent core disposed between a liquid-impermeable backing sheet and a liquid-permeable facing sheet and having means for closing and fastening the diaper around the waist which are independent from means fox sealing the diaper around the thighs of the wearer. The diaper employs two regions of adhesive for this purpose. The first said region is preferably located at the upper end of the diaper and comprises two adhesive areas at or near the corners of the diaper.
The second adhesive region is located at the other end of the diaper and comprises two adhesive areas which are located in the side margins of the diaper and are spaced away from the corners at said other end. There are slits between the corners of the diaper and the adhesive areas of the second adhesive region. These slits extend inwardly from the side margins of the diaper toward its center.

Description

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DOUBLE FASTENING SYSTEM_WITH A ~LIT

The present invention refers to a fastening system and more precisely to a double fastening system with a slit for disposable articles such as disposable diapers.

Backqround of the Invention Conventional prior art is mainly based on the use of adhesive tapes for closing or fastening diapers, especially disposable diapers, around the waist of the wearer. In addition, the prior art has provided sealing systems to prevent fluid from leaking from the diaper in the regions around the wearer's thighs and waist. Sealing systems which help prevent leakage in the thigh regions comprise elastic elements, such as elastic bands or one or more elastic strands, which are secured in the generally central portions of the side margins of the diaper.

Sealin~ systems which help prevent leakage of liquid at the waist of the wearer comprise elastic elements which are secured in the upper and/or lower margins of the diaper to provide a so-called "elasticized waistband"
diaper. In the prior art, the aforementioned astening or closure system and the aforementioned sealing system are interdependent and allowed, relative motion between the wearer's body and the diaper itself. This produced bagginess which in turn led to leakage of liquid especially at the leg regions of the diaper.
The present invention is directed to providing a closure system which allows a better fitting of such article to the user, thus reducing ri6ks of leakage by combining such closure system and elastic system.

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S _ ary of the Invention One object of the present invention is to interrupt the force-transmitting continuous surface which occurs in one-adhesive-region systems, by providing a cut at such adhesive region, which allows the xesulting two adhesive regions to work independently from another one.

Another objec-t is to provide a be-tter fi-t-ting of a diaper around the thighs and waist regions, which vary with the user's ergonomic characteristics, thus allowing the legs to move without also moving -the diaper relative to the body.
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~; Another advantage is the additional option for closing ~;, and fitting such article to the body, each of the ~, aforesaid adhesive regions being adapted to be used , independently from the other.
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In accordance with the present invention there is provided a closure system for a disposable article such as a disposable diaper, said closure system comprlsing two adhesive regions, symmetrically opposite with relation to the longitudinal axis of the article and applied on the outer corners of the liquid permeable covering of the article, said regions being separated by a slit which is generally parallel to the transverse axis of the article or which ex-tends inwardly from the side margin of the diaper toward a generally central region thereof.

According to a fur-ther broad aspect o~ the present invention there is provided a disposable diaper which 30 comprises a liquid impermeable backing sheet and a liquid permeable covering sheet. The covering sheet has a surface which contacts the body of the 28~
-2a-wearer when the disposable article is in use. An absorbent core is disposed between the backing sheet and the covering sheet. The diaper has an upper edge with an upper marginal portion adjacent the upper edge. A lower marginal portion is also provided adjacent the lower edge. A pair of side edges are also provided and each having a side marginal portion adjacent -thereto. A transverse axis 1les be-tween the upper edge and the lower edge and the longitudinal axis lies between the side edges. The transverse and lonyitudinal axes are mutually perpendicular and intersect in a central reg;on of -the disposable article. A first upper corner is provided in the region where the upper edge meets a first of the side edges. A second upper corner is provided in the region where the upper edge meets the second of the side edges. The backing sheet is secured to the covering sheet in the marginal portions.
A first area of pressure sensitive adhesive i-s-applied to the liquid permeable covering sheet at the first upper corner. A second area of pressure sensitive adhesive is applied to the li~uid permeable covering sheet at the second upper corner. A third area of pressure sensitive adhesive is applied to S a first of the side marginal portions and spaced a distance upwardly from the lower edge toward the transverse axis. A fourth area of pressuxe sensitive adhesive is applied to the other of -the side marglnal portions and spaced a distance upwardly Erom -the lower edge toward the -transverse axis. All of the areas oE pressure sensitive adheslve are applied to the body-con-tactiny surface of the liquid permeable covering sheet. A pair of slits are also provi.ded and the first of these extends inwardly of the diaper and toward the transverse axis Erom a point on a first of the side edges which lies between the third area of pressure sensitive adhesive and the point .a~

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-2b-of juncture of the fi.rstside edge of the lower edge.
The second of the slits extends lnwardly of the diaper and toward the tranverse axis from a point on the other side edges which lies between the four~h area of pressure sensitive adhesive and the poin-t of juncture of -the other side edge and the lower edge.

Brief Description of -the Drawings The invention can be better understood with reference to the following detailed description toge-ther with the appended drawings in which:

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Fig. 1 is a perspective view of a diaper provided with the closure system of the present invention.

Fig. 2 is a perspective view illustra~iny another embodiment of said closure system.

Fig. 3 is a front plan view of the diaper illustrated in Fig. 1.

Fig. 4 is a 6cheme of actuating forces in the system of the present invention.

Fig. 5 is a front plan view, with a portion cut away, of another embodiment of a diaper in accordance with the - 15 present invention.

Fig. 6 is a perspective view of the diaper of Fig. 5 in a closed configuration.

Detailed Description of the Invention Referring now to the drawings, there is shown a diaper 10 having a liquid-impermeable backing sheet 11, a liquid-permeable facing sheet or covering 12 and an absorbent core 22 disposed between said backing sheet and said covering. The diaper further comprises an elastic element 13 in the central portion of each of the side margins of the diaper and an elastic element 1~ in the central reyion of the top margin of the diaper. Backing sheet 11 may comprise a film of polyethylene or other liquid-impermeable material. Covering 12 may be a nonwoven fabric, highly porous paper or similar material which permits passage of liquid therethrough ~o the underlying absorbent core. The absorbent core 22 may comprise, ~.g. comminuted wood pulp or other material ~2~ 6 having good liquid absorbency. ~lastic elements 13 and 14 may be elastic monofilaments or a tape of hea~ shrinkable material which, after heat shrinking, has elastic properties. In the embodiment under discussion, elastic element 1~ is preferably in the form of an elastic monofilament which, as seen in Fig. 3, is secured while in a stretched state between backing sheet 11 and covering 12. When subsequently relaxed, elastic element 14 serves to gather the material along the upper margin of the diaper as shown in Figs. 1 and 2. Ela~tic elements 13, 13 at the opposed side margins of the diaper are preferably in the form of a tape of heat shrinkable material which, after application of heat thereto, displays elastic properties. Suitably sized lengths of the heat shrinkable material are secured in the side margins of diaper 10 between backing sheet 11 and cover 12 as shown in Fig. 3.
The side margins of the diaper are subsequently heated as a result of which the tapes of heat shrinkable material shrink to provide the gathered side margins, shown in Figs. 1 and 2, which encircle the thighs of the wearer during use. Since, as mentioned above, the tapes have elastic properties after their heat treatment, the gathered portions in the side margins of the diaper are extensible so as to fit comfortably around the thigh regions of the wearer and provide a gasketing effect to prevent the leakage of fluid.

It will be recognized that elastic element lg may compcise two or more elastic monofilaments rather than the single strand illustrated in the drawings. Alternatively, pieces of the aforementioned heat shrinkable tape material could be used as elastic element lg in the upper margin of the diaper. Similarly, the heat shrinkable tapes comprising elastic elements 13, 13 at the side margins of the diaper could be replaced by one or more elastic monofilaments.

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While in diaper 10 illustrated in the drawings. absorbent core 22 is smaller in size than the backing and facing sheets, it will be understood that core 22 can assume VariGUS sizes and shapes. Absorbent core 22 can be stabilized, e.g. by embossing along lines 23, as shown in Fig. 3. It will be understood by those skilled in the art that in diaper 10 illustrated in the drawings, backing sheet 11 and facing sheet 12 may be secured to each other, e.g. with a suitable adhesive or by heating sealing, at the marginal portion6 of the diaper. When the backing and facing sheets are joined around the margins of the diaper in the fashion just mentioned, the absorben~ core is prevented from moving; however, the absorbent core may be further secured against undesirable movement by giving it ~o the underlying backing sheet.

Two distinctive adhesive regions 15 and 16 are provided on the inner surface ~i.e. that surface which faces the reader in Fig. 3 and which contacts the body of the wearer when the diaper is in use) of liquid-permeable covering 12, at each of the upper corners of the diaper, generally adjacent the ends of elastic element 1~. As can be seen in Fig. 3, adhesive regions 15, 16 are placed symmetrically with respect to the longitudinal axis, Y-Y, of diaper 10 near the upper corners of the diaper.

The adhesive used for regions 15 and 16 may be of the pressure sensitive acrylic type or any other type well-known in the art. Preferably, the adhe6ive i6 of the type which can be readily released erOm the outer surface of ~acking sheet 11 without undue damage to the backing sheet or the adhesive. When this type of adhesive is used, it i~ an easy matter to release the adhesive coated portions of the diaper from engagement with the backing sheet when it is desired to adjust the fit of diaper or remove it from the wearer. If the adhesive used for regions 15, 16 i~ not readily releasable from ths outer surface of the backing sheet, then those portions of the backing sheet which will normally be contacted by the adhesive portions may be suitably treated, by methods known to those skilled in the art, to provide the necessary easy~release characteristics. The adhesive ultimately chosen for use may be applied in any convenient manner, e.g. by an adhesive transfer process.
The preferred embodiment illustrated in Fig. 3 comprises a pair of geneeally rectangular first adhesive regions 15, there being one such adhesive region at each upper corner of the diaper. Thus, each of first adhesive regions 15 i~
located in the upper margin of the diaper adjacent upper edge 25 and adjacent one of the opposed side edges of the diaper. Diaper 10 further comprises a pair of generally rectangular second adhesive regions 16, each of which is spaced downwardly from upper edge 25 of the diaper and from its associated first adhesive region 15. Each such second adhesive area 16 is located, as can be seen in Fig.
3, adjacent one of the side edges of the diaper.

- Adhesive regions 15 and 16 at each side of the diaper are Z5 separated by a slit 17 running from a side edge of the diaper toward the central region thereof and generally parallel to the transverse axis, X-X, of ~he diaper.

In the preferred embodiment, each slit 17 extends farther inwardly from its respective side edge than do its associated adhesive regions 15, 16. Each slit 17 terminates at its interiorly located end in a circular cutout 1~ which helps prevent undesirable tearing of the diaper by distributing forces applied thereto along such circular surface. As illustrated in Fig. 3, there is an JBD-10~

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adhesive free region between slit 17 and the lower edge of the first adhesive region 15 and an adhesive free region between slit 17 and the upper edge of second adhesive region 16.

In use, a child to be diapered is positioned facing upwardly on top of the diaper in the generally flat configuration shown in Fig. 3 so that the child's buttocks are disposed more or less centrally of the diaper. The lower part of the diaper is brought up between the child's leg so that lower edge 26 is in alignment with upper edge 25. Adhesive areas 15, 15 at upper edge 25 are adhered to the backing sheet at the corner regions where side edges 27 and 28 meet lower edge 26 (arrow A in Fig. 1). This action fixes the diaper in position around the child's waist. Adhesive regions 16, 16 at each side of the diaper are manipulated to conform the diaper around the thighs of the child and are then secured to the impermeable backing sheet 18 (arrow B in Fig. 1). The diaper prior to closing adhesive regions 15, 16 is illustrated at the right hand side of Fig. 1: the diaper after securing adhesive regions 15, 16 to the backing sheet is illustrated at the left hand side of Fig. 1.

As indicated earlier herein and as just described, the operation of closing and fastening the diaper of the present invention around the waist of the wearer (using adhesive regions 15, 15) can be accomplished independently of the operation of adjusting the fit of the diaper around the thighs (using adhesive regions 16, 16) so as to most effectively seal the diaper from undesirable leakage.
With the diaper of the present invention, a movement of the user's leg in one dirèction will pull the diaper and elastic portion around the thigh to the same direction and cause the diaper to follow the body. There is less J~D-109 relative movement of the body and the diaper with respect to each other. This reduces the amount of "gapping"
between the thighs of the wearer and the diaper itself so that the possibility of leakage is reduced.

In another embodiment, illustrated in Fiy. 2, an arcuate slit 19, similar to slit 17, separates adhesive regions 15 and 1~ at each side of the diaper and extends inwardly and downwardly from the side margin to terminate near the upper end of elastic element 13. Arcuate slit 19 terminates in a circular cutout 18 which prevents the diaper from ~earing when streæses are applied in the regions surrounding the slit. In this embodiment, there are no adhesive-free portions between adhesive region 15 and slit 19 or between adhesive region 16 and slit 19.

It will be understood the slits 17 and 13 allow the diaper to be fitted and closed around the waist of the wearer (using adhesive regions 15, 15) and to be fitted and sealed against leakage at the thighs ~using adhesive 1~, 16) in separate, independent steps.

Fig. 4 illustrates the scheme of actuating forces in the fastening system with a slit, wherein dot 15 represents the adhesive region 15 for fitting the diaper around the waist and dot 16 represents the adhesive region 16 for fittinq the diaper to the legs. Arrows Fl and F2 are possible exertions applied at the adhesive region.

Another embodiment of the diaper of the present invention is illustrated in Fig. 5. Diaper 107 has a central ~ransverse axis, X-X, located midway between and parallel to its upper edge 105 and lower edge 106 and a central longitudinal axis, Y-Y, located midway between its opposed side edges 115, 116, and intersecting the transverse axis at right angles. Diaper 107 comprises a liquid-impermeable backing sheet 118, an absorbent coee 119 and a liquid-permeable facing or covering sheet 120.
Diaper 107 further comprises an elastic element 114 secured between the backing sheet and the facing sheet in the upper margin of the diaper and elastic elements 113, 113 in the central portions of the left and right side margins.

The upper margin o~ the diaper, i.e., that portion lying generally between upper edge 105 of the diaper and upper edge ll9a of the absorbent batt, has a first region of pressure sensitive adhesive which comprises a generally rectangular adhesive area lOla at the upper right hand corner of the diaper and a generally rectangular adhesive area lOlb at the upper left hand corner. The lower portion of the diaper, i.e., that portion thereof which is nearer lower edge 106, has a second region of pressure sensitive adhesive which comprises adhesive area 102a and 20 adhesive area 102b. Adhesive area 102a is loaated in the right side margin of the diaper, i.e., that por~ion thereof which lie~ between right side edge 116 of the diaper and the extended right side edge ll9b of absorbent core 119, and is spaced a short distance upwardly, i.e. in the direction toward transverse axis, X-X, from lower edge 106. Adhesive area 102b is located in the left side margin of the diaper, i.e. that portion thereo~ which lies between left side margin 115 and the extended left side edge ll9c of absorbent core 119, and is also spaced a short distance upwardly, in the same fashion as adhesive area 102a, from lower edge 106 of the diaper. Adhesive areas lOla, lOlb, 102a and 102b are applied, e.g. by an adhesive transfer process, to the exposed surface of covering sheet 120.

~BD-109 -It will be understood that adhesive areas lOla and lOlb can be moved slightly downwardly from upper edge 105 or slightly inwardly from side edges 116 and 115, respectively. Adhesive areas lOZa and 102b can be shifted slightly inwardly from side edges 116 and 115, respectively, of the diaper.

Diaper 107 further comprises a pair of slits, 108a and 108b, in the lower portions of the right and left hand margins, respectively, and arranged generally symmetrically with respect to longitudinal axis, Y-Y.
Slit 108a is preferably arcuate in shape and extends inwardly and toward transverse axis, X-X, from a point on the righ~ side edge 116 of the diaper which lies between adhesive area 102a and the point of juncture of righ~ side edge 116 and lower edge 106 of the diaper.

Slit 108b has the same arcuate configuration as slit 108a and extends inwardly and toward transverse axis, X-X, from a point on the left side edge 115 of the diaper which lies between adhesive area 102b and the point of juncture o~
le~t side edge 115 and lower edge 106 of the diaper. The distance between lower edge 106 and the points where slits 108a and 108b meet side edges 116 and 115, respectively, should be at least equivalent to the length, measured parallel to longitudinal axis, Y-Y, of adhesive areas lOla and lOlb.

Slits 108a and 108b terminate in a circular opening lll located near elastic element 103 and inwardly of side edges 116 and 115 respectively, of the diaper. It will be understood that the radius o curvature of slits 108a and 108b may be varied and that these slits could be straight, if desired. In any event, when slits 108a and 108b are 35 provided as aforeGaid, flaps 127 and 128 are formed at the -~z~z~

side margins of the diaper, with adhesive area 102a being applied to and carried by flap 128 and adhesive area 102b being applied to and carried by flap 127.

In use, a child to be diapered is positioned facing upwardly on top of the diaper in the generally flat configuration shown ;n Fig. 5 so that the child 1 6 buttocks are disposed more or less centrally of the diaper. The lower part of the diaper is brought up between ~he child 16 legs so that lower edge 106 i5 in alignment with upper edge 105. Adhesive areas lOla and lOlb at upper edge 105 are inserted into 61its 108a and 108b, respectively, and adhered to the backing sheet at the corner regions where side edges 116 and 115, respectively, meet lower edge 106. This action fixes the diaper in position around the child's waist. Flaps 127 and 128 are manipulated ~o conform the diaper around the thighs of the child and are then secured, by way of adhesive areas 102b and 102a respectively, to the impermeable backing sheet 118. This sequence is illustrated at the right hand side of Fig. 6 where flap 128 has been moved aside so that adhesive area lOlb can be inserted into slit 108b as shown by directional arrow A. After adhesive area lOlb has been adhered to the backing sheet 118, flap 128 carrying adhesive 102b is then brought into adhering contact with the backing sheet. The diaper in its closed configuration around the waist is illustrated at the left side of Fig. 6.

It should be understood that the present invention is not limited to the descriptions and illustration6 of the disclo6ed embodiments, thus being likely to be achieved in different ways, however, within the scope of the following claim6.

Claims (6)

1. A disposble diaper comprising:
a liquid impermeable backing sheet;
a liquid permeable covering sheet, said covering sheet having a surface which contacts the body of the wearer when the disposable article is in use;
an absorbent core disposed between said backing sheet and said covering sheet an upper edge;
an upper marginal portion adjacent said upper edge;
a lower edge;
a lower marginal portion adjacent said lower edge;
a pair of side edges, each of said side edges having a side marginal portion adjacent thereto;
a transverse axis lying between said upper edge and said lower edge and a longitudinal axis lying between said side edges; said transverse and longitudinal axes being mutually perpendicular and intersecting in a central region of the disposable article;
a first upper corner in the region where said upper edge meets a first of said side edges;
a second upper corner in the region where said upper edge meets the second of said side edges;
said backing sheet being secured to said covering sheet in said marginal portions;
a first area of pressure sensitive adhesive applied to said liquid permeable covering sheet at said first upper corner;
a second area of pressure sensitive adhesive applied to said liquid permeable covering sheet at said second upper corner;

a third area of pressure sensitive adhesive applied to a first of said side marginal portions and spaced a distance upwardly from said lower edge toward said transverse axis;
a fourth area of pressure sensitive adhesive applied to the other of said side marginal portions and spaced a distance upwardly from said lower edge toward said transverse axis;
all of said areas of pressure sensitive adhesive being applied to the body-contacting surface of said liquid permeable covering sheet;
and a pair of slits, the first of said slits extending inwardly of said diaper and toward said transverse axis from a point on a first of said side edges which lies between said third area of pressure sensitive adhesive and the point of juncture of said first side edge and said lower edge, the second of said slits extending inwardly of said diaper and toward said transverse axis from a point on the other of said side edges which lies between said fourth area of pressure sensitive adhesive and the point of juncture of said other side edge and said lower edge.

2. A disposable diaper according to Claim 1 wherein the distance between said lower edge and the point where said first and second slits meet said first and second side edges, respectively, is at least equal to the length, measured parallel to said longitudinal axis, of said first and second areas of pressure sensitive adhesive areas.

3. A disposable diaper according to Claim 1 wherein said slits terminate in a circular opening.

4. A disposable diaper according to Claim 1 wherein said slits are arcuate in configuration.

5. A disposable diaper according to claim 1, 2 or 3 wherein said upper margin comprises an elastic element.

6. A disposable diaper according to claim 1, 2 or 3 wherein said upper margin comprises an elastic element and an elastic element is provided in the central portions of said side margins.