CA1234253A

CA1234253A - Diaper with fold points

Info

Publication number: CA1234253A
Application number: CA000469537A
Authority: CA
Inventors: John M. Blevins
Original assignee: Procter and Gamble Co
Current assignee: Procter and Gamble Co
Priority date: 1983-12-08
Filing date: 1984-12-07
Publication date: 1988-03-22
Also published as: ES8608820A1; EP0145080A2; ES283233U; EP0145080A3; ES538369A0; ES283233Y; US4601717A; EP0145080B1; DE3481811D1; GB8332828D0; ATE51516T1

Abstract

DIAPER WITH FOLD POINTS

ABSTRACT

A disposable diaper, or similar article, with elastic side-bands, is folded to bring the elastics into a curvilinear shape, thereby improving fit around the legs.

Description

3~S3 :

DIAPER WITH FOLD POINTS

- TECHNICAL FIELD

The present invention relates to absorbent structures, especially disposable baby diapers, adult incontinence products, and the like.

BACKGROUND
A goal in the manufacture of diapers us to find a structure which is sufficiently inexpensive to manufacture and sell what it can be disposed of after a single use, ye t has waste containment equivalent to cloth diapers, or cloth diapers with plastic overplants. One major problem in developing such a structure is to provide an appropriate, non-leaking fit around the leg openings. This search for an improved disposable diaper structure has been going on for the past two decades.
One method to achieve good leg fit in a rectangular disposable diaper is to use the so-called Z-fold configuration as described in U.S. Patent I 26151.
Another method to achieve even wetter fit is to use elastic bands running length-wise along thy sides of the diaper to provide elasticized leg openings, in-use, and/or to shape the diaper into a non-rectangular generally, "hourglass) shape thaw, in-use, confines rather well to the legs. See U.S. Patent 3 860 ~03.

I

In approaching this problem of leg openings, it may be speculated that it would be possible to improve leg figment even further if the elastic bands could simply be provided in a curvilinear configuration. In-use, the curvilinear elastic would be fitted around the legs, substantially in the manner of circularly-elasticized non-disposable under-garments. Of course, this would require that the elastics be affixed to the diaper in a curvilinear configuration, rather than in the "in-line" elasticization mode used in all current elasticized disposable diapers. See U.S. Patent 4 081 301 for a description of a preferred method for in line elasticization of disposable diapers.
However, on further consideration it is clear that applying elastics in other than a substantially in-line configuration would be quite expensive and not conducive to the efficient, high-speed manufacture of disposable diapers.
The present invention provides a preferred structure for a disposable diaper, or the like, whereby elastics applied substantially in-line with the absorbent core are made to assume a curvilinear shape. This is achieved by constructing the diaper and folding it, in the manner described hereinafter. The resulting structure exhibits improved leg figment, better waste containment, and it more comfortable than either folded (but non-elasticized) or in-line elasticized (but non-folded) diapers of the prior art.
SUMMARY OF THE INVENTION
The present invention encompasses absorbent structures such as disposable diapers, or the like. As is well-known in the art, such diapers will comprise : a buckshot (the sheet used outermost from the skin, and which is generally made from urine-impenetrable plastic material to give the containment effect of plastic pants); a core that will absorb and help contain urine and/or local matter; and, generally, a top sheet (the sheet closest to the skin) that is urine-permeable.

it Elasticized diapers have, in addition to the above elements, one or more elastic bands running substantially along each side. In use, such bands are fitted around the legs to provide elasticized leg-openings. In the preferred diaper structure described in U.S. Patent 3,860,003, the buckshot is somewhat broader than the core, and the elastics are positioned outwardly from the core to provide a spacing element, or flexible side-flap, that substantially enhances performance.
In the present invention, the basic diaper structure is generally similar to that disclosed in U.S.
3,860,003, but is further characterized by one or more fold points on one, or most preferably both, sides of the diaper, whereby the spacing elements are molded over and affixed at one (preferred) or more points to the top sheet or to the absorbent core. Thus, the elastics, which have been applied in a substantially in-line configuration, are thereby forced into a curvilinear shape.
An aspect of the invention is as follows:
An absorbent structure, comprising a buckshot, absorbent core, a top sheet, and at least one elastic member along each longitudinal side of the structure, said elastic member being situated away from said absorbent core to provide flexible spacing elements;
said spacing elements being folded over said absorbent core at at least one fold point and being affixed to said top sheet at at least one contact point, whereby at least one said elastic member is bent from its original configuration into a curvilinear shape, thereby providing an improved leg opening for the absorbent structure.
DESCRIPTION OF THE DRAWINGS
Figure l depicts a plan view of a flattened rectangular diaper embodying the present invention prior to folding;
Figure 2 shows a more preferred diaper of the present invention, again in flattened plan view ~3~3 Figure 3 depicts a flattened plan view of the most preferred embodiment of the present invention; and Figure 4 shows the article of Figure 3 fully-assembled.
Figure 1 depicts a plan view of a flattened rectangular diaper of the present type prior to folding, showing buckshot (1), core (2), top sheet (3) and elastics (4). The elastics shown in Figure 1 are positioned outwardly from the side edges of core (2) to provide spacing element (5) along each side of the core.
Points (6) and (7) are fold-points which, in the final diaper, are affixed to contact points I and (9), respectively, of the core/topsheet assembly, thereby forcing the elastics to curve. The degree of curvature . 15 can be. varied by varying the width of the spacing element, moving the contact points, etc.
Figure 2 shows a more preferred diaper of the present type, again in flattened plan vie, wherein the core, the buckshot, and preferably, the top sheet, are - 20 all in a preferred shaped ("hourglass") configuration.
Again, fold-~39L~

points (6) and (7) are affixed to contact points (8) and (9) in the final diaper.
Figure 3 depicts a flattened plan view ox a most preferred embodiment of the present invention, which optionally also has tape fasteners (10) affixed to both sides ox the diaper.
Fold-points I and (7) and contact points I and (9) are displaced forward of the longitudinal midpoint in the Figure 3 diaper. The diaper is folded to Juxtapose points (6) with (8) and (7) with I the resulting folds being held, for example, by glue spots. In-use, the diaper is placed around the child with the tapes to the rear, and with the fold described by the juxtaposition of the fold points with the contact points being towards the front of the child. The tape fasteners are then used to hold the diaper in place, in the manner described in U.S. Patent 1 458 5669 which describes a preferred "Y-tape" diaper fastener. Displacing the fold provides an especially comfortable diaper, and tends to hold the absorbent core slightly away from the child's genital and perineal areas thereby desirably decreasing contact between bodily waste products on the absorbent pad with the child' B
skin.
Figure 4 shows the article Or Figure 3 fully-assembled and illustrates the curvilinear shape of the elastics caused by the folding.
It is to be understood that multiple fold-points may be employed in the diapers, and that the drawings are provided only as a means of better illustrating the structures Or this invention. The cores may be rectangular, T-shaped, Shaped wedge-shaped, hourglass-shaped (preferred), and the like, according to the desires of the manufacturer.
It is also to be understood that the terms fold points and n contact-points" may be either a point described as by a drop of adhesive, or may be a line of adhesive or other hastening means. Obviously, a line Or adhesive (say 2.5 cm) will give a ~2;~4L2~3 stronger bond at the place of contact than will a drop of the same adhesive. This can be decided by the manufacturer.

Dwelled oE1GRln lo The articles disclosed herein can be prepared using materials that are very well known in current commercial practice, and reference can be made to the various patents mentioned herein before and to the general disposable diaper patent literature and trade catalogues for such materials.
Likewise, methods and apparatus for assembling disposable diapers are known from patents and engineering literature.
While materials used in the assembly of disposable diapers and the like are well-known, the following maybe mentioned 501ely by way of example. It is to be understood that the present invention resides in the assembly of such materials, or their equivalents, into the folded absorbent structure disclosed herein, rather than in the materials so.
Buckshot : The buckshot can comprise a urine-impervlous _ _ polymer sheet, for example polyethylene or polypropylene, that is thin enough to be flexible. A polyethylene sheet 0.01-2 mm thick is typical Absorbent Core : The core can comprise any urine--absorbent material, such as cotton cloth, cellulose fires, n super-absorbent" polymers such as the.polyacrylamides, and the like. Air-laid felt comprising compacted cellulosic fires is typical, especially when formed as a flexible mat having a Tuber stiffness of about 7, and above.
Topshe2t : me top sheet can comprise any loosely woven or non woven sloth or scrim-type material that is urine-porous and comfortable to the skin. A non wove sheet comprising polypropylene ~ibres is typical.

- 6 ~230~2~

: The elastics can comprise elastic bands or thread, or elastic adhesive applied as a band or ribbon.
One or more elastics can be applied longitudinally along both sides of the diaper, and laid-down either on the top sheet, on the buckshot, or sandwiched between said sheets. In a typical mode, the elastic is restretched then glued to the diaper using an elastic adhesive, all in well-known fashion.
(Lee U.S. Patent 4 081 301.) Fasteners : The absorbent structures can be fastened by any convenient means, such as pins, snaps and the like.
Typical fasteners comprise adhesive tapes, especially tapes in the yule configuration described in the patent literature.
Assembly Means : The articles herein can be assembled by any convenient bonding means, such as heat-sealing, ultrasonic sealing, and the like. Typically, urine-stable adhesives are used to assemble disposable diapers.
Assembly Methods and Apparatus : The apparatus used to form the absorbent articles herein constitutes no part of the present invention. Indeed, such articles may be assembled by hand. Herr briefly considering the sophisticated technology enbo~ied in the hdgh-speed, automatic assembly of disposable diapers by art-disclosed machinery may assist in the appreciation of the practicality of the present invention.
A typical diaper assembly system comprises means to :
1) lay-down the buckshot; 2) position the core on the buckshot; 3) position the top sheet over the core; I
stretch and glue-down the elastics; I fasten the top sheet to the buckshot; and 63 affix fastener tapes, all more-or-less in that sequence. All sheet material and the elastics are generally introduced onto a unidirectional moving belt as continuous items, which are assembled, then cut into individual diaper at the end of the line.
All operations are done "in-line", at the rate of hundreds ox drapers pox minute. Thus, it will be appreciated that Lo ii3 -- 7 -- .

any operation that cannot be accomplished in-line (for Example, somehow turning the in-line flow of diapers to allow elastics to be applied curvilinearly) slows production dramatically.
In the present in~entlon the diapers can be manufactured and folded in-line by, for example, allowing the leading edges of the diaper to enter a folding device, or "flap" arrangement which laps the spacing elements over and bring fold points (6 and 7) into contact with, for example, glue beads or glue lines affixed at any preselected contact points (8 and 9 in the Figures), thereby achieving a fold on each side of the diaper which bends the elastics into a curvilinear configuration.
(The construction of a folding device can follow the general structural features of an automatic envelope flap sealer of the type well-known in commercial postage meters, and thy Luke Other means of achieving the folds using robotics, or manual folding, will be apparent to one skilled in the art.

INDUSTRIAL, APPLICATION
_ The following Example illustrates a preferred diaper made according to the present invention. The dimensions listed in the Example are for a diaper intended for use with a child in the 6 to 10 kilogram size range. These dimensions can be modified proportionately for different size children, or for adult incontinence briefs, according to standard commercial practice.

~3~5~

EXAMPLE I
A diaper according to Figure 3 is assembled the following materials and folded to the Figure 4 confi-gyration.
1. Buckshot : Owe mm polyethylene : width at top and bottom 33 cm; notched inwardly on both sides to a width-at-center of 28.5 cm; length 50.2 cm.

2. Top sheet : spun-bonded polypropylene, basis weight 21.5g/m2-24.5g/m2; width at top and bottom 33. cm;
Ned inwardly on both sides to a width-at-center of 28.5 cm; length 50.2 cm.

3. Absorbent core : air-laid wood pulp fires, Tuber range 7 - 9.5, 8~4 mm thick, calendared; width at top and bottom 28.6 cm;notched inwardly at both sides to a width-at-center of 10.2 cm; length 44.5 cm.

4. Elastics : four individual rubber strips (2 per side); width 4.77 mm; length 370 mm; thickness Owe mm (all the foregoing dimensions being in the relaxed state.) The diaper of Example I is prepared in standard fashion by positioning the core covered with the top sheet on the buckshot and gluing.
The elastic bands deign at d "inner" and Neuter", corresponding to the bands closest to, and farthest from, the core, respectively) are stretched to cay 50.2 cm and positioned between the topsheet/backsheet along each longitudinal side (2-bands per side) ox the core. the inner bands along each side are positioned cay 55 mm from the narrowest width of the core (measured from the inner edge of the elastic band). Stated otherwise, the inner band and the edge of the shaped core approximate an ~34~3 arc of a circle having a radius of 52~ ROD. This provides a spacing element along each side of the diaper comprising the flexible ~op~heet/backsheet material between the inner elastic and the curved edge of the core.
The inner bands are glued down along their length in the stretched state. The outer bands are positioned cay 13 mm from the inner bands, and are glued down along their length in the stretched state. Since the topsheet/backsheet assembly is flexible, the glued-down bands contract to elasticize the sides of the diaper.
The elasticized diaper prepared in the foregoing manner is flattened preparatory to olden in the manner of this invention. Contact points 8 and 9 are selected on the top sheet. In this preferred embodiment, the contact points 8 and 9 are displaced towards what will be the front of the diaper, in-use, as shown in Figures 3 and 4. For this size diaper, the contact points are positioned on the top sheet over the core about 16.5 cm from the end edge of the core and about 30 mm inward from the left and right edges of the core, respectively.
Glue beads or glue lines are placed at each contact point.
Fold points 6 and 7 are selected on each spacing element. In this preferred embodiment, the fold points are each selected on their respective spacing elements approximately 30 mm from the edge of the diaper core and are each displaced away from the longitudinal midpoint of the diaper towards the front of the diaper (i.e., do in I 3) to a point about 16~5 cm measured from the end of the core.
Fold points and 7 are brought over in a simple fold into contact with the glue at contact points 8 and 9, respectively, and sealed. This results in the structure depicted in Figure 4. Fastener tapes are optionally, and preferably, affixed to the diaper as shown in the Figures.

lo ~23~53 In-use, the diaper of Example I is positioned on the child with the fastener tapes at the back and the folds at to front of the child. The elastics on both sides of the diaper are in the em of upward and outward-racing, curvilinear leg openings which snugly conform them-selves around the child's legs when the fastener tapes are attached to the front of the diaper to hold it in place.
It will be appreciated by those skilled in the art that the folds herein can be on either, or most preferably both, sides of the diaper. While Example I
employs a preferred non-rectangular shaped core/backsheet/
top sheet assembly, rectangular diapers may also be assembled an folded in the manner disclosed herein.
In an alienate mode, the core may be non-rectangular, and the buckshot rectangular, and vice-versa.
It will be further appreciated that the present invention encompasses not only the diaper structures, but also the method for converting essentially linearly-applied elastic members in an absorbent diaper, or the like, into curvilinear elastic members by folding in the manner disclosed herein. Of course, the degree of curving of the elastics can be routinely adjusted according to the desires of the manufacturer by adjusting such parameters as the width of the spacing element, positioning of the contact points, shaping of the core/
backsheet/topsheet, and the like.
Importantly, by selecting a fold position away from the longitudinal mid-point of the diaper (e.g., 2-5 cm forward in a Lowe Kg diaper) a bulge or "pocket" is created in the diaper which tends to hold it away from the skin, in-use.
Moreover, the folds used in the present diapers are made using the spacing element and the core, itself, is not molded over wince olden the core would lead to bunching and disk comfort to the user.

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. An absorbent structure, comprising a backsheet, absorbent core, a topsheet, and at least one elastic member along each longitudinal side of the structure, said elastic member being situated away from said absorbent core to provide flexible spacing elements;
said spacing elements being folded over said absorbent core at at least one fold point and being affixed to said topsheet at at least one contact point, whereby at least one said elastic member is bent from its original configuration into a curvilinear shape, thereby providing an improved leg opening for the absorbent structure.

2. A structure according to claim 1 wherein said spacing elements are folded over and affixed at at least one contact point, thereby providing generally outward-facing, curvilinearly-elasticized leg openings.

3. A structure according to claim 2 wherein said absorbent core and said backsheet, are substantially rectangular.

4. A structure according to claim 2 wherein said absorbent core, is substantially non rectangular.

5. A structure according to claim 4 wherein said absorbent core, said backsheet and said topsheet have an hourglass configuration.

6. A structure according to claims 1, 2 or 3 wherein said fold point and corresponding contact point are displaced away from the longitudinal midpoint of the absorbent structure.

7. A structure according to claims 4 or 5 wherein said fold point and corresponding contact point are displaced away from the longitudinal midpoint of the absorbent structure.

8. A structure according to claims 1, 2 or 3 wherein said fold point and corresponding contact point are displaced away from the longitudinal midpoint of the absorbent structure, said fold point and said contact point being displaced towards the front of the absorbent structure.

9. A structure according to claims 4 or 5 wherein said fold point and corresponding contact point are displaced away from the longitudinal midpoint of the absorbent structure, said fold point and said contact point being displaced towards the front of the absorbent structure.