Title:
PREFOLDED DIAPER WITH IMPROVED LEG FIT
United States Patent 3848595


Abstract:
A prefolded disposable diaper of the wing fold style and having a transverse fold in which each of the side edges adjacent the transverse fold are fastened securely to each other a predetermined distance from the transverse fold whereby the length of each of the side edges is made effectively shorter than the normal full length dimension of the diaper. These shortened side edges provide a closer fit around the child's leg at the interior thigh area. A downwardly depending fin formed at the side edges by the edge securement also defines a side pocket on each side useful as an additional entrapment area for excrement.



Inventors:
ENDRES D
Application Number:
05/354495
Publication Date:
11/19/1974
Filing Date:
04/26/1973
Assignee:
KIMBERLY CLARK CORP,US
Primary Class:
International Classes:
A61F13/15; (IPC1-7): A61F13/15; A61f013/16
Field of Search:
128/284,286,287
View Patent Images:
US Patent References:
3744494DISPOSABLE DIAPER WITH IMPROVED CONTAINMENT CHARACTERISTICS1973-07-10Marsan
3710797DISPOSABLE DIAPER1973-01-16Marsan
3426756DISPOSABLE DIAPER1969-02-11Romanek
3402715Diaper1968-09-24Liloia et al.
3196874Disposable prefolded diaper1965-07-27Hrubecky



Primary Examiner:
Medbery, Aldrich F.
Attorney, Agent or Firm:
Hanlon Jr., Daniel Herrick William Miller Raymond J. D. J.
Claims:
What is claimed is

1. In a disposable prefolded rectangular diaper of the wing fold type having top and side edges in which side portions of the diaper are first folded inwardly, in which marginal portions are then folded outwardly, and in which the diaper is further folded approximately in half in the transverse direction; the improvement wherein the facing surfaces of the folded diaper are securely fastened together at each of the side edges in an area closely adjacent the transverse fold in a manner to shorten each of said side edges to prevent extension of the side edges to full length and to provide downwardly extending fin portions adjacent the transverse fold of each of said side edges, which fin portions are retained when the prefolded diaper is opened up and applied to an infant.

2. The prefolded diaper of claim 1 wherein said wing fold comprises a triangular wing fold.

3. The prefolded diaper of claim 1 wherein said wing fold comprises a longitudinal wing fold.

4. The prefolded diaper of claim 1 wherein said side edges are shortened in an amount in the range of 8 percent to 14 percent of the original diaper length.

5. The prefolded diaper of claim 1 wherein the side edges of said downwardly extending fins portions are sealed.

Description:
BACKGROUND OF THE INVENTION

In the art of disposable diapers it is known that by prefolding rectangular diapers in a suitable manner it is possible to provide a somewhat better leg fit at the inner thigh which tends thereby to minimize leakage of both fluid and solid excrement. However, there is a need for still further improvements in leakage control. This invention is directed to one such improvement.

An example of one commercial form of prefolded disposable diaper to which the improved structure of this invention can be applied may be found in U.S. Pat. No. 3,196,874 to Hrubecky and assigned to the assignee of this invention. The diaper described in that patent, has inward and outward diagonal folds on each side of a central pocket at the medial transverse fold line which form leg receiving areas on each side of the diaper. This style of fold will be referred to hereinafter as a triangular wing fold.

Another example of a commercial form of prefolded diaper to which the improved structure of this invention can be applied may be found in U.S. Pat. No. 3,180,335, to Duncan, et al. The prefolded diaper described in that patent has inward and outward folds extending longitudinally for the full length of the diaper on each side of an elongate central panel section. The longitudinally folded diaper is also folded transversely in half. This style of fold will be referred to hereinafter as a longitudinal wing fold. It should be noted that this patent is cited only to illustrate the style of fold rather than its other distinctive aspects.

Both the longitudinal and wing fold diaper described in the above patents also suggest adhesive securement of facing surfaces of the prefolded diaper which securement is located a substantial distance inwardly of the diaper side edges to assist in retaining the folds at least until such time as the diaper is attached to the infant.

In studying the causes of diaper leakage at the thighs it was noted that for both the triangular and longitudinal wing fold diapers a fairly snug fit is obtained initially when either style diaper is first applied to the infant. However, the fit appears to become progressively less snug the longer the diaper is worn.

With the improved structure defined herein a tighter initial fit at the thighs appears to be obtained which is retained for the entire time the diaper is worn to aid in reducing the number of leakage incidents.

SUMMARY OF THE INVENTION

The invention is directed to an improvement in prefolded rectangular disposable diapers of the wing fold type. The fold may be either the triangular or longitudinal style of wing fold. The improvement comprises permanently securing together the side edges of the prefolded diaper at a predetermined distance from the transverse fold line of the diaper. This securement foreshortens the diaper sides, and the shorter sides permit the diaper to be fastened more snugly around the legs. Securing together the sides in this manner also forms a protruding external fin at the transverse fold line on each side of the diaper, as well as a small inwardly disposed pocket on each side adjacent each of the secured portions. The fins also serve to keep the diaper from being flattened when it is initially spread open for application to the infant. The side pockets provide additional catchments for body discharges. It has also been found that when the diaper is applied to an infant, the shortening of the diaper sides in the manner described holds the central portion of the diaper further away from the discharge orifices of the infant than a diaper without such structure. It is believed that this greater distance exposes a larger target area of the absorbent surface in the center of the diaper pad to the initial impact of urine and fecal discharges and thereby reduces the chances for run-off. In addition, the shortening of the diaper side edges provides a structure with a deeper pouch between the legs and appears to improve total capacity.

The above features and other advantages of the invention will become apparent by the following detailed description and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is a diagrammatic plan view of the surface of a rectangular diaper schematically illustrating the fold lines and a means for edge securement of one form of a triangular wing fold diaper embodying the invention.

FIG. 1A is a fragmentary plan view of a part of a diaper similar to FIG. 1, but showing another embodiment of the invention.

FIG. 2 is a perspective view of the FIG. 1 diaper illustrating the initial direction of fold taken by various parts of the diaper as it is being folded.

FIG. 3 is a perspective view of the FIG. 1 diaper with the folds almost completed.

FIG. 4 is a diagrammatic plan view similar to FIG. 1 but illustrating the fold lines and a means for edge securement of one form of a longitudinal wing fold diaper embodying the invention.

FIG. 5 is a perspective view of the FIG. 4 diaper illustrating the direction various parts of the diaper initially move as it is being folded.

FIG. 6 is a perspective view of the FIG. 4 diaper with the folds almost completed.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Turning now to the drawings, FIG. 1 is a plan view of a rectangular diaper schematically illustrating one form of the line pattern on which a triangular wing fold diaper may be folded. As will be noted, this diaper has a transverse fold line 12 dividing the diaper into approximate half sections; a pair of diagonal fold lines 14 extending from the approximate center of the diaper on each side of transverse line 12 to the respective edges of the diaper short of the diaper ends; and another pair of diagonal fold lines 16 extending from points on the transverse line 12 midway between the center and edges thereof to the same terminal points on the diaper edges as lines 14.

When folding the diaper to its marketed configuration, the diaper is folded inwardly on lines 14 and outwardly on lines 16 as partially shown in FIG. 2 to provide the folded configuration shown in FIG. 3, which is in its almost completed form.

While the FIG. 3 configuration is shown as partly opened it will be understood that the diaper in its final folded form will be collapsed with the surfaces of all folded sections in contact. It will also be understood that while, as shown in these drawings, lines 14 diverge to the outside edges from the approximate center of transverse line 12, lines 14 can also diverge from points spaced from the center and located between the center of line 12 and the diaper edges. The transverse fold line 12 need not divide the diaper into exactly equal halves, since it may be desirable for the waist portion to be higher or lower in front.

The improvement of this invention comprises shortening the diaper edges to a length dimension which is significantly shorter than the overall length of the diaper by securely fastening selected portions of the diaper side edges to each other adjacent the transverse medial fold line. The shortened area of the diaper edges, for example, may be that part of the diaper edge enclosed in brackets 18. When this foreshortening is done, for example, by utilizing an adhesive line 20 at the diaper edges, which adhesive line extends an equal distance on each side of transverse line 12, portions of the folded diaper edges are substantially permanently secured to each other in a manner to form a depending fin 22 at each edge of the diaper at transverse line 12. The fin 22 normally extends inwardly from the edge at least to fold line 16, where it may blend into the transverse fold line. In the embodiment illustrated, adhesive 20 also seals that portion of the side edges of the diaper which comprise each of the fins 22.

While this edge securement is shown as an adhesive line 20, other fastening means such as stapling, sewing or taping may be used. When a line of adhesive is used it may also be applied on only one side of line 14, rather than both sides as shown, as long as a secure joining of the edge is obtained. The securement areas may also comprise a spot joint spaced from line 14 rather than a continuous edge seal, but this is a less favored method of securement.

The edge securement, as described, serves several purposes:

First, it permanently shortens the dimension of the diaper edges to make the edge dimension significantly less than the overall length of the diaper.

Second, it provides a small functional pocket portion 24 at each side of the diaper on the transverse line 12 and adjacent each edge, which pocket serves as a supplementary excrement trap.

Third, by preventing the central bottom portion of the diaper along the transverse line from being drawn closely against the infant's body when worn, it allows that central portion of the diaper to hang lower and farther away from the infant when in place, thus in effect providing a bigger pouch for the reception, and mechanical holding therein, of body excretions without increasing the size of the diaper. With this structure, the functional absorption ability of the absorbent core element also appears to be increased. While the reason for the latter is not known, it is believed to be due, among other reasons, to the possibility that the lower hanging pouch exposes a larger target area for the body excretions to strike as they are discharged, as well as assisting retention by gravity.

Fourth, by shortening the edges the diaper is provided with a tighter leg fit in the thigh area when the diaper is in place on the infant. This tighter fit appears to remain effective for a longer time when compared to results for similarly folded diapers without the shortened edges.

FIGS. 4-6 illustrate another embodiment of the improvement of this invention as applied to a longitudinal wing fold diaper.

The plan view of FIG. 4 illustrates a pair of inward fold lines 34, transversely spaced from the center of the diaper and extending longitudinally for the length of the diaper on each side of transverse center line 28, and a pair of outward fold lines 36 disposed intermediate lines 34 and the diaper edges. These longitudinal fold lines divide the diaper into a large central panel flanked by two substantially equal narrower panels on each side. The direction in which the panels are longitudinally folded at the start of the folding operation is shown in FIG. 5. The longitudinally folded diaper is also folded transversely on line 28. The almost completed fold is shown in FIG. 6.

In this longitudinal wing fold embodiment, as in the embodiments of the triangular wing fold shown in FIGS. 1-3, the improvement comprises significantly shortening the length of the diaper edges by fastening the edges securely adjacent the transverse fold. In this illustration, the shortened portion comprises the edge length enclosed within brackets 38. As further illustrated in this embodiment, such shortening is obtained by utilizing an adhesive strip 40 extending the same distance on each side of transverse line 28. Thus, when the diaper is in its final transversely folded configuration, these adhesive lines are joined to form a permanent fin 44 on each edge of the diaper at the transverse fold line.

Securement of the diaper edges in this way, or by using other fastening means, provided the longitudinal wing fold diaper shown in FIGS. 4-6 with advantages similar to those set forth and described for the FIGS. 1-3 trinagular wing fold diaper.

The depth of the external fins 14 in the triangular wing fold diaper and external fins 44 in the longitudinal wing fold diaper may vary and still permit the fins to perform their improved function. From a performance standpoint an optimum fin depth has been established for each of the diaper sizes now marketed.

For example, a newborn size diaper is about 10 inches × 14 inches and the preferred depth of the fin for this size is 5/8 inch, or an overall edge shortening of 1-1/4inches.

A medium size diaper is about 11 inches × 16 inches and the preferred depth of the fin is 3/4 inch, or an overall edge shortening of 1-1/2 inches.

A toddler size diaper is about 12-1/2 inches × 17-1/2 inches and the preferred depth of the fin is 1 inch or an overall edge shortening of 2 inches.

A suitable depth of the fin may also be characterized as a percentage of the overall diaper length. Improved functions are obtained if the depth of the fin comprises from about 4 percent to about 7 percent of the overall diaper length, or stated another way, if the amount the diaper edges are shortened is from about 8 percent to about 14 percent of the overall diaper length, i.e., twice the fin depth. In general, the smaller size diaper desirably has a fin depth nearer the lower percentage range while the larger size diaper has a fin depth nearer the higher percentage range.

It is understood that this invention is particularly applicable to wing-folded disposable diapers of the type which generally comprise an absorbent core of fluffed wood pulp fibers or absorbent wadding and the like, a pervious top sheet, and an impervious backing sheet. Many variations of such disposable diaper structures are now being marketed by several manufacturers. The invention applies to all such diaper variations as long as it is feasible to shorten the edges and provide the fin structure as described above.

While in each instance, the diaper is shown as being fastened by a line of adhesive adjacent and parallel to each edge at the transverse fold line, it is understood that other permanent securement means may be used such as sewing, stapling, taping or the like. The important requirement is that the attachment be sufficiently strong to maintain the shortened edge dimension in use.

The entire side edge of the fin need not be sealed in the manner which results when one uses an adhesive line 20 parallel to the edge as shown in FIG. 1, although this is the preferred structure. Another way of sealing the diaper, for example, is by using a spot joining at the edge which spot is spaced from the transverse line; or as shown in the fragmentary plan view of FIG. 1A by a diagonal line or lines of adhesive 20a. As shown here, the line or lines extend diagonally from the edge of the diaper to the intersection of lines 12 and 16.

The following specific examples illustrate the effectiveness of the shortened edge structure in improving retainment of excretions and reducing leakage.

The diapers tested were taken from commercial lots of KIMBIES disposable diapers. Comparisons were made between modified and unmodified newborn, medium, and toddler size diapers. These diapers are manufactured substantially in accordance with the aforementioned Hrubecky U.S. Pat. No. 3,196,874 and are generally characterized herein as triangular wing fold diapers.

Each of the diapers have an absorbent core of airformed wood fluff fiber, wrapped in an absorbent creped tissue sheet, a fluid pervious cover sheet of scrim reinforced absorbent tissue, and a backing sheet of 1.0 mil embossed and white pigmented polyethylene. A pair of pressure sensitive adhesive tapes are attached near one end of the polyethylene backing for use in maintaining the diapers in place around the infant's waist.

In the following tables the unmodified diapers of each size are identified as regular diapers, and the modified diapers are identified as having a fin of specified depth. The newborn diapers were tested on infants of less than about 14 lbs. in weight, the medium on infants weighing about 12-22 lbs., and the toddlers on infants weighing over about 20 lbs. The newborn diapers tested had an average fluff and tissue wrap weight of about 28 grams; medium diapers 29 grams, and toddler diapers 29 grams.

Results were as follows:

Urine Leakage Sample Total Fecal Diaper Type Size Leakage Top Leg Heavy Leakage __________________________________________________________________________ Newborn Regular 299 23.7% 16.3% 10.1% 13.7% 13.1% Newborn 5/8" fin 300 17.9% 15.0% 3.0% 7.7% 10.0% Medium Regular 587 15.8% 8.6% 10.9% 7.0% 6.9% Medium 3/4" fin 597 11.9% 7.4% 7.4% 6.2% 3.8% Toddler Regular 313 20.0% 5.5% 16.9% 6.8% 6.4% Toddler 3/4" fin 156 14.0% 9.0% 7.7% 3.2% 4.2% Toddler 11/4" fin 310 10.7% 7.5% 7.5% 4.9% 2.1% __________________________________________________________________________

Urine leakage is a subjective trait measured by visual and/or tactile observations of the mothers, based on their identification of wet or damp garments or bed clothing. Top leakage refers to leakage at the waist. Leg leakage refers to leakage at the legs. Heavy leakage refers to leakage where fluids were visible. Fecal leakage refers to garments soiled by feces, and includes only those diapers which contained feces, the number of which was much lower than the total sample size in each case.

It should be noted here that both the Hrubecky U.S. Pat. No. 3,196,874 and the Duncan, et al, U.S. Pat. No. 3,180,335 mentioned earlier teach among other features the use of adhesive spots to retain their multifolded structure until the diapers are applied to the infant. However, it is clear that neither the positioning of these adhesive spots nor their disclosed function operate to permanently shorten the side edges of the diaper as disclosed herein. Accordingly, the manner of adhesive fastening of interior contacting faces of the folded diapers as set forth in these two referenced patents do not obtain the improved efficiency of the structure set forth in the present invention.