CA1100706A

CA1100706A - Shaped absorbent pad for disposable diapers

Info

Publication number: CA1100706A
Application number: CA318,637A
Authority: CA
Inventors: Virginia L. Repke
Original assignee: Johnson and Johnson
Current assignee: Johnson and Johnson
Priority date: 1977-12-29
Filing date: 1978-12-27
Publication date: 1981-05-12
Also published as: AU522382B2; GB2011791A; AU4199778A; BR7808293A; MX149618A

Abstract

Abstract of the Disclosure An improved disposable diaper containing a rectangular shaped absorbent pad. The pad has an indentation disposed along each long side nearer one end of the pad than the other. The front half of each indentation is a quadrant of a circle and the back half of each indentation is triangular in shape.

Description

~L00706 The present invention relates to shaped absorbent pads for use in disposable diapers~
Disposable diapers have and are continuing to gain wide acceptance as a substitute for previously used cloth diapers and as an adjunct to such cloth diapers. Most disposable diapers have been rectangular in shape and folded in a manner to aid in their application about the buttocks of the baby. In some instances, the diapers have been folded in geometric configura~ions to aid in their application to the baby. Also, some diapers contain hourglass shaped absorbent panels; that is, absorbent panels which are narrow in the center portion and wide at the front and rear end portions. :~
It has been known for some time now that if the bulk of the diaper could be reduced in the area between the legs of the wearer the fit of the diaper would be improved. However, reducing ~he bulk in the area between the legs means reducing the amount of absorbent material used in that area, an area where absorbency is very important. ~ :
What I haYe ~iscovered is a new and improved shaped absorbent pad for use in disposable diapers. My new and improved shaped pad reduces the bulk between the baby's legs while maintaining excellent absorptive efficiency of the pad both in the front portion and the

-2-ll~)V7V6 rear portion of the pad. IFurthermore, my lmproved pad provides an excellent fit about the baby's legs them-selves to produce an aesthetically appealing diaper and a more stable diaper during use.

SUMMARY OF THE PRESENT ~NVEMTION
_ _ .

The improved pad of the present in~ention is substantially rectangular in shape. The pad has a pair of short parallel ends and a pair of long parallel sides perpendicular to said ends. Disposed in opposed relation-ship on each longit~dinal side is an indentation. The deepest point of each indentation is positioned at approximately one-third the length of the rectangular panel to divide the pad into a short portion to be positioned in front of the ba~y and a longer rear portion to extend between the baby's legs and behind the buttocks.
The front edge of each indentation is arcuate and the front half of each indentation has substantially the shape of a quadrant of a circle. The rear edge of each indenta-tion has a uniformly straight slope from the deepest part of the indentation to the longitudinal side of the pad at an angle ~f from ahout 30 to 45 degrees to the center of the sides o~ the pad, The rear half of each indentation has a substantially triangular shape~

11L)0706 By virtue o~ the above-described shape, maximum absorpt~e capacity of the pad is retained in the crotch region; while at the same time improYed fit around the legs of the baby is provided.
In a preferred embodiment of the pad of the present invention, the four corners have extended portions to provide the pad with extra absorbent capacity. In another embodiment of my ~mpro~ed pad, the cross-sectional shape of the pad is contoured with the center portion Of the pad being thicker than the edge portions of the pad to provide extra absorbency in the central area.
The improved pad of the present invention is usually used between a pervious or permeable facing layer which is soft and is disposed against the baby's ~
skin and may be of such material as to ma~ntain the ~ -baby's skin relati~ely dry while the diaper is being worn and a backing layer on the opposite side of the pad from the facing layer. The backing layer is generally an imper~ious film material to prevent strike-through of liquid. In sQme embodiments, my improved pad may contain a densified paper-like skin area and one or more densified compacted geometrical areas to improve the wicking, capillarity and distribution of liquid through the absorbent pad and impro~e its efficiency. ~~~~~~~

According to a broad aspect of the present inven-tion there is provided a multi-layer diaper comprising a porous facing layer, an absorbent pad positioned in face~to face juxtaposition with the facing layer. -!The side edges of the pad terminate inwardly from the side edges of the facing layer, and a water-impervious bac]~ing sheet is positioned in face-to-face juxtaposition with the pad on the surface of the pad, opposite from the facing layer. The backing sheet i5 generally coextensive with the facing layer. The facing layer and the backing sheet are adhered to one another in marginal areas beyond the pad. The pad is substantially rectangular in shape and has an indentation along each longer parallel side, The indentations are disposed opposite each other and are positioned approximately one-third the distance from one end of the pad, to define a shorter front portion and a longer rear portion of the pad, where~y a diaper having an improved fit is produced. The sides of the pad immediately adjacent the indentations in the central portion of the pad is parallel with the longitudinal center line of the pad whereby the improved fit is obtained with minimum loss of absorptive capacity.

- 4a -~007a6 BRIEF DESCRIPTION OF THE DRAWIN~S

The invention will be more fully described in conjunction with the accompanying drawings where;n:
FIGURE 1 is a plan view of the improved pad of the present invention;
FIGURE 2 is a plan view of a disposable diaper incorporating the improved pad of the présent invention with a portion broken away to show the various ,~
layers;
FIGURE 3 is a plan ~iew of another embodiment of a disposable diaper incorporating the improved pad of the present invention;
FIGURE 4 is a plan view of another embodiment of a disposable diaper incorporating the improved pad of the present invention with a portion broken away to show the various layers;
~IGURE 5 is another em~odiment of a disposable diaper incorporating the pad o the present in~ention with portions broXen away to show the various layers;
FIGURE 6 is a cross-sectional view along line 6-6 of Figure 4;
FIGURE 7 is an enlarged cross-sectional view of a portion of an embadiment of the improved pad of the present invention;

FIGURE 8 is another corss-sectional view of another embodiment of the pad of the present invention.

DETAILED DESCRIPTION OF THE DRAWINGS

As shown in Figure 1, the absorbent pad of the present invention has a substantially rectangular shape.
The pad has parallel opposite end margins ll and 12 and parallel opposite longitudinal side margins 13 and 14.
Along ~he longitudinal margins there are disposed indentations 15 and 16. The deepest part of the indentations is approximately One-third along the length of the pad to form a smaller ~ront portion 17 and a larger rear portion 18. The front edge 19 o~ each indentation is arcuate and the front half of the indentation has the shape of a ~uadrant of a circle. In use, the fxont edge contacts the inner and front portion of the baby's leg or ~high to pro~ide a good fit in that area. The rear edge 20 of the indentation is generally uniformly sloped from the deepest part o~ the indentation to the longitudinal edge portion. In use, this rear edge fits about the rear of the baby's leg or thigh to provide a good fit ~20 in that area. The sloped rear edge makes an angle of about 30 to 45 degrees to the ~enter line of the ~iaper. The side margins adjacent the indentations in the central 1101)706 portion of the pad are parallel with one another. This con~iguration provides the improved fit with a minimum loss of absorptive capacity. As shown in this Figure 1, the four corners 21, 22, 23, and 24 contain extended longitudinal side portions which fit about the waist area of the wearer and proYide increased absorbent material and capacity in the pad. ~he size and shape of the corners may vary greatly depending on the type and size of the diaper being produced.
The indentations, depending on whether the diaper is a newborn size, toddler size, or other size, will vary from about an inch to two inches in depth and preferably from about 1 1/4 to 1 3/4 inches in depth. The front edge or quarter circle is on a radius similar to the depth or equal to the depth dImension. The distance the daepest part of the indentation may be from the front end margin of the absorbent pad may vary from about four to six inches and from about 30~ to 40% of the total length of the pad and preferably from about 30% to 35% of the . .
total length of the pad to provide the desired fit and aesthetically shaped pad. In some embodiments o the indentation, the portion of the front edge which meets the longitudinal side of the pad may be a straight portion;
i.e., perpendicular to the side, depending on the size of the diaper being produced. The gently sloped rear edge, _z_ where it starts from the deepest part of the indentation, may also be gently rounded be~ore it straights out to its desired slope, again depending on the size of the diaper being produced. The indentation as described provides a close, neat fit around the wide variety of leg sizes.
The narrowed crotch area; i. e., the dimension of the pad between indentations, may also be varied according to diaper size. This dimension may be as small as 3 to 3 1/2 inches for a newborn size diaper or as large as 4 1/2 inches or more for toddler or other large size diapers. I have found a narrowed crotch area dimension of 3 1/2 to 4 inches to be satisfactory for most size diapers.
In Figure 2, there is shown a diaper 27 comprising an impervious backing sheet 28, shaped absorbent pad 29, and a pervious or permeable facing sheet 30. At one end of the diaper along both -longitudinal side margins are a pair o~ adhesive tape tabs 31 for affixing the diaper about the infant. The pad 29 has two parallel end margins and two parallel longitudinal side margins. Disposed along each longitudinal side portion is an indentation 32 with the indentations opposite each other. The indentations ha~e a quarter circle front portion and a uniformly sloped back portion and ar~

110(~706 ~BP 100 po~itioned approximately one-third of the distance along the length of the pad.
In the emb~diment in Figure 3~ there is shown a diaper 33 ha~ing backing sheet 34, a per~ious facing sheet 35 and a substantially rectan~ular absorbent pad 36.
At the one end of the diaper, are a pair of tape tabs 37 for affixing the diaper about the infant. The pad shown in this ~mbodiment includes four outwardly extending corners 38. These corners provide extra absorbent material to increase the capacity of the pad.
Referring to Figure 4, there is shown another embodiment of a disposable diaper 40 incorporating the newly shaped pad of the present invention. The diaper comprises a shaped impervious film backing member 41 and a co-extensive shaped pervious facing member 42 with a shaped pad 43 of the present invention disposed therebetween. At one end of the diaper are a pair of oppositely disposed tape ta~ 44 for affixing the diaper about the baby. The shaped pad has a pair of oppositely disposed shaped indentations 45 and 46 along the longitudinal side edges of the pad. As seen, the shaped indentations haye a quarter circle front portion and a gently sloped rear edge. The longitudinal edges 47 and 48 of the facing and backlng layers are ~ndented to provide the diaper with _g_ 11~(970~i an overall shape.
As seen in the cross-sectional view shown in Figure 6, the facing 42 and backing 41 layers are sealed together along their longitudinai edges 47 and 48 and the absorbent pad includes a wicking layer, or dense area 49 at the surface next to the ~acking layer and a plurality of densified or compa~ted longitudinal lines 50 to aid in.the wic~ing and distribution of fluid being absorbed by the pad.
As may be more clearly seen in the enlarged cross-sectional view of Figure 7, the absorbent pad. 51, in many embodiments of the present in~ention, may have a densified surface 52 preferably the surface which is d~sposed adjacent the Lmpervious backing member. This densified ~ 15 paper-like surface may be formed by applying moisture : to the pad and applying pressure as disclosed in U.S.
Patent 3,017,304 or U.S. Patent 3,993,820. The later patent includes the addition of longitudinally densified lines 53 to provide for improved capillarity, wicking :
and distribution of liquids absorbed by the pad.
Referring to Figures 5 and 8, there is shown another embodiment of a disposable diaper 53 which incorporates the newly shaped pad 54 of the present invention.
In this embodiment the backing layer 55 is shaped as des-cribed in conjunction with Figure 4 and the co-extensive )V706 JBP lO0 .
facing layer 56 is similarly shaped An end portion of the diaper contains oppositely disposed adhesive tabs 57 for affixing the diaper to the baby. The shaped pad of the present in~ention is disposed between the backing and facing layers and contain the indentations 58 disposed approximately one-third along the length of the pad. Along the longitudinal side edges of the pad are rubber stxips 59 which are inserted in the diaper ~ in their extended or stretched state, sealed to the :~ lO backing and/or facing layer and allowed to relax to .: provide elastic sides in the diaper to provide a tight fit :: about the baby's legs.
The absorbent pads of the present invention are preferably formed of loosely compacted, short cellulose fibers, such as wood pulp fibers, or cotton : linters, or mixtures thereof, which are primarly held : together by interfiber bonds requiring no added adhesive, as is known in the art.
The term "short fibers" as used herein, refers ~ 20 ~o fibers less than about 1/4 inch in length, in contrast to "long fibers" or "textile length fiber " which are longer than about l/4 inch in length, and generally are between l/2 inch and 2 l/2 inches in length.
The backing layers used in making the disposable diapers of the present invention may be any of the thermo--lI-11~()7()6 plastic films such as polyethlene, polypropylene and the li~e and may contain perforations or breathin~ areas as desired if these areas are placed in such a manner as not to allow liquid to pass throuqh.
The facing layers may be any ~f the facing layers presently used on disposable diapers including the facing layers described and disclosed in conjunction with Mesek, et al. U.S. Patents 3,777,758 and 3,768,480 or other non-woven fabrics. Other facing layers that may be also used in the diapers of the present invention are the polyester fabrics or the perfora~ed film materials.
The foregoing description and the drawings are intended as illustrative and are not to be taken as limiting. Still other variations are possible without departure from the spirit and scope of this invention.

Claims

The embodiments of the invention in which an exclu-sive property or privilege is claimed are defined as follows:

1. A multi-layer diaper comprising a porous facing layer, an absorbent pad positioned in face-to-face juxta-position with the facing layer, the side edges of the pad terminating inwardly from the side edges of the facing layer, and a water-impervious backing sheet positioned in face-to-face juxtaposition with said pad on the surface of said pad, opposite from said facing layer, said backing sheet being generally coextensive with said facing layer and said facing layer and said backing sheet being adhered to one another in marginal areas beyond said pad, said pad being substantially rectangular in shape and having an indentation along each longer parallel side, said indentations being disposed opposite each other and being positioned approxi-mately one-third the distance from one end of said pad, to define a shorter front portion and a longer rear portion of the pad, whereby a diaper having an improved fit is produced, the sides of said pad immediately adjacent to said indenta-tions in the central portion of the pad being parallel with the longitudinal center line of said pad whereby said improved fit is obtained with minimum loss of absorptive capacity.

2. A multi-layer diaper comprising a porous facing layer, an absorbent pad positioned in face-to-face juxta-position with the facing layer, the side edges of the pad terminating inwardly from the side edges of the facing layer, and a water-impervious backing sheet positioned in face-to-face juxtaposition with said pad on the surface of said pad, opposite from said facing layer, said backing sheet being generally coextensive with said facing layer and said facing layer and said backing sheet being adhered to one another in marginal areas beyond said pad, said pad being substantially rectangular in shape and having an indentation along each longer parallel side, said indentations being disposed symmetrically opposite each other and being positioned approximately one-third the distance from one end of said pad, to define a shorter front portion and a longer rear portion of the pad, said indentations having an arcuate front edge adjacent the short portion of the pad and an angled rear edge adjacent the longer rear portion of the pad, whereby a diaper having an improved fit is produced, the sides of said pad immediately adjacent to said indentations in the central portion of the pad being parallel with the longitudinal center line of said pad whereby said improved fit is obtained with minimum loss of absorptive capacity.

3. A diaper according to claim 2 wherein the rear edge is at an angle of from 30° to 45° to the longitudinal center line of the diaper.

4. A diaper according to claim 2 wherein the pad includes a densified, compacted layer on one of the surfaces of the pad.

5. A diaper according to claim 2 wherein the pad includes a plurality of densified and compacted areas disposed throughout the pad to improve absorbency and stability of the pad.

6. A diaper according to claim 2 wherein said arcuate front edge is approximately 120°.

7. A substantially rectangular shaped absorbent pad having one indentation in each long side, each indentation being disposed symmetrically opposite the other, and being positioned approximately y one-third the distance from one end of the pad to provide a short area between the one end of the pad and a first portion of the indentation, and a long area between the opposite end of the pad and a second portion of the indentation, the first portion of the indentation having substantially the shape of a minor portion of a circle, the arc of which ranges from about 90° to about 120°, providing the deepest part of the indentation, a second portion of each indentation being formed by a line of uniformly straight slope from the deepest part of the indentation to the longitudinal side of the pad at an angle from about 30°
to about 45° to the sides of the pad, the second portion of each indentation having a substantially triangular shape.

8. An absorbent pad according to claim 7 wherein the four corners of the pad extend outwardly beyond the long sides of the pad.

9. An absorbent pad according to claim 7 wherein two corners at one end of the pad extend outwardly beyond the long sides of the pad.

10. A shaped disposable diaper comprising an impervious backing layer and a pervious facing layer, said layers being coextensive, and an absorbent pad disposed between said layers and spaced inwardly from the end margins and side margins of said facing and backing layers, said facing and backing layers having their greatest width at said end margins and a narrower width between said end margins, said pad having its widest portions adjacent the end margins and being narrower in the center portion of the pad, said pad having an indentation in each longitudinal edge adjacent said side margins, said indentations being disposed symmetrically opposite each other and being positioned approximately one-third the distance from one end of the pad to provide a short area between the one end of the pad and a first portion of the indentation, and a long area between the opposite end of the pad and a second portion of the indentation, the first portion of the indentation having substantially the shape of a minor portion of a circle having an arc from about 90° to about 120°, providing the deepest part of the indentation, a second portion of each indentation being formed by a line of uniformly straight slope from the deepest part of the indentation to the longitudinal side of the pad at an angle from about 30° to about 45° to the sides of the pad, the second portion of each indentation having a substantially triangular shape.

11. A shaped diaper according to claim 10 wherein an elastic member is disposed in each side margin between the facing and backing layers and adjacent the pad.