CA1097451A - Contractable side flaps for disposable diaper - Google Patents

Abstract

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CONTRACTABLE SIDE PORTIONS FOR DISPOSABLE DIAPER

Kenneth B. Buell ABSTRACT OF THE DISCLOSURE
An elastically contractable, flexible side por-tion for an integral disposable diaper. The side portion extends along the lateral edge of the diaper and an elastic contracting member is attached to the side portion ad-jacent the outer lateral edge of the side portion to elastically contract the outer edge of the side portion.

Description

BI~CKGROUND OF THE INVENTION
This invention relates generally to receptors comprising portable appliances intended to be used to receive or tending to receive discha-ge from the body and in particular relates to disposable diapers, incon-tinence pads, and the like designed to be worn on the body and having a contractable portion which conforms to the contours of the body and permits movement of the body while maintaining contact with the body in motion.

l:SI3SCRIPTION OF THE PRIOR ART
Absorptive devices such as disposable diapers are well known in the art. These devices are used to absorb liquid from the human body and retain that liquid.
Present disposable diapers are generally flat composite ' sheets which are fitted to a baby in the flat state or incorporate geometrical folding to achieve a suitable "baby shape". A major in-use problem with all of these diapers is that gaps between the diaper and a baby's leg tend to develop due to the semi-rigid nature of the absorbent body, especially after the diapcr has been ~ -. .

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worn for some time. These gaps permit leakage from a ~ disposable diaper, thereby creating damp or absolutely wet outer clothing and bedding around a baby.
Disposable diapers, relative to cloth diapers 5, in plastic pants, generally involve single-pinned attach-, ments at the waist. Single taping each side or single pinning tends to force the,mother into choosing between leg leakage or waist leakage. Mothers can pin or tape a disposable diaper "low" so that the edge wraps tightly around the thigh and thus minimizes leg leakage but only at the cost of encouraging the front of the diaper to b~ossom or pouch outward as though it were trying to form a damp apron. When the child is expected to be sleeping, she can avoid this by taping or pinning "high"
along the waistline which is not only aestheticall~ more acceptable but also minimizes waist leakage, albeit at the expense of increased leakage at the legs.
The above disadvantage has been overcome with ~;, cloth diapers in plastic pants because ~he legs and waist . 20 of plastic pants are usually elasticized and they gener-.
ally employ either multiple snaps on both sides (at the ; waist closure, the leg closure, and an intermediate po-, sition) or a "pull-on" style which needs no snaps at all.
One of the problems facing disposable diaper designers, then, is to develop a diapèr in which a single closure along each side can successfully effect closure both , along the thigh and waist without excessive use of ex-pensive tape or use of multiple pins or tape., If disposable (i.e.l sinyle use) diapers could be made from compliant 30 woven materials, this would not be a serious problem. , It does become a serious problem, however, when one recog-niæes that paper-based diapers are considerabl~ less 9~'1 compliant than cloth and do not, therefore, stretch and conform readily to body movements. The solution of this inherent problem associated with a single use absorptive pad integrally formed with single-use plastic pants is not obvious from the prior art teaching independent, non-attached, multiple use plastic pants.
- The prior art teaches elasticization of leg openings for diaper covers and diaper holders such as is shown in U.S. Patents 3,000,381; 2,969,065; 2,675,805; 2,509,674, and

2,468,445. A11 of this prior art is concerned with and teaches elastic leg openings for devices which are not part of an integral disposable diaper, but does not teach the problems and advantages of an elastically contractable side flap on an integral disposable diaper. The above prior art is concerned with a separate plastic pant device which is put over a diaper already applied to an infant or a separate carrier member for detachable absorbent pads held in place by the carrier.
Thus, the prior art shows separate devices which require separate application by the user rather than an integral absorptive device having elastically contractable leg openings, and it does not teach how to overcome the problems associated with combining elastically contractable side flaps with a semi-rigid absorbent body.
; SUL~MARY OF THE INVENTION
In accordance with the present invention, there is provided an integral disposable diaper, comprising: (a) a flexiblé moisture impermeable backsheet; (b) a semi-rigid absorbent body having a Taber stiffness of at least 7 gm.-cm.
superposed on and associated with the backsheet; (c) the back-sheet extending laterally beyond the edges of the absorbent body in the crotch area thereof whereby a flexible side flap is formed ~J - 3 -7~
along each edge of the diaper in that area with the absor-bent body being immobilized for movement relative to the side flaps; ~d) an elastic member longitudinally opera-tively associated with each side flap in an elastically contractable condition, to provide a longitudinally elas-tically contractable side flap, the elastic member being effective to longitudinally gather the side flap thereby providing an elasticized contractable line through the side flap; and (e) the portion of the elasticized contractable line in the crotch area being spaced outwardly from the edge of the semi-rigid absorbent body at least 3/4 inch;
whereby effective elastic side flaps are formed on the integral diaper and the side flaps are compliant and con-tractable and form effective seals about an infant's leg.
: BRIEF DESCRIPTION OF THE DRAWING
While the specification conc].udes with claims partic-ularly pointing out and distinctly claiming the subject ; matter which is regarded as forming the present invention, . it is believed that the invention will be better understood from the following description taken in connection with the accompanying drawinqs in which the th;ckness of some of the materials are exaggerated for clarity and in which:
Figure 1 is a plan view of a disposable diaper of this invention in an unfolded configuration and partially fragmented;
Figure 2 is a cross-sectional view of the diaper of Figure 1 taken along line 2-2 of Figure l;
` Figure 3 is a cross-sectional view of the diaper of Figure 1 taken along line 3~3 of Figure l;
Figure 4 is a perspective view of the diaper of-Figure 1 in its configuration as applied to an infant;
Figure 5 is a plan view, partially fragmented, of another embodiment of a diaper having the improvement '~

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of this invention;
Figure 6 is a plan view, partially fragmented, of another embodiment of a diaper having the improvement of this invention;

Figure 7 is a transverse cross-sectional view of the diaper of Figure 5 in a "Z" folded configuration;
and Figures 8 and 9 are alternate embodiments of absorbent bodies.
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DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to Figures 1l 2, 3 and 4, there is shown a preferred embodiment of an integral disposable diaper having a semi-rigid absorbent body and the elastically contractable flexible side portions (hereinafter referred to as side flaps) of this invention. Although "flap"
may generally mean a thin member, hereinafter it is also ~`~ intended to encompass any portion having the requisite ` flexural rigidity, whether it is thick or thin. The integral disposable diaper 21, i.e., a unitary diaper which does not require separate manipulatable parts like a separate holder and liner, has a backsheet 22, a top-sheet 23, an absorbent body 24, and a side flap 25 on each side of the diaper~ For the purpose of providing an elas-ticized contractable line within the side flap 25, an elastic member 26 is associated with each side flap Z5 thereby providing an elastically contractable portion in each side flap 25. A fastening tape 27 is shown as one means for attaching such a disposable diaper to an infant.

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The elasticized portion of each side flap 25 should be positioned sufficiently remote from -the semi-rigid - absorbent body 24 tv permit the elasticized contractable line through the side flap to maintain a good fit about the leg during normal in-use leg/diaper movements. The minimum desirable width, i.e~, transverse distance, of flexible side flap at each location aiong the edge of the diaper, the wid-th being the distance from the elastically contractable line to the nearest edge of the semi-rigid absorbent body, should be dimensionally equivalent to one-half of the maximum anticipated longitudinal displace-ment of the elastic contractable line at that point as experienced during normal in-use wearing. Since the maximum in-use displacements no:rmally occur in the wearer's crotch area, a preferred side flap design would maximize the side flap width in this region. In addition, since the relative leg movements in the upper leg pi~ot/thigh region are considerably lower, the side flap width may be narrower in that region without reducing the fit/contain-ment attributes of the side flaps.
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, The disposable diaper 21 has à longitudinal center line 28, a lateral center line 29, a back portion 30, a front portion 31, a back waist portion 32, a front waist portion 33 and a crotch area 34.
The back portion 30, in general, is that part of the diaper from the lateral center line 29 to the back end 35 of the diaper. The frnnt portion 31, in general, is that portion of the diaper from the lateral center line 29 to the front end 36 of the diaper. The back ~, waist portion 32 is that width across the diaper adjacentto and parallel with the back end 35. The front waist portion 33 is that width across the diaper adjacent to and parallel with the front end 36. The waist portions 32 and 33 cooperate with each other when the diaper is :L5 fitted and attached to an infant to encircle the waist and hold the diaper on the infant. The width of the waist portions on a diaper can vary, but in general are approximately l inch to 2-l/2 inches wide and extend transversely across the diaper at each end. Their effec-tive in-use width is established primarily by the diaper fastening means, e.g., fastening tape 27.
The crotch area 34 of the diaper is that area of the diaper which is generally located directly between the legs and around the lower portion of an infant when the diaper is fitted to an infant and is approximately centered on the lateral center line 29.
The preferred embodiment of a diaper having the improvement of this invention is shown in Figures l, 2,

3 and 4. This diaper has an hour-glass shaped absorbent body 24 wherein the absorbent body in the waist portions 32 and 33 is wider than the absorbent body in the crotch ~7~1 - area 34, thereby forming ears 37, 38, 39 and ~0 at each edge of the waist portions. The absorbent material can be any of the absorbent materials known to those of or-dinary skill in the bandage art, for exampl`e, a multi-plicity of plies of creped cel~:ulose wadding, fluffed cellulosic fibers or wood pulp -- wood pulp sometimes - ~nown as airfelt --, textile fibers or other absorbent materials. An acceptable absorbent body 24 made from cxeped cellulose wadding would comprise ten plies of tis-sue having a basis weight ~aix dried) of 13 to 15 pounds per ream of 3,000 sq. ft. before creping. The plies of wadding may have a 60 percent, or greater, crepe --the percent crepe being equal to 100 times the quotient - of the reduction in length caused by the creping of a piece of tissue dlvided by the length of the piece of tissue ir: uncreped form. Another, and presently preferred, j absorbent body is made of airfelt and is generally faced on each the top and the bottom surface by a layer of tissue. The airfelt and tissue combination for such an absorbent body in a daytime size" diaper which is intended to fit infants ranging from 14 to 28 pounds ordinarily has a basis weight of approximately 0.33 grams per square inchO
Absorbent bodies in disposable diapers are semi-rigid in nature due to the absorbent material used therein.
A measure of the rigidity of such absorbent bodies is Taber Stiffness per TAPPI standard T489 OS-70 and for the purposes of this disclosure, an absorbent body having a Taber Stiffness of 7 gram-centimeters or greater is considered as semi-rigid.

The absorbent body provides flexural rigidity ~ in the diaper and the ears, so that the ears are resis-tant to inward forces, whereby the ears are maintained in an outwardly extending position when subjected to moderate inwardly contracting forces. This flexural rigidity of the ears of the integral diaper is from about 20 to 200 grams per inch of width to produce a 90 bend as measured on a packaging industry standard test machine, i.e., a PCA Score Bend Tester, manufactured by Thwing-Albert Instrument Company, Philadelphia, Pa., in accor-dance with the standard published instructions for conducting tests on that machine.
` The greatest advantage is realized for the improve-ment of this invention when absorbent body 24 is a semi-rigid body. The absorbent body is held relatively im-mobile ~ith respect to the side flaps 25, that is, the backsheet does not slide back al1d forth over the absorbent body as is possible with the combination of a separate diaper and conventional plastic panties. The absorbent body can be rendered immobile with res?ect to the side flaps when part of the backsheet is in the side flap in many ways, for example, bonding the backsheet and absorbent body together, bonding the absorbent body to a topsheet and the topsheet to the backsheet, or merely tightly sandwitching the absorhent body between a topsheet and the backsheet.
; ~s shown in Figure l, the lateral edges 41 of the absorbent body 24 are directed inwardly from the diaper ends toward the diaper center to form an hour-glass shaped absorbent body. The lateral edge 41 of the absorbent body 24 in the front portion 31 forms a side flap angle a q -~0Ca7451 with the lateral centerline 29. The lateral edge 41 ~ of the absorbent body 24 in the back portion 30 forms a side flap angle ~ with the lateral centerline 29.
Angle a should be between 20 and 65 and preferably about 52. Angle ~ should be between 20~ and 70 and pre-ferably about 58o If a and ~ are adjacent as shown in Figure 1, as contxasted to being separated by a sub~
stantially linear segment in the crotch area, then the minimum of a plus ~ should be about 90. The lateral edges 41 of the absorbent body 2~ may be either linear `~ or curvilinear. If the edges 41 are curvilinear, the - angle a or ~ is the angle between the chord of the arc in the front portion 31 or back portion 30, respec-tively, and the lateral centerline 29.
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The width of the absorbent body 24 along the back i end 35 Ox the front end 36 is generally between 8 and 13 inches, preferably about 11 inches. The width of the absorbent body 24 along the lateral centerline 29, which is generally the narrowest portion of an hour-glass shaped pad, is between 1 inch and 6 inches, preferably 2 to 3 inches. The length of -the absorbent body 24 is typi~
cally from 11 to 18 inches long, preferably about 16 inches. The narrowest portion of the absorbent body 24, i.e., the width along the lateral centerline 29, is pre~
ferably displaced from 0 to 3 inches, and more preferably displaced about 1/2 inch, toward the front of the absor-bent body from the longitudinal center of the absorbent body.
The absorbent body 2~ is superposed on backsheet 22 and preferably attached thereto by attachment means such as those as are well known to those of ordinary skill in the art, for example, double sided pressure 1~ .

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sensitive adhesive tapes, hot melt glues, or other ad-hesives. The absorbent body 24 can be secured to the backsheet 22 by a uniform continuous layer of adhesive, a patterned layer of adhesive, or a number of separated spots of adhesive. In addition, it has been found to be advantageous to secure the lateral edges 41 of the absorbent body 24 to the side flap, for example, through the backsheet by a pad-edge attachment means 42. The pad-edge attachment means 42 ultimately provides an attach-ment means between the side flap 25 and its correspondinglateral edge of the absorbent body through the backsheet.
The backsheet 22 is a flexible moisture imperme-able sheet desirably being a low density, opaque poly-ethylene web which is about 0.001 inches thick, for example, a polyethylene web available from Monsanto Chemical Company and identified by them as film No~ 8020*~ In this embodi-ment, the backsheet 22 has a modified hour-glass configur-ation and extends beyond the periphery of the absorbent body around the entire periphery thereof. At each end, the backsheet extends beyond the absorbent body approxi-mately 1/2 inch. Along the lateral edges, the backsheet extends beyond and is parallel to the lateral edges 41 of the absorbent body from each end for a distance.
As the absorbent body gets narrowsr and toward the crotch area 34, the backsheet periphery is substantially linear and parallel to the longitudinal centerline 28, such as edge 44 as shown in Figure 1, so the backsheet is wider than the absorbent body and the side flap 25 becomes increasingly wider until the transverse centerline 29 is reached. This linear portion of the backsheet periphery *Trademark ~a74~i~
orms the contractable edge 44 of the side flap 25.
The linear portion of the lateral edge of the backsheet 22 is generally between 5 inches and 12 inches long and for a daytime size diaper about 9 inches long. The back-sheet 22 preferably is embossed and/or matte finished.
The portion of the backsheet extending beyond the lateral edges 41 of the absorbent body in the crotch area 34 of the diaper forms part of the side flap 25.
The "modified" hourglass shape described above - 10 and shown in Figure 1 for the backsheet 22 provides a ; diaper wherein the length of the diaper edge is longer than the length of the longitudinal center of the diaper, i.e., the longitudinal centerline. This difference in length provides a potential for a better fit as can be appreciated by considering the anatomy of a human, whether infant or adult. The length covered by the edge is longer than that covered by the longitudinal centerline of a diaper.
The topsheet 23 in this embodiment is coextensive with and superposed on the backsheet 22 with the absorbent body 24 disposed therebetween. The topsheet 23 is attached to the backsheet 22 where their surfaces meet, that is in the areas beyond the periphery of the absorbent body 24, by a topsheet -backsheet attachment means 43, said attachment means being highly flexible, especially in the side flap 25. Thus the side flap 25 in this preferred embodiment comprises portions of the backsheet and the topsheet and the coextensive attachment means therebetween.
The topsheet 23 may be any compliant, soft feeling, porous, paper or non-woven fabric web. One example thereof is an unwoven fabric sheet comprising 1.5 to 3.0 dcnier rayon and containing approximately 20 to 35 percent binder ~ .

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(for example, copolymers of an ester of acrylic acids such as is sold by the Rohm & Haas Company under the trade-mark Rhoplex, HA-8), and having a weight of about 15 to ~; 19 gm. per sq. yd. Another example of a topsheet which has been found to work well is a non-woven fabric sheet com~rising 35 to 64 percent of 1.5 to 3.0 denier polyester fibers, 14 to 40 percent of 1.5 to 3.0 denier rayon fibers, and approximately 20 to 30 percent of binder, for example, the above-mentioned Rhoplex HA-8; the fabric having a weight of about 25 to 35 grams per sq. yd. and a caliper of 00016 to 0.020 inches. ~`
Each side flap 25 in the diaper of this preferred embodiment is essentially triangular and can roughly be defined as being bound by the lateral edge 41 of the absor-bent body in the back portion 30 of the diaper, the lateral edge 41 of the absorbent body in the front portion 31 of the absorbent body, and the elast:;cized contractable line through the side flap which is established by the elastic member 26 and in this embodiment is the outside contractable edge of elastic member 26. The side flap 25 should be highly flexible and thus contractable. Thus it should have a flexural rigidity of no greater than about 6 gram-centimeters, preferably less than about 3 gram-centimeters, and most preferred less than 0.5 gram-centimeters, as measured using a Taber Stiffness instrument in accordance with TAPPI standard T489 OS-70.
In this embodiment the side flap comprises the backsheet material, the topsheet material, and the topsheet-backsheet attachment means. Thus, the topsheet-backsheet attach-ment means must also be of highly flexible material.

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The elastic member 26 is operatively assoeiatedwith the side flap 25 in an elastically contractable eondition so that in a normally unrestrained configuration, the elastic member 26 effectively contracts or gathers the side flap material thereabout to provide an elasti-ei~ed contractable line through the side flap, generally near and adjacent to the outward lateral edge 44 of the side flap.
The elastic member can be operatively assoeiated with the side flap in an elastically eontractable condition in at l~ast two ways, i.e., stretch the elastic member to its stretehed eondition and fix it to the side flap while the side flap is in an uncontracted or stretched eondition, or contract the side flap -for example, by pleating it - and fix the elastie member to the contracted side flap while the elastic mem~er is in its relaxes or unstretched condition.
The elastic mem~er within the flexible side flap of this invention preferably develops a skin contact pres-sure of from 0.2 to 2.5 pounds per sq. in. A skin eontactpressure within that range is acceptable to provide con-~inued contact with the infant's thigh without exerting pressure which detrimentally indents or marks the skin.
~n elastic me~ber to provide the proper skin contact pres-sure in a suitable flexible flap should have a tensionalforce therewithin in its prestretched condition in the range of from 35 to 150 grarns and preferably in the range ~f 60 to 100 grams. The elastic rnember should provide sueh a tensional force and thus establish its prestretched condition at an elongation from its relaxed state in the range of from 25 to 200 pcrcent and prcferably in the range o~ from 50 to 100 percent.

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One elastic member which has been found to work well is an elastic tape having a cross section of 0.007 inches by 0.25 inches and made from natural rubber which is available from Easthampton Rubber Thread Company and identified by them as L-1900* rubber compound. This elastic tape produces a tensile force of about 100 grams when stretched 100 percent from its relaxed condition. That rubber tape was used as elastic member 26 in the preferred embodiment of Figure 1 and was stretched 100 percent from its relaxed condition to place it in its stretched condition, i.e., its maximun stretched length as allowed by other materials in the side flap when attached to the side flap, and has a tension therewithin in its stretched condition of about 100 grams.
The elastic member 26, as shown in Figure 1, is operatively associated with the side flap 25 by securing it to the backsheet 22, the topsheet 23, or both with an elastic attachment means 45. This elastic attachment means 45 should be flexible and of sufficient adhesiveness to hold the elastic member 26 in its stretched condition substantially indefinitely. The elastic member 26 is shown in Figures 2 and 3 attached to the topsheet 23 by elastic attachment means 45. One material which has worked as a flexible elastic attachment means is a double sided transfer tape available from The Minnesota Mining and Manufacturing Company, St. Paul, Minnesota, which is compatible with the material of the elastic member and is known by their designation as No. 465* pressure-sensiti~e tape (high tack). Other flexible adhesives compatible with the elastic member could also be used as the attachment means 45. The elastic member 26 need not necessarily be secured to the side flap along its entire * Trademark 1~ 45~

length, but may instead, for example, be attached only at its two ends and be operatively associated with the side flap for the remainder of its length by extending through a sleeve within the side flap or loops integral with the side flap. -The laterally outer edge of elastic member 26 inthe embodiment of Figure 1 is the elasticized contract-able line through the side flap 25. The elasticized con-tractable line in the side flap is the "path of response"
set up in a flexible side flap by an elastic member.
~lthough the word "line" is used to describe the "path of response" in the side flap, this is not intended to pxeclude a "path of .response" having width. In this embodiment the elastic member is shown extending àlong the entire elasticized contracta~le line in the side flap, but that structure is not absolutely required. An elas~
ticized contractable line can be established in a flexible side flap by attaching an elastic member to the side flap which, in its stretched condition, is shorter than the elasticized contractable line. For example, an elastic member exte~ding only from the lateral centerline 29 to either intersect 60, or an elastic member shorter than elastic member 26 placed anywhere along the path of elastic member 26~ If an elastic member shorter than the elas-ticized contractable line is used, it is preferably locatedin the back portion of the diaper.
The elastic member 26 to be effective is spaced outwardly from the lateral edge 41 of the absorbent ~ody ;
24 to establish the elasticized contractable line a dis-tance from the lateral edge 41 of the absorbent body and provide a flexible side flap width, i.e., the distance ',:' l~

lQ~74~il from the elasticized contractable line to the edge of the semi-rigid absorbent body which in this embodiment is fxom the lateral outer edge of elastic member 26 to lateral edge 41 of the absorbent body 24. The most ef-S fective portion of the elastic member 26 in this embodimentis that portion in the crotch area of the diaper, Oe., adjacent the lateral centerline 29. The outward spacing of the elastic member is necessary to provide a contract-able side flap for a disposable diaper. The flexible side flap width should be a minimum of 3/4 inch in the crotch area, but preferably from about 1-3/4 to about

4-l/2 inches and most preferably about 3 inches.
An elastic member when operatively associated in an elastically contractable condition with a flexible side flap provides an elasticized contractable line or path of response through the side flap to form a longitudinally contractable side flap. There is a flexible side flap having an elasticized contractable line on each side of the diaper thereby providing oppositely disposed elasti-20 cized ~ontractable lines. Eash flexible side flap hasa width wl~ich extends inwardly toward the longitudinal centerline from the elasticized contractable line. The minimum separation between these oppositely disposed elasticized contractable lines is: 4 inches and prefer-25 ably 5-l/2 inches for babies weighing less than 14 pounds;

5 inches, preferably 6-l/2, and more preferably 7-l/2 inches for babies weighing from 14 to 35 pounds.
The elastic member 26 in its stretched condition may be lon~er than the elasticized contractable line 30 so that each end of the elastic member 26 extends to and beyond the lateral ed~e 41 of the absorbent body 24 at .. ~ ~

the elastic member-absorbent body intersect 60, and thereby overlaps the absorbent body 24. This structure is shown in Figures 1 and 3. The poxtion of elastic member 26 beyond intersect 60 may be operatively associated with the absorbent body in any of many ways, e.g., glueing it to the topsheet 23, or glueing it directly to the ab-sorbent body.
To perorm most effectively, the elastic member in its stretched condition should have a minimum effec-tive length of about 4 inches and preferably about 7inches, to p~ovide an effective elastically contractable side flap.

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~7~Sl The effective length of the elastic member in its stretched condition is that length available to contract.
In the embodiment of Figure 1, the effective length of the elastic member 26 in its stretched condition is the uncontracted S length through the side flap 25 from the elastic member-absorbent body intersect 60 on the back portion 30 of the diaper to the corresponding intersect 60 on the front portion 31 of the diaper.

An elastic member which does not extend outside the 10 flexible side flap has an effective length equal to the stretched length of the elastic member. In a "daytime"
diaper, i.e., one intended for ordinary daytime use on infants weighing about 14 to 28 pounds, an effective length of about 9 inches is preferred for a diaper as is shown in Figure 1.

~ fast~ning tape 27 is applied typically to the back waist portion 32 of a disposable diaper to provide a fastening means to hold the diaper on an infant~ Fastening tapes 27 can be any of those well known to those of ordinary skill in the art, such as the fastening tape disclosed in ~ 20 U. S. Patent 3,646,937 issued to Gellert on March 7, 1972.
; These fastening tapes, or other diaper fastening means --such as pins -- are typically applied near the top edge of a diaper in its "in-use" configuration. Thus such a diaper is fastened or fixed only near the top of the diaper and is 25 not fastened or fixed near the leg opening, as contrasted to the typical plastic panty which is fastened or fixed both at the top and at or near the leg opening.

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74~i3 An alternate embodiment is shown in Figure 6 wherein the absorbent body 46 is of a modified hour-glass shape which has ears 49 and where the elastic members 47 extend between the ears 49 of the back and front portions, 50 and 51 respectively, of the diaper. This places the elasticized contractable line laterally outward about as far as it can go and still be laterally inward from, or in line with, the edges of the ears. In this embodiment, the elastic member 47 is located outwardly about as far as it can be and still have the ends of the elastic member 47 coextensive with the ears 49 of the absorbent body 46. A diaper of the -~
configuration of Figure 6 then can be folded in a "Z" fold as is taught in U. S. Patent Re. 26,151 issued to Duncan et al. on January 31, 1967, or in a "C" fold.
Other embodiments of the absorbent body which provide ears which can be inherently stiff or stiffened through the use of stiffening members, such as stays, are "I" or "T" shapes such as are shown in Figures 8 and 9 respectively.
Another embodiment incorporating the improvement of this invention is shown in Figure 5. The topsheet 5~, backsheet 55, and absorbent body 56 have different configurations than those described with the diaper of Figure 1, but the diaper is put together in essentially the same manner as that described for the diaper of Figure 1. In the diaper of Figure 5, the absorbent body 56 is essentially rectangular.

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The backsheet is wider than the absorbent body 56 so that a portion of the backsheet 55 extends beyond each edge of the absorbent body 56 an amount ~ufficient to form the flexi-ble side flap 58 which can be 2 to 3-1/2 inches wide, and a 5 minimum of 3/4 inch wide. The backsheet is also longer than the length of the absorbent body to provide a small margin of backsheet at each end of the absorbent body 56. An elastic member 57 is operatively associated with each side flap 58.
The side flap 58 is formed by the portion of the backsheet 10 56 extending beyond the edges of the absorbent body 56. The elastic member 57 is attached to the side flap 58 and is lo-cated a distance from the lateral edge 59 of the absorbent body 56. The distance between the elastic member 57 and the lateral edge 59 is as taught above to form a contractable or elasticized side flap for a disposable diaper.

m e diaper of Figure 5 can also be forme~d in a "C"
fold or "Z" ~old as mentioned above in conjunction with the diaper of Figure 6. A transverse cross section of the diaper -~ of Figure 5 in a "Z" fold configuratio~ is shown in Figure 7.

An additional alternative embodiment is one wherein the diaper is essentially the same as that shown in Figure 1 with the exceptions that the absorbent body is "T" shaped and the front ends of the elastic member 26 are not attached to the absorbent body but are attached to the backsheet or top-sheet in the same manner as disclosed in detail for the major length of the elastic member 26 of Figure 1. A "T" shaped absorbent body is one which does not have the ears 39 and 40 on the ~ront portion o~ ~he dia~er.

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Although the above descriptions have not specifically disclosed any absorbent material within the side flaps of the diaper, some absorbent material could be present therein. The amount of absorbent material within the side flap, for example, located between the topsheet and the backsheet in the side flap area, would have to be limited so that the flexural rigidity of the side flap does not exceed the above stated maximu~ for flexible side flaps, i.e., a maximun of 6, preferably less than 3, and most 10 preferably less than 0.5 gram-centimeters. . :
If some absorbent material were provided in the flexible side flap the width of the side flap would be the distance between the elasticized contractable line and the lateral edge of the absorbent body. In most instances the edge of the absorbent body occurs at the point where the flexibility of the diaper is less than the minimum above-mentioned.
Thus, it is apparent that there has been provided, in accordance with the invention, an improvement for an integral disposable diaper that fully satisfies the objects, aims, and advantages set forth above. While the invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art .
in light of the foregoing description. Accordingly, it is intended to embrace all such alternatives, modifications, and variations that fall within the spirit and broad scope of the appended claimsD

Claims (12)

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

1. An integral disposable diaper, comprising:
(a) a flexible moisture impermeable backsheet;
(b) a semi-rigid absorbent body having a Taber stiffness of at least 7 gram-centimeters super-posed on and associated with the backsheet;
(c) the backsheet extending laterally beyond the edges of the absorbent body in the crotch area thereof, whereby a flexible side flap is formed along each edge of the diaper in that area, with the absorbent body being immobilized for movement relative to the side flaps;
(d) an elastic member longitudinally operatively associated with each side flap in an elastically contractable condition, to provide a longitudinally elastically contractable side flap, the elastic member being effective to longitudinally gather the side flap thereby providing an elasticized contractable line through the side flap; and (e) the portion of the elasticized contractable line in the crotch area being spaced outwardly from the edge of the semi-rigid absorbent body at least 3/4 inch;
whereby effective elastic side flaps are formed on the in-tegral diaper and the side flaps are compliant and con-tractable and form effective seals about an infant's leg.

2. The diaper claimed in claim 1 including attachment means between the side flap and its corresponding lateral edge of the absorbent body so that tension forces in the side flap are transmitted to the lateral edge of the absorbent body, whereby the absorbent body if compacted by the legs of the infant during wearing is uncompacted or stretched out by outward movement of the infant's legs due to tension imposed on the edge of the absorbent body developed in the side flaps by outward movement of the infant's legs.

3. The diaper claimed in claim 2 including an ear portion at a longitudinal end of the absorbent body, the ear portion extending outwardly beyond the lateral edge of the absorbent body in the crotch area and having flexural rigidity so that it is resistant to inward forces imposed on the ear portion, the elastic member being laterally inward toward the longitudinal center line of the diaper from the lateral edge of the ear portion, whereby the ear portion tends to remain extended outwardly when subjected to forces imposed by the elastic member.

4. The diaper claimed in claim 1, 2 or 3 which includes a topsheet coextensive with and superposed on the backsheet with the absorbent body disposed therebetween, said topsheet con-sisting of a compliant, soft feeling, porous web.

5. The diaper claimed in claim 1 including an ear portion at a longitudinal end of the absorbent body, the ear portion extending outwardly beyond the lateral edge of the absorbent body in the crotch area and having flexural rigidity so that it is resistant to inward forces imposed on the ear portion, the elastic member being laterally inward toward the longitudinal center line of the diaper from the lateral edge of the ear portion, whereby the ear portion tends to remain extended outwardly when subjected to forces imposed by the elastic member.

6. The diaper claimed in claim 5 wherein the minimum effective length of the elastic member in its stretched condi-tion is 4 inches.

7. The diaper claimed in claim 5 wherein the side flap is essentially triangular.

8. The diaper claimed in claim 7 wherein the absorbent body has lateral edges directed inwardly from the diaper front and back ends toward the diaper center to form an hour-glass shape, with the lateral edge of the absorbent body in the front portion forming an angle .alpha. of 20° to 65° with the lateral centerline of the absorbent body and the lateral edge of the absorbent body in the back portion forming an angle of .beta. of 20°
to 70° with said lateral centerline, and .alpha. plus .beta. being between 90° and 135°.

9. The diaper claimed in claim 8 wherein the angle .alpha. is about 52° and angle .beta. is about 58°.

10. The diaper claimed in claim 3, 5 or 6 wherein one end of the elastic member intersects the front portion of the absorbent body and the other end of the elastic member intersects the back portion of the absorbent body.

11. The diaper claimed in claim 1, 2 or 5 wherein the elasticized contractable line in the crotch area is spaced outwardly from the lateral edge of the absorbent body at least 1-3/4 inches.

12. The diaper claimed in claim 1, 2 or 5 wherein the elasticized contractable lines in the crotch area are spaced from each other by a distance of at least 4 inches.