Disposable diaper having an improved side closure

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PRESENTATION WRITING πυ166255 B ds) DENMARK

patent Office

TAASTRUP (21) Patent Application No: 1448/87 (51) lnt.CI.5 A 61 F 13/56 (22) Filing Date: Mar 20, 1987 (41) Atm. available: 22 Sep 1987 (44) Submitted: 29 Dec 1993 (86) International Application No: (30) Priority: 21 Mar 1986 US 842326 (71) Applicant: The * Procter &amp; Gamble Company; One Procter &amp; Gamble Plaza: Cincinnati; Ohio 45202, US (72) Inventor: John Wiliam 'Toussant; US, Margaret Henderson * Hasse; US (74) Plenipotentiary: Lehmann &amp; Ree A / S (54) One-time bid with improved side closure (56) Published publications

US Patent Nos. 3776232, 3860003, 4253461, 4388075, 4402690 (57) Summary:

1448-87

The disposable diaper is provided with outer fasteners and inner fasteners. The outer fasteners hold the waist portion, the diaper in an overlapping position, while the inner fasteners reduce the displacement of the overlap dies.

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1448-87

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Fig.2 1448-87

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The present invention relates to a disposable diaper comprising:

a liquid-permeable headpiece, a liquid-impermeable backpiece attached to the headpiece, an absorbent means for absorbing liquids between the headpiece and the backpiece, longitudinal edge regions at the longitudinal sides of both disposable diapers, elastic members operatively associated with both the longitudinal edge regions, a first and a second waist portion provided at opposite ends of the disposable diaper having longitudinally extending edges, said second waist portion having a first and a second panel containing the portions of the second waist portion which are overlapped by the first waist portion when the diaper is secured around the wearer's waist, outer fasteners, for retaining the first waist portion and the second waist portion; an overlapped condition wherein at least a portion of the outer fasteners is provided adjacent the respective long sides of the disposable diaper.

More particularly, the invention relates to an improved disposable side closure for disposable diapers having elastic leg openings with an outer and an inner fastener.

Disposable diapers are well-known items worn by children and incontinent people. Disposable diapers are worn around the lower torso and are intended to absorb and retain urine and excrement, thereby preventing urine and excrement from contaminating, moisturizing or otherwise contaminating objects (e.g., clothing, beds, etc.) that come into contact with the diaper carrier .

In general, all disposable diapers have the same basic structure, which consists of an absorbent core enclosed between a liquid-impermeable headpiece in contact with a liquid-impermeable backpiece. Many different embodiments of elements are known in addition to the actual headpiece, backpiece and absorbent core arrangement. For example, the performance of disposable diapers has been improved by the addition of an elastic member along the portion of the disposable diaper which contacts the wearer's thighs, thereby providing elastic leg openings as the diaper is worn.

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When a disposable diaper with elastic leg openings is used, the diaper user places the diaper on the wearer and attaches it around the wearer's waist, thereby providing a side closure. The application of the diaper to the wearer usually requires that the front and rear waist portions of the diaper overlap. When the diaper is worn, the wearer's movements and the forces produced by the elastic members at the leg openings will tend to cause the front and rear waist portions to move relative to one another. In other words, the front and rear waist portions that overlap are affected by forces that tend to cause the front and rear waist portions to occupy a position relative to each other, different from the position they occupy, when the diaper is placed on the wearer. Unless such shifts are limited, the diaper's fit around the legs and waist and its holding capacity deteriorate during use.

A number of ideas for attaching disposable diapers around the waist of the wearer have been proposed. For example, US Patent No. 3,848,594 issued November 19, 1974, discloses a tape fastening system for inducing a side closure in disposable diapers having an improved connection of the manufacturer end (i.e., the fastening between the fastened tape and the diaper made by manufacturer). U.S. Patent No. 3,359,980 issued December 26, 1967 and U.S. Patent No. 3,638,651 issued No. 1. February 1972 indicates both diapers in which a side closure is produced by the diaper overlap portions. Further side closures are disclosed in U.S. Patent No. 3,776,232 issued December 4, 1973 and U.S. Patent No. 4,122,552 issued October 31, 1978. Both of these patents are to improve the side closures by affixing the front and rear posterior waist portions of one another over a relatively large area. U.S. Patent No. 4,122,552 achieves this result by using two fastening mechanisms, while U.S. Patent No. 4,197,197 3,776,232 uses a single attachment system covering a relatively large area.

None of the patents mentioned are particularly directed to disposable diapers having elastic leg openings, and the particular problems associated with such diapers to maintain good fit properties. U.S. Patent No. 4,253,461, issued March 3, 1981, relates to a disposable diaper with elastic leg openings and where an improved lateral closure is obtained by providing separate fasteners at the waist and at the thigh.

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Disposable diapers according to the prior art lack the features provided by the present invention, where an improved side closure having an outer and an inner fastener is provided which together prevent relative movement between the front and rear waist portions.

It is therefore an object of the present invention to provide an improved side closure for a disposable diaper with elastic leg openings.

A further object of the present invention is to provide an improved side closure which maintains the diaper's fit better at the waist and at the elastic leg openings during use.

A further object of the invention is to provide a disposable diaper with elastic leg openings which have improved urine and excretory uptake properties.

These objects of the invention will become more apparent when viewed in connection with the following description and drawing.

According to the present invention, a disposable diaper with elastic leg openings is made so that an absorbent member is enclosed between a liquid-permeable headpiece and a liquid-impermeable "

backsheet. Part of the contraction force produced by the elastic members at the leg openings in such diapers is directed into the waist portion of the diaper. These forces, together with the diaper carrier's movements, will tend to cause displacements of the front and rear waist portions. Shifts shall mean movement of the front and rear waist portions relative to each other from the position they occupy when the diaper is applied. When such relative movement occurs, the fit around the wearer's legs and waist becomes looser and thereby less effective at retaining the waste products.

The disposable diaper of the present invention is characterized in that the diaper also comprises internal fasteners for resisting shear forces between the respective overlapping first and second waist portions, each of the inner fasteners being disposed in the region of its respective panel, and having the largest dimension oriented parallel. 166255 Β with the longitudinal edges of the waist portions extended. The disposable diaper according to the invention is provided with outer and inner fasteners which together prevent the displacements between the front and rear figures.

When the disposable elastic disposable diaper is placed around the waist of the wearer, the elastic disposable diaper waist portion is made to overlap. The outer fasteners attach the overlap portions of the waist members to each other and hold them in contact with each other. The inner fasteners restrict and preferably prevent displacement of the overlap portions, thereby maintaining a good fit around the wearer's legs and waist. The disposable diaper thus obtained thus exhibits improved properties for the uptake of urine and excrement from known diapers.

The outer fasteners prevent the waist overlap parts from splitting. Therefore, the outer fasteners must withstand the pulls and tearing forces that occur when the diaper is worn. Adhesive tapes, well known in the art of disposable diapers, are suitable for use as the outer fasteners.

The inner fasteners can take many forms. Any device by which displacement of the waist overlap members is restricted or preferably prevented is suitable as internal fasteners. For example, the inner fasteners may be a surface coated with adhesive portions so that the waist portions of the diaper adhere to each other as they overlap. Alternatively, the inner fasteners may consist of a surface of one waist portion which, when brought into contact with the other waist overlap portion, is mechanically entangled therewith. Further, the inner fasteners may be of a type that is either passive (i.e., it does not require any special treatment by the diaper user) or active (i.e., it requires the diaper user to take action to activate the innermost fasteners ).

BRIEF DESCRIPTION OF THE DRAWINGS The invention will now be explained in more detail with reference to the accompanying drawing, in which: Figure 1 is a partially cut-away perspective view of a disposable elastic diaper according to the present invention; Figure 2 is a partially cut-away perspective view showing

DK 166255Β disposable diaper in Figure 1 in the form it will assume when placed on a carrier.

In the drawing, there is shown a preferred embodiment of the present invention as used in a disposable diaper intended to be worn by a child. The term disposable diaper means a garment which is generally worn by children or by incontinent persons, which is pulled up between the legs and fastened around the waist of the wearer, and which is further intended to be discarded after a single use (that is, it is not intended to be washed or otherwise brought back to its original state and recycled).

Figure 1 is a partially sectioned perspective view of the disposable diaper 10 of the invention before being folded and applied to the diaper carrier by the diaper user. As can be seen in Figure 1, a preferred embodiment of a diaper 10 comprises a liquid-permeable head 12, an absorbent member 14, a liquid-impervious back piece 16, and elastic members 18. The headpiece 12, the absorbent member 14, the liquid impervious backing 16, and the elastic members 18 can be assembled into a number of well-known designs, but particular reference is made here to a preferred disposable diaper design disclosed generally in U.S. Patent No. 3,860,003 issued January 14, 1975.

Figures 1 and 2 show a preferred embodiment of the diaper 10, in which the headpiece 12 and the backpiece 16 have the same shape and size and generally have greater length and width dimensions than the absorbent member 14. The headpiece 12 is laid on top of the backpiece 16, thereby forming a periphery 20 on diaper 10. The periphery 20 constitutes the outermost periphery, or in other words, the outermost outline of the diaper 10. The periphery 20 has a first end 20, a second end 22, a first long side 26, and a second long side 28.

The headpiece 12 may be attached to the backpiece 16 in any suitable manner well known in the diaper manufacturing technique. In a preferred embodiment, a plurality of longitudinal adhesive tapes 30 of hot melt adhesive are disposed along the full length of the backing member 16 substantially parallel to the longitudinal centerline 70 of the backing member 16. The longitudinal adhesive tape 30 serves to secure the headboard 12

DK 166255Β to the rear piece 16 at the points where these three components meet. The extent and location of the points where the top piece 12, the back piece 16 and the longitudinal adhesive tape 30 meet will depend on the space between the longitudinal adhesive tape 30 and the distance at which the top piece 12 and the back piece 16 extend beyond the absorbent member 14. The number of longitudinal adhesive tapes 30 and the space between them must be sufficient to securely bond the top piece 12 to the back piece 16 in the region between the periphery 20 and the edge of the absorbent member 14.

A suitable hot melt adhesive for use with the longitudinal adhesive tapes 30 is manufactured by Eastman Chemical Products Company of Kingsport, Tennessee and sold under the trade designation Eastobond A-3. It will be seen that the above-described way of attaching the headpiece 12 to the backpiece 16 causes the headpiece 12 to be attached to the backpiece 16 at intervals along the first and second ends 22 and 24. The absorbent means 14 is thereby enclosed between the headpiece 12 and the backpiece. 16th Of course, many alternative methods can be used to attach the headpiece 12 to the backpiece 16 with satisfactory results. For example, the headpiece 12 may be attached to the backpiece 16 indirectly rather than directly, as shown in Figure 1. Thus, an intermediate member may be used to attach the headpiece 12 to the backpiece 16.

The diaper 10 has a first and a second waist portion 42 and 44 extending from the first end 22 and second end 24 of the diaper periphery 20 toward the transverse center line 31 of the diaper 10 for a length of about 1/5 to about 1/3 of the total length of the diaper. The waist portions 42 and 44 constitute the parts of the diaper 10 which, when worn, go around the waist of the wearer. The crotch portion 46 is the portion of the diaper 10 lying between the first and second waist portions 42 and 44, and it constitutes the portion of the diaper 10 which, when worn, is located between the wearer's legs and covers the lower torso of the wearer. The first and second waist portions 42 and 44 are formed with longitudinally extending edges 45 and 47, respectively, which are arranged parallel to the center line 70.

Absorbent means 14 may be any means which is generally compressible, suitable, non-irritating to the wearer's skin, and capable of absorbing and retaining fluids. A preferred absorbent member 14 has two opposing surfaces 32 and 34 and

DK 166255 Β consists of an absorbent layer 36 and two tissue layers 38 and 40 which cover the main surfaces of the absorbent layer 36 and form the opposing surfaces 32 and 34 of the absorbent member 14.

The absorbent layer 36 is intended to absorb and retain liquid, and can be made in a wide variety of sizes and shapes (e.g. rectangular, hourglass-shaped, etc.) and a wide variety of liquid absorbent materials commonly used in disposable diapers, such as e.g. finely divided wood pulp, generally referred to as air felt. Other liquid absorbent materials may also be used in the manufacture of absorbent layer 36, such as a multilayered cellulose crepe material, polymeric gelling material, absorbent foam or sponge material, or any similar material or combination of such materials. However, the total absorbent capacity of the absorbent layer 36 must be sufficient to absorb the liquid load for which the absorbent layer must be sized for the intended use of disposable diaper 10. Furthermore, the size and absorbent capacity of absorbent layer 36 can be varied to suit carriers of all age classes, ranging from toddlers to adults.

The preferred embodiment of diaper 10 illustrated in FIGS. 5 to approx. 12 kg. Therefore, the absorbent layer 36 is a 1-inch-1 sheet with a length of approx. 41 cm measured along the longitudinal centerline, a width of approx. 32 cm at the first and second ends 22 and 24 and a width of approx. 10 cm at the narrowest point on the narrowed step portion 46. The absorbent capacity of the air felt used for the absorbent layer 36 is sufficient to absorb and retain from approx. 8 to 16 g of water per g of absorbent material. Accordingly, in the preferred embodiment shown in Figures 1 and 2, the air felt used weighs from approx. 30 to approx. 56 g, and is of substantially uniform thickness. However, it will be appreciated that the size, shape, design and overall absorbent capacity of absorbent layer 36 must be varied to accommodate carriers of all ages from toddlers to adults. Therefore, the dimensions, shape and shape of the absorbent layer 36 must be able to be varied (for example, the absorbent layer 36 may have a varying thickness, or a hydrophilic gradient, or contain polymeric gelling materials).

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The two tissue layers 38 and 40 are intended to enhance the absorbent core

14's tensile strength and to reduce the tendency of absorbent yoke 36 to divide, clot together, or form balls when wet.

The two tissue layers 38 and 40 are also instrumental in improving the transverse fluid seeding, thereby obtaining a more even distribution of the liquid in the absorbent layer 36. Many different materials and manufacturing methods can be used to prepare the tissue layers 38 and 40.

Satisfactory results have been obtained with sheets of tissue paper with one

3 basis weight of approx. 16 g per m and with an air permeability of approx. 30 mo

per minute per m over a pressure drop of 13 mm water. The tissue layers 38 and 40 preferably have the same shape and size as the absorbent layer 36, but they may also have divergent dimensions or shapes, or they may be completely omitted.

The absorbent member 14 is disposed on top of the backing 16 and is preferably attached thereto in any manner known in the art of diaper. For example, the absorbent core 14 may be attached to the backing 16 by a uniform continuous layer of adhesive, a patterned layer of adhesive or a number of separate lines or points of adhesive. In the preferred embodiment illustrated in Figures 1 and 2, the longitudinal adhesive tapes 30 are used to attach the absorbent core 14 to the backing piece 16.

The backing 16 is liquid impervious and prevents the liquids absorbed in the absorbent member 14 from wetting underwear, clothing, beds and other items in contact with the disposable diaper carrier 10. Preferably, the backing 16 is a polyethylene film having a thickness of approx. 0.012 to 0.051 mm (0.0005 to 0.002 inches), however, other flexible liquid impervious materials may also be used. By the term flexible materials is meant materials which are compliant and which readily adapt to the shape and contours of the human body. A suitable polyethylene film is manufactured by Monsanto Chemical Company and is sold under the trade name Film No. 8020. The backing 16 is preferably embossed with pattern and / or matte finish to give a more clothing-like appearance. Furthermore, the backing 16 may have passages which allow vapor to escape from the absorbent member 14 while still preventing fluid from passing through the backing 16.

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In a preferred embodiment, the backing 16 has a modified hourglass shape extending at least 1.3 cm (0.5 inches) beyond the absorbent layer 36 around the entire diaper periphery 20. The edge portion 48 is the portion of diaper 10 located between the diaper periphery. 20 and the edge of the absorbent layer 36 and consists of the longitudinal edge portions 50 in the immediate vicinity of the first and second long sides 26 and 28, respectively, of the crotch portion 46.

The headpiece 12 is resilient, feels soft and non-irritating to the wearer's skin, and prevents it from contacting the absorbent core. Furthermore, the head 12 is liquid permeable and allows liquid to readily penetrate through its thickness. A suitable headpiece 12 may be made of many different materials, such as natural fibers (e.g. wood or cotton fibers), synthetic fibers (e.g. polyester, polyethylene or polypropylene) or a mixture of such fibers. Alternatively, the headpiece 12 may be a foam, such as the reticulated foam which is well known in the art or any of the finished films which are also well known in the art.

Many different manufacturing methods can be used for the manufacture of the headpiece 12. For example, the headpiece 12 may be woven, nonwoven, spunbonded, carded or the like. A preferred headpiece 12 is carded and thermally bonded by a method well known in the art of nonwoven fabrics. Preferably, the 2 headers 12 have a weight of approx. 20 to approx. 30 g per m (18 to 25 g per square yard), a dry tensile strength of at least 400 g per cm in the web direction, and a wet tensile strength of at least 55 g per cm across the web direction.

The elastic members 18 are attached to the diaper 10 along both of the longitudinal edge regions 50 so as to serve to pull and hold the diaper against the wearer's legs. Thereby, the diaper 10, when worn, will have elastic leg openings. This result can be achieved by a variety of organs well known in the diaper field. Particular preference is given to a diaper construction with elastic strips, as described in detail in previously mentioned US Patent No. 3,860,003. Another suitable method and apparatus for producing a disposable diaper with elastic leg openings is disclosed in U.S. Patent No. 4,081,301 issued March 28, 1978.

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By referring to the preferred embodiment shown in Figs. 1 and 2 of U.S. Patent No. 3,860,003, it can be seen that elastic members 18 are operatively connected to both the longitudinal edge regions 50 of the crotch portion 46 in an elastically contractible state so that that the elastic members 18 in a normal non-tensioned form will effectively contract or contract the longitudinal edge regions 50. By the term operatively associated with, it is meant that two or more components interact with each other. In the preferred embodiment shown in Figures 1 and 2, the elastic members 18 are operatively connected to both the longitudinal edge regions 50 of the crotch portion 46. The elastic members 18 are attached to the longitudinal edge regions 50 so that the longitudinal edge regions 50 of the crotch portion 46 are constricted. or overall. A suitable method for inserting the resilient elements 18 into a disposable diaper is described in the previously mentioned US Patent No. 4,081,301.

In the preferred illustrated embodiment, the elastic members are attached to a portion of the backing 16 in the longitudinal edge regions 50. A suitable adhesive must be flexible and must have sufficient adhesive capacity to hold the elastic members 18 to the backing 16 while the elastic members are stretched. . An adhesive that has been used satisfactorily is manufactured by Findley Adhesives Corporation, Elm Grove, Wisconsin, and sold under the trade name Findley 581-334-01.

The elastic members 18 can be operatively connected to the longitudinal edge regions in an elastically contractible state in at least two ways. For example, the elastic members 18 can be stretched and fastened in the stretched state to the unstretched and extended longitudinal edge regions 50. Alternatively, the longitudinal edge regions 50 may be contracted (for example, by pleating), whereupon the unstretched elastic members 18 are attached to the contracted longitudinal edge regions 50. .

Suitable elastic elements 18 can be made of widely varying elastic materials such as natural rubber or elastomeric films such as Kraton, ethylene propylene dimonomer and polyurethane.

Furthermore, the elastic members 18 can take many forms. For example, the width of the elastic members 18 may vary from approx. 0.038

DK 166255 Β mm to approx. 25 mm (0.015 to 1.0 inches) or more. The elastic members 18 may consist of a single strip of elastic material or of several parallel or non-parallel strips of elastic material. The elastic members 18 may be rectilinear or curved. Furthermore, the elastic members 18 can be attached to the diaper 10 in a variety of ways well known in the art. For example, the elastic members 18 may be ultrasonically bonded or heat-sealed into the diaper using various bonding patterns, or they may simply be glued to the diaper 10. The outer fasteners with the inner fasteners are particularly effective in preventing the elastic leg openings yawns due to curved elastic elements.

A material which has been found to be suitable as an elastic member 18 is an elastic band having a cross section of approx. 0.18 mm x approx. 6.4 mm (0.007 inches x 0.25 inches) and made of natural rubber. Such a product is marketed by Easthampton Rubber Thread Company under the trade name L-1900 rubber compound. The preferred elastic members produce a tensile force of about 100 g when stretched 100% relative to their relaxed state.

The diaper 10 is provided with outer fasteners 54 for holding the first and second waist portions 42 and 44 in an overlap position when the diaper 10 is worn. When the diaper 10 is placed on the carrier, a side closure is formed in this way.

More specifically, the outer fasteners 54 attach the first waist portion 42 to the second waist portion 44, thereby holding the first and second waist portions 42 and 44, respectively, in an overlap position. Therefore, the outer attachment means must be attached to both the first waist portion 42 and to the second waist portion 44 in a manner and with a strength sufficient to withstand the forces which, in use, seek to separate the first waist portion and the second waist portion, respectively. 42 and 44, apart.

The outer fasteners 54 may be provided with any of the well-known means for obtaining a side closure such as

Velcro strips or patches, buttons or snaps. A preferred outer fastener 54 is an adhesive tape 55 which is well known in the art of diaper.

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The adhesive tape may have any of the well-known designs and constructions. For example, the adhesive tape may be for single use or for multiple use (i.e. reattachable). A preferred adhesive tape 55 is a Y-shaped tape, which is described in detail in U.S. Patent No. 3,848,594 issued November 19, 1974. The outer fasteners 54 are disposed at both the first and the second longitudinal sides 26 and 28, respectively.

The preferred adhesive tape 55 illustrated in Figure 2 has a manufacturer end 56 and a user end 58. The manufacturer end 56 is the end of the adhesive tape 55 that the manufacturer of the diaper 10 attaches to the diaper 10, while the user end 58 is the end of the adhesive tape 55 that the user attaches. to diaper 10 when diaper 10 is placed on the carrier. The manufacturer end 56 is attached to the first waist portion 42, and after the diaper is applied to the waist of the wearer, the user end is secured to the second waist portion 44, whereby the diaper 10 encloses the waist of the wearer and constitutes a side closure.

The second waist portion 44 has panels 62. The panels 62 are those portions of the second waist portion 44 which are overlapped by the first waist portion 42 when the diaper 10 is secured around the waist of the wearer. The extent to which the second waist portion is overlapped and thereby the extent of the panels 62 will depend on the overall dimensions, the shape of the diaper 10 and the size of the wearer.

The diaper 10 is provided with an inner fastener 60 (see Figure 2) to reduce, and preferably prevent, the panels 62 and the first waist portion 42 from displacing one another. The inner fastener 60 therefore resists the pulling forces which seek to cause the panels 62 to change position relative to the first waist portion 42 when the diaper 10 is worn.

As previously described, the diaper 10 is generally placed on the wearer such that the diaper 10 adapts to the wearer's waist and legs, thereby providing protection against spills. It is desirable that the diaper 10 maintains the position in which it is placed so that the fit around the waist and legs of the wearer is maintained. Therefore, it is important that the panels 62 are retained and preferably prevented from moving relative to the first waist portion 42 when the diaper 10 is worn. The purpose of the inner fasteners 60 is therefore to hold the panels 62 and the first

DK 166255 Β waist portion relative to each other in the position they occupy when the diaper 10 is placed on the wearer. As shown in Figure 2, the inner fasteners 60 are provided with the largest dimension oriented parallel to the longitudinal edges 45 and 47 of the waist portions 42 and 44.

After applying the panel 62 to the first waist portion 42 upon application of the diaper 10 to the wearer, the contact surface between the panel 62 and the first waist portion 42 is subjected to shear forces acting in such a way as to cause the panel 62 and first waist portion 42 moving in relation to each other. If such movements occur between panel 62 and first waist portion 42, the fit of diaper 10 around the waist and legs of the wearer will deteriorate. Therefore, the inner fasteners 60 must have a shear resistance sufficiently large to withstand the shear forces acting on the interface between panel 62 and the first waist portion 42. These shear forces are produced by the elastic members 18 and by the diaper carrier's movements.

By the term shear forces is meant the forces that occur when the diaper 10 is worn and which seeks to cause panel 62 to move relative to the first waist portion 42. The concept of shear forces must be kept separate from the notion of tearing forces which release or move the panels. 62 away from the first waist portion 42. The tearing forces are resisted by the outer fasteners 54, while the shear forces are resisted by the inner fasteners 60.

The inner fasteners 60 may have many different designs, but it has been found that an inner fastener 60 with a capacity to withstand shear forces of at least 500 g and preferably of at least 750 g and most preferably of at least 1000 g works well. The shear resistance of the inner fastener 60 can be determined in accordance with the procedure described below.

The inner fasteners 60 can either be continuous (i.e., a discrete spaced member attached to the diaper 10) or form a unit (i.e., a single piece of material which is neither split nor broken) with the panels 62, or with the first waist portion 42 or with both the panels 62 and the first waist portion 42. For example, the

The surface of the panels 62 touching the first waist portion 42 is manufactured so that the portion of the first waist portion 42 overlapping the panels 62 is mechanically fixed. Alternatively, the inner fasteners may be constituted by a layer of adhesive applied to the panels 62 having a sufficiently high shear resistance to prevent the panels 62 from moving over the overlap portions of the first waist portions 42. Alternatively, the adhesive may be applied to the first waist portion 42. It is not necessary for the inner fasteners 60 to have a high tear resistance as the overlap portions of the first and second waist members 42 and 44 are held together by the outer fasteners 54.

In the illustrated preferred embodiment, the inner fastener 60 is integral with the panels 62 and consists of a material layer which is attached to the panels 62 and which can be mechanically attached to the head piece 12 (i.e., the material layer is filtered into the head piece 12's fibers). A suitable material is sold by 3M Corporation, St. Paul, Minnesota, under the trade name SJ 3492. Another preferred inner fastener 60 consists of a layer of adhesive, for example, which is sold by 3M, St. Paul, Minnesota, under the designation OEM 1524, which is applied to panels 62.

The inner fastener 60 is preferably attached to both panels 62 and covers an area 25 mm wide (1 inch) (i.e. perpendicular to the longitudinal centerline 70) and 65 mm long (2.5 inches) (i.e. say parallel to the longitudinal centerline 70) at the corners of the diaper 10.

The shear resistance of the inner fasteners 60 is a measure of the ability of the inner fasteners 60 to withstand shear forces and thus to prevent the panels 62 from moving relative to the first waist portion 42. The shear resistance of the inner fasteners 60 can be determined using any of the any method which measures the force required to initiate a movement between panels 62 and the first waist portion 42 at a contact pressure of approx. 17 g / cm. The following procedure for determining the shear resistance of the inner fasteners 60 has been used successfully. Two samples are cut by the diaper 10. The first sample is cut by one of the panels 62 and it contains the portion of the panel 62 that overlaps with the first waist portion 42 when the diaper 10 is worn and the second sample is cut by the first waist portion. 42 and includes that portion of the first waist portion 42 that overlaps panel 62 as the diaper 10 is worn. The first sample shall have dimensions sufficient to cover the surface of a 63.5 mm x 63.5 mm sled and the second sample shall be at least 63.5 mm x 63.5 mm. If the inner fastener 60 has dimensions less than 63.5 mm x 63.5 mm, the sample must be selected so that it constitutes as much of the inner fastener 60 as possible.

Both specimens are cleaned of all loose or foreign materials, such as the absorbent member 14. The first specimen is attached to a friction slide 63.5 mm x 63.5 mm and 6 mm thick and covered with at least one surface. 3.2 mm thick medium-density (medium density) foam rubber, which is tightly wrapped around the sled and fastened in place. The wrapped sled with the added weight weighs 710 + 5 g. In attaching the first sample to the friction carriage, the inner surface of the first sample of the back piece 16 is placed against the friction carriage. The second sample is attached to a friction platform with the innermost overlap of the second sample of the headpiece 12 positioned against the friction platform.

The covered friction carriage is then put on top of the second sample, thus simulating the condition when the diaper 10 is worn. The friction carriage is applied to a shear force along a line parallel to the friction platform, and the force required just to initiate a sliding of the friction carriage with respect to the friction platform is equal to the shear resistance of the internal fastener 60. The shear force can be applied and measured by any method or apparatus well known in the test field. However, it has been found that the shear resistance of the innermost fasteners can be readily determined with a tensile testing apparatus of the type manufactured by Instron Corporation, Canton, Massachusetts and negotiated under the trade names Instron 1101-TM, 1102-TMS, 1122 and 1130.

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