US 3865111 A
The disclosed diaper structure incorporates raised ribs that form sealing beads along each lateral edge of the diaper and also includes a lateral extension on a tissue layer which overlaps in face-to-face relationship with another tissue in the folded diaper structure thereby providing an overlapped section trapping a pulp pad between the tissue layers.
Description (OCR text may contain errors)
tlnited States Patent 1191 1111 mass 111 Brooks Feb. 11, 11975 EASHILY DHSPOSABLE DIAPER WITH 3.521.624 7/1970 Gander et al. 128/132 R SEALHNG READ 3.658.063 4/1972 Schuar 138/287 3,710.797 1/1973 Marsan 128/284  Invento William ictor H ye oo s, 3,731,688 5/1973 Scarsdale 128/287 Toronto, Canada  Assignee: lDomtar Limited, Montreal, Canada  Filed: Mar. 29, 1974 Primary ExaminerAldrich F. Medbery pp No I 455 9996 Attorney, Agent, or Firm--C. A. Rowley  Foreign Application Priority Data 168,237 Apr. 9, 1973 Canada 7] BSTRACT The disclosed diaper structure incorporates raised ribs g gigig that form sealing beads along each lateral edge of the  W i 287 286 diaper and also includes a lateral extension on a tissue e 0 layer which overlaps in face-to-face relationship with  Ref rences Cited another tissue in the folded diaper structure thereby e providing an overlapped section trapping a pulp pad UNITED STATES PATENTS between the tissue layers. 2,507,197 5/1950 DeMatZdorf 128/287 3512.529 5/1970 Nimoy 128/287 6 Claims, 4 Drawing Figures EASILY DISPOSABLE DIAPER WITI-I SEALING BEAU FIELD OF THE INVENTION The present invention relates to a diaper, more particularly to a diaper incorporating raised beads as seals along its lateral edges and to a diaper construction facilitating retaining of the pulp pad in position.
DESCRIPTION OF THE PRIOR ART Disposable diapers incorporating a facing sheet of hydrophobic water permeable material and a backing sheet of imperforate material with an absorbent pad sandwiched therebetween are quite well known and have gained substantial acceptance particularly in the United States. These diapers normally are pleated along the opposite sides so that the diaper may be expanded to extend around the babys middle and yet be sufficiently narrow in the crotch area, so that they may be worn comfortably. Generally, the plastic backing sheet is folded over onto the facing side of the diaper and contact between this folded-over portion of the backing sheet and the baby is relied on to prevent escape of moisture around the side edges of the diaper. Such a seal is not always adequate.
To overcome these difficulties it has been proposed, for example, in Canadian Patent No. 903,401, issued June 27, 1972 to Lindquist et al to provide compressible fluid impermeable strips along each side of the diaper. These strips contact the baby and prevent the escape of moisture from beneath the diaper. Obviously, this arrangement is considerably more complex in that it requires further manufacturing operations to apply the extra elements and requires further component parts thereby rendering the diaper more expensive.
It is an object of the present invention to provide a simple inexpensive mechanism for a better sealing of the side edges of the diaper.
SUMMARY OF THE INVENTION Broadly, the present invention relates to a diaper comprising an impermeable backing sheet and a hydrophobic porous facing sheet with an absorbent pad sandwiched therebetween, said absorbent pad extending to the edges of said plastic backing sheet and being folded over adjacent each of the lateral edges to form a sealing bead along opposite side edges of the diaper, said bead providing a raised rim at each edge of the diaper to ensure better contact between the side of the diaper and the baby thereby provide a better seal along the side edges.
In the preferred construction of the present invention, the pad is provided with a tissue interposed between the facing sheet and the pad and between the plasticbacking and the pad. The tissue sheet interposed between the plastic backing and the pad is wider than both of these and projects at opposite sides of the dia per so that when the side edges are folded over the projecting ends overlap and lie in face-to-face contact with the other tissue sheet thereby to provide an overlapping area of tissue which traps the pulp pad in the diaper.
BRIEF DESCRIPTION OF THE DRAWINGS Further features, objects and advantages will be evident from the following detailed description of the preferred embodiments of the present invention taken in conjunction with the accompanying drawings in which:
FIG. 1 is an isometric view of a diaper constructed in accordance with the present invention;
FIG. 2 is an enlarged transverse cross-sectional view of the diaper slightly extended to show the various layers;
FIG. 3 is a detailed view of the edge structure at each side of the diaper, and
FIG. 4 is a detailed view of a modified form of edge structure.
DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. I, the diaper I0 is generally formed with pleats 12 along each side thereof. These pleats 12 may be extended or opened outside of the crotch area to the width of the diaper thereby to facilitate encircling the baby and better ensure a good fit. It will be noted that a bead 14 is formed at each side edge of the diaper by folding over of the pad structure as will be described in more detail hereinbelow.
As can be seen from FIG. 2, the preferred arrangement of the present invention, the diaper 10 comprises a non-woven facing sheet 16, a first or upper tissue sheet 18, an absorbent pad 20, a second or lower tissue sheet 22 and an impervious flexible backing sheet 24. In the arrangement illustrated the tissue sheet 18, pad 20 and backing sheet 24 are essentially the same width with their end edges terminating in a plane. The second tissue or lower tissue sheet 22 extends laterally beyond the free edges of these other elements as indicated at 25 and overlaps with the tissue sheet 18 in the area gen erally designated at 26 at each end of the diaper. In this area 26, adhesive may be applied as indicated at 27 to secure the plys 18 and 22 together and in some cases the facing sheet 16 together. The plastic backing sheet 24 is normally adhesively secured to the tissue 22.
In the preferred arrangement of the present invention no adhesive is applied to the overlapped areas 26 and the diaper structure is secured together by an adhesive strip 29 securing the non-woven 16 to the folded over portion of the backing sheet 24 as illustrated.
It will be noted that the pad 20, the tissue 18 and the tissue 22 together with the backing sheet 24 are folded back on themselves in a reversed fold 28 to provide the raised edge 14 at each side of the diaper. In the arrangement illustrated in FIG. 2, the pad 20 has been reduced in thickness in the area of the raised edge but it will still be noted that the edge projects above the height of the remainder of the pad whereby the pressure between the baby and the diaper is concentrated along the raised edge to improve the seal. The pad thickness should not be reduced by more than 40 percent of its thickness in this area so that when doubled over it will project above the remainder of the diaper.
The two strips of adhesive 27 one at each side of the diaper secure the diaper together. These strips 27 of adhesive are located entirely in the area of the overlap between the extensions 25 of the tissue 22 and the tissue 18 so that any free adhesive may penetrate the pad 20 and normally will do so thereby ensuring that when the diapers are folded in face-to-face relationship during manufacture there will be little if any tendency for the faces of the diapers to stick together.
In the arrangement illustrated, the facing sheet 16 is positioned on top of the backing sheet 24 in the area of the rolled edge or rim 14. This makes the diaper more comfortable without significantly increasing the lateral leakage of the diaper particularly when the facing sheet 16 does not extend to the side edges of the diaper. Preferably the side edges 17 of sheet 16 will not be less than /a inch from the side edge of the diaper as defined by the outer edge of the sealing beads 14.
The adhesive seams 27 or 29 in the illustrated arrangements are formed by continuous adhesive lines, but it is also possible to use an-intermittent adhesive line and retain the required strength.
If desired, the backing sheet 24 may be separated from the tissue 22 at least in the area of the upper section of the folded section 28 and the extension 25 eliminated as shown in FIG. 4. in this arrangement, the nonwoven sheet is laid in direct contact with the tissue 22 in the area of the raised rim l4 and then the plastic backing sheet 24 is folded over onto the adhesive strip 29 which functions to secure the plastic backing sheet to the non-woven sheet and the non-woven sheet to the tissue 22. With the structure shown in FIG. 4, the plastic backing 24 directly contacts the baby along the raised edge and provides a slightly better seal at the expense of the comfort of the infant.
When the diaper is formed either using the FIG. 1 to 3 or the FIG. 4 embodiment of the present invention the pleats 12 are secured together in the crotch area by tack points generally indicated at 30 in FIG. 1. These tack points hold the pleat together and prevent it from being opened in this area thereby forming a crotch section that is permanently equal in width to the width of the folded diaper. These tack points 30 may be located along the transverse centre line of the diaper or may be positioned forwardly of this centre line to provide a front and a back to the diaper, the front being the shorter section. Generally these tack points will not be shifted forward more than about 2 inches.
In the arrangement illustrated the Z-fold at the side of the diaper terminates a distance in from the lateral edge of the diaper. If desired, the fold may be rearranged so that the fold forming the outside of the raised edge 14 is located at the lateral edge of the diaper.
The double thickness provided by the reverse fold 28 normally will not project from the free edge 15 of the diaper pad is towards the centre thereof a distance of more than 2 inches and preferably will extend in between h and 1 /2 inches from the free edge.
No tying devices have been shown, however suitable adhesive tabs may be applied to the backing sheet 24 at the side thereof and adjacent the back of the end of the diaper. These adhesive tabs secure the front and rear sections of the diaper together around the baby and thereby hold the diaper in position. The adhesive used is such that the tab may easily be separated from the front of the diaper to facilitate removal of the diaper for changing.
Modifications may be made without departing from the spirit of the invention as defined in the appended claims.
1. A diaper comprising a porous hydrophobic facing layer, an impervious backing layer, an absorbent pad sandwiched between said facing and said backing layers, said pad being substantially the same width as said backing layer, a means for providing a moisture seal comprising a pleat extending outwardly toward each side of said diaper and terminating in a folded edge portion at the lateral extremities of the pad formed by a portion of said pad and said backing sheet folded over into a reverse fold in an inward direction and providing a raised sealing bead along each side edge of the diaper.
2. A diaper as defined in claim 1 wherein each said reverse fold extend in from a lateral free edge of said pad a distance of at least /2 inch.
3. A diaper as defined in claim 2 wherein said pad comprises a top tissue and a bottom tissue with an absorbent padding therebetween, said bottom tissue being wider than the other components of said diaper and forming lateral extensions on each side of said pad and backing sheet, said lateral extensions overlying said top tissue in the area immediately adjacent the side edges of the pad when the diaper is folded to form said reverse fold.
4. A diaper as defined in claim 1, wherein said facing sheet overlies said raised beads.
5. A diaper as defined in claim 2 wherein said facing sheet oyerlies said raised beads.
6. A diaper as defined in claim 3 wherein said facing sheet overlies said raised beads.