GB1588115A

GB1588115A - Disposable diapers

Info

Publication number: GB1588115A
Application number: GB2831876A
Authority: GB
Original assignee: Robinson and Sons Ltd
Current assignee: Robinson and Sons Ltd
Priority date: 1977-06-27
Filing date: 1977-06-27
Publication date: 1981-04-15

Description

(54) DISPOSABLE DIAPERS (71) We, ROBINSON & SONS LIMITED, a British Company, of Wheat Bridge Mills, Wheat Bridge, Chesterfield, Derbyshire S40 2AD, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- This invention concerns disposable diapers, that is diapers adapted to be used once and then discarded.

According to this invention there is provided a disposable diaper comprising a generally rectangular pad of absorbent fluffed pulp material attached to one surface of a generally rectangular moisture-proof backing sheet and with a generally rectangular moisture-permeable (preferably hydrophobic) top sheet completely overlying the pad and backing sheet, and, with the backing sheet, providing an envelope therefor, the pad being shorter and narrower than the backing sheet and top sheet and being generally centrally disposed with respect to the backing sheet and top sheet so that edge portions of the backing sheet and top sheet extend beyond the corresponding edges of the pad, the assembly comprising the pad together with the backing sheet and top sheet being Z-folded so that edge portions of the pad adjacent its two longitudinal edges are turned inwardly of the pad towards each other and the edge portions of the backing sheet and top sheet which extend beyond the longitudinal edges of the pad are folded outwardly, and an inner envelope being provided within the envelope defined by the backing sheet and top sheet for containing the fluffed pulp material, which has little or no inherent dimensional stability, thereby to provide a degree of dimensional stability thereto.

The inner envelope is preferably formed of cellulose tissue or the like, and is conveniently arranged as a bottom tissue having longitudinal edges folded around the longitudinal edges of the pad and a top tissue overlying the pad, the top tissue for preference being substantially the same size as the pad al though, if desired, it could be longer so as to have the same length as the backing sheet and top sheet in which case it could be incorporated into end seal areas of the diaper.

The preferred diaper construction according to the invention thus has a fluffed pulp pad laid on to a bottom tissue of substantially the same length dimension but greater width than the pad, and with the longitudinal edges of the tissue turned over to contain the corresponding edges of the fluffed pulp pad. A top tissue completes the containment of the fluffed pulp pad. The pad, together with the bottom tissue, is adhered to a polythene backing sheet of greater length and width than the pad and the longitudinal edges of the backing sheet are turned over to form folded edges.

The top sheet, which is the same length as the backing sheet and slightly greater in width than the backing sheet as reduced by its turned over edges, is laid on the pad and all four perimeter edges are secured. The edges of the pad are folded inwardly, together with the top sheet and backing sheet adjacent thereto, and the excess of top sheet and backing sheet material beyond the longitudinal edges of the pad are folded outwardly.

It is preferred to secure the folding of the diaper in a region which, in use of the diaper will locate between the legs of the infant. This is most conveniently achieved by suitable adhesion of one or other of the various diaper layers.

The preferred diaper construction above described is well suited for manufacture on automatic machinery arranged such that fluffed pulp pads, contained within bottom tissue and top tissue material as previously described, are cut from continuously formed composite web material whilst forming continues and are delivered on to a continuous, moving web of backing sheet material with spacing between successive pads. The top sheet material, in continuous web form, is laid on as a continuous web and attached to the folded over edges of the backing sheet by adhesive. Crimp sealing is performed between the successive pads, uniting the backing sheet material with the top sheet, and the discrete diapers, still attached to one another by virtue of their manufacture from continuous webs, are Z-folded by passing the continuously moving web structure through appropriately formed folding stations, and are then separated by cutting within the region of the crimped seals. The folds can be fixed in by application of suitable adhesive, for instance of hot melt type, in localised manner immediately prior to folding.

In order that the invention might be well understood, an exemplary embodiment thereof will now be described with reference to the accompanying drawings wherein: Figure 1 is a schematic cross-sectional view through a diaper according to the invention prior to Z-folding; and Figure 2 is a view of the diaper of Figure 1 after Z-folding.

It is to be appreciated that the constituent parts of the diaper hereinafter described are all of generally rectangular configuration.

The differences in the width dimensions of the constituent parts will be apparent from the accompanying drawings which show transverse cross-sectional views, and differences in length dimensions will be mentioned as the following description proceeds.

Referring first to Figure 1, the diaper is shown there in its unfolded state and comprises a fluffed pulp pad 1 contained by means of a bottom cellulose tissue sheet 2, the longitudinal edges whereof are turned around the edges of the pad 1 as shown, and a top cellulose tissue sheet 3, the longitudinal edges whereof extend outwardly to cover the inwardly folded over edges of the bottom tissue approximately to the transverse extent of the pad 1. A polythene backing sheet 4 has longitudinal edges which extend beyond the transverse extent of the pad 1 and are turned upon themselves as shown. A top sheet 5 of non-woven, hydrophobic, moisture-permeable material overlies the diaper pad 1, and, as can be seen, is dimensioned to cover and extend outwardly beyond the portions of the backing sheet 4 which otherwise would be exposed to view from the front of the diaper.

The pad 1 is secured to the backing sheet 4 by means of a plurality of lines 6 of waterbased adhesive which are applied on to the backing sheet before the pad 1 and bottom tissue 2 are laid thereupon. The adhesive penetrates the tissue 2 and into the fluffed pulp of the pad 1 and holds all three constituents together. Similarly, lines 7 of adhesive serve to secure the hydrophobic top sheet 5 to the turned-over edges of the backing sheet 4.

Although not shown in the drawings, the pad 1, bottom tissue 2 and top tissue 3 are made of the same length (being conveniently cut from a continuously formed length of such), which length is less than the length of the backing sheet 4 and the top sheet 5 which are both of the same length. The longitudinal ends of the diaper, comprising a two layer structure of backing sheet 4 and top sheet 5, are sealed by crimping in a manner well known in this art.

Figure 2 shows the diaper of Figure 1 in its Z-folded configuration. As can be seen, the pad 1 has its longitudinal edges turned in towards each other, taking with it the accompanying top and bottom tissues 2 and 1 respectively, as well as backing sheet 4 and top sheet 5, and then the outermost edges of the backing sheet 4 and top sheet 5 are returned outwardly. Each longitudinal edge of the pad 1 is, by this arrangement, C-folded, and the corresponding edges of the backing sheet 4 and top sheet 5 are Z-folded.

Reference numerals 8 in Figure 2 designate spots of hot melt adhesive provided approximately mid-way between the longitudinal ends of the diaper in order to retain the Cfold of the pad 1. The precise location of this adhesive spot can be varied with respect to the transverse dimension of the diaper. Transverse locations more towards the centre of the diaper than the location shown might be preferred. Similarly, the precise longitudinal location can be varied, being a matter of preference.

In use of the illustrated diaper, the longitudinal ends of the diaper are opened out to accommodate the girth of the infant, whilst the central region of the diaper is substantially retained in its folded configuration, predominantly by the adhesive spots 8, and thus fits the narrower regions of the infant's anatomy between its legs. The folding effectively provides a pocket for solids defecated by the infant and concentrates the pad for enhanced moisture absorbency adjacent the moisture source.

Many variations and modifications, particularly in regard to the particular materials employed, will occur to those acquainted with the disposable diaper art. It is the intention hereof to embrace all such modifications as might fall within the scope of the invention as defined in the appended claims. Among these are the provision of integral tabs of adhesive tape for securing the diaper around the waist of the infant, and a further preferred construction with some materials would be to emboss the pad, together with one or both of its associated tissues, to provide a more intimate combination and to aid the spread of fluid in use. Another modification which might be made, for example to enhance the formation of the diaper end seals by crimping, would be to provide a further, intermediate layer of tissue of the same lateral width as the pad 1 in the embodiment des cribed and extending longitudinally the full length of the diaper so as to be incorporated in the end seal crimping and to provide more substance for the crimping operation to act upon, this intermediate layer lying between the top sheet 5 and the top tissue sheet 3.

WHAT WE CLAIM IS: 1. A disposable diaper comprising a generally rectangular pad of absorbent fluffed pulp material attached to one surface of a generally rectangular moisture-proof backing sheet and with a generally rectangular moisture-permeable top sheet completely overlying the pad and backing sheet, and, with the backing sheet, providing an envelope therefor, the pad being shorter and narrower than the backing sheet and top sheet and being generally centrally disposed with respect to the backing sheet and top sheet so that edge portions of the backing sheet and top sheet extend beyond the corresponding edges of the pad, the assembly of the pad together with the backing sheet and top sheet being Z-folded so that edge portions of the pad adjacent its two longitudinal edges are turned inwardly of the pad towards each other and the edge portions of the backing sheet and top sheet which extend beyond the longitudinal edges of the pad are folded outwardly, and an inner envelope being provided within the envelope defined by the backing sheet and top sheet for containing said fluffed pulp pad thereby to provide a degree of dimensional stability thereto.

2. A disposable diaper as claimed in claim 1 wherein said top sheet is formed of hydrophobic material.

3. A disposable diaper as claimed in claim 1 or 2 wherein said inner envelope is constituted by a bottom tissue having longitudinal edges folded about the longitudinal edges of the pad, and a top tissue overlying the pad.

4. A disposable diaper as claimed in claim 3 wherein the top tissue is of substantially the same size as the pad.

5. A disposable diaper as claimed in claim 3 wherein the top tissue has the same length as the backing sheet and top sheet and is incorporated into end seal areas of the diaper.

6. A disposable diaper as claimed in any of the preceding claims further comprising means to secure the folding of the diaper in a region thereof which, in use of the diaper, will locate generally between the legs of the user.

7. A disposable diaper as claimed in claim 6 wherein said securement means includes adhesion of one or other of the diaper layers.

8. A disposable diaper as claimed in any of the preceding claims including integral tabs of adhesive tape adapted for use in securing the diaper around the user's waist.

9. A disposable diaper as claimed in any of the preceding claims wherein the pad is adhered to the backing sheet by means of adhesive which penetrates from the backing sheet through the intervening inner envelope and into the fluffed pulp of the pad.

10. A disposable diaper as claimed in claim 9 wherein a plurality of lines of adhesive are provided to adhere the pad to the backing sheet.

11. A disposable diaper as claimed in any of the preceding claims wherein the pad, together with any associated enveloping tissue, is embossed to aid the spread of fluid in use.

12. A disposable diaper substantially as herein described with reference to the accompanying drawings.

13. A method of making a disposable diaper as claimed in any of the preceding claims comprising: delivering fluffed pulp pads contained within enveloping material on to a continuous, moving web of backing sheet material with spacing between successvie pads; laying on the top sheet material, in continuous web form, and attaching it by adhesive to folded over edges of the backing sheet; crimp sealing the embryo diapers thus formed, between successive pads, to unite the backing sheet material with the top sheet; continuously moving the continuous web structure thus defined through appropriately formed folding stations so as to Z-fold the pads together with their backing and top sheets; and separating the discrete diapers from the folded continuous web structure thus defined by cutting within the region of the crimp seals.

14. A method as claimed in claim 13 wherein the fluffed pulped pads in the finished diapers are contained within envelopes comprising top and bottom tissues, and wherein the fluffed pulp pads are delivered to the backing sheet material by cutting the pads from continuously formed composite web material comprising fluffed pulp, bottom tissue and top tissue whilst forming continues.

15. A method as claimed in claim 13 or 14 wherein the folds are fixed by application of adhesive in localized manner immediatelv prior to folding.

16. A method of forming a disposable diaper, substantially as herein described with reference to the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. cribed and extending longitudinally the full length of the diaper so as to be incorporated in the end seal crimping and to provide more substance for the crimping operation to act upon, this intermediate layer lying between the top sheet 5 and the top tissue sheet 3. WHAT WE CLAIM IS:

1. A disposable diaper comprising a generally rectangular pad of absorbent fluffed pulp material attached to one surface of a generally rectangular moisture-proof backing sheet and with a generally rectangular moisture-permeable top sheet completely overlying the pad and backing sheet, and, with the backing sheet, providing an envelope therefor, the pad being shorter and narrower than the backing sheet and top sheet and being generally centrally disposed with respect to the backing sheet and top sheet so that edge portions of the backing sheet and top sheet extend beyond the corresponding edges of the pad, the assembly of the pad together with the backing sheet and top sheet being Z-folded so that edge portions of the pad adjacent its two longitudinal edges are turned inwardly of the pad towards each other and the edge portions of the backing sheet and top sheet which extend beyond the longitudinal edges of the pad are folded outwardly, and an inner envelope being provided within the envelope defined by the backing sheet and top sheet for containing said fluffed pulp pad thereby to provide a degree of dimensional stability thereto.