Disposable Diaper

Abstract

A disposable diaper having a C-folded pad within a wrapping envelope, the envelope being substantially wider than the C-folded pad to provide side flaps adapted to initially underlie the pad and be selectively folded outwardly for securing the pad in place, the C-fold providing a lined channel on one side of the pad which encourages more even, rapid, and complete dispersion of body fluid.

Parent Case Text

This application is a continuation-in-part of our copending application Ser. No. 32,560, filed Apr. 28, 1970, now Pat. No. 3,667,468.

Description

BACKGROUND AND SUMMARY OF INVENTION

In the above-identified application, now patent No. 3,667,468, a C-folded construction of pad is disclosed which encourages more even, rapid, and complete disperson of body fluids. We have found that this construction is eminently suitable for diapers, particularly when disposed in a substantially wider enveloping wrap which, when installed, insures that the pad is held snugly against the baby.

DETAILED DESCRIPTION OF THE INVENTION

The invention is described in conjunction with the accompanying drawings, in which:

FIG. 1 is an elevational view of the diaper just prior to application on a baby;

FIG. 2 is a side elevational view;

FIG. 3 is a cross-sectional view seen along the line 3--3 of FIG. 1;

FIG. 4 is a perspective view of the diaper configuration in the form it assumes when applied on a baby;

FIG. 5 is a side elevational view, partially schematic, of apparatus employable in the practice of the inventive method; and

FIGS. 6-9 are fragmentary enlarged cross-sectional views of the diaper at various stages of its development corresponding to the sight lines 6--6, 7--7, 8--8, and 9--9, respectively, as applied to FIG. 5.

In the illustration given, and with particular reference to FIG. 3, the numeral 10 designates generally a C-folded pad of fluff or like soft absorbent material. It will be seen that the pad is achieved by folding, as at 11 and 12 (still referring to FIG. 3), to develop a C-shape in cross section wherein there is a central channel 13. The channel 13 is essentially T-shaped and is defined by the inner pad portions 14 and 15 in combination with the outer pad portion 16. The transverse spacing between the inner pad portions 13 and 14 is normally of the order of one inch to one and one/quarter inch, which provides more comfort for a male baby. It also provides a receptacle for the solids and makes the pad more form-fitting in the crotch. When folded as just indicated, the pad 10 is generally rectangular in plan, with the longer dimension being parallel to the length of the channel 13.

Advantageously the pad fluff or like soft, moisture-absorbent material is completely wrapped or encased in a wadding web 17, also of moisture-absorbent material. This web 17 is likewise disposed in a C-shape in cross section, and can be advantageously provided in the form of the carrier sheet to be described hereinafter upon which the fluff is deposited incident to manufacture of the diaper. Alternatively, the wadding web 17 may be introduced after the pad is formed. In either case it is wrapped around the pad before the C-folding takes place. The wadding web 17 is seen to consist of a single sheet with an overlap, as at 18, within the channel 13. In this fashion there is an extra dispersion sheet within the channel 13 which improves the absorbing qualities of the pad. Further, this facilitates the manufacturing operation to be described hereinafter.

The pad 10 complete with wadding web 17 is positioned within an enveloping wrap generally designated 19 and which is seen to consist of two generally rectangular, coextensive sheets arranged on opposite sides of the pad 10. Adjacent the inner pad portions 13 and 14, i.e., on the side of the diaper facing the baby, we provide a substantially moisture-pervious sheet 20 which advantageously may be constructed of non-woven or like material that has the absorbing qualities and wet strength needed as well as being comfortable for the baby. Adjacent the other side of the pad 10, i.e., adjacent the outer pad portion 16, we provide a second sheet 21. This sheet 21 is constructed of substantially moisture-impervious material such as polyethylene or like material of proper strength and moisture-repelling qualities. The moisture-pervious sheet 20 and moisture-impervious sheet 21 are perimetrically united, as by lines of adhesive at 22 and 23, along the longitudinal side edges, and, at 24 and 25, at the extreme transverse edges -- thereby developing an envelope. It will be noted that the length of the pad 10 is less than the length of the envelope 19, thereby providing reduced thickness ends as at 26 and 27 (see FIG. 2).

Additionally, the sheets 20 and 21 are united along transverse lines, as at 28 and 29, which immobilize the pad 10 in place. Still further, the sheets 20 and 21 are united along the longitudinal edges of the C-folded pad 10, as at 30 and 31, to further immobilize the pad and develop side flaps which are generally designated 32 and 33.

Advantageously, the side flaps 32 and 33 are folded "under the diaper" -- this in the sense that the channel 13 is positioned uppermost when the diaper is laid on a changing table incident to applying the same on a baby. In the illustration given, the side flaps are seen to be reverse-folded, as at 34 and 35, to develop a gusset arrangement.

To further assist in the development of an advantageous diaper configuration -- of the type depicted in FIG. 4 --, we povide additional spots of adhesive as at 36 and 37, these being between the reverse fold lines 34 and 35 and the associated edges of the C-folded pad 10, and are effective to join the side flaps 32 and 33 centrally longitudinally to the moisture-impervious sheet 21. This prevents the gussets from being completely pulled out round the leg portion of the baby, and insures that the pad is held snugly against the baby.

From the foregoing it will be seen that nothing but the upper sheet 20 (viz., the non-woven material) touches the skin of the baby. We also provide securing tabs 38 and 39 at one end of each of the side flaps 32 and 33, the tabs being equipped with adhesive which is temporarily covered by means of release strips 40. Thus, when the pleats or folds in the side flaps 32 and 33 are drawn from the bottom of the pad (at the ends thereof) and secured around the baby's waist, they tend to snug up the pad against the baby. Leakage around the legs is therefore minimized.

Further, there is far less fluff and wadding needed because of the excellent dispersing qualities of the C-fold, and the fact that the pad itself is relatively small. Instead of 2,000 pounds per hour of fluff production and forming for large, overnight diapers, 1,200 pounds is a more realistic figure. For example, instead of a 16 inches long by 12 inches wide fluff pad, the inventive pad can be 13 inches long by 9 inches wide. This results in a saving of 40 percent of fluff and wadding with an increase of the effectiveness in dispersl of solids and liquids.

Apparatus for producing the inventive diaper is seen in FIG. 5. At the extreme left-hand portion of FIG. 5 we provide an unwind mechanism 41 which carries a parent roll of wadding web material providing the previously mentioned wadding web 17. This is conducted over various idler rolls to an overwrap folding unit 42. At this point, the configuration seen in FIG. 6 is developed, which, it will be appreciated, is the blank employed to develop the C-folded pad 10. For that purpose, a fluff unit 43 is provided which disintegrates a cellulosic web 44 provided from a parent roll on an unwind 45. The fluff web 46 also enters the overwrap fold mechanism and is enveloped or overwrapped by the wadding web 17. The composite web is advanced through the action of the top and bottom conveyor belts generally designated 47, after which the web configuration or blank seen in FIG. 6 is C-folded by means of the folding device 48 into the configuration seen in FIG. 7.

The continuous C-folded pad 10 is advanced through the nip of a pair of rolls generally designated 49 which serve to compress the continuous web at spaced-apart transverse areas corresponding to the ends of the pads 10 ultimately developed. The pads are developed by virtue of passing through a pad cutoff generally designated 50, wherein one roll is equipped with knives and the other roll equipped with anvils or recesses accommodating the knives so as to sever the C-folded web transversely.

The compressed portions of the web blank can be seen schematically at 51 between the units 49 and 50.

After the operation of the pad cutoff 50 to achieve discrete length pads 10, the pads are supported on a bottom powered conveyor 52 and are advanced by the cooperation of the conveyor 52 with a top conveyor (also equipped with a belt) as at 53. The conveyors 52 and 53 operate at a speed faster than the conveyor 47 (constituting a "speed-up" conveyor) so as to develop a larger spacing 51a between pads 10 and thus accommodate the greater length webs 20 and 21 (see FIGS. 2 and 3).

An unwind for the moisture impervious web 21 is provided at 54, and a similar unwind 55 is provided for the moisture pervious web 20. The webs 20 and 21 are led through a nip defined by a pair of rolls 56 so as to envelop the pads 10. Prior to the entrance of the web 20 into the nip defined by the ros 56, the side seal adhesive for the seams 22, 23, and 30, 31 is applied by nozzles as at 57. Before the web 21 reaches the nip defined by the rolls 56, transverse lines of adhesive are laid down by a glue printer generally designated 58, which results in the seams 24, 25 and 28, 29.

After leaving the nip defined by the rolls 56, the composite web passes through pull conveyor belts generally designated 59 and which have positioned therein end seal pressure wheels as at 60. Just prior to encountering the pull conveyors 59, the web configuration is as seen in FIG. 8.

As the web in composite form (seen in FIG. 8) issues from the pull conveyors 59, adhesive is applied by means of nozzles 61 to develop the spots 36 and 37 (see FIG. 1). Thereafter the composite web goes through a gusset former to develop the side flaps 32 and 33 (see FIG. 9), this being achieved by the gusset former 62. Thereafter the diaper is equipped with tabs in a tab applicator generally designated 63, the adhesive tape providing the tabs 38 and 39 coming from the unwind 64, while the release strips 40 are provided from the unwind 65. These are transversely severed after uniting by means of a cutoff roll 66. The individual diapers are developed by means of a diaper cutoff mechanism generally designated 67, after which the individual diapers are advanced through pull belt conveyors generally designated 68 into the nip defined by a pair of folding rolls generally designated 69. From the folding rolls 69, the diapers are automatically stacked in predetermined count units on the leaving conveyor generally designated 70.

Claims

We claim:

1. A disposable diaper comprising a generally rectangular pad of soft, moisture-absorbent material, a wadding web of moisture-absorbent material surrounding the pad, the pad and wadding web being folded into a C-shape along a pair of spaced apart lines to provide an outer pad portion and a pair of inner pad portions superposed on the outer pad portion to form an elongated channel extending parallel to said spaced-apart lines, the inner pad portions and the outer pad portion being of approximately the same thickness, each inner pad portion being separated from the confronting part of the outer pad portion by a double thickness of said wadding web, an enveloping wrap encircling the C-folded pad and wadding web and extending across said channel, said enveloping wrap providing side flaps adapted to be unfolded in the direction transverse to the length of said channel and thereafter united at the respective ends thereof and about a baby's waist.

2. The structure of claim 1 in which said enveloping wrap includes a substantially liquid-pervious sheet adjacent said inner pad portions and having a width exceeding the width of said C-folded pad, said enveloping wrap also including a substantially liquid-impervious sheet adjacent said outer pad portion and generally coextensive with said liquid-pervious sheet, said sheets being perimetrically united to form said enveloping wrap, said sheets being united along the edges of said C-folded pad to provide side flaps.

3. The structure of claim 2 in which prior to use said flaps are folded into positions adjacent said outer pad portion.

4. The structure of claim 3 in which said side flaps are each reverse folded along a line parallel to but spaced from the union at the edge of said C-folded pad.

5. The structure of claim 4 in which each of said side flaps is united in the portion thereof between said reverse fold line and the edge of said C-folded pad to a portion of said liquid-impervious sheet, the last mentioned union being located approximately midway of the length of said diaper whereby the ends of said side flaps are free but the intermediate portions are restricted during unfolding.

6. The structure of claim 3 in which ends of said side flaps are equipped with securing tabs.

7. The structure of claim 3 in which said wadding web is a single sheet having longitudinal edges overlapped within said channel.

8. The structure of claim 1 in which said channel between said inner pad portion is at least about one inch wide.