In the improvement of this invention fluff pad 11 is attached to the backing film by lines of adhesive 18 in a selected pattern, shown in section in FIGS. 2 and 3, and in a diagrammatic plan view in FIG. 4.
In FIG. 4, the outer border line represents the outer border of the backing film as folded around the fluff pad and dotted line 11a represents the disposition of the fluff pad within the backing film. Panels 13a represent the folded over longitudinal edges of the backing film as in FIG. 1, and panels 14 represent the baffle film at each end.
With the location of these elements in mind, reference may now be made to the lattice-like diamond pattern of lines indicated at 18. The pattern shown is the preferred adhesive pattern for adhering the fluff pad to the backing film. It should be noted that the adhesive is spaced inwardly from the edges of the folded over backing film 13a and from the edges of the baffle film 14. The reason for this will be set forth later.
In this preferred pattern the dimension W which is the width or narrow dimension of the individual diamonds making up the pattern should be between about 1.5 inches and 2.0 inches with 1.9 inches preferred. Dimension L which is the length or long dimension of the individual diamonds should be between 2.5 inches and 3.0 inches with 2.8 inches preferred.
Stated another way, the open area encompassed within the invidual segments of the pattern should be from about 2 square inches to 3 square inches in area.
The width of the adhesive lines themselves may suitable be from about 0.075 inch to about 0.125 inch with 0.10 inch preferred.
While the diamond lattice pattern is preferred, other suitable patterns may be used within the prescribed limits.
One other suggested pattern is shown partially in FIG. 5.
The adhesive used may be any non-toxic flexible adhesive which adheres to the plastic film, which film in the preferred embodiment is polyethylene. Many such adhesives are known and it is not necessary to detail them here although polyvinyl acetate type latices are preferred ones to use.
The adhesive should be applied in sufficient amounts to penetrate the fluff pad to a short depth, but should not be applied in such large quantity as to cause stiffness.
Also in manufacturing all-fluff pads it is more convenient to handle the pad if a thin carrier sheet or wrap of cellulose wadding is used to cover each side of the fluff pad. When such a carrier sheet is used it is important to use a sheet which does not have wet strength since the latter interferes with the desired disintegration of the fluff pad during rinsing and tends to hold the fluff pad together in one piece.
In FIGS. 6, 7, and 8 there is illustrated a sequence of steps used to dispose of the fluff pad. After the diaper has been soiled during use and is ready for disposal, it is carefully laid flat on a counter or the like to prevent the contents from falling out and creating a mess. If the diaper is folded and adhesively attached at the crotch area, these attachments are broken and the diaper pulled open to assure that it lies flat. The untaped end of the diaper is then pulled apart as shown in FIG. 6. This is easily done because while heat seal 16 has good shear strength, it peels open without much difficulty.
The fecal contents of the diaper are then dumped into the toilet and the ends of the diaper grasped at the corners near the tapes (FIG. 1). The diaper is then lowered into the toilet and allowed to wet out for a moment. It is then rinsed up and down in the toilet, whereupon the adhered filler pad will fall out in controlled size pieces which stay dispersed and are easily flushed away.
After most of the fluff pad has been rinsed out, and the cover sheet thoroughly rinsed, if needed, the cover 10 sheet is rolled up inside the plastic backing film and discarded separately (FIG. 8).
As indicated above, the adhesive pattern should be spaced from the edges of the film components in the diaper and not extend under the folded over backing ]5 sheet or under the baffle film. If the adhesive extends under these areas to any extent, the fluff pad will not break up readily in these areas because the rinsing action is not as effective since the water is blocked out by the film. Accordingly, some material might tend to remain behind in these areas, rather than being com20 pletely dispersed in the toilet.
Preferably the spacing of the adhesive pattern from the baffle film at the top or taped end of the diaper may be greater than at the bottom end, but this is not essential.
25 In any event, the fluff pad should not be attached to
the backing film adjacent the ends and sides of the dia-
per, otherwise normal rinsing is not sufficient to detach
the fluff in those areas.
What is claimed is:
1. In a disposable diaper comprising a substantially 30 rectangular absorbent pad of intermingled wood pulp
fibers, a fluid-pervious cover sheet, a fluid-impervious backing sheet of thin plastic film and narrow plastic film baffle members extending transversely across the diaper at each end thereof; in which the longitudinal 35 edge portions of said backing sheet are folded around the respective pad edges to extend over the top of the pad for a short distance and are attached to said cover sheet along the entire length thereof; in which each of the ends of said backing sheet and said cover sheet extend beyond each of the ends of said pad and have said 40 baffle member interposed therebetween; in which the cover sheet, backing sheet and baffle are bonded to each other on a line adjacent the pad ends; and in which the free edge of said baffle member opposite from the bonded portion is interposed between said 45 pad and said cover sheet; the additional structure wherein said pad is adhered to said backing sheet by interconnected lines of adhesive disposed in a selected lattice-like open pattern in only that area of said pad which does not underlie said baffle members or said folded-over portion of said backing sheet, said adhesive 50 being applied in sufficient quantity to penetrate said pad for a short depth, the open area encompassed within the individual segments defined by the unbonded spaces between the lines of said pattern being between about 2 square inches and 3 square inches in 55 area.
2. The disposable diaper of claim 1 wherein said pattern is a diamond grid pattern.
3. The disposable diaper of claim 2 wherein the dimensions of the individual diamonds in said diamond grid pattern are in the range of between about 1.5 inches and 2.0 inches at the narrow dimension and between about 2.5 inches and 3.0 inches at the wide dimension and the width of said adhesive lines which make up the pattern are between about 0.075 inch and and 0.125 inch.
65 4. The disposable diaper of claim 1 wherein an absorbent non-wet strength tissue is disposed on each side of the absorbent pad.