US 3402715 A
Description (OCR text may contain errors)
Sept. 24, 1968 G. .1. L.|| o|A ET A1. 3,402,715
DIAPER Filed May 9, 1966 627% 0 d. u a//f ATTORNEY INVENTOR aa/5 f.' M4); c/fP.
United States Patent O M 3,402,715 DIAPER Gerald J. Liloia, North Brunswick, and Louis F. May, Jr., Old Bridge, NJ., assignors to Johnson & Johnson, a corporation of New Jersey Filed May 9, 1966, Ser. No. 548,711 Claims. (Cl. 12S-287) The present invention relates to disposable diapers and more particularly to disposable diapers of the type which are adapted for single use land then to be discarded, which are prefolded to aid in application and which are backed with a moistureproof film to avoid leakage through the diaper.
It is an object of the present invention to provide prefolded diapers having high fiuid absorbent capacity and backed with a moisture-impermeable lm, the backing film and the absorbent of the diaper bei-ng so interrelated in the construction and disposed with respect to each other that on application of the diaper to an infant there is no portion of the moisture-impermeable film which is held in continuous contact with the skin of the infant. Thus there is avoided the uncomfortableness and irritation which otherwise would be caused by keeping in contact with the infants skin a water-impervious plastic film which would tend to interfere with normal moisture transmission from the skin surface and aeration of the skin.
The invention is more fully described wit-h reference to the drawings. Other objects and .advantages of this invention will become apparent from the following description taken in connection with the accompanying drawings wherein are set forth -by way of illustration and example certain embodiments of this invention.
FIGURE 1 is `an illustration of a prefolded diaper of the present invention;
FIGURE 2 is a top perspective view of the diaper of FIGURE 1 prior to folding with a portion of the cover sheet broken away;
FIGURE 3 is a cross-sectional View taken along line 3-3 of FIGURE 2; and
FIGURE 4 is a perspective view of the underside of the bottom -absorbent sheet of a diaper of the present invention.
Referring to FIGURES 2 through 3 of the draw-ings, the diaper contains a top moisture-permeable cover sheet and a bottom absorbent sheet 11. Between the cover sheet 10 and absorbent sheet 11 is an absorbent pad 12, formed of wood pulp or other highly absorbent material. The absorbent pad 12 is substantially narrower than the cover sheet 10 and bottom absorbent sheet 11 and is spaced from the side edges of sheets 10 and 11 so as to lie along the center portion of the diaper, i.e., the portion which would, in use, be positioned at the crotch of the infant. The bottom absorbent sheet 11 is of the same width as the cover sheet 10 but is longer than the cover sheet 10 and has extending ends 13 and 14.
In the preferred embodiment, the cover sheet 10` is also absorbent, both the top and bottom sheets being made of relatively inexpensive absorbent sheet materials. It is necessary, however, that the top sheet have sufficient wet and dry strength to resist tearing or abrasion under normal diaper use.
The bottoni absorbent sheet 11 has secured t-o one side thereof, as best illustrated in FIGURES 3 and 4, a thin Water-impervious film 15. Film 15 extends completely across the bottom absorbent sheet 11 from one side edge to the other. Film 15 is substantially shorter than bottom absorbent sheet 11 and is so placed on absorbent sheet 11 as to leave marginal areas 16 and 17 which are not covered by the water-impermeable film 15. The absorbent sheet 11 may be made of any inexpensive highly-absorb- 3,402,715 Patented Sept. 24, 1968 ent sheet material, the same preferably being formed of nonwoven fabrics of the t-ype formed predominately of short cellulosic fibers such as those claimed and described in eopending application Serial No. 515,874. In the preferred diaper construction both the bottom absorbent sheet 11 and the top absorbent sheet 10 are formed of such nonwoven fabric-like materials of short cellulosic fibers, the sheets being in the form of fiber webs which are through bonded with a relatively flexible bonding agent.
In the preferred practice the film 15 is formed by extrusion coating one surface of absorbent sheet 11 with a thermoplastic film such, for example, as polyethylene, care being taken during extrusion coating to leave the uncoated margins 16 and 17. In extruding the film onto the web, the web and film are both fed in the direction of arrow 18 shown in FIGURE 4. In extru-ding film 15 onto the absorbent web to form the bottom absorbent sheet 11, the molten polyethylene or other thermoplastic film-forming material being extruded narrows in width as it moves from the extrusion die to the fiber web on which it is being placed, i.e., it necks in, with the result that a bead or edge area is formed of substantially greater thickness than the main body of the film. This thicker edge area or bead 19 because of the direction of extrusion, runs along the ends of the diaper adjacent to the uncoated portions 16 and 17 of the underlying fiber web. This adds further strength in the waistband portion of the diaper when applied `as hereinafter more fully described.
In forming the diaper the bottom absorbent web 11 is placed with the water-impervious film 15 down and absorbent uncoated side up. The absorbent filler pad 12 is then placed on the fiber surface of bottom absorbent sheet 11 in the approximate center of the sheet, spaced from the side edges 22 `and 23 of the diaper as best illustrated in FIGURES 2 and 3. The top cover sheet 10 is then placed over the absorbent filler pad 12 and bottom sheet 11 so that its side edges coincide with the side edges of the bottom absorbent sheet 11. The cover sheet 10 has the same width las the bottom sheet 11 but is shorter, the cover sheet 10v having substantially the same dimensions as that of film 15. In placing cover sheet 10 over the absorbent filler and bottom absorbent sheet 11, it is placed so as to substantially coincide with the underlying film 15.
The film free margins 16 and 17 are then turned over the ends of the cover sheet 10 and secured in place by any suitable adhesive to form waistband portions 20 and 21, as best illustrated in FIGURES l and 2 of the drawings.
Each of the side edges 22 and 23 of the composite diaper so formed are then folded over towards the center of the diaper. 'Ihis provides a first fold 24 running along each side of the folded diaper substantially parallel to a center imaginary line running the length of the absorbent filler pad and bisecting the diaper. The infolded edges 22 and 23 are then folded back on themselves to where the respective edges 22 and 23 of the composite diaper on each side of the diaper substantially coincide with the first folds previously described. This provides two outer folds or rst folds 24 extending lengthwise of the diaper and two inner folds or second folds 25 also extending lengthwise of the diaper but positioned between the first folds and the center portion of the diaper. The second folds 25 are so spaced from each other as to leave a substantial portion 26 of the center part of the diaper open and not covered by the folded in sides. This open area in the center portion of the diaper substantially coinciding with the absorbent pad 12 although it may be somewhat narrower. The folded sides are anchored in their folded positions by adhesive spots 27 placed substantially centrally between the ends of the diaper. The diaper is thus maintained in the prefolded state at least during its application to an infant.
When the diaper is applied, the center portion of the diaper is placed between the legs of the infant. The corners of the diaper are then grasped `at one end and spread apart to open up the folds at the end. This is repeated at the other end of the diaper. The opened ends are then wrapped around the waist of the infant and pinned or otherwise secured in position to hold the diaper in place.
It will be noted that on application of the diaper to an infant the parts of the diaper which on attaching to the infant will remain in continuous contact with the infants skin, namely: the upper portions 28 and 29 of the folds, and the waistband portions 20 and 21, are all formed of fibrous fabric-like absorbent material. There is no contact, at either the waist or where the diaper Wraps around the infants legs, of plastic film with the skin. Thus at all points where the diaper is kept in continuous contact with the skin, there is no water-irnpermeable film which would cause maceration or other irritation of the underlying skin. Thus the construction of the diaper and the manner of folding co-operate to assure that when the diaper is applied there is no portion of the diaper, other than the absorbent fabric-like material, which is held in intimate contact with the infants skin. Also, the thickened edge 19 of the extruded thermoplastic lm backing now lies along the waist-encircling portion of 'the diaper where the most stress is applied on the diaper when placing the diaper on the infant. This aids to further reinforce the diaper in this area where greater strength is needed.
Particular embodiments of the invention have been used to illustrate the same. The invention, however, is not limited to these specific embodiments. In View of the foregoing disclosure, variations or modifications thereof will be apparent, and it is intended to include Within the invention all such variations and modifications except as do not come within the scope of the appended claims.
Having thus described our invention, we claim:
1. A diaper comprising a water-pervious cover sheet, an absorbent bottom sheet having substantially the same width as said water-pervious cover sheet, an absorbent pad positioned between said water-pervious'cover sheet and said absorbent bottom sheet and spaced from the side edges of said water-pervicus cover sheet and said bottom sheet and disposed approximately centrally with respect to the side edges thereof, a water-impermeable film secured to the under surface of said bottom sheet said water-impermeable film extending from one side edge of said absorbent bottom sheet to the other side edge thereof and spaced from the ends of said absorbent bottom sheet to provide film-free portions at each end of said absorbent bottom sheet, said film-free portions being folded over the end portion of said diaper and secured to said cover sheet to provide absorbent waistbands at each end of said diaper, said diaper having both side edges infolded and thenoutfolded along lines substantially parallel to the center longitudinal axis of said diaper to provide a pair of double folds the exposed surface of the side edges of said diaper resulting from the outfolding being absorbent.
2. A diaper of claim 1 in which said film has edges paralleling said uncoated portions of said absorbent bottom sheet which are substantially thicker than the remainder of said lm.
3. A diaper of claim 2 in which said water-pervious cover sheet is absorbent.
4. A diaper of claim 3 in which said cover sheet and said absorbent bottom sheet are both formed of bonded nonwoven fibers.
5. A diaper of claim 4 in which said cover sheet and said absorbent bottom sheet are formed of cellulosic fibers the major portion of which have a length of less than one-half inch.
References Cited UNITED STATES PATENTS 1,979,899 11/1934 OBrien 12S-284 3,180,335 4/1965 Duncan et al. 128-287 3,196,874 7/ 1965 Hrubecky 128--287 3,211,147 10/1965 Pherson et al. 12S-284 3,295,526 1/1967 Sabee 12S-287 CHARLES F. ROSENBAUM, Primary Examiner.