US 3572342 A
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United States Patent O 3,572,342 DIAPER Julius Liudquist, Somerville, and Robert J. Trewella, North Brunswick, NJ., assignors to Johnson & `Iohnson Filed Jan. 19, 1968, Ser. No. 699,097 Int. Cl. A61f 13/15 U.S. Cl. 128-287 5 Claims ABSTRACT OF THE DISCLOSURE Diapers are prepared in which a seal is provided between the surface of the diaper and the body of the infant wearing the same to prevent leakage between the diaper and the infant. The seal is formed of resilient hydrophobic polymer foam which is secured to the upper surface of the diaper. By placing hydrophobic resilient strips along each side of the diaper on the surface which is adjacent the child when the diaper is in place leakage from the edge of the diaper is controlled.
BRIEF DESCRIPTION OF THE INVENTION One of the problems with diapering children, particularly active children, is to obtain a good fit between the edges of the diaper and the surface of the infants body so as to prevent leakage. One of the reasons for the popularity of diaper pants is to provide this security against leakage because of the loose t and poor leakage preventive characteristics of most diapers. The present invention is directed to the provision of sealing strips in diapers to prevent surface passage of liquids between the body and the edge of a diaper or a portion of the diaper surface beyond which it is desired to prevent movement of liquid. In accordance with the present invention such leakage is prevented by placing along the top surface of the diaper, in the area beyond which movement of liquid is to be prevented, resilient hydrophobic strips. These resilient hydrophobic strips in the preferred practice of the invention are made of a soft hydrophobic polymer foam, the same preventing lateral movement beyond the location of the strip of fluids between the surface of the diaper and the body of the infant. Lateral side leakage is prevented by placing such strips on the top surface of the diaper along the two opposing side edges of the diaper. Movement of fluid along the abdomen and back may also be prevented by placing such resilient hydrophobie strips crosswise of the diaper in the area beyond which it is desired to prevent the flow of fluid.
DETAILED DESCRIPTION OF THE INVENTION In accordance with the present invention seals are provided on the top surface of a diaper to inhibit or prevent lateral movement of liquids between the surface of the diaper and the body of the infant. Although the practice of the invention may take many forms, in order to more clearly describe the invention certain embodiments thereof are illustrated in the accompanying drawings. These embodiments, however, are given for the purpose of illustration only and the invention is not limited thereto.
Referring to the drawings:
FIG. 1 is a top plan view of a diaper made in accordance with the present invention;
FIGS. 2(a), 2(b), and 2(c) are views taken along line 2-2 of FIG. l showing cross-sectional views of diapers all having the same general appearance in the top plan view as shown in FIG. 1 but having different constructions, as illustrated by the cross-sectional views;
FIG. 3 is a View of the diaper of FIG. 1 in a prefolded form;
FIG. 4 is a `cross-sectional view taken along lines 4 4 of FIG. 3;
FIG. 5 is a view of the folded diaper of FIG. 3 as opened when applied to an infant;
FIG. 6 is a top plan view of a diaper of somewhat different construction to that of FIG. l embodying the present invention;
FIG. 7 is a cross-sectional view taken along line 7-7 of FIG. 6; and
FIG. 8 is a cross-sectional view taken along line 88 of FIG. 6.
Referring to FIG. l, a diaper 10, is illustrated having a backing sheet 11, an absorbent 12, and a facing or top sheet 13. The backing may be formed of any suitable diaper backing materials. In the preferred form flexible moisture impervious sheet material is used such as polyethylene or other flexible water impervious polymeric film. The absorbent 12 may be formed of several ply of cellulose wadding, macerated wood pulp or other conventional absorbent material. The facing may be any exible pervious sheet material having adequate wet and dry strength. The preferred facings are formed of gauze or nonwoven fabrics. The facing may be treated with a water repellent such, for example, as the acrylic copolymer water repellents sold under the trade name Rhoplex HA-S. Other materials such as silicone emulsions, polysiloxanes and vinyl acrylic copolymers sold under the trade names Syl-Mer 72, Cravinette Super Silicone and Resyn 2833 may be used.
Secured to the top surface of the diaper along the side edges 14 and 15 are flexible resilient hydrophobic strips 16 and 17 formed of a soft, easily compressible resilient material. The preferred materials for forming strips 16 and 17 are the hydrophobic polymer foams, the preferred foam being the relatively soft, resilient polyurethane foams. The polyurethane foam strips 16 and 17 have a width of about 1A; to 1/2 inch and a thickness of about V16 to 1A inch. However, strips of lesser or greater Width may be employed and of lesser or greater thickness as long as the thickness is sufficient to permit adaptation to small changes in surface contour. Although polyurethane foams are one of the preferred materials to be used as the sealing strips, other flexible resilient hydrophobic strip materials may be employed such as those formed of other hydrophobic foam or opening material such as foamed styrene butadiene, foamed polyethylene, foamed silicones, foamed vinyl plastics, soft sponge rubber and the like. Care should be taken to use, as the material for forming the seal strips 16 and 17, a material which is nonirritating to skin when placed in contact therewith. As some foam rubbers may be irritating, particularly those of the sulphur type, it is generally preferred to avoid such materials-this being one of the reasons the synthetic essentially pure polymer foams are preferred.
It is important that the hydrophobic sealing strips are soft, reslient and easily compressible. The resiliency and compressibility should preferably be in the range of about l0 to 60 percent rebound by A.S.T.M. Test Method D 1564-64T and compressibility of about .02 to 1 p.s.i. at 25 percent compression Iby A.S.T.M. Test Method D 1564 (Suifex N).
Also it is important that the hydrophobic sealing strips be placed on the surface of the diaper where it comes in intimate Contact with the skin of the infant when the diaper is in place. The following Table A, which gives averages of test results run, will illustrate the substantial improvement in leakage prevention obtained by securing the hydrophobic foam sealing strips to the surface of the diaper as compared with diapers having the same construction except for the absence of such strips or where the strips are placed on the edge of the diaper but have the diaper facing covering the same.
In obtaining the leakage results set forth in Table A, test strips 21/2 by 81A inches were cut from actual diaper constructions containing the edge portion of the diaper which heretofore has presented the leakage problem. The test strips were weighed and then placed on the leg of a test subject as hereinafter described, and distilled water was then poured into the upper center pad of the test strip between the diaper backing and absorbent pad of the test strip. As soon as leakage occurred, as shown by liquid seeping past the edge of the diaper test strip, addition of further fluid was discontinued. The ratio of fluid weight added to weight of dry test strip is considered the leakage coeflicient. Thus, the higher the leakage coeicient the more efficient seal obtained.
As previously indicated, each test strip was adhered to the calf muscle of the leg at an angle of 25i5 under a constant tension of 5 oz. with use of a Chatillon spring seal. Water was introduced at the top center of the test strip using a flexible tubing attached to a 50 ml. burette. The ilexible tubing was inserted between the backing and absorbent pad about l inch below the top of the test strip. Five milliliters of water were added at 30 second intervals. The end point or capacity was the point at which water leaked between leg and test strip.
DISPOSABLE DIAPER SEAL TEST (I) Purpose To provide a standard test for determining the seal characteristics of diaper side test strips.
(II) Materials required (A) Cellophane tapes, 3M x 3 inches long. (B) Burette, 50 ml. capacity.
(C) Flexible tubing 1A inch I.D.
(D) Ring stand.
(E) Burette clamp.
(G) Distilled water.
(H) Diaper test strips 21/2 x 8% inches.
(III) Procedure (A) Secure one piece of tape on each end of test strip. The edge of the tape should be even with lower edge of the test strip.
(B) Apply the test strip at a 25 i5 angle against the calf muscle and secure one tape. Secure the second tape to the hook of a Chatillon scale, pull to a tension of 5 ounces and secure the tape to the leg.
(C) Place the exible tubing between the backing and/ diaper absorbent pad at the center about one inch from the top.
(D) Introduce 5 ml. of water, wait 30 seconds then add additional 5 m1. increments at 30 second intervals.
(E) Record end point as the number of milliliters of water required to cause leakage between the surface of the diaper test strip and calf muscle.
This test was repeated with four different diaper constructions identical with respect to backing, facing, and absorbent contained therebetween and differing solely in their edge construction. Diaper A had an edge construction in which the polyethylene backing was wrapped around the edge of the absorbent and facing and then secured to the facing along a line spaced approximately one half inch from the polyethylene edge thus leaving a loose flap. Edge construction of this type is described and illustrated in Voigtmann Pat. No. 2,896,626. Diaper B had an edge construction which was similar to that of Diaper A except that the edges of the polyethylene were folded over the edges of the absorbent and in contact with the underlying absorbent and the facing extended over the nfolded edges of the polyethylene. Diaper construction C was similar to diaper construction B differing only in that a strip of hydrophilic polyurethane foam of 1/2 inch width and %4 inch thickness along the side edge was placed between the inturned polyethylene edge and the overlying facing extending over the polyurethane foam strip. Diaper D, which incorporates the present invention,
TABLE A Leakage coctcient weight; Water added Weight of test strip Weight of- Added water Test strip Diaper:
The structure of the diaper may take various forms such as illustrated, for example, in the cross-sectional views as shown in FIGS. 2(a), 2(b), and 2(c). In FIG. 2(a) the facing sheet 13 is substantially wider than the backing iilm of polyethylene 11 and absorbent 12 and is wrapped around the edges of the diaper, the side edges 18 and 19 then being secured to the surface of the backing sheet 11. In the construction illustrated by the cross-sectional view of 2(17) the absorbent 12 which may be of cellulose wadding or ground wood pulp, has the backing lrn sheet 11 extending over the side edges thereof, the edges 20" and 21 of the backing film 11 then being bonded to the underlying absorbent 12. The facing 13 is extended over the inturned edges 20" and 21 of the backing sheet 11 and is bonded thereto. The resilient strips 16 and 17 for preventing lateral leakage are then secured along the edges of the diaper to the surface of facing sheet 13'.
In FIG. Z(c) a still different construction is shown differing primarily from the construction of 2(b) in that the inturned edges 20" and 21" of the flexible lm backing sheet 11" overlie the edge of the facing sheet 13 and are bonded thereto. The sealing strips 16" and 17" are then secured to the inturned edges 20" and 21 of the backing sheet 11".
It is of assistance to the mother in placing a diaper on the child if the diaper is in a prefolded state such that the same can be more readily applied to the child while being sure that the sealing edges are brought into proper relationship with the childs body. One manner of folding which accomplishes this is best illustrated in FIGS. 3, 4, and 5. FIG. 3 illustrates a diaper of FIG. 1 in its prefolded state prior to application. IFIG. 5 illustrates the diaper of FIG. 3 when opened in applying to a baby. Referring to FIG. 3 and cross-sectional view thereof, FIG. 4, it will be noted that the prefolded diaper is prepared by folding the sides of the diaper 10 in towards the center along lines 22 and 23 shown dotted in the diaper of FIG. 1. The folded over sections 24 and 25 of the diaper are held in the folded position by adhesive spots 26 placed about midway between the fold 27 and the edges 14 and 15 of the diaper as best illustrated, for example, in FIGS. 3 and 4. When the diaper is to be placed on a baby, one-half of the diaper is rst opened by grasping the corners 28 and 29 and pulling apart. The baby is then placed on the diaper in the thus partially opened position. The half still folded is then brought between the -babys legs and the corners 30 and 31 grasped and the remainder of the diaper opened. The diaper at this stage takes somewhat the form as illustrated in FIG. 5. The diaper is then attached by Wrapping the edges 32 and 33 around the front and back of the infant and pinning or otherwise securing the corners 28-30 and 29-31 together.
In opening the diaper and placing it on the baby care should be taken to have the diaper completely opened, so that the resilient sealing strips 16 and 17 come in contact `with the skin of the infant. The folding of the diaper in the manner described helps to place the sealing strips 16 and 17 in such position. The resiliency of the sealing strips 16 and 17 make the edges of the diaper follow closely the contour of the surface skin and maintain close and intimate contact therewith even during active movement of the diapered infant, thus preventing lateral leakage between the surface of the diaper and the skin.
As previously indicated, resilient sealing strips used in accordance with the present invention may be placed on any portion of the surface of the diaper depending on the particular areas beyond which surface seepage is not to extend. The diaper illustrated in FIGS. 6, 7, and 8 of the drawings well illustrates the use of such sealing strips in other portions of the diaper in addition to the edge portions. Referring to FIG. 6, the diaper 34, besides having sealing strips 35 and 36 which extend along the side edges, also contains sealing strips 37 and 38 which extend laterally across the diaper. With normal diapering, particularly when an infant is lying on its back or on its stomach and the infant wets, the diaper becomes wet aling the whole underlying area. Thus, 'with a conventional diaper if the infant is lying on its back the whole back area covered by the diaper becomes and remains wet. The same is true if the infant is lying on its stomach with the whole covered abdomen area becoming wet and remaining wet until the diaper is changed. The structure illustrated in FIGS. 6y through 8 is directed to ameliorating this problem and limiting the surface area of the diaper which becomes wet to prevent the wetting of any more of the surface of the infant than is necessary.
Referring more particularly to the structure of the diaper as illustrated in F IGS. `6 and 7, it will be noted that the backing dilm 39 of polyethylene or the like is substantially longer than the diaper 34, extending beyond the absorbent pad 40 both at the top and the bottom. The portions 41 and 42 of the polyethylene backing 39 extending beyond the absorbent pad 40 are infolded over the top and bottom edges of the absorbent 40 to form protective moisture impervious panels or zones 43 and 44 wherein the absorbent r40 is covered by the infolded polyethylene ends 41 and 42.
The side edges of the diaper 34 are prepared by sealing together the facing 45 and the backing sheet 39, the backing and facing extending beyond the absorbent 40 as back illustrated in FIG. 8 with the absorbent 40 sandwiched between the same. The facing y45 of the diaper is preferably formed of a moisture permeable yet substantially nonabsorbable facing material such as nonwoven fabric treated with a semirepellent binder. Binders suitable for this purpose are, for example, acrylic binders such as those sold under the trade name Rhoplex IIA-8. The facing may also be formed, for example, of a perforate nonwoven fabric such as disclosed in Pat. No. 2,862,- 251, treated with such a binder, or may be formed of gauze or other open-mesh material.
Resilient sealing strips 37 and 38 are placed on the surface fabric of the diaper and bonded thereto so as to extend laterally across the diaper the sealing strips in the embodiment illustrated in FIGS. 6 through 8 being placed along the edge of protective zones 43 and 44 formed by the infolded polyethylene ends. With a diaper of this construction when wetting occurs the 4fluids passing into the diaper are rapidly dispersed through the diaper where the same are absorbed. However, because of the sealing action of the sealing strips 37 and 38 liquid is prevented from extending along the surface of the diaper into the areas covered by the protective polyethylene panels 43 and 44 thus leaving the upper and lower portions of the diaper dry. The result is a substantially more comfortable diaper for the infant after the same has become wetted as well as a diaper which minimizes side leakage with resulting soiling of garments or bedclothes.
Although specic embodiments have been used in illustrating the practice of the present invention, the invention is not limited thereto but is to be limited only as indicated by the appended claims.
Having thus described our invention, we claim:
1. A diaper having two opposed ends and two opposed side edges and havingr a flexible facing pervious to moisture, a backing impervious to moisture and an ab sorbent contained between said facing and said backing, said facing having an outer surface adapted to contact the skin of an individual when Iworn, said surface having secured thereto along said side edges compressible, fluid impermeable strips which act to inhibit fluid flow between said surface and the skin of an individual when said diaper is worn by said individual.
2. A diaper of claim 1 in which said compressible fluid impermeable strips are formed of a hydrophobic resilient polymer in cellular form.
3. A diaper of claim '2 in which said strips are formed of resilient hydrophobic polymer foam wherein the polymer is of the group consisting of polyurethane, styrene butadiene, polyethylene, silicone, polyvinyl and rubber.
4. A diaper having two opposed ends and two opposed side edges and having a front portion, a back portion and an absorbent contained between the front and back portion said front portion comprising a flexible facing pervious to moisture, said back portion comprising a backing layer impervious to moisture, said backing layer extendingover the ends of said diaper and underlying the exible facing at the ends of said diaper, compressible fluid impermeable sealing strips affixed to outer surface of said front portion and extending along .both side edges of said diaper and additional compressible uid impermeable sealing strips extending across the Width of the diaper in parallel lines over-lying the folded-over terminal ends of said backing layer.
S. A diaper of claim 4 where said polymer foam is a polymer of the group consisting of polyurethane, styrene butadiene, polyethylene, silicone, polyvinyl and rubber.
References Cited UNITED STATES PATENTS 2,649,859 8/1953 Hermanson et al. 12S-2.87 3,081,772 3/196-3 Brooks et al. `128---287 3,301,257 1/1967 Crowe et al. 128-287 3,369,547 2/1968 Sack et al. 128-287 3,417,751 12/1968 Murdoch `128--287 3,431,911 3/1969 Meisel 12S-287 RICHARD A. GAUDET, Primary Examiner J. B. MITCHELL, Assistant Examiner