US3512529A - Diaper - Google Patents

Description

United States Patent 3,512,529 DIAPER Melvin Nimoy, East Brunswick, N.J., assignor to Johnson & Johnson, a corporation of New Jersey Filed June 22, 1967, Ser. No. 648,138 Int. Cl. A61f 13/16 US. Cl. 128--287 4 Claims ABSTRACT OF THE DISCLOSURE The instant invention is with respect to an adult diaper having a water repellent layer where fabric bunching due to differential in shrinkage in the diaper is obviated, diaper flexibility is insured and the useful life of the diaper is increased,

Generally the elderly, the sick and some others of the mature populace are, for a variety of reasons, in need of a diaper. Such. a diaper is termed an adult diaper because it does represent one that differs from that manufactured for children, since it has a water repellent barrier over all, or part, of total area and can be worn With or without protective pants.

The present invention provides an absorbent medium adapted to receive human body discharges comprising a plurality of layers of gauze diaper fabric superimposed in facewise engagement with a lesser diameter water repellent layer substantially centrally disposed and secured in facewise engagement with at least one of said gauze layers, said repellent layer being able to withstand laundering and drying cycles without loss of flexibilty, and said diaper fabric within the confines of the area defined by said repellent layed, being in an amount sufficient to accept the differential diaper shrinkage and thus preclude fabric bunching.

The term differential diaper shrinkage as used herein shall define the difference in dimensional stability between the gauze fabric and the water repellent layer in the diaper when said diaper is exposed to repeated laundering and drying.

The repellent layer of the diaper of this invention must be flexible and must remain flexible through repeated laundering and drying. It must not stiffen and crack to provide liquid strike through areas and it must not provide the discomfort factor that is defined by a stiffened or stiff layer in a diaper.

The repellent layer of the diaper of this invention thus comprises a layer of flexible, water impervious material which does not lose the major portion of its flexibility after undergoing repeated laundering and drying cycles. It must be resistant to attack by laundry soaps, detergents, bleaches and other such materials or chemicals used in the normal washing or laundering of such diapers. It must be nonirritating to the skin of the average person under reasonable conditions and it must not present a disagreeable odor.

Since normal laundering takes place in the presence of water heated to a temperature range between about 170 F. and about 200 F., and normal drying takes place at temperatures ranging up to about 350 F., the water impervious repellent layer of this invention must retain the major portion of its flex life through at least about one hundred each of the laundering and drying cycles defined herein. Additionally, this repellent layer must exhibit a dimensional stability such that having undergone such repeated laundering and drying, it is defined by no more than about a 3% total loss in either its lengthwise or widthwise dimensions.

Preferably the material used in, or for, the repellent layer is butyl rubber since it easily satisfies all of the above requirements, although acrylic polymers and silicone rubbers can also be utilized. Also, the repellent layer may consist in total of a sheet of these abovedefined materials, however, present day plastics do not combine desirable hand and strength. For example, if any of the present day plastics are made into sheet form thin enough to use, they will be too weak to withstand tearing, while if they are thickened to provide suflicient tear strength, flexibilty and hand are often sacrificed and the economics involved become prohibitive. Additionally, washing and drying machines are loaded on a weight basis and the economics of such operations are sacrificed with the use of heavier underpads. Thus the repellent plastic film is usually secured to a textile sheeting fabric having a count of at least about 48 x 44 since a more open fabric would not provide good adherence and the shrinkage of the fabric would be such as to cause problems of separation. Preferably this textile sheeting is of high count, however, the economics involved provide a commercial ceiling.

The repellent plastic sheeting must not shrink during repeated launderings such as to exhibit greater than about a 3% total loss in either the length or width of the pad. A greater shrinkage in either direction would establish separation between the backing sheet which is secured to the repellent film. This would also place a severe strain on the stitching holding the plastic film in place in the diaper together with resultant fabric bunching adjacent the terminal edges of the repellent sheet in the diaper.

As used herein laundry cycle and laundering shall be synonymous and shall be defined with respect to a Prosperity Junior Washer, Model 20, Serial No. 1054, utilizing a normal wash load of 20 pounds of diapers where a first washing shall initiate the cycle and shall comprise adding 12 gallons of water at about 160 F., a charge consisting of 15 grams of White Ribbon Chip Soap sold by Hampden Color and Chemical Company, cc. of Chlorox chlorine bleach, 15 grams of soda ash and 8 grams of Calgon water conditioner, and agitating for fifteen minutes. This is followed by a second washing which is a repeat of the first washing cycle except that the charge consists of 8 grams of White Ribbon Chip Soap, 8 grams of soda ash and 2 grams of Calgon water conditioner. This second washing cycle is followed by four five minute rinse cycles where the first two shall each utilize 24 gallons of water at F. and the last two shall each utilize 24 gallons of unheated normal tap water, except that with the last rinse there shall be added 100 cc. of Velva-Soft G, sold by Armour & Company and 2 grams of zinc silicon fluoride. The cycle timer for automatic control is Formatrol, Model FA 2093, No. 4777.

As used herein drying and drying cycle shall be synonymous and shall consist of drying such normal wash load of diapers in a Huebsch Gas Dryer Ser. No. 67093, at preferably 200 F. for twenty minutes.

The gauze diaper fabric used in the diaper must be present in an amount suflicient to satisfy minimum absorbency. Preferably the instant diaper contains at least three layers of gauze diaper fabric whose primary function is to absorb liquids deposited on the diaper.

Diaper fabric is usually low count woven cotton fabric. It is characterized by a woven construction of warp and filling yarns wherein the warp yarns extend substantially parallel to the length of the fabric and the fill yarns extend in the widthwise direction of the fabric, which is usually produced in continuous lengths. This fabric may have a plain, twill, sateen, satin, birds-eye, etc., weave, all of which are familiar to those skilled in the art.

Because of techniques of spinning, weaving and finishing used in the manufacture of cotton fabrics, the fabric as a whole is usually under tension due, for example, to the twist of the yarn, the Weave, etc.; therefore, it must be appreciated that it will be stretched to a greater or lesser extent. Washing, or laundering of the fabric, will quite naturally relieve the tension and with the internal tension relieved the fabric will, on drying, change in dimension since the individual yarns will assume positions closer to the adjacent yarn member of the fabric throughout, and the interstices between yarn will be lessened appreciably. Thus, the original unit area of the fabric is diminished. It is the result of this diminution of fabric and the effect it produces in the adult diaper that is overcome by this invention.

The fabric used in diapers of this invention is that which is considered and known by the art as gauze diaper fabric, however, any absorbent fabric ordinarily used in diapers can be substituted therefor. Thus, within this definition and considering the then appropriate yarn sizes, the fabric will only be so open as is acceptable for diaper fabric measured in terms of acceptable absorbency, strength, softness or lack of roughness, corrugation and abrasion resistance.

The invention will be more readily understood by reference to the accompanying drawings wherein:

FIG. 1 is a planar view of a prior art launderable adult diaper with a cutaway portion showing its construction,

FIG. 2 is a cross section taken along line 22 of FIG. 1,

FIG. 3 is a plan view of one embodiment of an adult diaper of this invention, and

FIG. 4 is a planar view of another embodiment of an adult diaper of this invention.

With particular reference to FIG. 1, there is shown a representative prior art diaper which is depicted as having undergone several washing and drying cycles, since in the absence of such washing and drying this diaper is substantially flat, i.e., devoid of corrugation 9 and upturned edges 7. Diaper 1 is composed of three layers of diaper fabric, i.e., a facing layer 2, two inner layers 3 and 3', and a backing layer 4 of diaper fabric. Sandwiched therebetween is a thin layer 5 of vinyl plastic, of lesser dimensions than the diaper, which is designed to act as a repellent barrier to insure that liquid deposited on the surface of the facing layer 2 will not penetrate through the diaper 1 to the backing fabric 4. The gauze layers 2, 3 and 3' act as the absorbent medium, while gauze backing layer 4 acts as a protective layer to keep the repellent layer 5 from direct contact with the skin of the user. The gauze layers are secured in position by straight line stitching *6 circumscribing the diaper 1 adjacent its edges while the repellent layer 5 is secured in position by straight line stitching 30. The diaper 1 in FIG. 1 is shown in a state reperesentative of the actual physical state and appearance that it would present after having undergone about thirty-five laundry cycles and about thirty-five complementary drying cycles.

tAfter diaper 1 has been subjected to about ten each of such laundering and drying cycles, the vinyl plastic repellent layer 5, the layers of diaper fabric 2, 3, 3' and 4 have undergone about 85% of their over-all reduction due to shrinkage. As a result, the physical appearance of the diaper is similar to that depicted via FIG. 1 where the edges have begun to curl up as is shown in the enlarged cross section, that is, FIG. 2, which is taken along line 2-2 of FIG. 1. As a result of this washing and drying and the differential in shrinkage exhibited by the materials of diaper 1, corrugation 9 of the repellent layer 5 does occur and is attended by corresponding bunching of the diaper fabric 9 in many instances as is shown via FIG. 1 and the enlarged cross section which is FIG. 2. After about twenty-five washing and drying cycles, the vinyl repellent layer 5 has begun to stiffen, and cracks 8 begin to appear as is depicted via the cutaway of FIG. 1 and the cross section FIG. 2. These areas of corrugation 9, whether or not they hide edges of cracks 8, contribute a severe discomfort feature to the diaper 1 as do the upturned edges 7. These areas each receive the brunt of the abrasive wear that this diaper receives and this localized abrasive wear causes premature fabric failure and exposure of the repellent layer 5. The cracks 8 in the stiffened repellent layer present edges (as do the upturned terminal edges 7 of the repellent layer 5) that act in a fashion suggestive of a knife blade to scratch and cut the user and to cause damage to articles of clothing with which they come into direct contact.

The stiffening of the vinyl plastic of the repellent layer 5 is caused by the leaching out of the plasticizer during repeated laundering and drying. The resulting loss of flexibility causes the cracks which destroy the functionality of the repellent layer 5. Many other plastics or synthetic sheet materials which have good flex life built into them by the use of a plasticizer, undergo similar results when they are exposed to repeated laundering and drying.

The liquid repellent layer of this invention must consist of a material which is flexible and retains sufiicient of its flexibility after undergoing at least about each of the laundering and drying cycles defined herein, to exhibit good flexibility, i.e., no stiffness, and no cracking. It should also have good dimensional stability under these same conditions, such that either the lengthwise or widthwise shrinkage is more than about 3%, and it must be a material which is not a skin irritant. Butyl rubber is the preferred member of the several materials that satisfy these requirements. Other such materials are acrylic polymers and silicone rubbers.

As previously stated, this repellent barrier material may be a sheet in and of itself, thus providing the complete repellent layer 5, or it may be coated onto a fabric such as ordinary sheeting to provide a coated fabric layer which is water repellent.

FIG. 3 depicts one embodiment of this inevntion rep resented by diaper 10 which is defined by three layers of gauze diaper fabric, i.e., a face layer 11 which contacts the skin of the wearer and two inner layers 12 and 13, which combine to provide the absorbent media of the diaper 10. The backing layer 14 is a ply of sheeting material shown in cutaway and shown with one corner upturned to expose the outer surface or face 16. This backing layer is also the repellent layer and has its inner surface 15, i.e., the surface in facewise engagement with the inner ply 13 of gauze diaper fabric, coated with a layer of butyl rubber which has been calendered onto the sheeting. The exposed facing surface 16 of the repellent layer 14 presents the soft surface of the sheeting material and is the surface that forms the backing face of the diaper 10.

The butyl rubber coating on the repellent layer 14 is applied in an amount sufficient to insure impermeability to urine and other such liquids which it is meant to bar. The butyl coating is thus present in an amount of preferably 7 to 8 ounces per square yard to provide a substanti ally uniform coating thickness throughout this surface of the sheeting material, of at least about 0.008 inch.

This insures that tufts or errant fiber protrusions which might provide sites of liquid seepage are eliminated.

The plies of diaper fabric 11-13 and the repellent layer 14 are secured together by zigzag stitching 17 which effectively insures that the terminal portions of the gauze fabrics 11-13 remain closely adhered in facewise engagement and protects against separation or curling of these consituents along the terminal edge of the diaper thus eliminating another discomfort factor and factor contributing to premature destruction of the diaper fabrics by the process of raveling. rSafety stitching is present to secure the repellent layer 14 in position.

Prior to securing in place of the diaper constituents, the features which provided the upturned edges of the diaper and the corrugation of the repellent layer are eliminated by establishing a built-in shrinkage differential characteristic.

The repellent layer 14 will undergo about a 2% shrinkage in both the lengthwise and widthwise directions of the diaper during repeated laundering, while the gauze layers 11-13 will each undergo about a 12% over-all shrinkage in each such direction. The shrinkage differential is thus about 10% total in each of the lengthwise and widthwise dimensions. To preclude the above discussed corrugation in the diaper, this 10% shrinkage differential is actually determined with respect to the dimensions of the diaper cloth utilized in plies 11-13 of the diaper 10, and the diaper 10 is constructed with sufficient excess of diaper fabric present in the area defined by the repellent layer, such as to readily accept this shrinkage differential and to thus preclude the aforediscussed corrugation phenomena which established localized sites of discomfort and premature wear in a diaper. This is shown by excess fabric sites 18 in FIGS. 3 and 4. The unwashed diaper would thus present an apparent surplusage of diaper fabric represented by this excess of 10% in the length and in the width of the diaper. About 75% to 80% of the shrinkage in both the repellent layer and in the composite of diaper fabric layers takes place in the first laundering and drying cycle, with only about 2% to 5% residual shrinkage remaining in the materials after the first four or five laundering and drying cycles. Thus this excess material is soon dissipated.

FIG. 4 depicts yet another embodiment of the instant invention via diaper 20 which consists of three layers of gauze diaper fabric, i.e., a facing layer 21 and two inner layers 22 and 23, and a repellent layer 24- of coated sheeting material shown with one corner portion upturned to expose its inner surface 26 which is coated with a substantially uniform layer of butyl rubber. The outer or backing surface 25 of the repellent layer 24 presents the soft surface of sheeting fabric and forms the greater portion of the backing face of the diaper 2f Zigzag stitching 28 insures that the edges of the repellent layer 24 will remain flat to the surface of gauze layer 23. This particular diaper has an over-all dimension of 40 x 24, while the repellent layer 24 is 29 x 12.

Considering that the diaper fabric will shrink about 12% over-all during repeated laundering and drying while the repellent layer will shrink about 2%, the differential in shrinkage in the lengthwise direction of diaper 20, limited by the length of repellent layer 24, is about 3 inches while the shrinkage differential in the widthwise direction, limited by the width of repellent layer 24, is about 1.2 inches. Thus an excess of about 3 inches of composite diaper fabric, i.e., layers 21, 22 and 23, must I be gathered within the area defined by lines A-A and A-A while an excess of about 1.2 inches of composite diaper fabric must be gathered within the area defined by lines B-B and B'B'. This excess composite diaper fabric is depicted as loose fabric 27 in FIG. 4.

For obvious reasons, the diaper of this invention should be constructed utilizing the same construction of diaper fabric for each ply of the diaper; however, should this not be the case, the shrinkage differential may still be determined and taken into account in the provision of excess material Within the area defined by the repellent layer.

It is to be readily understood that this diaper construction could readily be utilized as an underpad by simply increasing its over-all length and width.

The invention has been described in connection with its preferred embodiments, but many modifications thereof are easily included without a departure from the inventive concept which is limited only by the scope of the appended claims.

What is claimed is:

1. An absorbent medium adapted to receive human body discharges comprising a plurality of layers of absorbent gauze diaper fabric superimposed in facewise engagement with a lesser dimensioned water repellent layer substantially centrally disposed and secured in facewise engagement with at least one of said gauze layers, said repellent layer being adapted to withstand laundering and drying cycles without loss of flexibility and said diaper fabric, within the confines of the area defined by said repellent layer, having greater lengthwise and widthwise shrinkage than said repellent layer but being secured to said repellent layer with a predetermined excess of lengthwise and widthwise material in an amount sufficient to accept the shrinkage differential between said fabric and said repellent layer as to dissipate said excess material during subseqeunt laundering and drying cycles and thus preclude subsequent fabric bunching and corrugation and the establishment of attendant discomfort and quick wear features.

2. An absorbent medium as defined in claim 1 wherein said water repellent layer comprises butyl rubber.

3. An absorbent medium as defined in claim 1 wherein said gauze diaper fabric is innermost and contacts the human body and said water repellent layer is outermost from the human body, said water repellent layer having a soft outer surface and a water repellent coated inner surface.

4. An absorbent medium as defined in claim 1 wherein said water repellent inner surface is coated with butyl rubber.

References Cited UNITED STATES PATENTS 2,558,215 6/1951 Habig et a1. 128-287 2,577,398 12/1951 Blake 128-287 2,931,360 4/1960 Dexter 128284 3,291,162 12/1966 Jamison l28284 3,339,548 9/1967 Seltzer 128284 CHARLES F. ROSENBAUM, Primary Examiner

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