Quick-drying, Absorbent Nether Garment

Abstract

A highly liquid-retentive, quick-drying nether garment, such as a diaper or training pant for infants or adults, having a crotch area (which may be specifically defined) for covering the main excremental body orifices, including at least three flexible thicknesses each of one or more similar or dissimilar layers: (1) a centrally disposed thickness substantially of integrated hydrophobic fibers; (2) an innermost predominantly hydrophilic fiber thickness of one or more integrated layers; and (3) a thickness including one or more layers selected from those integrated layers consisting of hydrophilic fibers, hydrophobic fibers, mixtures of hydrophilic and hydrophobic fibers, substantially impervious films, microporous and apertured films and porous nonfibrous acretions and foams.

Description

This invention is concerned with nether garments such as diapers and training pants useful not only for infants and children but also for incontinent persons of all ages.

BACKGROUND OF THE INVENTION

Nether garments such as diapers and training pants incorporating hydrophobic layers and hydrophilic layers are well known. In the main, combinations of these layers have incorporated a fibrous hydrophobic layer next to the body orifices with the general purpose of keeping the body dry, the theory being that the hydrophobic layer wicks the fluid away from the body and into the adjacent absorbent hydrophilic layer. An early patent in this field, French Pat. No. 1,165,801 applied for in 1950 and published Oct. 29, 1958, illustrates the principle of this prior art. U.S. Pat. No. 2,905,176 to H. F. Davidson illustrates a typical diaper of this type with a contacting layer of knitted mesh and a backing layer of hydrophilic material such as woven cotton fabric. U.S. Pat. No. 2,894,511 to C. Devaud illustrates a variation wherein knitted hydrophobic mesh is the skin contact layer of a three-layer diaper in which an absorbent pad is the center layer with the outer layer of impermeable sheet material. Of this same general construction are the diapering garments illustrated in U.S. Pat. No. 2,695,025 issued to F. W. Andrews and the infants' garments illustrated in U.S. Pat. No. 3,063,452 to V. R. Del Guercio. A variation in which the contact layer is a single layer including hydrophobic yarns and hydrophilic yarns with the hydrophobic yarns predominately on the contact side is illustrated in U.S. Pat. Re. 26,515 to W. T. Holliday, et al. A further variation of this construction having hydrophobic contact surfaces on both sides so that either may be applied to the skin is illustrated in U.S. Pat. No. 3,409,012 issued to Norman L. Seltzer.

Another development in the field of diapering has involved the use of foam materials such as polyether and polyester urethane foams and foam rubber. A construction in which a diaper composed entirely of this spongy foam is illustrated in U.S. Pat. No. 3,072,123. These foams are nonfibrous, the open cell varieties capable of drawing in a limited amount of liquid when compressed and released. Functionally they are spongelike and merely store the liquid until they are compressed. At least two prominent baby garment manufacturers having incorporated polymeric foams into their training pants. These garments usually are knit of fabric with a special crotch area including a combination hydrophobic yarn and cotton yarn signal layer as the contact layer, with the hydrophobic yarns predominately on the contact surface. The polymeric foam is sandwiched between this layer and an outer knitted layer which may include a surface repellent impregnation or coating.

These latter garments, while widely accepted, have certain characteristics which are undesirable, amount which are inadequate fluid retention, the difficulty with which they may be dried, and the tendency toward yellowing which foams of this type presently exhibit. Under some laundering conditions some of these foams may become somewhat stiff with a tendency to crumble, especially at the edges.

In general the effectiveness of a diaper or a training pant as an absorbent mechanism is directly proportional to the weight, assuming it is made of one material. It has been assumed that hydrophilic materials, being the most absorbent materials, necessarily are the most efficient with respect to fluid retention. Normal cotton diapers vary in weight from a low of 50 grams to a high of about 70 grams in day diapers and 100 grams in night diapers. The more efficient diapers concentrate the weight in a central panel portion or even more locally in the crotch area. Unfortunately, when the extra material is permanently fastened to the diaper or panty so as to make the garment more efficient as a moisture retentive garment, it has been past experience that the garment has been slow drying.

SUMMARY OF THE INVENTION

This invention is concerned with washable nether garments such as diapers and training pants of novel construction having such desirable characteristics as high fluid retention and quick drying not theretofore present in such garments. The results of comparative testing are unexpected and surprising, as will be evident upon examination of table 1 and FIG. 3 of the drawings.

The garments of this invention includes a portion intended to cover at least the area of the human crotch and comprising at least three flexible superimposed thicknesses. At least two and optionally all three of these thicknesses include integrated fibrous layers. The crotch portion may consist of three single layers. The three thicknesses are not confined to a single layer, however. Rather, any or all of the thicknesses may consist of a plurality of layers which may be similar or dissimilar.

Of the three thicknesses, the first (that which is most closely adjacent the body in the crotch area when the garment is worn) is preponderantly of hydrophilic fibers. For instance, this thickness may consist of one or more layers of cotton gauze or other reticulated fabric made from hydrophilic yarns, such as knitted, netted blended crosslaid fabric, or it may consist of a washable integrated fibrous batting of hydrophilic fibers. Alternatively, this thickness may include one or more completely hydrophobic porous layers or a layer partly of hydrophobic fibers and partly of hydrophilic fibers. For instance, the skin contact layer of this thickness may be a polyester yarn gauze or it may be a gauze with cotton warp yarns and acrylic weft yarns, or it may consist of yarns blended of hydrophilic and hydrophobic fibers. The hydrophilic fibers should be preponderant in the total thickness, however.

The second of the three thicknesses, which lies between the first and third thickness, is preponderantly of hydrophobic fibers. For instance, it has been found that a layer of polyester strands bonded to form a batting of high capillarity makes an excellent intermediate thickness. One or more layers of polyester gauze may constitute this thickness. Other integrated layers of hydrophobic fibers may be substituted. While one or more layers of hydrophobic material is the preferred structure of this intermediate thickness, one may use a combination of hydrophobic fiber layers and hydrophilic fiber layers, or one or more layers of mixed hydrophobic and hydrophilic fibers. The hydrophobic fibers should be preponderant in the whole layer, however.

It is surprising that the partial substitution of hydrophilic fibers in this thickness, particularly in the same layer, reduces the fluid retentive properties and increases the drying time. While no explanation is necessary and the claims in no event are to be interpreted as being in any manner affected by the correctness of the rationalization, a possible explanation of this phenomenon might be that the addition of hydrophilic material partially nullifies the capillarity of the hydrophobic structure so that less fluid is retained by the combined structure even through the substitution replaces nonabsorbent material with absorbent material. A possible explanation for the quicker drying of the structure of the invention might be that in modern washing machines the wet wash is given a spin cycle at the end of the wash. The hydrophobic material which under wear conditions retains large amounts of fluid gives up a great deal of such fluid when the capillary action is countered by centrifugal force. Hydrophilic material does not give up absorbed water so readily when subjected to centrifugal force so that when the wet wash garments are subjected to drying, the hydrophobic-fiber-containing garment contains less moisture than the all-hydrophilic fiber garment.

The third and outer most of the three thicknesses may consist of a single layer or a plurality of layers. Preferably it includes an integrated layer of hydrophilic fibers and optionally a microporous film outermost layer but a garment without the film layer may be preferred by many because it is more comfortable and flexible. In any event, this third thickness may be of any of flexible integrated layer or layers chosen from hydrophilic fibrous layers, hydrophobic fibrous layers, mixed hydrophilic fiber--hydrophobic fiber layers, substantially water-impervious polymeric films, microporous and apertured polymeric films and porous nonfibrous layers such as foams and accretions.

One of the tests which has been utilized as a practical method of measuring the moisture retention of the garments of the invention in comparison with other nether garments used for the same purpose is a laboratory creation which is essentially a doll with controllable wetting action. This device, upon which each type of garment is carefully fastened in the same way, has a 2-inch crotch plumbed to deliver water from a reservoir at an adjustable predetermined rate. It has been determined that a rate which delivers about 100 milliliters in 10 seconds is more than four times the average rate and volume delivered by a 6 months to 1 year-old infant at each wetting. In practice the diapered or pantied doll is placed over a beaker so that any water passing through the garment can be caught and measured. This is done three times to simulate repeated wettings. In table 1 below, "A" represents an average of diapers of the invention similar to that in FIG. 2. "B" represents an average of diapers similar to "A" in every respect except the polyester batting 36 of FIG. 2 was replaced by layers of cotton gauze of equivalent weight. "C" represents an average of diapers to "A" in every respect except the polyester batting 36 of FIG. 2 was replaced by layers of polyester scrim of equivalent weight. The figures represent the averages of retained fluid in milliliters of each of three successive wettings. --------------------------------------------------------------------------- --------------------------------------------------------------------------- TABLE 1

A B C __________________________________________________________________________ 1. 65 ml. 47 ml. 57.5 ml. 2. 28 ml. 22 ml. 18.5 ml. 3. 10.5 ml. 13 ml. 7.5 ml. __________________________________________________________________________

As is apparent from table 1, diaper "A,"a diaper of the invention, retained an amount of fluid on the first wetting more than two and one-half times the average wetting volume per voiding of a 6-months to 1-year infant (25 ml.) and almost twice the wetting volume per voiding of a 1-year to 2-year-old child (35 ml.). Furthermore, this diaper retained more than 38 percent more fluid on the first wetting than similar all-cotton diaper "B" of the same weight.

Diaper "c," whose fluid retentivity is shown in table 1, is also a diaper of the invention which substitutes polyester scrim for the preferred polyester batting 36 of FIG. 2. This diaper while not so fluid retentive as diaper "A" which contains the preferred polyester fiber batting, was nevertheless significantly more fluid retentive on the first wetting and somewhat better over three wettings than all-cotton diaper "B." It is believed, however, that the first wetting is far more significant than any of the subsequent wettings because normally an appreciable interval exists between recurrence of natural wetting by infants.

To demonstrate the effect of the hydrophobic layer, a further test was made (table 2 2), a shaped diaper substantially similar to FIG. 2 but of lighter construction. In this test the two diapers were originally of equivalent weights but diaper "E" had the hydrophobic layer removed without replacement. The figures are averages of retained fluids. --------------------------------------------------------------------------- TABLE 2

D E __________________________________________________________________________ 1. 52.5 ml. 35.5 ml. 2. 16 ml. 18 ml. 3. 10 ml. 10 ml. __________________________________________________________________________

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a front view of a typical garment of the invention in the form of a training pant.

FIG. 2 illustrates another typical garment of the invention in the form of a diaper.

FIG. 3 illustrates graphically comparative drying curves for the diaper of FIG. 2, an embodiment slightly modified from FIG. 2, and an all-cotton diaper, all of the same weight.

FIG. 4 illustrates a three-layer pad suitable as a diaper either alone or in conjunction with another garment.

DETAILED DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a front view of a typical garment of the invention in the form of a training pant 10 composed of knitted material except for the stitching holding the garment together, elastic in the waistband and a polyester batting layer included in the central panel. Knitted fabric was chosen in this embodiment because of its comfortable feel when worn but obviously other fabric may be substituted. Only the materials of the central panel are important for their primary functional characteristics. The form of the polyester thickness is preferably that of a batting layer because of its resiliency and comfort factor but any structures, including woven, crosslaid, knitted and other structures which will hold moisture by capillary attraction, is suitable. The panty 10 of FIG. 1 has side panels 11 and 12 which are single-layer raschel-knit cotton. These panels, which depend from the waist to the leg openings at the sides, extend circumferentially from flat front seams 24 and 25 to rear flat seams 22 and 23 respectively. A multithickness panel 20 is attached to said side panels by said flat seams 24 and 25 and 22 and 23. Panel 20 includes an outer cotton raschel-knit thickness in the form of layer 19 which contacts the immediately contiguous thickness of nonwoven polyester batting 27 which in turn separates the front layer 19 from the back thickness 26 a cotton jersey knit fabric layer. The panel 20 extends from the waist in front of the waist in the rear, forming the pant bottom and crotch area. Panel 20 has cutout areas conforming to the leg openings 15 and 16. The waist opening 13 is finished with a knitted binding 14 which includes an elastic band in the portions spanning the respective side panels 11 and 12. Leg openings 15 and 16 are also finished with knitted bindings 17 and 18 respectively.

FIG. 2 illustrates another typical garment of the invention, a diaper 30. The outer surface of this embodiment comprises an absorbent thickness preferably in the form of a typical diaper gauze layer but the outer fabric 31 may be knitted or crosslaid or otherwise formed into any fibrous absorbent layer which may be laundered. In the embodiment shown in FIG. 2 the outer layer 31 is continuous from front to back, being folded along fold 32 and cut to the contoured form shown, contact thickness 31' and back thickness 31" being mirror images. A teardrop or other more or less arbitrary crotch shape is die-cut in the form of a pad 32 from the thicknesses of which it is to be composed, the edge 34 indicating the shape. Pad 33 is sewn to contact thickness 31' as shown by the stitches 35 before the front and back of the diaper are edge seamed. Pad 33, which includes a nonwoven polyester fiber batting thickness 36, also includes a thickness of four layers of diaper gauze 37, 38, 39 and 40. Obviously, if less absorbency is desired, the diaper gauze, or any other washable absorbent flexible fibrous structure which might be substituted, may be limited to a single layer. Curved edges of the respective front and back outer fabric 31' and 31" are turned to the inside on each side as is illustrated by edges 41' and 41", and seams 43 and 44 are made with the diaper inside out. The diaper is then inverted. The diaper end opposite the folded end is preferably left open, edges 42' and 42" preferably being selvage edges, but, optionally, this end may be sewn shut or may be left open with hemmed edges or pinked edges.

FIG. 3 illustrates graphically the drying curve for three diapers all of substantially the same weight and of the form illustrated in FIG. 2. The diaper represented by line "A" was identical to that illustrated in FIG. 2 and had a dry weight as represented by the horizontal line A'. The diaper represented by the line "B" was identical to the diaper represented by line "A" except that for the polyester fiber batting 36 of FIG. 2, polyester woven scrim sheets of the same configuration were substituted to closely approximate the weight of the replaced polyester fiber batting. The total dry weight of this diaper is represented by the line B'. The third diaper represented in FIG. 3 by the line "C" is also identical to the diaper represented by line "A" except that in this diaper the polyester fiber batting was replaced by woven gauze similar to layers 37, 38, 39 and 40 and of the same configuration to closely approximate the weight of the replaced polyester fiber batting. As is indicated by the graph, diapers "A" and "B" reached their dry weight approximately 10 minutes before diaper "C." A possible explanation of this phenomenon may be that in the washing machine the spin cycle tends to throw water from the hdyrophobic material to a much greater degree than the same cycle throws water from the hydrophilic materials so that although the diaper containing the hydrophobic material is able to retain more fluid normally, it does not retain so much when subjected to centrifugal force. The rate of drying as is indicated by the slope of the curves is not appreciably different as between the diapers represented by the lines "A," "B," and "C," but diapers represented by lines "A" and "B" left the washer with less moisture retained.

FIG. 4 is a very much simplified form of a pad 60 suitable in itself as a nether garment of the invention, which may be utilized in conjunction with another garment or harness or may be provided with pins, snaps, tapes or tie strings for fastening it in place when used alone. It may be provided with grommets and laced at each side like a shoe, or it may be provided with permanent or detachable elastic strips to hold it in place. At any rate, the basic pad 60 includes at least a thickness 61 of absorbent washable fabric. A thickness of hydrophobic fibrous material of a construction to support capillary action (in the particular embodiment illustrated, a layer of bonded fibrous polyester nonwoven batt 62) is placed between said layer 61 and a back thickness, layer 63. The construction of this back thickness is not critical, a preferred material being similar to the fabric or layer 61, in which case a very simple and economical construction, as will be explained hereinafter, is possible. But the back thickness may be entirely different than the front thickness and may include interposed between it and batt 62 one or more additional layers which are preferably absorbent. The back layer, if of the same unitary material as layer 61, may be folded as is illustrated at 64 with selvage edges left open at 65 with the arrows indicating the machine direction. The back thickness may be of folded layers in a "Z" fold to interpose several layers between the batting thickness, layer 62 and the back layer. In any event, when the outer layers for the pad 60 are to be of the same fabric, the latter may be folded along the warp direction to form a front cover layer and one or more back layers. As the outer fabric is folded, longitudinally extending layer of the batting 62 may be placed to overlie the folded material. The material may then be sewn by a double-needle reversible machine with spaced-apart needles and a reversible cutter between, with the machines traveling a transverse track to form seam 66 and the companion seam on the next adjacent oppositely facing diaper pad sewing from one side while a similar machine sews simultaneously from the other side to form seam 67 and its companion seam. The diapers may then be inverted by air jets. On the diaper pad shown in FIG. 4 the open side is 65 and the folded is 64. Diaper pads may be the above method disposed on either side of pad 60, however, would have the small side (continuous before cutting with 65) open, while the folded side would be the large side, continuous before cutting with folded edge 64.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Preferred nether garments of this invention are of two types, diapers and pants. Preferred diapers are similar to the diaper illustrated in FIG. 4. In the preferred diapers the contact thickness and the outermost thickness are of cotton diaper gauze, preferably fine-mesh gauze. FIG. 4 illustrates the lightest weight preferred diaper with the contact thickness a single layer and the outermost thickness a single layer, but the cotton gauze thickness on either or both sides may be increased by zigzagging the fabric. In the single layer diaper the open end 65 preferably has selvage edges but one raw edge may be folded in about an inch. When either or both thicknesses include more than one layer, either open edge may be a selvage edge or such an edge plus a folded edge. Increasing the cotton thickness does increase the fluid retention but it of course increase the drying time. The intermediate thickness 62 of the preferred diaper is a layer of bonded polyester batting. A layer of about 3/8-inch thickness is preferred but even a thin layer has some effect. This material is preferred because, in addition to being most effective in imparting fluid retention capacity and relatively quick drying, it also imparts a cushion effect.

The most preferred diaper of the invention has the outer layer of thickness and the contact thickness of similar material so that either side may be used as a contact side but if it is desirable, a polyester mesh may cover one or both surfaces or a fabric with both polyester yarns and cotton yarns or with blend yarns may be used for this purpose. If only one side is covered in this manner it may be desirable to tint either the contact layer or the outermost layer to indicate the proper contact side.

The preferred pant of this invention is a training pant similar to that illustrated in FIG. 1. The description of FIG. 1 applies. The outer shell of the pant consists of three pieces of raschel-knit cotton fabric and rib-knit cotton binders for the waist and leg holes. Flat stitching is used and the waist is made elastic by incorporating elastic at least spanning the circumferentially stretchable sides 11 and 12. The fabric 19 is of the same raschel knit as the sides but it is oriented so that its stretch is in the vertical direction rather than circumferentially; however, being sewn to the intermediate thickness of bonded polyester batting 27 limits any vertical stretch. The contact thickness is preferably of a single thickness of jersey knit cotton but more than one thickness be employed to increase the retained fluid with the penalty of longer drying time. The contact layer of the contact surface may, of course, be a woven or knitted fabric of polyester or other hydrophobic yarns, or this layer may be of mixed polyester and cotton yarns or blend yarns. Such constructions may be preferred by some mothers.

Claims

I claim:

1. A training pant including an outer shell comprising knitted pieces of fabric stitched together to provide a covering for the lower torso and defining a waist opening and two leg openings, a multithickness panel extending at least in the crotch area thereof having an inner contact thickness, an intermediate thickness and an outer thickness, said outer thickness including a portion of said outer shell, said intermediate thickness including a bonded batting substantially of hydrophobic fibers and said contact thickness including a fabric predominantly of hydrophilic fibers.

2. The garment of claim 1 wherein said multithickness panel extends substantially from the waist in front to the waist in the rear.

3. The garment of claim 1 wherein said multithickness panel consists of a single outer layer being a portion of said outer shell, said intermediate thickness consists of a single layer of bonded polyester fibers and said contact layer consists of a single layer of knitted fabric predominantly of cotton fibers.

4. A method of forming washable unitary garments adapted to be worn adjacent the main excremental body orifices, comprising layering down in any other in superimposed relationship, extended lengths of three integrated thicknesses of one to several layers each, one thickness being of substantially fibrous material having a total fiber content predominantly of hydrophilic fibers any layer of which varying in fiber content from 100 percent hydrophilic fibers to 100 percent hydrophobic fibers, a second thickness selected from the group consisting of integrated hydrophilic fiber layers, integrated hydrophobic fiber layers, integrated layers of mixed hydrophilic and hydrophobic fibers, microporous polymeric films, foams and accretions, water-impervious films, apertured films and combinations thereof, and a third fibrous thickness having a total fiber content predominantly of hydrophobic fibers, any layer of which varying in fiber content from 100 percent hydrophobic to 100 percent hydrophilic fibers, fastening said superimposed extended lengths transversely along pairs of parallel lines, each pair being separated from immediately adjacent pairs along said extended lengths by the desired width of garment, said pairs delineating the division of said extended lengths into garments each of trapezoidal configuration, each of said lines constituting one of a pair of fastening lines being separated from its pair by sufficient distance to permit cutting therebetween without cutting across either fastening line, cutting said extended lengths between fastening lines of each pair thereof to form individual garments and inverting said garments to dispose said third thickness and the raw severed edge portions adjacent said fastening lines between one or more layers of said first thickness and one or more layers of said second thickness.

5. The method of claim 4 wherein each fastening line is a line of sewn stitches made simultaneously with its pairing line of sewn stitches.

6. The method of claim 5 wherein the fabric constituting each garment is transversely severed between lines of stiches constituting a pairing line of sewn stitches by the same relative movement forming the lines of stitches.

7. A washable unitary nether garment adapted to contact the lower trunk of the human body and to receive and releasably retain body wastes from the urethral and alimentary canals thereof, comprising essentially a body-contacting thickness, an intermediate thickness and an outer thickness, said body contacting thickness being of at least one at least practically absorbent integrated fibrous layer and having a total fiber content preponderantly cellulosic, said intermediate thickness being an integrated structure of discrete flexible fibers preponderantly of hydrophobic polymer such as a bonded batting or the like, said outer thickness having at least one layer selected from the group of integrated fibrous layers and polymeric film layers.

8. The nether garment of claim 7 wherein the intermediate thickness is a layer of discrete polyester fibers bonded together to form a batting with capillary interstices.

9. The nether garment of claim 7 in the form of a diaper wherein the contact thickness includes a layer of woven gauze.

10. The nether garment of claim 7 wherein unitary extensions of at least one layer of said contact thickness and of said outer thickness define a diaper having a narrow crotch portion and a wider portion at one end for fastening the ends about the wearer's waist.

11. The nether garment of claim 7 in the form of a diaper wherein the contact thickness includes a woven contact layer, some of the yarns of which are at least partially of hydrophobic polymeric fibers.

12. The nether garment of claim 8 in the form of a diaper wherein the contact thickness includes a layer of woven gauze incorporating polyester yarns and cotton yarns and at least one other layer of all-cotton gauze.

13. The nether garment of claim 8 in the form of a diaper wherein the contact thickness includes a layer of woven gauze incorporating acrylic yarns and cotton yarns and at least one other layer of all-cotton gauze.

14. The nether garment of claim 7 in the form of a diaper wherein the outer thickness includes a woven cotton gauze layer to which a substantially liquid-impervious polymeric film is bonded.

15. The nether garment of claim 7 substantially narrower at one end than the other.