WO2004028419A1

WO2004028419A1 - Bed pad

Info

Publication number: WO2004028419A1
Application number: PCT/US2003/013431
Authority: WO
Inventors: David Arthur Fell; Toan Thanh Leminh
Original assignee: Kimberly-Clark Worldwide, Inc.
Priority date: 2002-09-27
Filing date: 2003-04-29
Publication date: 2004-04-08
Also published as: US20040060112A1; AU2003223782A1

Abstract

The present invention provides a solution to improving the absorbent structure of a bed pad (20) to prevent leakage by folding the absorbent structure (32) at least twice to form a central channel (38) and a pair of oppositely disposed side dams (40). By creating a central channel (38) and side dams (40), lateral leakage of bodily wastes is reduced and performance of the bed pad (20) is increased. Hence in one aspect, the invention resides in a bed pad (20) including an absorbent structure (32) disposed adjacent a bottomsheet (30), the absorbent structure having a stabilized absorbent material, and the absorbent structure is folded at least twice. The bed pad having a width WP, the absorbent structure having a width WA, and the ratio of WA/WP is from about 0.2 to about 0.8.

Description

BED PAD

BACKGROUND

Bed pads are used by hospitals, long term care facilities, and private homes to protect bedding, mattresses, cushions, seats, and so forth from being soiled by individuals. Often these bed pads are prone to leakage resulting in damage to the article the bed pad was supposed to protect. The leakage often results from lateral leakage of bodily wastes before being fully absorbed by the absorbent structure of the bed pad. Hence, there is a need to improve the absorbent structures of bed pads in order to enhance their functionality.

SUMMARY

The present invention provides a solution to improving the absorbent structure of a bed pad to prevent leakage by folding the absorbent structure at least twice to form a central channel and a pair of oppositely disposed side dams. By creating a central channel and side dams, lateral leakage of bodily wastes is reduced and performance of the bed pad is increased.

Hence in one aspect, the invention resides in a bed pad including an absorbent structure disposed adjacent a bottomsheet, the absorbent structure having a stabilized absorbent material, and the absorbent structure is folded at least twice. The bed pad having a width W_P, the absorbent structure having a width W_A, and the ratio of W_A/Wp is from about 0.2 to about 0.8.

In another aspect, the invention resides in a bed pad with a central longitudinal axis and a central transverse axis, and the bed pad having a center portion and a pair of transversely disposed side portions. The center portion having an absorbent structure disposed between a topsheet and a bottomsheet, and the side portions free of the absorbent structure. The absorbent structure being folded from an absorbent material into a central channel and a pair of transversely disposed side dams adjacent the central channel, and the central channel having a width W_c greater than about 200 mm.

In yet another aspect, the invention resides in a bed pad with a central longitudinal axis and a central transverse axis. The bed pad including a center portion and a pair of transversely disposed side portions. The center portion having an absorbent structure disposed between a topsheet and a bottomsheet, and the side portions free of the absorbent structure. The absorbent structure folded from a stabilized absorbent material into a central channel, and a pair of transversely disposed side dams adjacent the central channel, and the central channel having a width WC greater than about 200 mm.

BRIEF DESCRIPTION OF THE DRAWINGS The above aspects and other features, aspects, and advantages of the present invention will become better understood with regard to the following description, appended claims, and accompanying drawings:

Figure 1 illustrates a plan view of one embodiment of the invention. Figure 2 illustrates a cross-section view of the embodiment of Figure 1. Figure 3 illustrates a cross-section view of an alternative embodiment of the invention.

DEFINITIONS

As used herein, "absorbent capacity g/g" is the grams of saline retained by the absorbent material per gram of the absorbent material. Absorbent capacity is determined by conditioning the test samples in a standard laboratory atmosphere of 23 ± 1 °C and 50 ± 2% RH for at least 24 hours prior to testing the sample. All testing is conducted under the standard laboratory conditions. Weigh a piece of absorbent material to the nearest 0.001 gram and place in a bath of 0.9 percent by weight sodium chloride solution at 20°C. Allow the sample to soak for 20 minutes ensuring an excess amount of saline is present in the bath to completely saturate the sample. After 20 minutes, remove the sample and place on a vacuum box having a suitable mesh screen for holding the sample while removing excess saline from the sample. Cover the vacuum box and sample with a flexible latex sheet. Apply a 3.45 kPa vacuum to the vacuum box and sample for a period of 5 minutes to remove excess non-absorbed saline from the sample. After 5 minutes, remove the sample and weigh to the nearest 0.001 gram. Calculate the absorbent capacity g/g by subtracting the dry sample weight from the saturated sample weight and dividing the result by the dry sample weight.

As used herein, "side dams" refers to an area where the absorbent structure is folded one or more times such that the absorbent structure has an increased thickness and basis weight in the folded area relative to the absorbent structure adjacent to the folded portion.

As used herein, "side margins" refers to an area of the absorbent structure transversely disposed outward of the side dams where the absorbent structure returns to its original thickness and basis weight. As used herein "stabilized absorbent material" means an absorbent material containing a binder that causes bonds to form between fibers such that the absorbent material has a tensile strength of at least 5 Newtons per 50 mm (N/50mm) in either the machine or cross machine direction. The tensile strength of the material can be tested using a tensile tester such as MTS/Sintech model 1/S which is commercially sold by MTS Systems Corporation having a mailing address of P.O. Box 14226, Research Triangle Park, North Carolina. The tensile strength at peak load for the purpose of this invention is measured by securing a 50 mm wide strip of stabilized absorbent material between two movable jaws of a tensile tester. A distance of about 10 cm initially separates the two jaws. The two jaws are then moved outward away from one another at a rate of 25 cm/minute until the strip of material breaks. The tensile strength is recorded as the peak load.

DETAILED DESCRIPTION Referring now to Figure 1 a bed pad 20 is illustrated in plan view. The bed pad 20 has a center portion 22 and two oppositely disposed side portions 24. The side portions 24 are substantially free of an added absorbent material, which is located in the center portion 22 (see Figure 2); although, the material forming the side portions may be absorbent to some degree depending on the specific material utilized. The bed pad has a longitudinal central axis 26 and a transverse central axis 28.

The bed pad can be any suitable length and width required. Generally, the bed pad will have a width from about 750 mm to about 3000 mm. The length of the bed pad can be from about 500 mm to about 2500 mm. In one embodiment, the bed pad has a longitudinal length of about 1000 mm and a transverse width of about 2000 mm. Referring now to Figure 2, the bed pad 20 of Figure 1 is shown in a cross-sectional view. The bed pad 20 has a bottomsheet 30 and an absorbent structure 32. Optionally, the bed pad 20 can include a barrier layer 34 disposed between the absorbent structure 32 and the bottomsheet 30. A topsheet 36 is optionally disposed over at least a portion of the absorbent structure 32. The absorbent structure 32 of the bed pad is folded one or more times to form a central channel 38, a pair of transversely disposed side dams 40, and a pair of oppositely disposed side margins 42 adjacent the side dams. Although the embodiment of Figure 2 shows the absorbent structure 32 "Z" folded on either side of the central channel 38, it is possible to "C" fold the absorbent structure and eliminate the side margins 42. It is also possible to eliminate the side margins 42 and fold the absorbent structure 32 two, three, four or more times on either side of the central channel 38 to form the side dams 40. Desirably, the side margins 42 are present to collect and absorb any bodily wastes that may not be fully contained by the side dams 40 and the central channel 38.

While Figure 2 illustrates the central channel 38 positioned adjacent to and underneath the topsheet 36, it is also possible to construct the bed pad with the absorbent structure 32 inverted. In such a configuration, the central channel 38 would be adjacent to the barrier layer 34, with a layer of the absorbent structure above the central channel positioned adjacent to the topsheet 36. Such a configuration also provides improved transverse leakage protection from the increased basis weight of the side dams. The central channel 38 has a transverse width W_c. The width of the central channel W_c is large enough to collect and contain bodily wastes between the side dams 40 when a person is lying on the bed pad 20. In one embodiment, the width W_c was greater than that of a person's posterior or buttocks when centrally positioned on top of the bed pad and lying parallel to the longitudinal axis 26. Such a width is preferred since the side dams will have their greatest utility if they remain outside the portion of the pad being laid on by the user and therefore uncompressed by that person's weight. When the side dams are uncompressed, they have a greater ability to retain and absorb bodily wastes enhancing leakage protection. Since the width of an individual's body can vary considerably, it is envisioned two or more sizes of the bed pad having a different W_c dimension can be made to accommodate different sized individuals ranging from infants to large adults. Specifically, the width W_c can be greater than about 200 mm. More specifically, the width W_c can be greater than about 400 mm. More specifically still, the width W_c can be greater than about 600 mm.

The absorbent structure 32 can be formed from any suitable absorbent material such as natural or synthetic fibers, cellulose, foams, and superabsorbent particles. In one embodiment, the absorbent structure 32 is a stabilized absorbent material. A stabilized absorbent material is desirable due to its superior performance in resisting bunching and tearing when wet as a person using the bed pad moves and shifts position. In addition, the stabilized absorbent material is readily folded and processed by converting equipment to create the side dams 40 and central channel 38 as opposed to a conventional fluff pulp/suberabsorbent material, which has a much lower tensile strength. The absorbent structure can have a density ranging from about 0.1 grams per cubic centimeter (g/cc) to about 0.4 g/cc under a load of 0.35 kPa. The absorbent capacity of the absorbent structure can be greater than about 8 g/g. The basis weight of the absorbent structure can range from about 100 grams per square meter (gsm) to about 1000 gsm. The stabilized absorbent material can be an airlaid or a wet laid material. Desirably, the stabilized material is an airlaid material, constructed of a blend of cellulose fibers, a binder, preferably in the form of a second group of fibers, and a superabsorbent. The blended mixture is cured to form a stabilized, airlaid absorbent material. One suitable stabilized absorbent material is a 175 gsm SMARTCORE material, product number 175.1341 , commercially available from Concert Fabrication LTEE having an office at 1680 Atmec Street, Gatineau, Quebec, Canada JAP7G7.

The cellulose fibers of the stabilized absorbent can include about 25 percent to about 96 percent of the stabilized absorbent material by weight. One suitable cellulose pulp is identified as NB-416 southern softwood sold by Weyerhauser Corporation having an office in Tacoma, Washington, USA.

The binder of the stabilized absorbent can comprise from about 4 percent to about 15 percent by weight of the stabilized absorbent material. The binder can be a chemical agent such as the wet strength additive KYMENE available from Hercules, Inc. having an office at 7510 Bay Meadows Way, Jacksonville, Florida 32256, USA. Desirably, the binder will consist of a second group of fibers. The second group of fibers can be synthetic binder fibers. Synthetic binder fibers are commercially available from several suppliers. One such supplier is Trevira GmbH & Company KG having a mailing address of Max-Fischer-Strasse 11 , 86397 Bobingen, Deutschland. Another supplier of binder fibers is Fibervisions A S having a mailing address of Engdraget 22, Dk-6800 Varde, Denmark. A third supplier of binder fibers is KoSa having a mailing address of P.O. Box 4, Highway 70 West, Salisbury, North Carolina 28145. Desirably, the binder fibers are bicomponent fibers having a polyester core surrounded by a polyethylene sheath. Alternatively, the binder fibers can be bicomponent fibers having a polypropylene core surrounded by a polyethylene sheath. One suitable binder fiber for use in the stabilized absorbent is a KoSa T255, 2 denier, 6 mm, polyethylene sheath polypropylene core fiber. The optional superabsorbent of the stabilized absorbent can include from about 0 percent to about 60 percent by weight of the stabilized absorbent material. The superabsorbent can be a polyacrylic acid and is desirably in the shape of small particles, although fibers, flakes or other forms of superabsorbents can also be used. One suitable superabsorbent is Stockhausen Superabsorber FAVOR 880. FAVOR 880 is commercially available from Stockhausen, Inc. having an office located at 2408 Doyle Street Greensboro, N.C. 27406. Other superabsorbents, some of which are commercially available from Dow Corporation having an office in Midland, Ml, USA, can also be used. Referring back to Figure 2, the absorbent structure, after folding, has a width W_A which also defines the width of the center portion 22. As mentioned, the side portions 24 are substantially free of an added absorbent material, such as absorbent structure 32, although the material forming the side portions may be absorbent to some degree depending on the specific material utilized. The side portions 24 can include a topsheet layer 36 or a barrier layer 34 if desired. The bed pad has an overall width W_P as illustrated.

To maximize the leakage performance of the bed pad, it has been determined that the ratio of W_AΛΛ/_P can be maintained within specific ranges. By centralizing the absorbent structure 32, bodily wastes will be contained in the center of the bed pad 20, and the side portions 24 can be used to hold the bed pad to the mattress by tucking the side portions 24 underneath the mattress similar to a sheet. In one embodiment, the bed pad 20 has an absorbent structure width W_A equal to 810 mm, an overall width W_P equal to 2000 mm, and a ratio W_A/W_P equal to 0.4. Specifically, the ratio W_A W_P ranges from about 0.2 to about 0.8. More specifically, the ratio W_A/W_P ranges from about 0.3 to about 0.6. More specifically still, the ratio W_A/W_P ranges from about 0.4 to about 0.5.

The bottomsheet 30 can be liquid impermeable or liquid permeable, and constructed from a woven, a nonwoven, a film, or a plastic material. Desirably, the bottomsheet is liquid impermeable or treated to be liquid impermeable with a coating such as a polyethylene. In one embodiment, the liquid impermeable bottom sheet is a 32 gsm material formed form a 22 gsm spunbond/meltblown/spunbond nonwoven treated with a 10 gsm clear polyethylene coating.

To further enhance the liquid impermeability of the bed pad, a barrier layer 34 can be optionally located between the absorbent structure 32 and the bottomsheet 30. The barrier layer is a liquid impermeable material and can cover the entire width and length of the bed pad if desired. Generally, the barrier layer 34 will be disposed only in the area underneath the absorbent structure 32 or in a slightly larger area than the absorbent structure to minimize costs. In one embodiment, the barrier layer is a 25 μm blue polyethylene film, product number 152S available from Australian Challenge, Artlou Division having an office at 103 Bernard Street, Cheltenham, Victoria 3192, Australia.

To provide a soft, comfortable, non-irritating surface for the patient, a topsheet 36 can be disposed over the absorbent structure 32. The topsheet is desirably less hydrophilic then the absorbent structure, and is liquid permeable to permit liquids to readily pass through to the absorbent structure. Suitable topsheets can be manufactured from a wide selection of materials such as woven fabrics, nonwovens, and apertured films. In one embodiment, the topsheet is a 17 gsm nonwoven polypropylene spunbond available from Kimberly-Clark Corporation having an office in Roswell, Georgia, USA. The topsheet can be treated to render it more hydrophilic, if desired, as known to those of skill in the art. The various layers of the bed pad can be joined together using suitable adhesives applied by spraying, slot coating, or other means as known to those of skill in the art. Alternatively, ultrasonic bonding, heat welds, stitching, or other means known to those of skill in the art can be used to join the layers together. In one embodiment, hot melt adhesive having a product code 234-5610 supplied by National Starch having an office in Bridgewater, New Jersey, USA is used. Depending on the specific material used for the absorbent structure 32, one or more adhesive beads 44 can be applied to one or more of the folds within in the side dams 40 to secure the absorbent structure. For instance, absorbent structures that are highly resilient may require the addition of the adhesive bead 44 to tack the side dams into position. Referring now to Figure 3, an alternative embodiment for the bed pad is illustrated.

In this embodiment, the topsheet 36, the absorbent structure 32, and the bottomsheet 30 are plied together and joined to each other by suitable adhesives. Then the entire laminate is "Z" folded twice to form the central channel 38 and the side dams 40.

Alternatively, only the bottomsheet 30 and absorbent structure 32 can be joined together and folded with the topsheet 36 disposed over the assembly after the central channel 38

~ and side dams 40 have been formed. The adhesive beads 44 are applied to the bottomsheet 30 prior to folding to tack an upper portion 48 of the folded assembly together. A lower portion 50 of the folded assembly adjacent the central channel 38 is not joined by the adhesive bead 44 as illustrated. In use, the width of the central channel W_c can be adjusted by moving the side portions 24 in the direction indicated by arrow 46. As the side portions are moved transversely outward, the width of the central channel W_c is increased since the lower portions 50 of the folded assembly are not glued into position. Thus, the side dams 40 can rotate and stand more upright as the side portions 24 are moved outward. As a result, the height of the side dams 40 is increased as the width of the central channel W_c is increased. The side portions 24 can be moved to their desired location and then tucked or held in position. The incontinent patient is then placed onto the bedpad 20 lying in the central channel 38 with the side dams 40 located along either side of the patient. It will be appreciated that the foregoing description, given for the purposes of illustration, is not to be construed as limiting the scope of the invention, which is defined by the claims and all equivalents thereto.

Claims

CLAIMSWe Claim:

1. A bed pad comprising: an absorbent structure disposed adjacent a bottomsheet, the absorbent structure having a stabilized absorbent material, and the absorbent structure is folded at least twice; and the bed pad having a width W_P, the absorbent structure having a width W_A, and a ratio of W_A/W_P is from about 0.2 to about 0.8.

2. The bed pad of claim 1 wherein the folded absorbent structure comprises a central channel and a pair of transversely disposed side dams adjacent the central channel.

3. The bed pad of claim 2 wherein the folded absorbent structure comprises a pair of oppositely disposed side margins adjacent the side dams.

4. The bed pad of claim 2 wherein the central channel has a width W_c and the width W_c is greater than about 200 mm.

5. The bed pad of claim 4 wherein the width W_c is greater than about 400 mm.

6. The bed pad of claim 1 wherein the ratio W_A/W_P is from about 0.3 to about 0.6.

7. The bed pad of claim 1 wherein the bottomsheet and the absorbent structure are plied together prior to folding, and the folded portion is joined together by at least one adhesive bead.

8. The bed pad of claim 7 wherein the bed pad comprises a central channel and the width of the central channel is adjustable.

The bed pad of claim 1 further comprising a barrier layer disposed between the bottomsheet and the absorbent structure, and a topsheet disposed adjacent the absorbent structure.

10. A bed pad having a central longitudinal axis and a central transverse axis comprising: a center portion and a pair of transversely disposed side portions, the center portion having an absorbent structure disposed between a topsheet and a bottomsheet, and the side portions free of the absorbent structure; the absorbent structure folded from an absorbent material into a central channel, and a pair of transversely disposed side dams adjacent the central channel, and the central channel having a width W_c greater than about 200 mm.

11. The bed pad of claim 10 wherein the width W_c is greater than the width of a person's posterior when lying longitudinally on the bed pad.

12. The bed pad of claim 10 wherein the absorbent structure comprises a stabilized absorbent material.

13. The bed pad of claim 10 wherein the topsheet, the absorbent structure, and the bottomsheet are plied together prior to folding and the folded portion is joined together by at least one adhesive bead.

14. The bed pad of claim 13 wherein the width W_c is adjustable by pulling transversely on the side portions.

15. The bed pad of claim 10 wherein the absorbent structure further comprises a pair of oppositely disposed side margins adjacent the side dams.

16. The bed pad of claim 10 wherein the bed pad has a width W_P and the absorbent structure has a width W_A and a ratio of W_A/W_P is from about 0.2 to about 0.8.

17. The bed pad of claim 10 wherein a barrier layer is disposed between the absorbent structure and the bottomsheet.

18. A bed pad having a central longitudinal axis and a central transverse axis comprising: a center portion and a pair of transversely disposed side portions, the center portion having an absorbent structure disposed between a topsheet and a bottomsheet, and the side portions free of the absorbent structure; the absorbent structure folded from a stabilized absorbent material into a central channel, and a pair of transversely disposed side dams adjacent the central channel, and the central channel having a width W_c greater than about 200 mm.

19. The bed pad of claim 18 wherein the stabilized absorbent material has a basis weight from about 100 gsm to about 1000 gsm.

20. The bed pad of claim 18 wherein the stabilized absorbent material has a density from about 0.1 g/cc to about 0.4 g/cc under a load of 0.35 kPa.

21. The bed pad of claim 18 wherein the stabilized absorbent has an absorbent capacity greater than about 8 g/g.

22. The bed pad of claim 18 wherein the side dams remain uncompressed when a . person lays on the bed pad.