Water resistant bandage

Abstract

A water resistant light compression and/or retention bandage for retaining an orthopedic splint, padding or medical device against a body part, includes a knitted fabric formed of synthetic yarns having a moisture vapor transmission rate from an inner face of the bandage to an outer face of the bandage of at least 500 g/m.sup.2 per 24 hours.

Claims

1. A knitted bandage, consisting of: an inner face adapted to be positioned contacting skin and an outer face adapted to be positioned apart from the skin; nylon monofilament yarns knitted into only the inner face and having a maximum diameter of 0.1 mm; polyproylene monofilament yarns knitted into only the outer face and having a maximum diameter of 0.1 mm; and elastic yarns knitted or laid in with wales of the knitted bandage to impart elasticity in the knitted bandage; wherein the knitted bandage has a moisture vapor transmission rate of at least 500 g/m.sup.2 per 24 hours.

2. The knitted bandage of claim 1, wherein the polypropylene monofilament yarns are knitted into a chain stitch of the knitted bandage, the nylon monofilament yarns are knitted into both the chain stitch and an inlay stitch of the knitted fabric, and the elastic yarns are laid or knitted in a warp or chain stitch direction.

3. The knitted bandage of claim 1, wherein the outer face of the knitted bandage has a greater hydrophobicity than the inner face of the knitted bandage.

4. The knitted bandage of claim 3, wherein the nylon monofilament yarns of the inner face are formed into loops that protrude through a knitted fabric thickness of the polypropylene monofilament yarn of the outer face.

5. The knitted bandage of claim 1, wherein the elastic yarns comprise a segmented polyester or polyether/polyurethane.

6. The knitted bandage of claim 5, wherein the elastic yarns have a modulus of elasticity 90 Cn at a breaking elongation of 470%.

7. The knitted bandage of claim 1, wherein the knitted bandage has windows ranging between 380 and 640/m.sup.2.

8. The knitted bandage of claim 1, wherein the knitted bandage includes a number of courses in a weft direction in a relaxed state that is between 5 and 12 per cm.sup.2, and a weight of the knitted bandage in a relaxed state is 70+/5 gsm.sup.2.

9. The knitted bandage of claim 1, wherein the inner and outer faces are formed of single monofilament yarns having a maximum diameter of 0.1 mm.

10. The knitted bandage of claim 1, wherein yarns of the inner face are nylon 1/33 dtex monofilament yarn, and yarns of the outer face are 0.1 mm polypropylene monofilament yarn.

11. The knitted bandage of claim 1, wherein the knitted bandage has a lengthwise directional stretch of at least 30% and up to 75% in a relaxed state.

12. The knitted bandage of claim 1, wherein the knitted bandage has a widthwise directional stretch of between 25% and 45% in a relaxed state.

13. The knitted bandage of claim 1, wherein the knitted bandage has a thickness ranging from 1.1 mm to 2.6 mm in a relaxed state and from 0.6 mm to 1.5 mm in a stretched state.

14. The knitted bandage of claim 1, wherein a hook fastener is positioned on one end of the knitted bandage and a complimentary loop fastener is positioned on an opposing end of the knitted bandage.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Some of the objects of the invention have been set forth above. Other objects and advantages of the invention will appear as the description of the invention proceeds when taken in conjunction with the following drawings, in which:

(2) FIG. 1 is a view of one embodiment of the novel light compression and retention bandage;

(3) FIG. 2 is a view of a cast bandage of a type over which an embodiment of the light compression and retention bandage shown in FIG. 1 would be wrapped;

(4) FIG. 3 shows application of the light compression and retention bandage;

(5) FIG. 4 shows the splint with the light compression and retention bandage in place over the splint; and

(6) FIG. 5 is a photograph, enlarged in scale, of an embodiment of a light compression and retention bandage according to the preferred embodiment of the invention disclosed in this application.

DESCRIPTION OF THE PREFERRED EMBODIMENTS AND BEST MODE

(7) Referring now specifically to the drawings, a retention bandage according to a preferred embodiment of the present invention is shown generally in FIG. 1 at reference numeral 10.

(8) The knitted structure of the bandage 10 preferably includes a combination of nylon and polypropylene monofilament yarns and, in addition, a small amount of elastic. The knit construction gives the fabric a thickness that is greater than the thickness of the yarns themselves and is thus considered three dimensional. This three dimensional characteristic is shown along the facing edge and cut end of the bandage 10 in FIG. 1, and provides separation between the bandage's major opposing outer and inner faces 12 and 14. The bandage 10 is typically rolled as shown in FIG. 1 for ease in packaging and in manipulating the bandage 10 onto the injured limb.

(9) The nylon is the softer of the two fibers and is knitted into the structure in a manner whereby the nylon is on the inner face 14 and therefore against the body part, with the polypropylene outer face 12 facing outwardly and not contacting the skin. The polypropylene is the more resilient of the fibers and has natural hydrophobic properties. The polypropylene therefore provides enhanced stability to the construction and acts as the drainage medium for moisture.

(10) Elastic yarns are preferably incorporated into the fabric structure of the bandage 10 to provide additional elasticity. One suitable elastic yarn is Dorlastan, a filament fiber of segmented polyester- or polyether/polyurethane. A relatively small amount of this fiber is sufficient to obtain elasticity, elastic recovery and dimensional stability.

(11) The knitted construction of the bandage 10 uses monofilament yarns that are very fine, generally having a maximum diameter of 0.1 mm. This allows for a very open knitted structure and extremely low weight which promotes rapid moisture transmission through the thickness of the fabric from the nylon inner face 14 to the polypropylene outer face 12, and into ambient air.

(12) One exemplary embodiment of the bandage 10 is set out below:

Example 1

18 Gauge Single Bar Warp Knitting Machine Equipped with 4 Bars

Threading and Run-In

(13) Bar 1 and 2 fully threaded, PP 0.1 Plasticel Polypropylene, Run-Ins 1650 mm/Rack,

(14) Bar 3 Fully Threaded, Nylon 1/33 dtex, Run-Ins 2550 mm/rack.

(15) Bar 4 Half Threaded with ends in first and last needle, Elastic Dorlastan 1/80 dtex, Run-Ins 550 mm/rack. Beaming Tension 50%.

Bandage Details

(16) 73 needles for 3 bandage.

(17) 97 needles for 4 bandage.

(18) 49 needles for 2 bandage.

Fabric Specifications

(19) 700 courses per meter cpm on machine.

(20) 900-950 cpm out of roll.

(21) 70+/5 gsm.sup.2 relaxed fabric weight.

(22) TABLE-US-00001 Thickness in relaxed state. 1.26 mm Thickness in stretched 0.85 mm (140% of relaxed) state.

Notation of Structure

(23) 1-0/0-1 Full Sett Polypropylene Mono.

(24) 0-0/4-4 Full Sett Nylon.

(25) 1-1/0-0 Half Sett Elastic.

(26) The above-referenced bandage has been tested to Standard BS7505, Elastic Properties of Extensible Bandages. The test is conducted on a Instron Tensile testing machine and is used to characterize a bandage by measuring its elastic properties using information obtained from the second retraction curve. The test indicates that the bandage 10 of Example 1 meets a Type 2 characterization for application of light compression.

(27) FIG. 2 shows a forearm splint 20 of the general type over which the bandage 10 is placed. The splint 20 may be of any type or construction, including plaster/gauze or synthetic cast tape.

(28) As is shown in FIG. 3, the bandage 10 is wrapped around the limb and overlying splint 20 with sufficient tension to maintain the splint 20 in its required location and shape. As is shown in FIG. 4, when application is completed the bandage 10 overlaps the splint 20 and contacts the skin on opposite ends of the splint 20. The bandage 10 is applied with nylon inner face 14 against the skin in the manner shown. The nylon yarns create a channel effect that allows moisture underneath the bandage 10 to migrate through the bandage 10 to the polypropylene yarns of the outer face 12. To facilitate the movement of moisture, nylon loops of the inner face 14 protrude through the thickness of the fabric to the polypropylene outer face 12.

(29) Suitable embodiments of the bandage include a fabric structure defining an inner face, and an outer face that comprise a plurality of wales (warp yarns) that are constructed of hydrophobic single monofilament threads, and a plurality of courses (weft yarns) that are inserted in the wales yarn that creates holes or windows that allow for breathability and conformability of the structure. The bandage may also include a plurality of fine elastic threads, knitted or laid in with the wales to improve the stretch characteristics of the fabric structure to improve conformability to the anatomy of the patient.

(30) The moisture vapor transmission rate of the fabric of one embodiment of the bandage 10 is not less than 500 g/m.sup.2 per 24 hours. The moisture vapor transmission rate of the fabric of other embodiments of the bandage 10 may be as much as not less than 1400 g/m.sup.2 per 24 hours. The bandage 10 may be provided with a release and lock closure system, such as hook and loop fasteners, to secure the bandage to the patient. Patches of conventional hook material are secured at or near both ends of the bandage 10 to assist in self-application. Other fasteners, such as adhesive tapes with release liners and landing areas may be used.

(31) The knitted stretchable fabric of the bandage 10 may also include polypropylene monofilament yarns knitted into the chain stitch, and nylon monofilament yarns in both the chain stitch and inlay stitch, with the elastic yarn laid or knitted in the warp or chain stitch direction.

(32) The number of holes or windows in the knitted structure of the bandage 10 in a relaxed state is between 380 and 640/m.sup.2, and the number of threads or courses in the weft direction is between 5 and 12 per cm.sup.2 in a relaxed state. A typical length of the bandage 10 is between 4.4 m and 5.1 m.

(33) The weight per unit area of the bandage 10 is preferably between 30 and 90 grams per m.sup.2 and the stretch of the bandage 10 in the lengthways direction is between 30% AND 75%. The widthways stretch of the bandage 10 in a relaxed state is preferably between 25% and 45%.

(34) The monofilament yarns may be between 0.03 and 0.14 mm in diameter, with a tenacity between 45 and 60 centinewtons/Tex, and the elastic fiber may be between 40 and 80 d/tex. The thickness range of preferred embodiments of a bandage according to the application is 1.1 mm to 2.6 mm in its relaxed state and 0.6 mm to 1.5 mm in a 40% stretched state.

(35) Preferably, the elastic thread is knitted or laid into the chain stitch and has a modulus of elasticity 90 Cn at breaking elongation 470%. Alternatively, the elastic threads may be synthetic rubber or natural rubber.

(36) A photograph of fabric of the bandage 10, enlarged to show detail, is shown in FIG. 5.

(37) An improved medical bandage is described above. Various details of the invention may be changed without departing from the scope of the invention. Furthermore, the foregoing description of the preferred embodiment of the invention and best mode for practicing the invention are provided for the purpose of illustration only and not for the purpose of limitation, the invention being defined by the claims.