GB2218908A - Cooling bandage - Google Patents

Abstract

A bandage for applying cold to an affected area has fluid filled reservoirs (1) formed from sheets (3a, 3b) of plastic laminate, especially one comprising polyvinylidene chloride. The fluid stays as liquid or slush on cooling to below - 20 DEG C allowing the bandage to be stored in a refrigerator/freezer. The reservoirs (1) are interconnected by narrow passages (12) allowing slow flow of the viscous reservoir fluid. <IMAGE>

Description

BANDAGE The present invention relates to a bandage for use in treating injuries. It is well known to treat some injuries, such as sprains, with a cold compress, a chill spray, or other cooling agent. Such treatments are also used for conditions such as migraine. Further, it is often desirable to keep a patient's head cool during an operation.

UK 1600505 and UK 2160425A describe bandages (in the former case for vetinary use) which may be applied with a cooling effect. Such a cooling bandage may provide a complete first-aid treatment for many common minor injuries and also be used in other conditions and situations requiring cooling treatment.

We have now found it advantageous to incorporate polyvinylidene chloride as an impervious layer in such a bandage.

The present invention thus provides a bandage comprising at least one reservoir defined by a flexible boundary layer and containing a reservoir fluid which is not solid at 0 C, characterised in that the flexible boundary layer comprises a laminate in which polyvinylidene chloride is sandwiched between layers of other polymer, and provides a layer which is impervious to the reservoir fluid.

Preferably the layers of other polymer are both layers of polyurethane. If no other layers are present the laminate will then be a polyurethane - polyvinylidene chloride - polyurethane sandwich. The outer layer may provide the outer surface of the bandage. In this case it is desirable to provide the outer side of the layer with a fine grain embossing so that it does not contact the skin smoothly. This helps to avoid giving freezer burns to the injured person.

Alternatively the bandage may have an outer fabric cover. In this case there is no need for the outer side of the boundary layer to be embossed.

Preferably the reservoir fluid is not solid at the operating temperature of the freezing compartment of a domestic refrigerator. For convenience it is most preferable that the reservoir fluid is not solid at temperatures at least as cold as -20 C, ideally several degrees lower, so as to be usable with the coldest domestic refrigerator freezing compartments and with domestic deep freezers which usually operate at -18 C to -20 C.

The bandage can then be kept in a freezer or freezing compartment, and only removed when needed to treat an injury. If the bandage is used in conjunction with a thermally insulated bag or holder, it may be kept in the freezer or freezing compartment normally but taken in the bag on any occasion when injuries are anticipated, e.g. by a coach or trainer attending an athletics meeting or a football match.

Preferably the reservoir fluid has a high heat capacity so that it keeps its low temperature for a long time when the bandage has been removed from the freezer.

It is desirable that the reservoir fluid should stay reasonably uniformly distributed over the area of the bandage. It is therefore desirable that the bandage has a plurality of reservoirs, which are separate, or connected only by passages which restrict flow.

According to a second aspect, the invention provides a bandage comprising a plurality of reservoirs defined by a boundary layer and containing a reservoir fluid which is not solid at 0 C, characterised in that the reservoirs are separated from each other by subdivisions which extend across a substantial part of the width of the bandage but leave communicating passages between adjacent reservoirs, which passages each extend across no more than 15% of the width of the bandage.

In a preferred arrangement the bandage is formed by two layers of laminate, bonded together around the edges of the bandage and bonded together across a substantial part of the bandage width to separate the reservoirs from each other.

It is also desirable that the reservoir fluid is thick and slow flowing. Suitably it may contain a gelling agent which provides it with a suitable viscosity at all operating temperatures.

Examples of suitable reservoir fluids are given in UK 2160425A the disclosure of which is incorporated herein by reference.

The dimensions of the bandage should be such as to allow it to be wrapped, and tied if necessary, around an injured limb. Various sizes and shapes could be used. A suitable example is a rectangular bandage about 50cm long and about 15cm wide. The reservoir( 8 ) could occupy substantially the whole of this area, the boundary around the bandage and any internal subdivisions being e.g. about 2mm wide. This sized bandage could, for example, contain about 700g - 800g of the fluid formulation given above.

As mentioned above the boundary layer is preferably made of two sheets of laminate forming the reservoirs between them. The sheets may be bonded by any convenient method around the boundary of the bandage and to provide any internal subdivisions as described above. The bonded subdivisions, as well as providing uniform distribution of the reservoir fluid by inhibiting migration of fluid between reservoirs, also greatly improves the flexibility of the bandage. This construction also allows a simple fabrication process suitable for large scale production. The bonding may, for example, be by an adhesive, by heat sealing, or by high frequency welding.

The bandage may be tied in place when being used to treat an injury. This may be facilitated by providing one or more holes, not piercing any of the reservoirs, through the bandage at one or both ends, through which hole or holes a cord (e.g. of polypropylene) may be passed.

Alternatively one or more cords may be permanently bonded or otherwise fastened to the bandage.

An embodiment of the invention, given by way of example, will now be described with reference to the accompanying drawings, in which: Figure 1 is a plan view of a bandage embodying the present invention; Figure 2 is a side edge view of the bandage of Figure 1; and Figure 3 is a detail view.

The bandage shown in the drawings has fluid-filled reservoirs 1 bounded by a boundary layer 3. The boundary layer is made of an upper sheet 3a and a lower sheet 3b, both of which are a polyurethane-polyvinylidene chloridepolyurethane laminate as described above. The bandage is about 50cm long and 15cm wide, the reservoirs are defined by a heat-sealed boundary strip 5 around the edge of the bandage and by internal barrier sections 6 between each of the reservoir regions.

At each end of the bandage there is a fastening tab 7 which may be strengthened by heat sealing a strengthening strip between this area of the upper and lower sheets 3a, 3b. These fastening tabs 7 are each provided with four holes through which a cord (not shown) may be passed to assist in fastening the bandage around an injured limb.

The reservoir fluid is a thick fluid of high heat capacity, which remains fluid at temperatures at least as low as -20 C, for instance it may have one of the detailed compositions given in UK 2160425A. There is overall about 70 - 80g of this fluid in the bandage.

As best seen from the detail view, Fig 3, the pattern of heat sealing is arranged to allow very limited flow of fluid between adjacent reservoirs.

The heat sealed boundary strip 5 fully encircles the reservoirs and prevents escape of liquid. The barrier sections 6 extend across 80% of the width of the bandage, terminating in closed loops 10 of heat sealing. These enclose areas 11 in which there is no fluid, and leave a channel 12 through which fluid can pass from one reservoir to the next. However, each channel extends across the bandage for only 10% of the width of the bandage, and has a noticeable axial length indicated at 1B. Consequently each channel 12 provides only a small cross section for flow.

Furthermore, as the reservoirs 1 bulge with the fluid in them, the bandage tends to pucker at the channels 12, further inhibiting flow through them.

The result is that fluid will flow from one reservoir to another if the reservoir is squeezed, but displays very little tendency to drain to the lowest point of the bandage. This assists the bandage to mould to the shape of a patient's limb when it is applied.

The outer surfaces of the sheets 3a, 3b are embossed with a fine pattern, as mentioned above.

In use, the bandage is cooled by being kept in a e.g. the freezing compartment of a domestic refrigerator or a domestic deep freezer. When needed, it can be removed and wrapped around an injured portion of the body to provide a cooled bandage. It may be useful to provide a thermally insulated bag in which the pre-cooled bandage can be transported to an event where its likely need is anticipated.

The embossing on the outer surface of the bandage helps to avoid freezer burns from it. If the outer side of the boundary layer 3 does not form the outer surface of the bandage, e.g. the bandage has a fabric cover, then the embossing is not necessary and the outer side of the boundary layer 3 may be smooth.

Claims (9)

CLAIMS:

1. A bandage comprising a plurality of reservoirs defined by a boundary layer and containing a reservoir fluid which is not solid at 0 C, characterised in that the reservoirs are separated from each other by subdivisions which extend across a substantial part of the width of the bandage but leave communicating passages between adjacen#t reservoirs, which passages each extend across no more than 15% of the width of the bandage.

2. A bandage according to claim 1 formed by two layers of sheet material bonded together around the edges of the bandage and bonded together across a substantial part of the bandage width to separate the reservoirs from each other.

3. A bandage according to claim 1 or claim 2 wherein the sheet material is a laminate of polymer layers.

4. A bandage comprising at least one reservoir defined by a flexible boundary layer and containing a reservoir fluid which is not solid at 0 C, characterised in that the flexible boundary layer comprises a laminate in which polyvinylidene chloride is sandwiched between layers of other polymer, #nd provides a layer which is impervious to the reservoir fluid.

5. A bandage according to claim 4 wherein the layers of other polymer are both layers of polyurethane.

6. A bandage according to claim 5 wherein the laminate is a polyurethane - polyvinylidene chloride polyurethane sandwich, whose outer layer provides the outer surface of the bandage.

7. A bandage according to any one of the preceding claims whose outer surface has a fine grain embossing.

8. A bandage according to any one of the preceding claims wherein the reservoir fluid is a viscous fluid containing a thickening agent.

9. A bandage substantially as herein described and exemplified.