GB2544081A

GB2544081A - Support surface or support surface topper having a cover comprising a moisture vapour permeable mesh

Info

Publication number: GB2544081A
Application number: GB1519572.0A
Authority: GB
Inventors: David Irlam Jon; Elizabeth Milnes Joanne
Original assignee: MEDSTROM Ltd; Redwood Ttm Ltd
Current assignee: MEDSTROM Ltd; Redwood Ttm Ltd
Priority date: 2015-11-05
Filing date: 2015-11-05
Publication date: 2017-05-10
Anticipated expiration: 2035-11-05
Also published as: GB201519572D0; GB2544081B

Abstract

Water resistant cover (3; Fig 1) for a support surface (1; Fig1) or a support surface topper. The cover is formed from a textile that comprises an elastic monolithic polymer coating. The cover further includes an air and moisture vapour permeable mesh 4 extending along a side of the cover. The support surface may have a rectangular shape with a head end 5 and a foot end 6 connected by parallel sides 701. The support surface topper may be a mattress, a mattress overlay or a cushion. The elastic monolithic polymer coating may be polyurethane, polyvinyl chloride or butyl rubber. The cover can include an overlap (2; Fig 1) with a liquid resistant coating. There may be straps (10, 11; Fig 3) for securing the support surface to a bed. A fan can be connected to an aperture in the cover to provide a flow of air.

Description

Support surface or support surface topper having a cover comprising a moisture vapour permeable mesh

Technical Field of the Invention

The present invention relates to support surfaces and support surface toppers such as cushions, mattresses and mattress or recliner overlays.

Background to the Invention

There are many circumstances where it is beneficial to have a wipe clean and essentially water resistant support surface, or support surface topper, such as a cushion, mattress, or mattress/ recliner overlay. Unfortunately, water resistant surfaces often compromise the moisture vapour permeability of the total article which is also desirable as high moisture vapour permeability tends to reduce instances of pressure sores. Water resistant wipe clean support surfaces are used in hospitals and various healthcare facilities where the comfort and hygiene of a patient is of great importance.

Microclimate management systems are known in the art. These systems may be incorporated into patient support surfaces in order to improve air circulation. A mattress is disclosed in US2010/175196 which comprises a compressible 3D fabric layer that includes air flow passages extending laterally and transversely through the layer surrounded by a cover of moisture vapour permeable, but liquid impermeable, material such as GORE Medical Fabric.

It is unfortunate that the more moisture vapour permeable water resistant materials that are readily available on the market are less durable than those with lower moisture vapour permeability (MVP). Water resistant materials made from expanded polytetrafluoroethylene (e-PTFE), such as those marketed by W.L. Gore and proposed in US2010/175196 Al, have very high MVP but the e-PTFE membrane is vulnerable to damage that would result in the loss of water resistant properties very easily. For this reason some mattress covers made from such materials are made with the water resistant membrane in the inside of the article where it can be protected by outer layers. A disadvantage of this, therefore, is that the cover does not have a true wipe clean surface as required for infection control purposes within a hospital.

Hydrophilic polyurethane is known to be used in manufacture of water resistant MVP cover materials. The inclusion of the hydrophilic segments into the polymer chain significantly reduces the resistance of the polymer to cleaning agents. Hydrophilic polyurethanes also swell through water absorption when wet and the associated reduction in density significantly reduces the abrasion resistance of the polymer. Again, this has led to the manufacture of articles with the hydrophilic polyurethane film layer situated interiorly to other layers in the article and thus lacking the desirable wipe-clean properties. In clinical environments there is an increasing focus on disinfection of surfaces in order to reduce the risk of hospital acquired infections. This has led to an increased frequency of cleaning and with more aggressive chemical cleaning agents.

Summary of the Invention

According to a first aspect of the invention, there is provided a water resistant cover for a support surface or support surface topper, the water resistant cover formed of a textile comprising at least one elastic monolithic polymer coating, the cover further comprising an air and moisture vapour permeable mesh extending along a side of the cover.

The moisture vapour permeable region allows for rapid exchange of moisture vapour found in the atmosphere within the support surface or support surface topper with the external atmosphere surrounding the support surface or support surface topper. This is largely due to its high level of air permeability. Water resistant covers formed of a textile with elastic monolithic polymer coatings tend to have lower moisture vapour permeability than water resistant materials made from e-PTFE and the like, but are much more durable and less susceptible to damage by cleaning materials. It has been found that by providing an air and moisture vapour permeable mesh extending along a side of the support surface or support surface topper the reduced moisture vapour permeability properties can be offset/improved by allowing more air to pass through the mattress, thereby increasing the amount of dry air in the mattress and thereby increasing the gradient of water vapour across the cover by reducing the water vapour on the interior face of the material.

Preferably when in use the cover extends around the support surface or support surface topper and the mesh extends along a side of the support surface or support surface topper. Preferably the mesh, or open textile, is attached to the textile comprising at least one elastic monolithic coating. The mesh may be sewn to the textile comprising at least one elastic monolithic coating, or attached thereto by high frequency welding.

The moisture vapour permeable region may be situated on the periphery of the support surface or support surface topper. Beneficially, the air and moisture vapour permeable region is situated on the periphery to allow for an optimised rate of moisture vapour transmission, or breathability, of the support surface or support surface topper. This is achieved by air exchange between the air within the support surface or support surface topper and the drier exterior environment.

The moisture vapour transmission rate (MVTR) is driven by the existence of a water vapour concentration gradient between the atmosphere within the support surface or support surface topper and the external atmosphere surrounding the support surface or support surface topper. It is known that the greater the concentration gradient, the greater the rate of moisture vapour transmission. It is, therefore, provided that the moisture vapour permeable region is positioned so as to afford a concentration gradient by allowing dry air into the support surface or support surface topper and wet air out of the support surface or support surface topper.

Incorporating an air and moisture vapour permeable region onto the support surface or support surface topper at, for example, the base of the support surface or support surface topper, would not be as effective in maintaining a water vapour concentration gradient. This is because the moisture vapour permeable region may be blocked as a result of the support surface or support surface topper being placed on a significantly closed bed frame or seat, therefore, not allowing for the transfer of moisture vapour from within the support surface or support surface topper to the surrounding atmosphere.

Further, a moisture vapour permeable region on the top-surface of the support surface or support surface topper will be disadvantaged by the ingress of any bodily fluids originating from a patient, or other person, who is positioned on top of the support surface or support surface topper. This would render the composite not suitable for wiping clean to disinfect the surface.

It is, therefore, desirable for the moisture vapour permeable region to be located on the periphery of the support surface or support surface topper whereby it will be largely unobstructed and thus able to maintain a greater moisture vapour concentration gradient than if the region were to be placed elsewhere on the support surface or support surface topper. It also allows the use of a loose cover flap to prevent liquid ingress and interior contamination as the vertical orientation of the air permeable section will result in any fluid running down the cover and not entering the interior of the surface.

Typically, the elastic monolithic polymer is one of polyurethane, polyvinyl chloride or butyl rubber but may be any elastic monolithic polymer that affords water resistant properties.

In a preferred embodiment, the water resistant textile coating, which affords a water resistance of preferably between 35kPa and 165kPa, more preferably between 70kPa and 130kPa and most preferably between 90kPa and 1 lOkPa to the support surface or support surface topper, is the outermost surface of the support surface or support surface topper. This embodiment, therefore, provides for an improved moisture vapour transmission rate, without compromising on fluid ingress over the lifespan of the article. This may be compared to hydrophilic polyurethanes; in which such materials exhibit high moisture vapour permeability levels and are water resistant but, which have a limited resistance to typical disinfection agents, therefore, resulting in the hydrophilic polyurethane materials being easily damaged by cleaning leading to a loss of water resistant properties.

Preferably, the coated textiles provided a water resistance of between 2 and 40%, more preferably between 4 and 30%, and most preferably between 5 and 20%. The water resistance test was carried out according to the ‘Testing coated fabrics. Method 37. Method for determination of water vapour permeability index (WVPI)’. A water resistance test on the e-PTFE and hydrophilic polyurethanes would typically be in the region of 50 - 80%. Preferably, the support surface or support surface topper comprises a head end and a foot end.

Preferably, the head end and the foot end are connected by two parallel sides.

Preferably, the air and moisture vapour permeable region covers at least half of the length of one side of the support surface or support surface topper, more preferably at least 75% of the length of one side of the support surface or support surface topper, and most preferably substantially all of the length of one side of the support surface or support surface topper.

Preferably, the air and moisture vapour permeable region extends along the periphery for part of the head end, preferably at least half of the head end, continuing to the peripheral vertex of the head end and along the entire length of the support surface or support surface topper.

Even more preferably, the air and moisture vapour permeable region continues along the foot end of the support surface or support surface topper, preferably along at least half of the foot end.

Beneficially, incorporating an air and moisture vapour permeable region along the length of the support surface or support surface topper achieves a greater surface area of air and moisture vapour permeable mesh. A greater surface area of the air and moisture vapour permeable region allows for a greater moisture vapour transmission rate through air exchange.

Advantageously, the opening to the air and moisture vapour permeable region comprises a mesh with a pore size of at least between 0.5mm and 5mm, preferably between 1.25mm and 4mm, and most preferably between 2.5mm and 3.5mm (typically 1mm - 3mm).

There is a direct correlation between air and moisture vapour permeability and pore size; therefore, a mesh with larger pore size will afford greater air and moisture vapour permeability than one with smaller pores. However, excessively large pores may lack sufficient tensile strength to withstand the forces associated with mattress or cushion use, or overlays for the same. Thus a compromise must be drawn between the mesh pore size and the ability for the mattress, cushion or overlay to exhibit a tensile strength capable of withstanding the forces associated with the uses of the present invention.

Preferably, a fastener preferably in the form of a zipper, is provided around the periphery of the support surface or support surface topper where there is an absence of mesh. The fastener, preferably a zipper, facilitates opening and closing of the mattress, cushion or overlay and also provides a region of lesser air permeability compared to the mesh region. Further, the fastener, preferably a zipper, allows for inspection of the interior of the mattress, cushion or overlay to confirm that fluid ingress has not occurred.

The zipper is positioned on the periphery of the support surface or support surface topper; for a support surface topper, for example a mattress or recliner overlay, the zipper is preferably between 15 mm and 40 mm from the edge of the upper surface, more preferably between 20 mm and 35 mm from the edge of the upper surface, and most preferably between 25 mm and 30 mm from the edge of the upper surface. For a support surface, for example a cushion or mattress, the zipper is preferably between 20 mm and 130 mm from the edge of the upper surface, more preferably between 45 mm and 105 mm from the edge of the upper surface, and most preferably between 65 mm and 85 mm from the edge of the upper surface.

Preferably, the moisture vapour permeable region has a total area of between 0.025 m2 and 0.25 m2, more preferably between 0.045 m2 and 0.14 m2, even more preferably between 0.050 m2 and 0.12 m2, and most preferably the moisture vapour permeable region has a total area of 0.057m2. It is important to note that an air and moisture vapour permeable region as encompassed by the present invention affords an air and moisture vapour permeable region of substantial surface area, therefore, allowing for a greater area for air and, therefore, moisture vapour exchange with a far lower manufacturing cost of the assembly than that found in the prior art, such as US2014/0196216 which discloses a plurality of relatively small exhaust openings, but requires an expensive material, which is susceptible to damage when warm, in order to achieve acceptable levels of moisture vapour permeability.

In one preferred embodiment, the mesh used is a 3mm polyester warp knit spacer, other suitable products would be other open net structures such as a 120 -200gsm warp knit polyester nets with various stitch configurations, ie bobbinet, tulle etc.

Preferably, the mesh region is covered by an overlap which extends over the air and moisture vapour permeable mesh, from the upper surface of the support surface or support surface topper towards the lower surface of the support surface or support surface topper.

In a preferred embodiment, the overlap comprises a water resistant textile coating on its inner facing and outer facing sides. Beneficially, the coating on both sides prevents any liquid from wicking into the moisture vapour permeable region.

Any liquid deposited on the top surface will migrate under the force of gravity down the overlap and off the support surface or support surface topper, therefore, not becoming in contact with the mesh of the moisture vapour permeable region. This prevents fluid from entering the air and moisture vapour permeable region. The ingress of fluid into the air and moisture vapour permeable region would affect the moisture vapour transmission rate by becoming a barrier to the transmission of water vapour from exiting the mesh into the surrounding atmosphere. Moreover, fluid inside the moisture vapour permeable region will have a detrimental effect on maintaining a favourable water vapour concentration gradient that allows for the efficient moisture vapour transmission rate exhibited by the preferred embodiment of the present invention.

Further, due to strict hygiene rules in hospitals, where the support surface or support surface topper is preferably to be used, certain fluid ingress into the support surface or support surface topper will result in contamination of the support surface or support surface topper and thus the need to dispose of it. As a result, incorporating the moisture vapour permeable region at the periphery of the support surface or support surface topper with a water resistant overlap provides great benefit.

The presence of the overlapping water resistant material provides a technical advantage to the present invention over the prior art. As described previously, a significant disadvantage of the prior art is the poor durability of the water resistant materials that offer moisture vapour permeability characteristics. The overlapping water resistant material, as positioned in the present invention to cover the moisture vapour permeable region, results in a highly durable water resistant and moisture vapour permeable support surface or support surface topper compared with those of the prior art. The protection of the air and moisture vapour permeable region afforded by the overlap allows the support surface or support surface topper to maintain its moisture vapour permeability while still offering water resistant properties by preventing the ingress of fluids into the moisture vapour permeable region.

Preferably, the overlap comprises a water resistant textile coated on its inner facing and outer facing sides. Alternatively, the overlap may comprise a material coated on one side, but folded double such that both external faces are coated. Both embodiments of the overlap ensure that fluid cannot wick up through a capillary action and become in contact with the mesh of the moisture vapour permeable region where it may affect the moisture vapour permeability of the invention.

Preferably, the overlap extends over the mesh of the moisture vapour permeable region and over the zipper, preferably located on the periphery of the support surface or support surface topper where there is an absence of mesh.

In a preferred embodiment, the overlap extends for between 5 and 50mm, more preferably between 20 and 40mm, and most preferably between 25 and 35mm; extending from the upper surface of the support surface or support surface topper to the lower surface of the support surface or support surface topper, thus covering the mesh and zipper.

Preferably, in a support surface, such as a mattress or cushion, the overlap extends for between 5 mm and 190 mm, more preferably between 30 mm and 150 mm, and most preferably between 60 mm and 120 mm; extending from the upper surface of the support surface to the lower surface of the support surface, thus covering the mesh and zipper.

In a preferred embodiment, the water resistant surface material has a moisture vapour permeability of between 2 and 40%, more preferably between 5 and 25%, and most preferably between 6 and 15%.

In another preferred embodiment, the air and moisture vapour permeable region has a moisture vapour permeability of between 80% and 300%, more preferably between 120% and 275%, and most preferably between 150% and 250%

Preferably, the overall moisture vapour permeability of the support surface or support surface topper is between 80 and 1000 Rwet (m2Pa/W), more preferably between 90 and 800 Rwet (m2Pa/W) and most preferably between 100-300 Rwet (m2Pa/W).

Preferably, a water vapour concentration gradient is established between the atmosphere within the support surface or support surface topper and the atmosphere surrounding the support surface or support surface topper. The moisture vapour transmission rate is driven by an establishment of a water vapour concentration gradient between the abovementioned atmospheres; the greater the water vapour concentration gradient, the greater the rate of moisture vapour transfer from the atmosphere within the support surface or support surface topper to the atmosphere surrounding the support surface or support surface topper. By continually exchanging the air within the abovementioned atmospheres, the water vapour concentration gradient is kept at a high value and maximises the moisture vapour transmission rate.

Preferably, the water vapour concentration gradient allows for an at least 0.5°C reduction in temperature of the support surface or support surface topper, more preferably 1°C - 3°C, and most preferably a 2°C - 3°C reduction in temperature of the support surface or support surface topper, for a non-fan assisted support surface or support surface topper. Typically, for a fan assisted support surface or support surface topper, the water vapour concentration gradient allows for a 6°C - 12°C, more typically a 7°C - 11°C, and most typically an 8°C - 10°C reduction in temperature of the support surface or support surface topper.

Typically, the air within the support surface or support surface topper is warmer than the air surrounding the support surface or support surface topper, predominantly due to the enclosed nature of the support surface or support surface topper and for the reason that the invention is designed for a bed and so will be beneath a patient. The exchange of air may, therefore, be an effective method of maintaining a lower and more beneficial temperature under the body of a patient. This also reduces the propensity for perspiration which also reduces the water vapour concentration at the skin interface, therefore, preventing the accumulation of bacteria and thus preventing potential infections and undesirable smells.

Preferably, especially when the support surface or support surface topper is a support surface topper, for example a mattress overlay, the support surface topper is provided with apparatus for securing it to a mattress, bed or other surface below.

The apparatus for securing the topper to a mattress, bed, or other surface below may comprise a strap attached to the cover of the topper.

Preferably, the strap includes a buckle with male and female buckle members to adjust the length of the strap.

Preferably, the support surface or support surface topper is a mattress or mattress overlay to be used on a bed.

Preferably, the support surface or support surface topper comprises a filling material. Preferably the filling material includes a spacer fabric, open cell foam or other support with an open air structure such as a gel grid

Preferably, the support surface or support surface topper comprises a base material with antislip properties.

Another aspect of the invention provides a support surface comprising the cover as set out above.

Preferably the support surface is provided with a fan, or provided with connection means for connection to a source of driven airflow, either into the assembly or withdrawing air from the assembly.

It is understood herein that a support surface includes, but is not limited to, any type of patient support, for example, any mattress, integrated bed system, mattress replacement, overlay, or seat cushion, or seat cushion overlay as defined by the National Pressure Ulcer Advisory Panel; or stretcher or recliner.

Detailed Description of the Invention hi order that the invention may be more clearly understood an embodiment thereof will now be described, by way of example only, with reference to the accompanying drawings, of which:

Figure 1 shows a perspective view of a mattress overlay, including a cover according to the invention;

Figure 2 shows a side view of the mattress overlay of figure lwith the overlap of the cover raised making the mesh visible;

Figure 3 shows a plan view of the mattress overlay of figures 1 and 2 with apparatus to affix the mattress overlay to a bed below;

Figure 4 shows a side on view of the mattress overlay of figures 1-3; and

Figure 5 shows a head end view of the mattress overlay of figures 1-4.

Referring to figures 1 to 5, a support surface in the form of a mattress overlay 1 is formed in a typical rectangular shape with an upper surface 101, a lower surface 102, a head end 5, a foot end 6 and two long sides 701, 702. There are two straps 10 with an adjustable male buckle 8 and two straps 11 with an adjustable female buckle 9; one strap 10 with male buckle 8 is connected to one side 701 near the head end 5 and one strap 11 with female buckle 9 is connected to the other side 702 near the head end 5; a second strap 10 with another male buckle 8 is connected to one side 701 near the foot end 6, and one strap 11 with female buckle 9 is connected to the other side 702 near the foot end 6 of the mattress overlay 1, enabling attachment to a bed (not shown) beneath.

The mattress overlay 1 is suitably about 840 mm x 1980 mm and about 55 mm thick. A mesh 4 is provided in a cover, in order to provide a moisture vapour permeable region. In this embodiment, the mesh is between 2700 mm and 3500 mm long and extends around the periphery of the support surface 1; the remainder of support surface periphery which does not contain mesh 4 comprises a zipper (not shown in the figures). The mesh 4 has a height of 20 mm and is positioned on the periphery of the overlay 1 between 20 mm and 40 mm from the edge of the upper surface 101.

The mesh 4 extends for an entire length of one of the long sides 701 and continues to half of the length of the head end 5 and half of the length of the foot end 6 of the mattress overlay 1, therefore, a 20 mm high mesh region extends for 420 mm of the head end, 1980 mm of one of the long sides and 420 mm of the foot end. A water resistant surface material 3 of the mattress overlay 1 covers the entire outer surface (apart from the mesh 4) of the mattress overlay 1 and includes an overlap 2 which is coated with a water resistant textile coating on both faces. The overlap 2 extends for 45 mm from the edge of the upper surface 101 in order to cover the mesh 4 of a moisture vapour permeable region and a zipper (not shown in the figures) which are positioned on the periphery of the mattress overlay 1. In this embodiment, the top surface; side surfaces and overlap of the surface material of the mattress overlay 1 is formed of Redwoods TE059 Xtreme material, the details of which are set out below: FABRIC DESCRIPTION Knitted Polyamide, coated with anti-microbial polyurethane coating COMPOSITION Polyamide / Polyurethane WEIGHT 240 g/m2 +/- 5%

WIDTH 110, 220 CM

TENSILE STRENGTH Warp> 700N, weft > 250N

TEARING STRENGTH Warp> 35 N, weft > 20N BREAKING EXTENSION Warp> 80%, weft> 170% WATER VAPOUR PERMEABILITY @ 37°C 400 g/m2/24h

Similar materials which may also be used for this purpose of the invention are available from Dartex Coatings (for example, Dartex Performance or Endurange Range), Sioen Industries, Seyntex, Uretek, Plastibert (for example, Dahlia Bi-Elastic Premium), Gentug, Cateks etc. The lower surface 102 of the mattress overlay 1 is formed from Marine Griplock TE043 material, the details of which are set out below: FABRIC DESCRIPTION Weft knitted nylon coated with flame-retardant polyurethane, which has been treated with a biocide. High grip surface. COMPOSITION Polyamide / Polyurethane WEIGHT 215 g/m2 +/- 5%

WIDTH 110,220 CM

TENSILE STRENGTH Warp> 600N, weft > 250N

TEARING STRENGTH Warp> 40 N, weft > 40 N BREAKING EXTENSION Warp> 90%, weft> 200% WATER VAPOUR PERMEABILITY @ 37°C 600 g/m2/24h

The surface material is formed with a water resistant textile coating, such as polyurethane, polyvinyl chloride or butyl rubber, which forms the outermost, external surface of the mattress overlay 1, such that its surface material exhibits substantial water resistant properties, to prevent the ingress of bodily fluids.

The dimensions of the mesh 4 and the overlap 2 allow for the overlap 2 to cover the mesh 4 in order to prevent the ingress of bodily fluids. This is assisted by the water resistant properties of the overlap 2 which is formed of a water resistant surface material, as are the top and side surfaces, preventing any bodily fluids from permeating the surface material, via a wicking action. Advantageously, the bodily fluids migrate under the force of gravity down the overlap 2 and off the mattress overlay 1, therefore, not coming in contact with the mesh 4 of the moisture vapour permeable region. This combination of features in the preferred embodiment of the invention allow for an increase in durability of water resistant and moisture vapour permeable support surfaces or support surface toppers as a high level of moisture vapour permeability can be attained from the inclusion of the mesh 4 region which is protected from detrimental fluid ingress by the overlap 2.

In this embodiment, the mesh 4 comprises a 3 mm spacer fabric filler material with an open mesh face. A suitable spacer fabric is Baltex A1301 spacer material, the details of which are set out below: QUALITY REF A1301-235

FABRIC DESCRIPTION: 6MM PES SPACER COURSES PER INCH 58 WALES PER INCH 27 COLOUR Pure

WIDTH 235 CM TENSILE STRENGTH BS EN ISO 13934-1 50KGS Warp; 46KGS Weft WEIGHT 320 GM/M2

THICKNESS BS EN ISO 5084 (BS 2544) 4.5 MM FR FINISH ISO 1021 PARTS 1 AND 2

DIMENSIONAL STABILITY 6O0C 2.5% WARP AND WEFT COMPRESSION STRENGTH 40% COMPR.,

ISO 3386-1 11KPA

Alternative, polyester meshes, e.g. ones with visible pores and for example 120 gsm, may be used.

Typically, the strap length between the mattress overlay 1 and the male buckle 8 is 1500 mm and the strap length between the mattress overlay 1 and the female buckle 9 is 150 mm. The straps 10, 11 comprise 25 mm webbing. The straps 10 are bound to a 25 mm male buckle 8 and the straps 11 are bound to a 25 mm female buckle 9.

High frequency welded seams are used throughout the mattress overlay 1. For example, to join the material of the upper surface 101 to the sides 701, 702, head end 5 and foot end 6 side portions of surface material and to join those surfaces 701, 702, head end 5 and foot end 6 to the zipper. High frequency welded seams are also used to join the lower surface material to the sides 701, 702, head end 5 and foot end 6 portions of surface material and to join those surfaces 701, 702, head end 5 and foot end 6 to the zipper.

High frequency welded seams are used to join the straps 10, 11 to the mattress overlap 2.

In use, the mattress overlay 1 of the preferred embodiment is placed on a bed (not shown in the figures) and oriented such that the foot end 6 of the mattress overlay 1 is at the base of the bed, and the head end 5 is located over the opposite end of the bed where the user is to place their head.

The mattress overlay 1 may be attached to the bed using the straps 10, 11 and buckles 8, 9 used to adjust the length of the straps 10, 11 in order to fit around the bed, typically a hospital bed, beneath the mattress overlay. A fan (not shown) is preferably then connected through an aperture in the cover (not shown) so as to provide a flow of air through the mattress overlay 1.

Examples

Tests were carried out to compare the effect of the cover including the mesh 4 with mattresses with ordinary covers, not having such a mesh 4. The conditions are set out in table 1 below.

Table 1 A human analogue was applied to each example at T1 and measurements of the interface and ambient temperatures along with relative humidity were taken over 24 hours.

The results of the temperature measurements are set out in table 2 below:

Table 2

The impact on relative humidity is set out in table 3 below

Table 3

It can be seen that the interface temperatures increased sharply after application of the human analogue at T2 and reached temperatures of between 33-37 °C for all test conditions (Table 2). Over the subsequent 24 hours the trend was of decreasing temperatures at the support surface interface, with the temperature changes over a 24 hour period ranging from 1.9 W/cm2 for the non-fan assisted comparative example 1 to 3.4 W/cm2 for the mattresses provided with the cover of the invention.

More notable still is the difference in relative humidity values at the support surface-human analogue interface. The relative humidity values increased steadily during the application of sweat, peaking near to saturation values at 79 to 100%RH for all test conditions. The support surfaces without an active fan (comparative example 1 and example 1) remained high throughout the 24 hour test, but notably, the support surface having the mesh region of example 1, only reached a maximum of 84%RH, compared to 100%RH in the comparative example.

Where the fan was active (comparative example 2 and example 2), relative humidity reduced, and the most pronounced reduction was that where the mesh regions of the invention were included (example 2), in which RH values reached 79% after simulated sweating, but over 24 hours returned to basal levels.

This shows that the covers of the invention incorporating a mesh, represent an improvement even with no fan, and a very substantial improvement, when used in conjunction with a fan to increase airflow through the mattress.

The above embodiment is described by way of example only. Many variations are possible without departing from the scope of the invention as defined in the appended claims.

Claims

1. A water resistant cover for a support surface or support surface topper, the water resistant cover formed of a textile comprising at least one elastic monolithic polymer coating, the cover further comprising an air and moisture vapour permeable mesh extending along a side of the cover.

2. A cover for a support surface or support surface topper according to claim 1, wherein in use the cover extends around a support surface or support surface topper and the mesh extends along a side of the support surface or support surface topper.

3. A cover for a support surface or support surface topper according to any preceding claim, wherein the mesh is attached to the textile comprising at least one elastic monolithic coating.

4. A cover for a support surface or support surface topper according to any preceding claim, wherein the mesh is sewn to the textile comprising at least one elastic monolithic coating, or attached thereto by high frequency, or ultrasonic welding.

5. A cover for a support surface or support surface topper according to any preceding claim, wherein the air and moisture vapour permeable mesh is situated on the periphery of the support surface or support surface topper.

6. A cover for a support surface or support surface topper according to any preceding claim, wherein the elastic monolithic polymer is one of polyurethane, polyvinyl chloride or butyl rubber.

7. A cover for a support surface or support surface topper according to any preceding claim, wherein the water resistant cover formed of a textile coating affords a water resistance of between 35kPa and 165kPa to the support surface or support surface topper.

8. A cover for a support surface or support surface topper according to any preceding claim, wherein the support surface or support surface topper comprises a head end and a foot end connected by two parallel sides.

9. A cover for a support surface or support surface topper according to claim 8, wherein the air and moisture vapour permeable region covers at least half of the length of one of the parallel sides of the support surface or support surface topper,

10. A cover for a support surface or support surface topper according to claim 9, wherein the air and moisture vapour permeable region covers at least 75% of the length of one side of the support surface or support surface topper cover.

11. A cover for a support surface or support surface topper according to claim 10, wherein the air and moisture vapour permeable region extends along substantially all of the length of one side of the support surface or support surface topper cover.

12 . A cover for a support surface or support surface topper according to any of claims 8 to 10, wherein the air and moisture vapour permeable region extends along the periphery of the support surface for part of the head end.

13. A cover for a support surface or support surface topper according to any of claims 8 to 12, wherein the air and moisture vapour permeable region extends along the foot end of the support surface or support surface topper cover.

14. A cover for a support surface or support surface topper according to any of claims 8 to 13, wherein the air and moisture vapour permeable region extends along at least half of the head end and/or foot end.

15 . A cover for a support surface or support surface topper according to any preceding claim, wherein the mesh has a pore size of between 0.5 mm and 5 mm.

16. A cover for a support surface or support surface topper according to any preceding claim, wherein a fastener in the form of a zipper exists around the periphery of the support surface or support surface topper cover where there is an absence of mesh.

17. A cover for a support surface or support surface topper according to claim 16, wherein the zipper is located on the periphery of the support surface or support surface topper cover between 15 mm and 40 mm from the edge of the upper surface of a cover for a support surface topper, and between 20 mm and 130 mm from the edge of the upper surface of a cover for a support surface.

18. A cover for a support surface or support surface topper according to any preceding claim, wherein the moisture vapour permeable region has a total surface area of between 0.025 m2 and 0.25 m2.

19. A cover for a support surface or support surface topper according to any preceding claim, wherein the mesh used may be a 3mm polyester warp knit spacer.

20. A cover for a support surface or support surface topper according to any preceding claim, wherein the mesh is covered by an overlap which extends from the edge of the upper surface of the support surface or support surface topper cover over the mesh.

21. A cover for a support surface or support surface topper according to claim 20, wherein the overlap comprises a water resistant textile coating on its inner facing and outer facing sides.

22. A cover for a support surface or support surface topper according to claim 21, wherein the overlap comprises a material coated on one side, and folded double such that both external faces are coated.

23. A cover for a support surface or support surface topper according to any of claims claim 20 to 22 when dependent directly or indirectly on claim 16, wherein the overlap extends over the opening of the mesh and over the zipper.

24. A cover for a support surface or support surface topper according to any of claims 20 to 23, wherein the overlap extends for between 5mm and 190mm

25. A cover for a support surface or support surface topper according to any preceding claim, wherein the water resistant surface material provides a moisture vapour permeability of between 2 and 40%.

26. A cover for a support surface or support surface topper according to any preceding claim, wherein the air and moisture vapour permeable region provides a moisture vapour permeability of between 80% and 300%.

27. A cover for a support surface or support surface topper according to any of the preceding claims, wherein the overall moisture vapour permeability of the support surface or support surface topper is between 80 and 1000 Rwet (m2Pa/W).

28. A cover for a support surface or support surface topper according to any preceding claim, wherein a water vapour concentration gradient is established between the atmosphere within the support surface or support surface topper and the atmosphere surrounding the support surface or support surface topper.

29. A cover for a support surface or support surface topper according to any preceding claim, wherein the water vapour concentration gradient allows for an at least 0.5°C reduction in temperature of the support surface or support surface topper.

30. A cover for a support surface or support surface topper according to any preceding claim wherein the support surface topper is a mattress or mattress overlay.

31. A support surface or support surface topper comprising a cover according to any of the preceding claims.

32. A bed comprising a support surface or support surface topper according to claim 31.

33. A cover for a support surface or support surface topper substantially as described herein with reference to the figures.