BED MATTRESS WITH ALLERGEN BARRIER

Field of the Invention

The invention relates to bed mattresses, in particular mattresses fitted with an allergen-barrier cover below an outer comfort covering, as well as to beds which includes such mattresses.

Background of the Invention

Bed mattresses are usually made of a mattress substrate fully encapsulated in an outer comfort cover. The mattress substrate has a structural core that comprises a spring arrangement, a foam body, a latex body or another similar elastic material or a combination thereof, e.g. a spring arrangement in a latex body. To improve the comfort of the mattress, one or more inner comfort layers of soft material, typically a wadding, fibrefill or padding, are applied to the structural core. Typically, the mattress substrate has a layer of ticking to enclose the structural core and the optional inner comfort layers. The outer comfort cover fully encloses the mattress substrate and usually includes several layers. This outer comfort cover is effective in creating a comfortable feeling to the user, inter-alia by controlling the air and vapour flow into the mattress. Typically, the comfort cover has an air permeability in the range of 300 to 800 l/m ² /s. Commercial outer comfort covers often have a decorative surface and are optionally removable, i.e. provided with a zipper or other closure means at one end of the cover, so it can be separately washed by the user or dry cleaned or otherwise serviced

(e.g. repaired) or replaced.

To protect the outer comfort cover against mechanical wear and dirt, in particular liquids, the user may choose to apply a mattress pad, i.e. a quilted removable layer, to cover at least part of the mattress

upper side on which the user can lie. Such pads have an air permeability below 100 l/m ² /s when they are made of a single layer and even well below 50 l/m ² /s especially when made of two or more layers. Such pads significantly inhibit air and vapour flow and reduce the comfort of the user.

It is well known that unprotected mattresses are likely to harbour allergens, in particular excrements produced by dust-mites. Dust mites have a size of 100 to 300 micron. Their excrements are key components which cause allergic reactions and have a size of the order of 10 micron. To avoid exposure of the user to such allergens, it has been proposed to protect mattresses with an allergen-barrier that prevents passage of dust- mites and their excrements as well as other allergy- causing particles.

Commercially-available allergen-barrier layers can form an impervious film (as with laminates) applied to a component of the mattress or can be tightly woven (as with 300-count cotton sheeting) or may have a pore size that is too small to permit allergen penetration (as with nonwoven) .

Typically, the allergen-barrier layer forms a cover for enclosing the entire mattress, i.e. mattress substrate and outer comfort cover. For example, US Patent 5,321,861 (Dancey/Dancey) discloses a removable allergen- barrier cover that has a pore size of less than 0.5 micron and that is fitted around the entire mattress. It is made of sheets of air and moisture permeable microperforated ultrafilter material sealed along their edges by glueing, heat sealing or high frequency welding. One end of the allergen-barrier cover has an opening for inserting the mattress which opening is closed by a zip- fastener and sealed by a strip of adhesive tape.

US Patent 6,174,584 (Keller/Maderek) discloses a mattress' washable outer comfort cover made of an outer textile layer, an inner textile layer and a batting

therebetween which are joined together at least pointwise by threads. An allergen-barrier layer is laminated onto the inner textile layer after the latter is joined to the outer layer and batting.

US Patent 6,277,770 (Smith/Duckett ) discloses an allergen-barrier layer made of a fabric of a woven natural and/or synthetic filament and/or spun yearns, the fabric having a mean pore size of 4 to 10 microns. The allergen-barrier layer can take the form of a mattress ticking, pad, or removable outer cover. In US Publication 2005/0034243 (Carlitz) allergen impermeable barrier layers are permanently attached to the interior sides of a non-removable outer cover that encloses a mattress substrate. The impermeable barrier layers cover all interior sides of the non-removable outer cover and are joined to one another along their periphery by sewing, taping or relative fusion so as to permanently seal the mattress substrate and make it impermeable to allergens.

US Patent 5,050,256 (Woodcock) discloses a permeable mite barrier having a pore size of less than 10 microns. The mite barrier can be used as a removable mattress outermost cover or as a ticking or as an enclosure within the mattress. For example, the entire mattress can be covered with a mite barrier that has peripheral portions which are seamed together to form a cover. This cover has an opening for inserting the mattress which is closed by a sliding fastener. Alternatively, the mite barrier can be used to form the mattress' ticking which is fully enclosed within the mattress' removable outer cover.

While the foregoing references indicate continued efforts to improve mattresses that are protected with an allergen-barrier, none suggests the following invention.

Summary of the Invention

A preferred object of the invention is to provide a high comfort mattress at a reduced cost which includes an allergen-barrier layer.

Another preferred object of the invention is to provide a high comfort mattress including an allergen- barrier layer and a washable outer comfort material.

The invention relates to a mattress having a mattress substrate and a removable outer comfort covering. The mattress substrate comprises: a structural core; and an allergen-barrier cover that fully encloses the structural core so that allergens are prevented from penetrating into the mattress substrate or escaping therefrom. The outer comfort covering comprises an outermost textile layer and a filler layer mechanically secured to the outermost textile layer. The outer comfort covering is air and vapour pervious and has in particular an air permeability of at least 200 l/m ² /s. The mattress substrate has an outer surface and a use position in which this outer surface has a top face, a bottom face and a lateral face that extends from the top face to the bottom face around the entire mattress substrate. The outer comfort covering is applied to this outer surface so that the filler layer faces this outer surface.

In the context of this invention, the air permeability expressed in litre per square meter and second [l/m ² /s] refers to the EN ISO 9237 standard for static measuring of a material's air permeability.

As mentioned above, optional multilayer mattress pads placed loosely, usually by the user, onto a mattress to protect the mattress and in particular the mattress' outer comfort layer against mechanical wear and dirt, such as spilled liquids, have a very poor air permeability, i.e. a permeability well below 50 l/m ² /s and significantly reduce the comfort of the user. In contrast, to improve the user's comfort by permitting air and vapour evacuation through the mattress, the multilayer outer comfort covering of the mattress has a high air (and vapour) permeability. This air permeability exceeds 200 l/m ² /s. The permeability of the outer comfort covering is typically of at least 350 l/m ² /s, in

particular at least 500 l/m ² /s, such as in the range of 600 to 1200 or 1500 l/m ² /s. Typically the thickness of the outer comfort covering is in the range of 3 to 50 mm, in particular 5 to 30 mm, such as 7 to 20 mm.

According to the invention, the outer comfort covering of the mattress extends over a limited portion of the outer surface of the mattress substrate so that the entire top face of the substrate is covered by the outer comfort covering and at least part of the substrate's lateral face and/or bottom face is/are uncovered by the outer comfort covering.

Hence, unlike prior art mattresses, the mattress according to the present invention has an outer comfort covering that does not fully enclose the mattress substrate but at least its upper face on which the user lies. The portions the mattress that are not covered or only partly covered by the outer comfort covering, in particular the lower part and possibly the lateral parts which are less exposed to wear than the upper part, are nevertheless confined and sufficiently protected by the allergen-barrier cover located all over the mattress substrate. Thus, the allergen-barrier cover which completely envelopes the mattress substrate, permits the use of the invention' s removable outer comfort covering that only covers a limited part of the mattress substrate. It follows that the mattress according to the present invention on the one hand provides a user comfort and wear resistance that is equivalent or better than prior art mattresses having an allergen-barrier layer, and on the other hand requires less material for its manufacturing which leads to significant cost savings. In particular, the outer comfort covering of the invention requires typically 10 or 20 to 50 or 60% less material compared to known outer comfort layers that fully enclose prior art mattresses.

For instance, the substrate's lateral face and the bottom face are uncovered by the outer comfort covering.

In this case up to 60% of the material necessary for making the outer comfort covering can be saved without reducing the user's comfort when he lies on the mattress.

For aesthetic reasons or to provide a supplementary protection to the mattress or to add supplementary contact surface between the outer comfort covering and the mattress substrate (with the view of improving the attachment therebetween and the stability of the system) , the upper part of the mattress substrate' s lateral face can be covered by the outer comfort covering, a lower part of the lateral face and the substrate' s bottom face being uncovered by the outer comfort covering. Moreover, the substrate' s entire lateral face can be covered by the outer comfort covering, the bottom face being uncovered by the outer comfort covering. It is also possible that the substrate' s lateral face and a peripheral portion of the bottom face are covered by the outer comfort covering, a central portion of the bottom face being uncovered by the outer comfort covering.

To secure the outer comfort covering onto the mattress substrate, such covering can have an elastic peripheral portion which extends on the substrate' s bottom face and/or on the lateral face. For the same purpose, the outer comfort covering may comprise one or more straps extending around the mattress substrate.

The outer comfort layer can be secured to the mattress substrate by one or more buttons and/or a zipper. However, when the outer comfort layer is mechanically secured to the allergen-barrier cover, for example by buttons or a zipper, any attachment means noticeably altering the functional integrity of the allergen-barrier should be avoided, bearing in mind that during use, movements of the user on the mattress may induce a mechanical stress between the outer comfort covering and the allergen-barrier cover, especially about their mechanical connection. Such mechanical stress may

reduce the imperviousness to allergens of the allergen- barrier cover.

The outermost textile layer of the outer comfort covering can comprise a fabric and/or cloth, in particular a single or double woven layer, such as a jersey cloth or another suitable cloth or fabric known in the art. The filler layer may include woven fibres and/or unwoven fibres. The filler layer of the outer comfort covering may comprise a foam layer alone or in combination with a fibre material. The filler layer can be joined to the outermost textile layer by at least one of seams, gluing, taping and welding.

The outermost textile layer and/or the filler layer comprises a natural fibre material and/or synthetic fibre material, in particular at least one of wool, cotton, nylon and silk.

To improve the user's comfort, the outer comfort covering may advantageously include a temperature regulating layer or climate layer. For instance, such a layer contains a wax material with an adjusted melting point, typically in the range of 25 to 40 ⁰ C, so that when the temperature reaches this melting point, the heat emitted by the user is absorbed by the melting wax which inhibits temperature increase beyond this point.

To reduce the risk of accidentally soiling the allergen-barrier layer, the outer comfort covering can comprise a layer which is substantially impervious to liquids, in particular aqueous liquids.

Preferably, the outer comfort covering is washable so that it can be washed by the user himself. However, it is also possible to make the outer comfort covering of materials that require dry cleaning.

Usually, the allergen-barrier cover is made of one or more sections of cloth and/or fabric having peripheral portions that are secured to one another to form an

enclosure containing the structural core. Typically, these peripheral portions are secured to one another by at least one of a seam, gluing, taping and welding.

In one embodiment of the invention, the allergen- barrier cover on the structural core is non removable. Making the allergen-barrier cover non removable avoids any problems related to allergen-pervious closure systems or to wrongful handling by the user. The allergen-barrier cover can have an inner surface that is bonded to the core and/or an intermediate layer on the structural core by at least one of seams, gluing, taping and welding. However, it has been observed that the mechanical bonding between the surfaces of the allergen-barrier layer and the inner part of the substrate is neither necessary nor particularly desirable. On the contrary, mechanically securing the inner surfaces of the allergen-barrier layer to the inner part of the mattress substrate induces the risk that during use tangential mechanical stress in the allergen-barrier layer (caused by movements of the user on the mattress) reduces the imperviousness of the allergen-barrier cover. Therefore, the inner surfaces of the allergen-barrier layer can be loose on the inner part of the mattress substrate. In this latter case, the allergen-barrier layer is preferably shaped so that it properly matches the geometry of the inner part of the mattress substrate to avoid unwanted relative displacements of the allergen-barrier layer. The allergen-barrier cover can be a ticking on the core.

In another embodiment of the invention, the allergen-barrier cover is a removable cover that has an opening for inserting the structural core, the opening being associated with a means for closing the opening, in particular a closely meshing sliding fastener. In this case, the allergen-barrier layer is preferably washable by the user himself. However, it is also possible to make the allergen-barrier layer of materials that require dry cleaning. As above, the allergen-barrier layer is

preferably shaped so that it properly matches the geometry of the inner part of the mattress substrate

Usually, the allergen-barrier layer comprises at least one of a laminated allergen-impervious film, a tightly woven sheet and a tight no woven fabric.

Preferably, the allergen-barrier layer is impervious to particles that have a particle size greater than 10 or 7 micron, in particular greater than 7 or 5 micron. The allergen-barrier layer can have an air permeability of at least 20 l/m ² /s, in particular in the range of 30 to 40 l/m ² /s.

The structural core may comprise at least one of a spring arrangement, a foam body and a latex body, and/or another suitable material or structure known in the art.

Usually, to increase the user's comfort, the mattress substrate includes an inner comfort layer between the structural core and the allergen-barrier cover extending at least under the entire top face of the mattress substrate. In order to save materials, it is not necessary to completely envelope the core within the inner comfort layer; it is sufficient that the inner comfort layer extends only under top face without significantly reducing the mattress' comfort. However, it is also possible to provide an inner comfort layer that extends under at least part of the substrate' s lateral face and/or bottom face.

The inner comfort layer may comprise a natural fibre material and/or synthetic fibre material, in particular at least one of wool, cotton, nylon and silk and/or another suitable material known in the art.

Another aspect of the invention is to provide a bed comprising a mattress as described above. The outer comfort covering of the mattress can be protected with a mattress pad against mechanical wear and dirt as discussed above.

Brief Description of the Drawings

The invention will be further described with reference to the accompanying schematic drawings, in which:

- Figure 1 is a schematic perspective view from above of a mattress of the invention; and

Figure 2 is a schematic perspective of the bottom part of the mattress of Figure 1.

Detailed Description

Figs 1 and 2 schematically show a generally parallelepipedic mattress 10 according to the invention having a mattress substrate 20 and a removable outer comfort covering 30. The mattress substrate 20 has a structural core 21, an allergen-barrier cover 22 that fully encloses the structural core 21 and thereinbetween an intermediate comfort layer 23.

The allergen-barrier cover 22 is made of PURACELL® by KIRCHOFF®, i.e. tightly woven microfibres. Cover 22 is totally impervious to particles that have a diameter of at least 5 micron and prevents diffusion of 99.7% of particles that have a diameter in the range of 3 to 5 micron. This allergen-barrier is perfectly suitable to avoid passage of the usual allergy causing particles and offers the advantage of being relatively soft (in comparison with other known allergen-barriers) and thus provides comfort to the user. However, in a variation, other known allergen-barrier materials can be used instead of PURACELL®. In particular, for special applications, for example in the medical field, it may be desirable to use an allergen-barrier cover that prevents passage of even smaller particles, for example covers with laminates as known in the art.

As opposed to prior art allergen-barrier covers that enclose the entire mattress, the mattress 10 of the

present invention has an allergen-barrier barrier cover 20 included within mattress 10 below the mattress' removable outer comfort covering 30. Thus the usual higher rigidity of the allergen-barrier cover 20 and its reduced air and vapour permeability does not provide discomfort to the user since softness, air and vapour permeability is mainly provided by the removable outer comfort covering 30.

The outer comfort covering 30 is a multilayer covering that comprises an outermost textile layer, an innermost textile layer and thereinbetween a filler layer. The outer comfort covering 30 is air and vapour pervious and has an air permeability of the order of 650

The mattress substrate 20 has an outer surface 25 including a top face 26, a bottom face 27 and a lateral face 28 that extends from top face 26 to the bottom face 27 around the entire mattress substrate 20.

As shown in greater details in Fig. 2, the outer comfort covering 30 extends over a limited portion of the outer surface 25 of the mattress substrate 20 so that the entire top and lateral faces 26,28 and a part of bottom face 27 are covered by the outer comfort covering 30, a central part 29 of bottom face 27 remaining uncovered by the outer comfort covering 30.

The removable outer cover 30 has an elastic peripheral portion 31 on bottom face 27 to secure outer cover 30 onto mattress substrate 20.

While the invention has been described in conjunction with specific embodiments thereof, it is evident that alternatives, modifications, and variations will be apparent to those skilled in the art without departing from the spirit of the invention. Thus, the scope of the present invention should be considered in terms of the following claims, and is understood not to be limited to the details described in the specification.