GB2549634A

GB2549634A - A mattress or mattress topper

Info

Publication number: GB2549634A
Application number: GB1709750.2A
Authority: GB
Inventors: Andrew Midgley Stephen; Mark Baron John; E L Bradshaw Bulman Sophie; Adrian Cotton Mark
Original assignee: John Cotton Group Ltd
Current assignee: John Cotton Group Ltd
Priority date: 2016-06-20
Filing date: 2017-06-19
Publication date: 2017-10-25
Anticipated expiration: 2037-06-19
Also published as: GB2549634B; GB201610705D0; GB201709750D0

Abstract

A mattress comprising a core layer 110, a quilt layer 122A, and an upholstery layer 120 between them comprising a moisture transport layer 124A and a moisture holding layer 124B where the holding layer has a greater water absorbency by weight than the transport layer and the transport layer is formed of a pleated non-woven web of fibres. Also claimed is a mattress topper without the core layer. Preferably the fibres of the holding layer are smaller and less densely packed than the fibres of the transport layer. Preferably the fibres of the non-woven web in the transport layer are in an anisotropic arrangement. In use the transport layer draws sweat away by capillary action and it is absorbed by the holding layer- it can then evaporate away when the mattress is not in use.

Description

A MATTRESS OR MATTRESS TOPPER

TECHNICAL FIELD

The present invention relates to mattresses and mattress toppers having a layered construction.

BACKGROUND

Known mattresses, in the form of a mat or pad, provide comfort and support through the use of a core between upholstery layers, which have a quilted outer covering. Mattress toppers are mat-like devices for use on mattresses, which may be configured to fit around at least the sides of the mattress.

In known mattresses, the core of the mattress provides most of the support to the sleeper’s body and is accordingly sometimes referred to as the “support layer”. Such mattress cores typically comprise a raft of steel coil springs (known as “spring interior mattresses”) a block of foam (known as “foam filled mattresses”), or a spring raft sandwiched between block foam. It is known to use shape-conforming latex foam or viscoelastic polyurethane foam (also known as “memory” foam or low-resilience polyurethane foam). Latex mattress cores generally come in two types of latex, Talalay® and Dunlop®.

The upholstery layer commonly consists of three sub-layers: a thin insulator layer, a middle upholstery layer, and an exterior quilt layer.

The insulator separates the mattress core from the middle upholstery, and may comprise a thin layer of laid fibres, mesh or foam, which is intended to keep the middle upholstery in place on the core.

The middle upholstery (also referred to as the “comfort layer”) comprises all the material between the insulator and the quilt. It is usually made from materials which are intended to provide comfort to the sleeper, including regular foam, viscoelastic foam (e.g. a polyurethane flexi-foam, also known as “memory foam”), or non-woven webs of polyester fibres and/or cotton fibres in the form of a flat or pleated sheet. However, for fire resistant applications, it is known to replace the foam middle upholstery layer with a layer of fibre wadding, prepared as a cross-laid non-woven web of fibres, in which the fibres are mostly laid generally parallel with the layer. Such cross-laid non-woven webs provide relatively little cushioning and comfort, as they quickly flatten under a load, do not conform well to the shape of the load, and struggle to recover after the load has been removed, as the fibres become matted to one another.

The quilt is the outer composite layer of the mattress, made of a quilt backing layer of light foam or fibres stitched to the underside of a protective fabric cover, known as “ticking”. The ticking encases the mattress and provides a soft surface texture to the mattress, being made of synthetic fibres like polyester, polypropylene, or acrylic; or of natural materials such as latex, cotton, viscose, silk, and wool.

When a mattress is in use, the user’s body temperature is regulated by the use of personal clothing and bedding items (e.g. typically an under-sheet between the user’s body and the mattress) in combination with the thermal performance of the mattress. During use, the user’s body releases water vapour, which affects the thermal performance of the mattress, personal clothing and bedding items. Additionally, the presence of moisture in the textiles that contact the user’s body affect the user’s level of comfort.

It is known to use porous materials in the quilt’s ticking layer, on the exterior of a mattress. Similarly, it is known to use a quilt backing layer that is porous. Accordingly, in use, some moisture can pass through to the middle upholstery. For a low level of moisture, this reduces the perception of dampness for the user, by allowing moisture to pass away from the under-sheet and personal clothing with which the user makes contact. However, the middle upholstery is only capable of absorbing low levels of moisture. Further, in known mattresses, it is undesirable for moisture to pass towards the core layer, as high density foam cores are largely impermeable to water, and spring-raft cores are substantially impermeable to the transmission of moisture by diffusion and capillary action. Additionally, in spring-raft cores, the springs are vulnerable to corrosion from water exposure.

Embodiments of the present invention seek to provide improvements to mattress upholstery layers.

SUMMARY OF THE DISCLOSURE

According to a first aspect, there is provided a mattress comprising: a core layer; a quilt layer; and a middle upholstery layer between the core layer and the quilt layer, wherein the middle upholstery layer comprises: a moisture transport layer; and a moisture holding layer between the core layer and the moisture transport layer, wherein the moisture holding layer has a greater water absorbency by weight than the transport layer, and the transport layer is formed from a pleated non-woven web of fibres (e.g. vertically-lapped).

According to a second aspect, there is provided a mattress topper comprising: a topper backing layer; a quilt layer; and a middle upholstery layer between the topper backing layer and the quilt layer, wherein the middle upholstery layer comprises: a moisture transport layer; and a moisture holding layer between the topper backing layer and the moisture transport layer, wherein the moisture holding layer has a greater water absorbency by weight than the transport layer, and wherein the transport layer is formed from a pleated non-woven web of fibres.

The water absorbency of the transport layer may be less than 40% of the weight of the transport layer. The water absorbency of the transport layer may be less than 30% of the weight of the transport layer. The water absorbency of the transport layer may be less than 20% of the weight of the transport layer.

The water absorbency of the holding layer may be more than 60% of the weight of the holding layer. The water absorbency of the holding layer may be more than 100% of the weight of the holding layer. The water absorbency of the holding layer may be more than 200% of the weight of the holding layer.

By weight, the water absorbency of the holding layer may be more than 150% of the water absorbency of the transport layer. By weight, the water absorbency of the holding layer may be more than 300% of the water absorbency of the transport layer. By weight, the water absorbency of the holding layer may be more than 1000% of the water absorbency of the transport layer.

The holding layer may comprise a greater proportion by weight of hydrophilic fibres than in the transport layer.

The transport layer may comprise no more than 50% by weight of hydrophilic fibres. The transport layer may comprise no more than 25% by weight of hydrophilic fibres. The transport layer may comprise 100% by weight of hydrophobic fibres.

The holding layer may comprise at least 50% by weight of hydrophilic fibres. The holding layer may comprise at least 90% by weight of hydrophilic fibres. The holding layer may comprise 100% by weight of hydrophilic fibres.

The median diameter of the fibres in the holding layer may be smaller than the median diameter than the fibres in the transport layer.

The holding layer may comprise fibres with a lower packing density than the fibres of the transport layer.

The transport layer may be formed from a non-woven web of fibres laid with an anisotropic arrangement of fibre orientations.

The holding layer may be formed from a web of fibres that have been laid with an isotropic arrangement of fibre orientations. The holding layer may comprise a non-pleated web of cross-laid fibres. The holding layer may comprise a web of air-laid fibres. Alternatively, the holding layer may be formed from a web or fibres laid with an anisotropic arrangement of fibre orientations.

In a mattress, the core layer is a central core layer and may be provided between a pair of the middle upholstery layers, and the middle upholstery layers and central core layer may be provided between a pair of the quilt layers. The mattress may be mirror symmetric about a plane through the middle of the core layer.

The quilt layer may comprise a ticking layer. The quilt layer may comprise a quilt backing layer of a cross-laid non-woven web of fibres stitched to the underside of a ticking layer. The ticking may be woven or knitted.

The transport layer may be a thickness of 10mm to 45mm. The holding layer may have a thickness of 10mm to 45mm. The quilt layer may be thinner than each of the moisture transport layer and the moisture holding layer. The quilt layer may a thickness of less than 8mm. The quilt layer may have a thickness of 2mm to 5mm.

DESCRIPTION OF THE DRAWINGS

Embodiments of the invention are further described hereinafter with reference to the accompanying drawings, in which: • Figure 1A is a partially cut-away view of a mattress according to the present invention; • Figure 1B is an enlarged view of part of Figure 1A; • Figure 2 is an enlarged cut-away view of a mattress topper according to the present invention; and • Figure 3 shows water evaporation results for the evaporation of water from a vessel with different coverings, as an indication of the water vapour permeability of the coverings.

DETAILED DESCRIPTION

In the described examples, like features have been identified with like numerals, albeit in some cases having one or more of: increments of integer multiples of 100. For example, in different figures, 124A and 224A have been used to indicate a moisture transport layer.

Figure 1A shows a partially cut-away view of a mattress 100, and Figure 1B shows an enlarged view of part of the mattress, corresponding with the circle indicated in Figure 1A.

The mattress 100 comprises a central core layer 110 between upholstery layers 120, in a mirror symmetric arrangement.

The illustrated mattress 100 is a foam filled mattress, and the core layer 110 is a block of high density foam, such as shape-conforming latex (e.g. Talalay® and Dunlop®) or viscoelastic memory foam. Alternatively, in the case of a spring interior mattress, the core layer may be a raft of steel coil springs, which may additionally be sandwiched between high density foam layers.

The upholstery layers 120 comprise an exterior quilt layer 122, middle upholstery 124, and may comprise an insulator layer 126 between the middle upholstery and the core 110.

The quilt layer 122 has an exterior surface provided by a ticking layer 122A, which is a protective fabric cover that also provides a soft surface texture to the mattress. The quilt layer 122 may also have a quilt backing layer 122B of a cross-laid non-woven web of fibres stitched to the underside of the ticking layer 122A. The ticking may be made from synthetic fibres, e.g. polyester (e.g. PET or PTT) or acrylic, or natural materials, e.g. cotton, latex, silk or wool. The ticking is highly porous to moisture (liquid and vapour). The ticking may be woven or knitted. The quilt layer 122 is a thin layer (e.g. thinner than each of the moisture transport layer 124A and the moisture holding layer 124B), having a thickness of less than 8mm. In the illustrated example, the quilt layer 122 has a thickness of 2-5mm.

The middle upholstery 124 comprises a moisture transport layer 124A and a moisture holding layer 124B, which is between the transport layer and the core 110.

The transport layer 124A provides moisture transport between quilt layer 122 and the holding layer 124B. The transport layer is porous and moisture transport may be by either or both of the diffusion of vapour under vapour pressure and by the wicking of liquid by capillary action, with moisture passing through gaps (interstices) between the fibres in the transport layer 124A, or across the surfaces of fibres. In the case that some of the fibres in the transport layer are hydrophilic, transport through the transport layer 124A may also be by an absorption process, in which moisture is absorbed into and travels through the hydrophilic fibres. However, the moisture absorbency of the transport layer 124A is low.

The transport layer 124A also provides cushioning and comfort to the user, resiliently deforming under the load, to support the user’s body. In the illustrated example, the transport layer 124A has a thickness of 10mm to 45mm.

In the illustrated example, the transport layer 124A is a pleated non-woven web (i.e. vertically-lapped material). The material may be reinforced by use of thermal bonding and/or needle-punching.

The holding layer 124B is highly absorbent of moisture. When the mattress is in use, moisture released by the user’s body provides a source of moisture, which is transported through the transport layer 124A and acquired in the holding layer 124B. Transporting the moisture through the transport layer 12A, away from user, reduces the moisture level of the quilt layer 122 and intervening bedding and any personal clothing between the quilt layer and the body of the user, reducing the perception of dampness to the user, enhancing the thermal regulation of the user, and so increasing the user’s comfort. When the mattress is aired, and the source of moisture provided by the user’s body is removed, the moisture gradient (e.g. vapour gradient) in the transport layer 124A is reversed, and the transport layer transports moisture back out of the holding layer 124B to the quilt layer 122, where it is released through the surface of the ticking 122A into the air circulating above. In the illustrated example, the holding layer 124B has a thickness of 10mm to 45mm.

The insulator layer 126 provides strength to the upholstery layers 120. The insulator layer 126 may be a polyester wadding (e.g. 100% polyester), which is both needled and thermally bonded. Alternatively, the insulator layer 126 may be recycled felt (e.g. made from shredded recycled clothing), thermally bonded using polypropylene, and calendered.

Foam used in the core layer 110 is a high density foam, and is impermeable to moisture. A spring-raft is formed within an airgap, which provides a barrier to the transmission of moisture by diffusion and capillary action, and the springs are vulnerable to corrosion from water exposure. Advantageously, the preferential level of moisture absorbency of the holding layer prevents or substantially reduces the transmission of moisture to the core, enabling moisture to be captured when the mattress is in use and transported to a storage layer that is spaced part from the user’s body, to maintain user comfort and thermal performance, before releasing the moisture from the mattress after use.

The holding layer 124B is substantially more absorbent of moisture than the transport layer 124A. The moisture to which the mattress is exposed in use is predominantly water, and so the relative absorbency may most conveniently be defined with respect to water absorbency. The water absorbency of the transport layer 124A, by weight, is less than 40% of the weight of the transport layer. The transport layer’s water absorbency may be less than 30% by weight of the transport layer, and may be less than 20% by weight. The water absorbency of the holding layer 124B, by weight, is more than 60% of the weight of the holding layer. The holding layer’s water absorbency may be greater than 100% by weight of the holding layer, and may be greater than 200% by weight of the holding layer.

The greater absorbency of the holding layer 124B than the transport layer 124A is provided by one or a combination of different compositional features of the layers.

The greater moisture absorbency of the holding layer may be provided by using a greater proportion by weight of hydrophilic fibres in the holding layer than in the transport layer. For the same size and arrangement of fibres, hydrophilic fibres provide greater moisture absorbency by weight than hydrophobic fibres. The transport layer may comprise solely hydrophobic fibres or a mixture of hydrophobic and hydrophilic fibres. The holding layer may comprise solely hydrophilic fibres, or a mixture of hydrophilic and hydrophobic fibres. The transport layer may comprise no more than 50% by weight of hydrophilic fibres, and may comprise no more than 25% by weight of hydrophilic fibres. The holding layer may comprise at least 75% by weight of hydrophilic fibres, and may comprise at least 90% by weight of hydrophilic fibres.

The hydrophobic fibres may be polyester, e.g. polyethylene terephthalate (PET) or polytrimethylene terephthalate (PTT). Bamboo charcoal particles may also be incorporated within the hydrophobic fibres. The hydrophilic fibres may be cellulosic materials, e.g. cotton, wool or regenerated cellulosic fibres. The regenerated cellulosic fibres may be rayon fibres, e.g. viscose, modal and lyocell (e.g. Tencel®).

Hydrophilic fibres swell when they absorb moisture, reducing the amount of free space between the fibres. In the holding layer, the swelling of the hydrophilic fibres during water absorption, and consequent reduction in the free space between the fibres, reduces the rate of moisture transmission by capillary action, reducing the transmission of moisture towards the core layer.

The greater moisture absorbency of the holding layer may be provided by forming the holding layer from fibres with a smaller diameter than the fibres in the transport layer (e.g. for comparable fibres, the holding layer may be formed from fibres with a lower denier measurement than the fibres in the transport layer). The water absorbency of a fibrous material is greater for comparable fibres with a smaller diameter (in the range of typical textiles fibres). This is because the water absorbency increases with the surface area per unit mass of the fibres, and for highly elongate fibres, the surface area per unit mass is approximately inversely proportional to the diameter of the fibre. The correlation between water absorbency of the material and the fibre diameter is greatest for hydrophobic fibres, which have very low water absorbency into the fibre, in contrast to hydrophilic fibres.

The greater moisture absorbency of the holding layer may be provided by forming the holding layer from fibres using a lower packing density (packing fraction) that in the transport layer, i.e. the fibres in the holding layer are less closely packed together than in the transport layer, so that the proportion of space between the fibres is greater. The holding layer may be formed from a web of fibres that have been laid with an isotropic arrangement of fibre orientations, e.g. the holding layer may be formed by an air-laid process. Alternatively, the holding layer may be formed from a web of fibres that have been laid with an anisotropic arrangement of fibre orientations, e.g. fibres that have been carded.

The transport layer may be formed from a non-woven web of fibres laid with an anisotropic arrangement of fibre orientations. The transport layer may be formed from fibres that have been carded (e g. combed) to provide the anisotropic arrangement of fibre orientations. The transport layer may be formed from a pleated (vertically-lapped) non-woven web of fibres with and anisotropic arrangement of fibre orientations. In the illustrated mattress 100 and mattress topper 200, the transport layers are formed from pleated (vertically-lapped_ non-woven webs of carded fibres. In the anisotropic arrangement of fibre orientations, the fibres may be laid into the web with more than 75% of the fibres of the non-woven web substantially aligned (e.g. aligned substantially perpendicular to the plane of the core layer, in a pleated web), and more than 90% may be substantially aligned.

In the illustrated example, the transport layer 124A comprises a pleated (i.e. vertically-lapped) web of carded fibres. In the transport layer 124A, the pleats are formed from a carded non-woven web of polyester fibres that is 3mm to 10mm thick before pleating (e.g. a mattress approximately 2000mm long has about 100 to 333 pleats, each pleat having the thickness of two sheets). The fibres may be 30 to 75 mm long and have a linear mass of less than 10 denier (and may be less than 5 denier). During manufacture, once pleated, the transport layer 110 is cross-needled. The pleating provides a transport layer 124A having a thickness of 10mm to 45mm, e.g. about 25mm. By means of a carding process when the fibres are laid, greater than 75%, and preferably 90% of the fibres of the non-woven web are aligned substantially perpendicular to the plane of the core layer 110.

The vertically-lapped structure of the illustrated transport layer 124A provides a high level of permeability to moisture (both liquid and vapour) in a direction from top to bottom. This means that moisture (e.g. sweat or urine) is not retained by the transport layer, especially since the polyester fibres are hydrophobic. Due to the arrangement of the fibres in the pleated transport layer 124A, when a load is provided on the mattress 100, the pleated layer supports the load in a spring-like manner, compressing vertically to accommodate the shape of the load without flattening in neighboring regions where no load is present. The pleats of the pleated layer are cross-needled to provide additional structural strength, reducing or preventing damage to the layer over life.

In the illustrated example, the holding layer 124B comprises a non-pleated web of cross-laid fibres. The fibres are 80% hydrophilic cellulosic fibres, reinforced by 20% polyester fibres. The presence of the high proportion of hydrophilic fibres provides the holding layer 124B with a moisture absorbency by weight that is considerably greater than that of the illustrated transport layer 124A.

Figure 2 shows an enlarged cut-away view of part of a mattress topper 250. The mattress topper 200 comprises a composite upholstery layer 220 corresponding with the upholstery layers 120 of the mattress 100 illustrated in Figures 1A and 1B, except with a topper backing layer 228 instead of the (optional) insulator layer 126. The exterior quilt layer 222 (comprising a ticking layer 222A and optional quilt backing layer 222B) and the middle upholstery 224 (comprising a moisture transport layer 224A and a moisture holding layer 224B) of the mattress topper 200 correspond with the exterior quilt layer 122 (comprising a ticking layer 122A and optional quilt backing layer 122B) and the middle upholstery 124 (comprising a moisture transport layer 124A and a moisture holding layer 124B) of the mattress 100 in Figures 1A and 1B. The topper backing layer 228 provides strength to the upholstery layers 220 of the mattress topper 250. The topper backing layer 228 may be a polyester wadding (e.g. 100% polyester), which is both needled and thermally bonded. Alternatively, the topper backing layer 228 may be recycled felt (e.g. made from shredded recycled clothing), thermally bonded using polypropylene, and calendered. The corresponding layers of the mattress topper have the same properties and functions as those described in relation to the mattress.

Table 1

Table 1 shows experimental results comparing the water vapour resistance and water vapour absorbency of four different materials.

The water vapour resistance was determined by measuring the evaporation of water from a dish through a covering fabric formed of the indicated fibres and orientations. Figure 3 shows experimental results comparing the evaporation of water from the dish when covered by a pleated (vertically-lapped) carded non-woven polyester fabric (labelled “PET vertically laid”), a cross-laid polyester fabric (labelled “PET crosslaid”) with corresponding fibres and an equal mass per unit area, and uncovered (labelled “Control”).

The water vapour absorbency was determined by measuring the increase in weight of a fabric formed of the indicated fibres and orientations, when stabilised in a flow of water vapour, having previously been stabilised under a control condition (control temperature and humidity) for 24 hours.

Fabrics formed with pleated carded fibres are used in the transport layer, due to their low water vapour resistance. Pleated carded polyester fibres are particularly suitable for use in the transport layer due to their low water vapour absorbency.

Fabrics formed with air-laid fibres may be used in the holding layer, due to having a high water vapour absorbency. Air-laid fibres of wool or polyester-cotton blend are particularly suitable, due to their particularly high water vapour absorbency. A mattress may comprise: a core layer; a quilt layer; and an upholstery layer between the core layer and the quilt layer, wherein the upholstery layer comprises: a moisture transport layer; and a moisture holding layer between the core layer and the moisture transport layer, wherein the moisture holding layer has a greater water absorbency by weight than the transport layer.

The figures provided herein are schematic and not to scale.

Throughout the description and claims of this specification, the words “comprise” and “contain” and variations of them mean “including but not limited to”, and they are not intended to (and do not) exclude other moieties, additives, components, integers or steps. Throughout the description and claims of this specification, the singular encompasses the plural unless the context otherwise requires. In particular, where the indefinite article is used, the specification is to be understood as contemplating plurality as well as singularity, unless the context requires otherwise.

Features, integers, characteristics, compounds, chemical moieties or groups described in conjunction with a particular aspect, embodiment or example of the invention are to be understood to be applicable to any other aspect, embodiment or example described herein unless incompatible therewith. All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive. The invention is not restricted to the details of any foregoing embodiments. The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

The reader's attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

Claims

1. A mattress comprising: a core layer; a quilt layer; and a middle upholstery layer between the core layer and the quilt layer, wherein the middle upholstery layer comprises: a moisture transport layer; and a moisture holding layer between the core layer and the moisture transport layer, wherein the moisture holding layer has a greater water absorbency by weight than the transport layer, and wherein the transport layer is formed from a pleated non-woven web of fibres.

2. A mattress topper comprising: a topper backing layer; a quilt layer; and a middle upholstery layer between the topper backing layer and the quilt layer, wherein the middle upholstery layer comprises: a moisture transport layer; and a moisture holding layer between the topper backing layer and the moisture transport layer, wherein the moisture holding layer has a greater water absorbency by weight than the transport layer, and wherein the transport layer is formed from a pleated non- woven web of fibres.

3. A mattress or mattress topper in accordance with claim 1 or claim 2, wherein the water absorbency of the transport layer is less than 40% of the weight of the transport layer.

4. A mattress or mattress topper in accordance with any one of claims 1, 2 or 3, wherein the water absorbency of the holding layer is more than 60% of the weight of the holding layer.

5. A mattress or mattress topper in accordance with any preceding claim, wherein the holding layer comprises a greater proportion by weight of hydrophilic fibres than in the transport layer.

6. A mattress or mattress topper in accordance with any preceding claim, wherein the transport layer comprises no more than 50% by weight of hydrophilic fibres.

7. A mattress or mattress topper in accordance with any preceding claim, wherein the holding layer comprises at least 50% by weight of hydrophilic fibres.

8. A mattress or mattress topper in accordance with any preceding claim, wherein the median diameter of the fibres in the holding layer is smaller than the median diameter than the fibres in the transport layer.

9. A mattress or mattress topper in accordance with any preceding claim, wherein the holding layer comprises fibres with a lower packing density than the fibres of the transport layer.

10. A mattress or mattress topper in accordance with any preceding claim, wherein the transport layer is formed from a non-woven web of fibres laid with an anisotropic arrangement of fibre orientations.

11. A mattress or mattress topper in accordance with any preceding claim, wherein the holding layer is formed from a web of fibres that have been laid with an isotropic arrangement of fibre orientations.

12. A mattress in accordance with any preceding claim, wherein the core layer is a central core layer provided between a pair of the middle upholstery layers, and the middle upholstery layers and core layer are provided between a pair of the quilt layers.