MATTRESS FOR IMPROVED SLEEP AND METHODS OF USE THEREOF
Mattresses and mattress toppers having an upper layer including a high heat capacity material are disclosed. The mattress is configured to reduce a core body temperature of the body supported thereon, and thus induce improved sleep, measurable as an increase in the time spent in slow wave sleep relative to standard mattresses having lower heat capacities. The high heat capacity of the mattress may be attributable to the geometry and nature of the support material and optional additives, including polymer gels and phase change materials. Methods for improving sleep quality and uses of the high heat capacity mattresses to improve sleep quality are also disclosed.
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This invention pertains generally to mattresses designed for improved sleep, and more specifically to high heat capacity mattresses configured to reduce a core body temperature of a user thereof.
BACKGROUNDA comfortable environment positively influences a person's sleep quality. Factors favoring initiation and maintenance of human sleep are darkness, a quiet setting, a horizontal body position, a familiar environment, and a comfortable ambient temperature.
Humans have two thermal zones to regulate, their core body temperature (CBT) and their shell temperature (ST). The CBT includes the temperature of the abdominal, thoracic, and cranial cavities, which contain the vital organs, and is regulated by the brain. The ST includes the temperature of the skin, subcutaneous tissues, and muscles, and is more affected by external temperature. The core is able to conserve or release heat through the shell.
A person's sleep pattern is closely related to the circadian rhythm of the CBT, which results from the relationship between heat production and heat loss. Sleep onset usually coincides with the maximal rate of decline of the CBT initiated by increased skin blood flow, skin warming, and body heat loss. These processes are controlled by the hypothalamus of the brain, which regulates the body temperature between 36° C. and 38° C. and involve increasing the blood distribution from the core of the body to the skin, thereby reducing the CBT in the first half of the sleep time and increasing the ST.
Cooling of the shell, i.e., reducing the ST, relies on conductive, convective, evaporative, and/or radiant heat loss. Conductive transfer of heat occurs when solids transfer heat by direct contact, such as a person's body contact with a cooled surface (e.g., a mattress). Convective transfer of heat occurs when the air near a person's skin absorbs body heat, and movement of that air pulls the warmed air away from the body. If there is not enough cool air, or a cool contact surface, the body will generate sweat to evaporatively cool the body. This is the case for standard mattresses where there is little air next to the skin for convective cooling, or to evaporate sweat. Thus, while initial contact with the cooler mattress surface may conductively cool the skin, and reduce the ST, over a very short period of time the mattress begins to act as an insulator, holding the warm air within the region close to the person's skin.
One solution is rolling over to expose the skin to fresh air, and thus achieve cooling. Rolling to cool hot areas during sleep obviously disrupts deep sleep and may prevent further sleep. Prior art solutions to this problem include lowering the surface temperature of the mattress, such as through a cooling system that provides a flow of air and/or a coolant liquid. While this works initially to remove heat from the body, such a solution eventually forces the body to stop or reduce the heat loss by increasing or maintaining the CBT, putting stress on the body and impairing quality sleep. Moreover, such solutions require a power source to drive movement of the air or coolant and may therefore produce noise that affects the sleep quality.
Other prior art solutions include foam mattresses or mattress toppers, wherein the open cellular structure of the foam may allow air flow, and thus movement of the warmer air near a user's skin to provide a cooling effect. Such foams are not very supportive, however, having low compressive strengths. Higher density, closed cell foams (e.g., memory foams), which are more supportive and are popular in the market, tend to be very dense and have low thermal conductivity. As such, these foams tend to absorb and retain heat.
Accordingly, there exists a need in the art for improved mattresses and/or mattress toppers which may aid in lowering a person's CBT during sleep so that they may attain a better quality and/or duration of sleep.
SUMMARYThe presently disclosed invention overcomes many of the shortcomings of the prior art by providing mattresses or mattress toppers which include an upper layer comprising a high heat capacity material. The mattress or mattress topper may be configured to reduce a core body temperature of a body supported thereon. Reduction in the core body temperature, such as by at least 0.1° C., or at least 0.2° C., leads to an increase in the time spent in slow wave sleep (SWS), such as by at least 5%, or at least 10%, or even at least 15%, with respect to a standard mattress or mattress topper (standard mattress comprises an average surface heat capacity of 15 kJ/° C.·m2 or less for an upper layer of 10 cm).
According to its major aspects and briefly stated, the present invention provides a mattress or mattress topper for supporting a body thereon, the mattress or mattress topper comprising an upper layer having an average surface heat capacity of at least 20 kJ/° C.·m2, such as at least 23 kJ/° C.·m2, or at least 26 kJ/° C.·m2, or at least 29 kJ/° C.·m2, or at least 32 kJ/° C.·m2, for the temperature range of 21° C. to 35° C. and calculated for a thickness of 10 cm, and a base layer disposed below the upper layer, wherein the mattress is configured to reduce a core body temperature of the body supported thereon.
The upper layer may have a thickness of 20 cm or less, such as 10 cm or less. The upper layer may have a density of at least 100 kg/m3, such as at least 500 kg/m3, or at least 900 kg/m3, or at least 1,100 kg/m3.
The upper layer may comprise a support material and/or a phase change material. The support material may comprise a gel, a gel infused foam material, a foam material, or a combination thereof. An exemplary gel includes a polyurethane gel. The phase change materials may have a phase transition temperature of between 18° C. to 40° C., such as between 21° C. to 35° C. Exemplary phase change materials include paraffins, esters of fatty acids, encapsulated paraffins, encapsulated esters of fatty acids, hydrated salts, encapsulated hydrated salts, crystalline alkanes, encapsulated crystalline alkanes, or combinations thereof.
The phase change material may be finely dispersed in at least a portion of the support material. The phase change material may be micro-encapsulated within a region of the support material, macro-encapsulated within a region of the support material, or a combination thereof. The phase change material may be coated on a surface of the support material and/or a surface of a textile layer of the mattress or mattress topper, wherein the surface is an outer surface, an inner surface, or a combination thereof. The phase change material may be incorporated within a textile layer of the mattress or mattress topper, such as a finishing on the textile or components of the textile (e.g., yarn or thread).
The upper layer of the mattress or mattress topper may further comprise a top layer having a thickness of 1 to 3 cm. The top layer may be positioned in an uppermost region of the upper layer, i.e., closest to the top surface of the mattress which may come into contact with a user thereof.
The top layer may have an average surface heat capacity of at least 14 kJ/° C.·m2, such as at least 16 kJ/° C.·m2, or at least 18 kJ/° C.·m2, or at least 22 kJ/° C.·m2, or at least 26 kJ/° C.·m2 for the temperature range of 21° C. to 35° C. and calculated for a thickness of 1.5 cm. The top layer may have a specific heat capacity of at least 2.0 kJ/kg·° C., such as at least 2.5 kJ/kg·° C., or even at least 3.0 kJ/kg·° C., for the temperature range of 21° C. to 35° C.
The top layer may comprise a support material and/or a phase change material. The support material may comprise a gel, a gel infused foam material, a foam material, or a combination thereof. The top layer may comprise 0% to 65% of a foam material, 0% to 100% of a gel material, such as a polyurethane gel, and 0% to 100% of a phase change material, based on the total area of the top layer. For example, the top layer may comprise 25% of a foam material, 75% of a gel material; or the top layer may comprise 100% of a PCM, based on the total area of the top layer.
The top layer may comprise 0 wt. % to 20 wt. % of a foam material, 55 wt. % to 100 wt. % of a gel material, and 0 wt. % to 25 wt. % of a phase change material, based on the total weight of the top layer. For example, the top layer may comprise 2 wt. % to 4 wt. % of a foam material and 96 wt. % to 98 wt. % of a gel material; or the top layer may comprise 15 wt. % of a phase change material and 85 wt. % of a gel material, based on the total weight of the top layer.
The top layer may comprise a plurality of towers that rise from a planar surface of a top surface of the top layer in a direction perpendicular to the planar surface.
The top layer may comprise a length that is less than a length of the upper layer, wherein the dimensions of the upper layer general match those of the mattress (e.g., the upper layer comprises a length and a width that define the dimensions of the mattress). The length of the top layer may be 75% or less, such as 65% or less, or 55% or less, or 45% or less, or even 35% or less, than the length of the upper layer. Moreover, the top layer may not extend to a top edge or a bottom edge of the upper layer. For example, the top layer may be positioned at a region of the upper layer corresponding to a position of a torso of a body supported on the mattress, or may be positioned at a region of the upper layer that corresponds to a position of at lumbar shoulder zone of a body supported on the mattress.
A surface temperature of a region of the mattress on which a body is supported may be at least 1° C. lower, such as at least 1.2° C. lower, or at least 1.4° C. lower, or at least 1.6° C. lower, or at least 1.8° C. lower, or at least 2.0° C. lower, or at least 2.5° C. lower, or at least 3.0° C. lower, or at least 3.5° C. lower, or at least 4.0° C. lower, or at least 5.0° C. lower, than a surface temperature of the region on a standard mattress (surface temperature difference; standard mattress comprises an average surface heat capacity of 15 kJ/° C.·m2 or less for an upper layer of 10 cm).
The surface temperature difference for the inventive mattresses disclosed herein relative to a standard mattress may vary with time during a sleep cycle, such that at 1 hour of sleep time, the surface temperature difference may be as much as 1° C., or even 2° C., lower than a surface temperature of the same region on a standard mattress; at 2 hours of sleep time, the surface temperature difference may be as much as 5° C. lower than a surface temperature of the same region on a standard mattress; at 4 hours of sleep time, the surface temperature difference may be about 3.5° C. lower than that of a standard mattress; and at 6 hours of sleep time, the surface temperature difference may be about 2.0° C. to 2.5° C. lower than that of a standard mattress.
The final difference in surface temperature after a 7 hour sleep cycle may be at least 1° C. lower, such as at least 1.2° C. lower, or at least 1.4° C. lower, or at least 1.6° C. lower, or at least 1.8° C. lower, or at least 2.0° C. lower than a surface temperature of the same region on a standard mattress.
The base layer of the mattress or mattress topper may comprise textiles, 3D spacer fabrics, foam materials, gel materials, pocket coils or springs, organic materials, or a combination thereof.
The presently disclosed invention further provides methods for improving sleep using the mattresses or mattress toppers described herein, and uses of a high heat capacity mattress or mattress topper as described herein for sleep improvement.
Aspects, features, benefits and advantages of the embodiments herein will be apparent with regard to the following description, appended claims, and accompanying drawings. In the following figures, like numerals represent like features in the various views. It is to be noted that features and components in these drawings, illustrating the views of embodiments of the presently disclosed invention, unless stated to be otherwise, are not necessarily drawn to scale.
In the following description, the present invention is set forth in the context of various alternative embodiments and implementations involving a high heat capacity mattress or mattress topper configured to reduce a core body temperature of a user thereof. While the following description discloses numerous exemplary embodiments, the scope of the present patent application is not limited to the disclosed embodiments, but also encompasses combinations of the disclosed embodiments, as well as modifications to the disclosed embodiments.
Various aspects of the high heat capacity mattress or mattress topper may be illustrated by describing components that are coupled, attached, and/or joined together. As used herein, the terms “coupled”, “attached”, and/or “joined” are interchangeably used to indicate either a direct connection between two components or, where appropriate, an indirect connection to one another through intervening or intermediate components. In contrast, when a component is referred to as being “directly coupled”, “directly attached”, and/or “directly joined” to another component, there are no intervening elements shown in said examples.
Various aspects of the high heat capacity mattress or mattress topper may be described and illustrated with reference to one or more exemplary implementations. As used herein, the term “exemplary” means “serving as an example, instance, or illustration,” and should not necessarily be construed as preferred or advantageous over other variations of the devices, systems, or methods disclosed herein. “Optional” or “optionally” means that the subsequently described event or circumstance may or may not occur, and that the description includes instances where the event occurs and instances where it does not. In addition, the word “comprising” as used herein means “including, but not limited to”.
Relative terms such as “lower” or “bottom” and “upper” or “top” may be used herein to describe one element's relationship to another element illustrated in the drawings. It will be understood that relative terms are intended to encompass different orientations of aspects of the high heat capacity mattress or mattress topper in addition to the orientation depicted in the drawings. By way of example, if aspects of the high heat capacity mattress or mattress topper in the drawings are turned over, elements described as being on the “bottom” side of the other elements would then be oriented on the “top” side of the other elements as shown in the relevant drawing. The term “bottom” can therefore encompass both an orientation of “bottom” and “top” depending on the particular orientation of the drawing.
It must also be noted that as used herein and in the appended claims, the singular forms “a”, “an”, and “the” include the plural reference unless the context clearly dictates otherwise. For example, although reference is made to “a” phase change material, “a” support material, “an” upper layer, “a” top layer, and “the” base layer, one or more of any of these components and/or any other components described herein can be used.
Moreover, other than in any operating examples, or where otherwise indicated, all numbers expressing, for example, quantities of ingredients used in the specification and claims are to be understood as being modified in all instances by the term “about”. Accordingly, unless indicated to the contrary, the numerical parameters set forth in the following specification and appended claims are approximations that may vary depending upon the desired properties to be obtained by the present invention. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques.
Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. Any numerical value, however, inherently contains certain errors necessarily resulting from the standard variation found in their respective testing measurements.
Unless defined otherwise, all technical and scientific terms used herein have the same meanings as commonly understood by one of ordinary skill in the art.
The present invention provides a high heat capacity mattress or mattress topper configured to reduce a core body temperature of a user thereof. The terms “mattress” and “mattress topper” may be used interchangeably through the remainder of this disclosure and in the appended claims. Thus, specific reference to a mattress may also include reference to a mattress topper, unless specifically indicated otherwise.
The mattress of the present invention may comprise an upper layer having a high heat capacity. As used herein, the term “upper layer” refers to one or more layers of a mattress which are located in an upper or uppermost region of the mattress, proximate to or forming the support surface of the mattress on which a body may recline. The upper layer may be supported by one or more base layers which in total constitute the mattress.
The upper layer may be directly attached to, and supported by, the base layer. Alternatively, the upper layer may form a separate, or separable, layer which may be attachable to the base layer, or may simply reside on the base layer.
The upper layer may comprise one or more support layers, wherein each layer may comprise a support material and/or a phase change material. The high heat capacity of the mattress may be due to either or both of the support material(s) and the phase change material(s) in the one or more support layers.
Support materials of the present invention may comprise one or more of the following: foam materials, gel materials, synthetic fibers, springs, textiles, organic materials (e.g., wood, wool, horse hair, and fibers), metal materials, and plastic materials. An exemplary support material of the present invention includes foam materials, such as foams produced using polyurethane, ethyl-vinyl-acetate, latex, rubber, neoprene, or polyethylene polymers.
Another exemplary support material of the present invention includes gel materials. The gel may comprise any gel that is stable, non-toxic, and generally known to provide a cushioning effect while maintaining a degree of structural stability and support. Exemplary gels include polyurethane gels, silicone gels, and soft TPE (thermoplastic elastomers).
Polyurethane gels are generally produced using raw materials having an isocyanate functionality and a hydroxyl functionality from a polyol. The gel structure comes about due to suitable choice of the functionalities and molecular weights of the starting components. In addition to these components, polyurethane gels used in the present invention may contain admixtures and additives which are conventional in polyurethane chemistry, such as catalysts for the reaction between isocyanate and hydroxyl groups, fillers, rheology modifiers, emulsifiers, flame retardants, stabilizers, blowing agents, etc.
An exemplary polyurethane gel may be prepared using raw materials having an isocyanate functionality and a hydroxyl functionality, such as from a polyol, wherein the product of the functionalities of the polyol and isocyanate is at least 5.2. The polyol component for producing the gel may include a mixture of one or more first polyols having hydroxyl numbers below 112, and one or more second polyols having hydroxyl numbers in the range 112 to 600, wherein the weight ratio of the first polyols to the second polyols lies between 90:10 and 10:90, the isocyanate characteristic of the reaction mixture lies in the range from 15 to 59.81, and the product of isocyanate functionality and functionality of the polyol component is at least 6.15.
In another exemplary polyurethane gel, the polyol component may comprise one or more polyols having a molecular weight between 1,000 and 12,000 and an OH number between 20 and 112, wherein the product of the functionalities of the polyurethane-forming components is at least 5.2, and the isocyanate characteristic lies between 15 and 60. The isocyanate component may comprise isocyanates of the formula Q(NCO)n, wherein n represents 2 to 4 and Q is an aliphatic hydrocarbon radical having 8 to 18 carbon atoms, a cycloaliphatic hydrocarbon radical having 4 to 15 carbon atoms, an aromatic hydrocarbon radical having 6 to 15 carbon atoms or an araliphatic hydrocarbon radical having 8 to 15 carbon atoms. The isocyanates may be used in pure form or in a conventional isocyanate modification, such as for example urethanisation, allophanatisation or biuretisation, as is known to one of skill in the field.
Examples of polyurethane gels capable of use according to the invention are disclosed in United States Published Patent Application Nos. 2004/0058163, 2004/0102573, 2004/0234726, 2007/0061978, and 2013/0000045, which are incorporated herein by reference.
The gels of the present invention may generally be good conductors of heat compared to prior art foams. For example, a polyurethane gel can have thermal conductivities of 0.10 W·m−1·K−1 or greater, whereas flexible polyurethane foams generally have thermal conductivities of 0.04 W·m−1·K−1 or less and rigid polyurethane foams generally have thermal conductivities of about 0.02 W·m−1·K−1. Polyurethane gels also typically have a greater density than foam. For example, polyurethane gel can have a density in the range of 500 Kg/m3 to 1,100 Kg/m3, while expanded polyurethane foams generally have densities in the range of from 30 Kg/m3 to 85 Kg/m3. Further, polyurethane gels commonly have a high total thermal capacity. This combination of increased ability to transport heat through the material, higher material mass per unit area, and high amount of energy needed to increase the material temperature may provide a significant contribution to the exchange of heat from the user to the gel over time. The heat exchange capacity of the gels used in the upper layer according to the invention may therefore contribute to the reduction in the user's CBT.
Thus, according to certain aspects of the present invention, the upper layer may comprise one or more support layers comprising a support material, wherein the support material may include a polyurethane gel. According to certain aspects of the present invention, one or more of the layers of the upper layer may include up to 100 wt. % of the polyurethane gel.
One or more of the layers of the upper layer of the mattress of the present invention may further comprise a phase change material. Phase change materials (PCM) absorb and store large quantities of heat from the surroundings during a phase change from the solid to the liquid physical state (e.g., melting) or during a solid-solid structural rearrangement (e.g., change in crystalline structure from one lattice configuration to another). These materials have the ability to change their physical state within a certain temperature range.
During a heating process, the PCM undergoes a phase transition (e.g., from the solid to the liquid state) on reaching the melting temperature, wherein the PCM absorbs and stores considerable latent heat. During a subsequent cooling process, the stored heat is released again from the PCM to the surroundings and the reverse phase transition occurs (e.g., from the liquid to the solid state, and/or crystallization or change in lattice structure). The temperature of the PCM remains virtually constant during the entire process, from melting to crystallization.
The transition of ice to water may be used to provide a better understanding of the amount of latent heat absorbed by a PCM during the phase transition. When ice melts, it absorbs a latent heat of 335 J/g. When the water is further heated, it absorbs a specific heat of only 4 J/g during a temperature increase of 1° C. The absorption of latent heat during the phase transition from ice to water is therefore almost 100 times greater than the absorption of specific heat during the normal heating process outside the phase transition range.
Many naturally occurring and synthetic PCM are available, each of which provide a phase change at a very specific temperature. For example, paraffins having from 16 to 21 carbon atoms melt at temperatures ranging from 16.7° C. to 40.2° C., and have latent heats of 200 J/g or greater. Specific selection of the one or more PCM used in the present invention may depend on any of the melt (phase change) temperature, latent heat, and compatibility with the support material.
Exemplary PCM include those having melting points or phase transitions at temperatures that are close to the average human body temperature. Thus, exemplary PCM are those having melting or phase transitions between 18° C. and 40° C., such as between 21° C. and 35° C. Furthermore, useful PCM include those materials that may be integrated with the support material. Exemplary PCM include at least paraffins, esters of fatty acids, hydrated salts, crystalline alkanes, or any combination thereof. Specific exemplary PCM are listed in Table I.
The PCM may be encapsulated and/or may be included in the raw form as a fine dispersion in the support material. For example, when the support material is a foam or gel, the PCM may be included in an encapsulated state or may be included as a liquid or powder, and these materials may be added to the starting materials used to produce the foam or gel. In examples where the foam or gel is a polyurethane, the PCM, encapsulated or not, may be included with the isocyanate and polyol reactants which form the polyurethane. As such, the PCM may become permanently integrated into the solid polyurethane structure being formed.
The term “encapsulated,” when used with reference to PCM, may be understood to mean that the PCM is contained in a protective coating or capsule. Encapsulation of the PCM may be macro-encapsulation, micro-encapsulation, or molecular-encapsulation. Macro-encapsulation refers to a technique where a significant quantity of PCM is encapsulated as a discrete unit. Micro-encapsulation refers to a technique in which tiny particles or droplets of the PCM are surrounded by a coating to give small capsules. An example of a micro-encapsulated PCM includes, but is not limited to, gel beads. Molecular-encapsulation is a technique for confining a single molecule of a PCM material inside a cavity of a host molecule.
Encapsulation may allow for storage and retention of the PCM, especially for PCM materials that transition from the solid to the liquid phase on thermal cycling, or for materials that may not be compatible with the support materials. Suitable materials for the protective coating or capsule (i.e., encapsulation materials) may be any known or future developed material which conducts heat, restricts leakage, and/or restricts corrosion. Exemplary encapsulation materials include at least polypropylene and polyolefin.
The PCM may be included in structures that remain separate or isolated from the support material. For example, the PCM may be included in a bag or other container positioned on or in the support material. The PCM in the bag or other container may be encapsulated, such as in gel beads, or may be included as a liquid or powder. Thus, when the support material is a foam or gel, the bag or other container may be positioned during formation of the foam so that it may reside within the support material, or at or near a surface of the support material.
Alternatively, the PCM, either encapsulated or in the liquid or powder state, may be included in a bag or container that forms a completely separate layer of the mattress, such as at least one layer of the upper layer of the mattress.
The PCM may be coated or printed on one or more surfaces of a textile layer of the mattress, and/or on one or more surfaces of a support layer of the mattress. The textile layer may include an outer covering of the mattress comprising a woven or non-woven material, or a textile covering of one or more layers of the upper layer of the mattress, such as one or more support layers, or even as a textile covering on a bag or container comprising the PCM material.
The PCM may be coated on surfaces of a fiber or other organic or synthetic material of one or more support layers of the upper layer of the mattress. For example, an organic fiber (e.g., wool, cotton, horse hair) or synthetic fiber (e.g., polyester fiber) may be coated by the PCM before the fiber is used in one or more support layers of the upper layer, or as a textile covering layer of one or more support layers of the upper layer. When coated on a surface, such as on a textile layer or a surface of a support layer, or on a fiber used as a support layer or a textile covering, the PCM may include a binder to aid in adherence of the PCM to the textile or support layer.
The binder may be a polymeric binder in the form of a solution, dispersion or emulsion in water or in an organic solvent. The polymeric binder may initially be polymeric, or in the form of monomers and/or oligomers, or low molecular weight polymers which upon drying and/or curing are converted to their final molecular weight and structure. These binders are preferably film-forming, elastomeric, and have a glass transition temperature in the range of about −45° C. to +45° C., depending upon the desired application. The polymers may be linear or branched. Copolymers may be random, block or radial. The polymers may have pendant reactive groups, reactive ends or other crosslinking mechanisms, or be capable of entanglement and/or hydrogen bonding in order to increase the toughness of the coating and/or its resistance to moisture, solvents, laundering or dry-cleaning, or other chemicals.
The raw PCM may be incorporated directly in the support material. When the support material is a foam or gel material, the support material may be produced particularly advantageously by emulsifying or dispersing the PCM with the liquid foam or gel components, which may then be reacted to form the foam or gel. For example, when the support material is a polyurethane gel, a liquid PCM may be first incorporated into a liquid polyol component to form a liquid/liquid emulsion, which may then be further reacted with the isocyanate to form the polyurethane gel. In another example, a powdered PCM may be included with either of the isocyanate or polyol components, which may then mixed to form the polyurethane gel. Alternatively, the PCM may be introduced into the final polyurethane mixture (i.e., mixture of the isocyanate and polyol components) before gel formation. Which procedure is selected may depend on the desired dispersion profile of the PCM within the support material.
The degree of fine dispersion of the PCM in the emulsion may also depend, for example, on the intensity and duration of mixing, and on the nature and amount of any additives, such as stabilizers, rheology modifiers, emulsifiers, etc.
The upper layer of the mattress may be composed entirely of a PCM. The upper layer of the mattress may comprise one or more support layers wherein at least one support layer is composed of 100% PCM. The upper layer of the mattress may comprise one or more support layers wherein at least one layer comprises up to 60 wt. % PCM, based on the total weight of the PCM containing layer.
According to certain aspects of the present invention, the support material may comprise a gel, a gel infused foam material, a foam material, or a combination thereof. The at least one support layer comprising the PCM may comprise 0% to 65% of a foam material, 35% to 100% of a gel material, such as a polyurethane gel, and 0% to 65% of a phase change material, based on the total area of the layer. The at least one support layer comprising the PCM may comprise 0 wt. % to 10 wt. % of a foam material, 75 wt. % to 100 wt. % of a gel material, and 0 wt. % to 25 wt. % of a phase change material, based on the total weight of the top layer.
The upper layer may include a surface of the mattress having a thickness of no more than 20 cm, such as 15 cm or less, or even 10 cm or less. In certain embodiments of the invention, the upper layer may have a thickness of 10 cm or less.
The upper layer may have a density of at least 100 kg/m3. When the support material is selected as a gel material, the upper layer may have a density of at least 500 kg/m3, or at least 900 kg/m3, or at least 1,100 kg/m3. The density may be related to the density of the gel material, and the geometry of the upper layer. Further, the upper layer may have an average surface heat capacity of at least 20 kJ/° C.·m2, such as at least 23 kJ/° C.·m2, or at least 26 kJ/° C.·m2, or at least 29 kJ/° C.·m2, or at least 32 kJ/° C.·m2, for the temperature range of 21° C. to 35° C. and calculated for a thickness of 10 cm.
The upper layer of the mattress may comprise a top layer having a thickness of from 1 cm to 3 cm, and one or more supporting layers. In certain embodiments, the PCM may be included in the top layer. The top layer may have an average surface heat capacity of at least 14 kJ/° C.·m2, such as at least 16 kJ/° C.·m2, or at least kJ/° C.·m2, or at least 22 kJ/° C.·m2, or at least 26 kJ/° C.·m2, for the temperature range of 21° C. to 35° C. and calculated for a thickness of 1.5 cm. The top layer may have a specific heat capacity of at least 2.0 kJ/kg·° C., such as at least 2.5 kJ/kg·° C., or at least 3.0 kJ/kg·° C., calculated for the temperature range 21° C. to 35° C.
When the top layer comprises a supporting material, the top layer may comprise up to 60 wt. % PCM. For example, the top layer may comprise 75 wt. % to 95 wt. % of a polyurethane gel and 5 wt. % to 25 wt. % of a PCM, such as 85 wt. % of the polyurethane gel and 15 wt. % of the PCM. The PCM may be encapsulated and/or may be included as a fine dispersion in the polyurethane gel, as described hereinabove.
Moreover, the support material may comprise a combination of a gel, a gel infused foam material, or a foam material. In such case, the top layer may comprise 0% to 65% of a foam material, 35% to 100% of a gel material, such as a polyurethane gel, and 0% to 65% of a phase change material, based on the total area of the layer. The top layer may comprise 0 wt. % to 10 wt. % of a foam material, 75 wt. % to 100 wt. % of a gel material, and 0 wt. % to 25 wt. % of a phase change material, based on the total weight of the top layer.
According to certain aspects of the present invention, the upper layer may include a top layer comprising 75 wt. % to 95 wt. % of a polyurethane gel and 5 wt. % to 25 wt. % of a phase change material, and one or more supporting layers. The upper layer may include a top layer comprising 85 wt. % of a polyurethane gel and 15 wt. % of a phase change material, and one or more supporting layers.
The top layer may comprise the PCM encapsulated in a bag or other enclosure that is incorporated into the support material. Alternatively, the top layer may comprise the PCM encapsulated in a bag or container that forms the entirety of the top layer (i.e., the top layer does not comprise a support material). Thus, according to certain aspects of the present invention, the top layer may comprise up to 100% of the PCM (exclusive of any covering textile).
The one or more supporting layers of the upper layer may comprise any type of support material as indicated above, and which may be generally known in the art of bodily support apparatuses, particularly in the art of mattresses. For example, the one or more supporting layers may comprise one or more of the following: foam materials, gel materials, springs, textiles, organic materials (e.g., wood, wool, fibers such as coconut fibers, horse hair or tail, cotton), liquid materials (water, colloidal solutions, salt solutions), metal materials, and plastic materials (polymer fibers and solid parts).
An exemplary support material of the present invention includes foam materials, such as open-cell foamed polymers (e.g., shape memory foams). Exemplary foams may be produced using polyurethane, ethyl-vinyl-acetate, latex, rubber, neoprene, or polyethylene polymers. Specific examples of polyurethane foams include, but are not limited to, polyester and polyether polyurethane foams, and combinations thereof. The foam material can comprise any density and/or cell size, depending upon the application for which it is intended. In addition, the density and/or cell size can be varied within certain thicknesses of the supporting layer, or amongst various supporting layers.
Examples of a suitable spring layer includes coil springs. The coil springs are not intended to be limited to any specific type or shape. The coil springs can be single stranded or multi-stranded, pocketed or not pocketed, asymmetric or symmetric, and the like. It will be appreciated that the pocket coils may be manufactured in single pocket coils or strings of pocket coils, either of which may be suitably employed with the mattresses described herein. The attachment between coil springs may be any suitable attachment. For example, pocket coils are commonly attached to one another using hot-melt adhesive applied to abutting surfaces during construction.
The coil spring construction can employ a stranded wire spring which is made of at least two wire strands that are twisted to form a multi-wire cord. The number of strands employed can vary according to the application and may vary based on the type of material used to form the strand. Thus, the wire may include two or more strands, and can include from three to fifty strands.
The strands may be twisted, weaved, clipped or bonded together and any suitable method for forming the stranded wire spring may be employed without departing from the scope of the invention. The strands may be steel, aluminum, plastic, copper, titanium, rubber or any other suitable material and the type of material selected will depend upon the application at hand. Moreover, the strands may have any suitable shape and may be long cylindrical wires, hexagonal wire, square wire or any other shape or geometry. Additionally, the wire strand gauge may vary according to the application.
Turning now to the figures, various embodiments of the present invention are illustrated with reference to
The length L and the width W of the mattress may be of any suitable length and width, including without limitation U.S. or non-U.S. standard sizes such as king, queen, double, full, twin, extra-long, California king, youth and crib.
As shown in
With reference to
The lateral sides 19 of the projections 15 may be perpendicular to a lower planar surface 18 of the top layer 12, or may be angled. In addition, other shapes may be employed including, e.g., long parallel plateaus of the projections 15 that extend along the length and/or width of the top layer 12. These structures may be linear, zig-zag, curvy, etc.
As shown in
In an exemplary embodiment of the present invention, the top layer 22 may comprise a PCM without additional support material. As such, the PCM may be incorporated into an enclosed bag or container that is attached or attachable to a top surface of the support layer 24. The top layer 22 may be covered by an additional textile layer (not shown).
With reference to
In an exemplary embodiment, the two supporting layers (34, 36) may comprise a foam material, while the top layer 32 may comprise a PCM embedded in or incorporated into a support material such as a polyurethane gel. The materials of the two supporting layers (34, 36) may be the same or may be different from one another. For example, the materials of the top supporting layer 36 may comprise a high-density memory foam material while the material of the bottom supporting layer 34 may comprise a less dense foam, such as an open-cell polyurethane foam.
In another exemplary embodiment, the top layer 32 may comprise a PCM without additional support material. As such, the PCM may be incorporated into an enclosed bag or container that is attached or attachable to facing surfaces of the two supporting layers (34, 36). The top layer 32 may be covered or surrounded by an additional textile layer (not shown).
With reference to
As shown in
Each of the embodiments in
For example, an as shown in
Alternatively, the top layer 52 may occupy a full width W of the mattress but less than the full length L of the mattress. As shown in
As discussed in more detail in Example II below, a majority of the heat transferred to the inventive mattresses disclosed in the present application occurs from the core of the user, specifically in a region proximal to the abdomen and upper shoulders. Since the high heat capacity materials of the present invention may increase the overall weight and expense of a mattress, configurations which utilize smaller amounts of the materials may be advantageous. As such, the length L2 of the top layer 52 may be set to include a region of the upper layer 50 of the mattress that is typically contacted by only those areas of the user's body that may dissipate heat efficiently (see
The upper layer comprises a length (L1+L2+L3 from
The mattresses of the present invention have been found to improve the sleep quality of user's thereof. Without wishing to be bound by theory, the present inventors have found that the improvement in sleep quality is linked to a reduction in the CBT, which is a result of the novel designs and materials of the presently disclosed high heat capacity mattresses.
Mattresses of the present invention have been found to reduce the CBT of the user by at least 0.10° C., such as at least 0.15° C., or at least 0.20° C., and to increase the amount of time spent in slow wave sleep (SWS) by at least 5%, such as at least 10%, or even at least 15%, with respect to a standard mattress. As used herein, the term “standard mattress” may be taken to mean a mattress which comprises an average surface heat capacity of 15 kJ/° C. m2 or less for an upper layer of 10 cm.
Mattresses of the present invention also demonstrate lower surface temperatures during the user's sleep time. For example, the surface temperature of a region of the mattress on which a body is supported may be at least 1° C. lower, such as at least 1.2° C. lower, or at least 1.4° C. lower, or at least 1.6° C. lower, or at least 1.8° C. lower, or at least 2.0° C. lower, or at least 2.5° C. lower, or at least 3.0° C. lower, or at least 3.5° C. lower, or at least 4.0° C. lower, or at least 5.0° C. lower, than a surface temperature of the same region on a standard mattress.
Moreover, the surface temperature of a region of the mattress on which a body is supported may vary with the duration of sleep time. For example, during a 7-hour sleep cycle, the surface temperature of the inventive mattresses disclosed herein decreases rapidly during the first 15 to 30 minutes, followed by a slow increase (see
The final difference in surface temperature after a 7 hour sleep cycle may be at least 1° C. lower, such as at least 1.2° C. lower, or at least 1.4° C. lower, or at least 1.6° C. lower, or at least 1.8° C. lower, or at least 2.0° C. lower than a surface temperature of the same region on a standard mattress.
While the mattresses of the present invention have been thus described as comprising a “passive” means to provide a lower surface temperature of the mattress, and to improve sleep quality by increasing the SWS and lowering the CBT of users thereof, the present invention may further provide active means to provide these same benefits. For example, flexible pipes or conduits may be included in the upper or top layer of the mattress which may be configured to provide “active” cooling to the upper or top layer of the mattress. These pipes may be configured to provide a flow of a cooling fluid therethrough, wherein regulation of the flow rate and the temperature of the cooling fluid may be manually and/or automatically regulated by a control unit and a cooling unit.
As example, as user may be able to set a preferred temperature of the cooling fluid using the control unit, and the system may regulate the flow rate and fluid temperature based on feedback from a surface of the mattress (e.g., temperature probe at the surface of the mattress), or from a temperature of the returning fluid (e.g., fluid returning to the cooling unit from a circulation cycle through the conduits in the mattress). The control unit may also be regulated as a function of time, so that various preset temperatures may be achieved throughout the sleep cycle (e.g., cool to a lower temperature during the first 30 minutes of the sleep cycle).
The conduits may be included in the upper layer, or may be included in the top layer. Whether included in the upper layer or the top layer, the conduits may cover less than the full length “L” and/or width “W” of the mattress, such as only 90%, or only 80%, or only 70%, or only 60%, or only 50%, or only 40%, or only 30% of the total surface area of the top surface of the mattress. For example, the conduits may be positioned within a region of the upper layer of the mattress that corresponds to a position of a lumbar shoulder zone of a body supported on the mattress.
The cooling fluid may be any fluid known in the art, such as water, colloidal solutions, carbohydrate solutions, PCM solutions, salt solutions, etc.
Thus, according to certain aspects of the present invention, a mattress comprising an active system, where a cooling fluid is actively circulated through conduits in the top or upper layer of the mattress, is disclosed. The active system may be used alone, or in conjunction with the high heat capacity mattress materials and configurations disclosed hereinabove. Mattresses which do include such an active cooling system may utilize less PCM material in the upper and/or top layer.
The present invention further includes methods for improving sleep. An exemplary method comprises providing the high heat capacity mattresses as described herein to a user. The user may experience a reduction in the CBT of at least 0.10° C., such as at least 0.15° C., or at least 0.20° C., and an increase in the amount of time spent in slow wave sleep (SWS) of at least 5%, such as at least 10%, or at least 15%, with respect to sleep on a standard mattress.
The present invention further includes uses of high heat capacity mattresses disclosed herein for sleep improvement. An exemplary use comprises providing a high heat capacity mattress for a user thereof, wherein the high heat capacity mattress is configured to reduce a core body temperature of the user, and wherein the high heat capacity mattress has an upper layer having an average surface heat capacity of at least 20 kJ/° C.·m2, such as at least 23 kJ/° C.·m2, or at least 26 kJ/° C.·m2, or at least 29 kJ/° C.·m2, or at least 32 kJ/° C.·m2, for the temperature range of 21° C. to 35° C. and calculated for a thickness of 10 cm. The upper layer may include a top layer of 1 to 3 cm thickness having an average surface heat capacity of at least 14 kJ/° C.·m2, such as at least 16 kJ/° C.·m2, or at least 18 kJ/° C.·m2, or at least 22 kJ/° C.·m2, or at least 26 kJ/° C.·m2, for the temperature range of 21° C. to 35° C. and calculated for a layer thickness of 1.5 cm.
While specific embodiments of the invention have been described in detail, it should be appreciated by those skilled in the art that various modifications and alternations and applications could be developed in light of the overall teachings of the disclosure. Accordingly, the particular arrangements, systems, apparatuses, and methods disclosed are meant to be illustrative only and not limiting as to the scope of the invention.
EXAMPLE I Heat Capacity MeasurementsHigh heat capacity mattresses according to the present invention and a control mattress were compared. The mattresses according to the present invention include a top layer of 1.5 cm thickness comprising (A) 100 wt. % polyurethane gel, or (B) 85 wt. % polyurethane gel+15 wt. % PCM (enthalpy of PCM is 180 kJ/kg; heat capacity of PCM+gel+foam is 1.9 kJ/kg ° C.). The upper layer includes the 1.5 cm thick top layer (as described above) and an 8.5 cm thick supporting layer comprising a foam material having a density of 40 kg/m3. The control mattress includes a foam material having a density of 80 kg/m3 (top layer of 1.5 cm thickness; upper layer of 10 cm thickness total). For all mattresses (control and inventive A and B), the additional 15 cm (European height) to 20 cm (USA height) comprising the base layer includes a foam material having a density of 35 kg/m3.
Shown in Table II are surface heat capacity values for the control and inventive mattresses (A and B, as described above) listed for various mattress sizes and thicknesses: top layer of 1.5 cm; upper layer, including the top layer, of 10 cm total; and European or USA mattress heights of 25 cm or 30 cm total (including the 10 cm thick upper layer).
With reference to Table II, the top layer (1.5 cm) exhibits an average surface heat capacity of 16 kJ/° C. m2 for mattress A and 32 kJ/° C.m2 for mattress B, as compared with an average surface heat capacity of only 2.3 kJ/° C.m2 for the control (all foam) mattress. The upper layer (10 cm total including the 1.5 cm top layer) exhibits an average surface heat capacity of 22 kJ/° C.m2 for mattress A and 39 kJ/° C.m2 for mattress B, as compared with an average surface heat capacity of only 15 kJ/° C.m2 for the control (all foam) mattress.
Various other materials and mattress configurations were tested and shown in Tables III and IV. Table III lists results calculated for various configurations of a 2 cm top layer (as defined therein), while Table IV lists results calculated for a 10 cm upper layer, both for a mattress size of 200 cm×90 cm. In Table III samples 1 and 8 include a 2 cm top layer formed of a polyurethane gel; comparative sample 2 includes a 2 cm top layer formed of foam, and samples 3-8 comprise a 2 cm top layer formed using a polyurethane gel and various amounts of PCM. In Table IV samples 9-13 comprise a 2 cm top layer (gel material with PCM) and an 8 cm supporting layer comprising either foam (samples 9-12) or pocket coil springs (sample 13); samples 14 and 15 include no gel in the top layer (foam only+PCM); and sample 16 includes a foam supporting layer of 9.4 cm and a top layer of 0.6 cm comprising water as the “PCM” material.
The total heat capacity (HC) values for the temperature range 21° C. to 35° C. (ΔT) for a 10 cm thick upper layer, as listed in Tables III and IV, are calculated as:
Total Heat Capacity (HC; kJ)=[CP×kgΔT]top layer+[CP×kg×ΔT]support layer+[CP×kg×ΔT]PCM1+[CP×kg×ΔT]PCM2+[enthalpy×kg]PCM1+[enthalpy×kg]PCM2
As demonstrated in Table III, there are various means to achieve a high heat capacity mattress. Samples 3-8 all achieve a total heat capacity of 28 kJ/° C.m2 using differing amounts of PCM or PCM and gel material in the top layer of the mattress, while sample 1, which includes only the gel material in the top layer, shows a total heat capacity of 14 kJ/° C.m2. Sample 2 is a comparative example which includes only a foam material in the top layer, and shows a total heat capacity of 3 kJ/° C.m2.
The data listed in Table IV demonstrates that various configurations of the supporting layers may be used in the high heat capacity mattress of the present invention. Samples 9-12 include an 8 cm supporting layer of foam, and a 2 cm top layer of gel material+PCM. The supporting layers of samples 9-12 include foams of differing densities: sample 9 foam has a density of 80 kg/m3, sample 10 foam has a density 50 kg/m3, sample 11 foam has a density 40 kg/m3, and sample 12 foam has a density 30 kg/m3. Sample 13 includes a supporting layer of Pocket Coils. Samples 14 and 15 include an upper layer of 10 cm comprising a foam material, wherein the foam of sample 14 has a density of 80 kg/m3, and the foam of sample 15 has a density of 50 kg/m3. Sample 16 includes a supporting layer which is 9.4 cm thick comprising a foam material having a density of 50 kg/m3 and a top layer which is 0.6 cm of water.
EXAMPLE II Sleep StudySleep quality and various thermic properties of subjects sleeping high heat capacity mattresses (HHCM) according to the present invention or a conventional low heat capacity mattress (LHCM) were studied.
Mattress Properties:
The HHCM according to the present invention includes (A) 100 wt. % polyurethane gel, or (B) 85 wt. % polyurethane gel+15 wt. % PCM on top of foam layers, whereas the LHCM (prior art comparative) is 100% foam. All mattress were 90×200×25 cm, wherein a top layer (at least 2 cm) of the HHCM had a density of 1006 kg/m3 and the LHCM had a density of 80 kg/m3 throughout. The total heat capacity for the top 1.8 cm of the mattresses in the temperature range studied 21-35° C. was about 25 kJ/° C. for the HHCM (A), 46 kJ/° C. for the HHCM (B), and about 5 kJ/° C. for the LHCM. All mattresses were covered with a bi-elastic non-quilted textile with a weight of 600 g/m2. Unless specifically indicated, reference to HHMC may be taken to include a reference to both HHCM (A) and HHCM (B).
Study Subjects:
Potential study subjects (28 male subjects, aged 25 to 30yr (BMI 19-25 kg/m2) were screened by a board-certified sleep medicine physician. Subjects were excluded at the initial evaluation for a number of causes, including: non-stabilized medical illnesses, history of alcoholism, drug dependence or abuse, neurological disorders, head trauma and mental disorders according to the Diagnostic and Statistical Manual of Mental Disorders (DSM-V, American Psychiatric Association, 2013), Mini Mental State Examination score <26, CNS active drugs assumption, excessive use of caffeine and/or smoke (respectively more than 2 cups and 5 cigarettes per day), history for sleep disorders.
Study subjects with no history for sleep disorders underwent an ambulatory polysomnography (PSG) and long term sleep-wake monitoring in order to exclude respectively sleep disorders (i.e. insomnia, motor and/or respiratory sleep related disorders) and assess habitual duration and sleep period. Ambulatory PSG was performed using a portable monitoring device (Embletta MPR PG with ST+ Proxy module, Natus Medical Inc, Pleasanton, Calif., US) monitoring four EEG channels, two electrooculogram channels, chin and anterior tibialis electromyogram, airflow (nasal-cannula), respiratory effort (thoracic and abdominal), oxygen saturation and cardiac frequency, body position, and snoring.
Evaluation of habitual sleep times, sleep onset latency, amount of sleep and sleep efficiency was accomplished by wrist actigraphy for 2 weeks (ActiGraph wGT3X and ActiLife+Sleep software, ActiGraph, Pensacola, Fla., US) in addition to sleep logs.
Following the evaluation visit and instrumental screening 13 subjects were excluded (5 at evaluation visit, 6 with sleep related breathing and/or movement disorders, 2 because of high variability of sleep period). Fifteen (15) subjects fulfilled the entire study criteria and finished the study without any complaints.
Study Design:
The mattresses were studied in a randomized single-blind crossover design at the Sleep Disorder Center, Department of Neurosciences, University of Turin, Italy. After an adaptation night in the sleep laboratory on a conventional LHCM, each subject slept for two further nights on different mattress types with an interval of one week, randomly starting either with HHCM or LHCM.
Temperature Measurements:
Room, skin, and mattress temperatures were measured using wireless temperature sensors (DS 1922L, Thermochron iButtons®; Maxim, Dallas, USA; resolution 0.0625° C.; sampling rate: 1 value per minute) which were fixed to the skin and mattresses with thin air-permeable adhesive surgical tape (Fixomull®; Beiersdorf, Hamburg, Germany). Air temperature was registered using an iButton in a mesh net bag installed at the wall in the sleep room.
Eighteen (18) temperature sensors were placed on the left and right site of the body on the following skin regions: ankle (inner side, between talus and Achilles' tendon), thigh (in the middle inner side of quadriceps), calf (in the middle inner side laterally of tibia), palmar sites of ring finger, wrist and middle of forearm, and infra-clavicular region, and one temperature sensor was placed on the sternum. Additional temperature sensors were placed on the left and right side of the back at the shoulder, and on the spinal cross.
Mattress temperatures were recorded from five temperature sensors placed on the mattresses: 3 sensors in a row 60 cm from the top, 15 cm distance between sensors and 30 cm to the edges, a fourth sensor in the middle 20 cm below the first row, and the fifth sensor 20 cm below the fourth.
The mean temperature value for the ankles, calves, thighs, right fingers, wrists and forearms was defined as mean distal skin temperature (DIS). The proximal frontal skin temperature (PROFR) was an average of the skin temperature of infra-clavicular regions and sternum and the proximal back skin temperature (PROBA) was an average of the skin temperature of the back shoulders and spinal cross. In contrast to PROBA, PROFR is not influenced by contact with the mattresses. Core body temperature was recorded using a telemetric, ingestible capsule sensor system (VitalSense Core Temperature Capsule, Hidalgo Ltd, Cambridge, UK; sampling rate: 4 values per minute, later averaged in I-min-bins).
Sleep Recordings in the Lab:
Video PSG was performed by Comet XL Lab-based PSG (Grass Telefactor, Astro-Med Inc., West Warwick, R.I. 02893 U.S.A.) using four EEG channels, two electro-oculogram channels (right and left outer canthus), chin electromyogram, heart rate, oxygen saturation, and body position. Room temperature was kept at approximately 23° C. within a range of ±0.5° C. and relative humidity between 45% and 55%. The subjects wore the laboratory standard cotton nightclothes and were covered by a cotton sheet during lights-off phase. PSGs were blindly scored by a sleep technician and interpreted by a sleep medicine-certified physician by using standard scoring procedures. PSG variables included time spent in stages N1, N2, N3 (=slow wave sleep, SWS), rapid eye movement sleep (REMS), total sleep time, sleep onset latency to sleep stage N2, sleep efficiency and wake time after sleep onset.
Results
Temperatures:
In comparison to LHCM, sleep on a HHCM significantly reduced the study subjects CBT (Table V;
Sleep Composition, Sleep Onset Latency and Sleep Efficiency:
The individual lights off times in the sleep lab matched the subject's habitual bedtimes (23:15±20 min). The results of total night sleep analysis are summarized in Table VI. In comparison to LHCM, the HHCM (B) increased sleep stage N3 (time in sleep stage N3 as % of total sleep time) from 23.1 to 26.8% corresponding to an increase of 16% (p<0.05).
The main outcome of the study is that, in comparison to a conventional low heat capacity mattress (LHCM), subjects sleeping on a high heat capacity mattress (HHCM) significantly reduced core body temperature (CBT;
An increase in all skin temperature occurred immediately after switching the lights off and lying down, but body temperature differences between LHCM and HHCM developed with a time lag. In comparison to LHCM, sleep on HHCM showed a slower increase of mattress surface temperature leading to a persistently increased external temperature gradient and hence to increased heat uptake by HHCM, which is in accordance with the higher heat capacity of this mattress. Significant differences between LHCM and HHCM(B) surface temperatures occurred around 10 min after lights off and maximum differences of about 6° C. one hour after lights off.
As mentioned earlier, standard LHCM tend to act as insulators, holding the warm air within the region close to the person's skin. This is clearly borne out by the data provided in Table VII, and in
The surface temperature of mattresses according to the present invention were also measured using an automated climate testing mannequin. The testing mannequin is shaped and sized to resemble an average height and weight person, and includes sensors along a back portion thereof that are configured to measure temperature and humidity. The testing mannequin further includes internal heating systems to regulate a temperature profile of the mannequin so that it mimics a temperature profile of an average person (e.g., a thermoregulatory simulation model which is a standardized method based on actual data and conditions of a recumbent person). Testing was performed at Ergonomie Institut München (Birkenfeld 15, D-83627 Warngau, Germany) using a proprietary method.
Such an automated climate testing mannequin was used to evaluate the microclimate of a low heat capacity mattress (LHCM; as defined above in Example II), another low heat capacity mattress (LHCM(B)), and two high heat capacity mattresses according to the present invention (HHCM(A) and HHCM(B), as defined in Example II). The LHCM(B) is a foam mattress which includes a small addition of a PCM coated on the top surface of the foam and the covering textile (e.g., fabric cover on the mattress). Testing was done in a room at ambient temperature and humidity (21° C. and 50% relative humidity), and with mattress having dimensions of 90 cm width×200 cm length×25 cm thickness. Surface temperatures and humidity were measured contact areas between the mattress and the back of the supine testing mannequin.
As can be seen from the thermal profiles shown in
The HHCM(A) and HHCM(B) both showed an initial rapid reduction in the surface temperature, and a reduction in the overall final surface temperature of the mattress with respect to the standard mattress (LHCM). For example, the HHCM(B) achieves a stable final temperature of 34.5° C., which is almost 2° C. less than the standard mattress (LHCM).
The data provided by thus study, which is shown in
The LHCM(B) is included to demonstrate that simple inclusion of a PCM as a coating on the foam of a standard mattress, such as is currently marketed, does not lead to a high heat capacity mattress as defined herein, and does not lead to the unexpected improvements in surface temperature reduction observed with mattresses formed according to the present invention. The PCM coated on the materials of the LHCM(B) are insufficient to general a difference in the final surface temperature, and are insufficient to provide an increase in the average surface heat capacity observed for the mattresses of the present invention. That is, the LHCM(B) has an average surface heat capacity of 15 kJ/° C.·m2 or less for an upper layer of 10 cm.
EXAMPLE VI Active SystemThe active system includes conduits placed in an upper layer of a HHCM of the present invention which circulate water that is thermoregulated to 22° C.—referred to as HHCM(C). The surface temperature of this system was compared to the surface temperature of a LHCM (as defined in Example II, foam mattress having density of 50 kg/m3 and dimensions of 90 cm width×200 cm length×25 cm thickness) when a human subject slept in a supine position in a room at ambient temperature and humidity (21° C. and 50% relative humidity).
As can be seen from the data presented in
Claims
1. A mattress for supporting at least a portion of a body thereon, the mattress comprising:
- an upper layer with a density of at least 500 kg/m3 for a thickness of 10 cm, and an average surface heat capacity of at least 20 kJ/° C.m2; and
- a base layer disposed below the upper layer,
- wherein the upper layer comprises a top layer having a thickness of 1 to 3 cm and positioned in an uppermost region of the upper layer, wherein the top layer comprises 75 wt. % to 95 wt. % of a support material and 5 wt. % to 25 wt. % of a phase change material, and
- wherein the mattress is configured to reduce a core body temperature of the body supported thereon and to improve sleep with respect to a standard mattress, wherein the standard mattress comprises an average surface heat capacity of 15 kJ/° C.m2 or less for an upper layer with a thickness of 10 cm.
2. The mattress of claim 1, wherein the average surface heat capacity of the upper layer of the mattress is at least 25 kJ/° C.m2.
3.-5. (canceled)
6. The mattress of claim 1, wherein the support material comprises a gel, a gel infused foam material, a foam material, or a combination thereof, and
- wherein the phase change material comprises a paraffin, an ester of fatty acid, an encapsulated paraffin, an encapsulated ester of fatty acid, or a combination thereof.
7. The mattress of claim 1, wherein the phase change material has a phase transition temperature of 18° C. to 40° C.
8. The mattress of claim 1, wherein the phase change material is finely dispersed in at least a portion of the support material, micro-encapsulated within a region of the support material, macro-encapsulated within a region of the support material, or a combination thereof.
9.-10. (canceled)
11. The mattress of claim 1, wherein the average surface heat capacity of the top layer is at least 20 kJ/° C.m2.
12. The mattress of claim 1, wherein the top layer has a specific heat capacity of at least 2.0 kJ/kg° C.
13. The mattress of claim 1, wherein the top layer has a specific heat capacity of at least 3.0 kJ/kg° C.
14. (canceled)
15. The mattress of claim 1, wherein the top layer comprises 85 wt. % of a polyurethane gel and 15 wt. % of a phase change material.
16. (canceled)
17. The mattress of claim 1, wherein the upper layer comprises a length and a width that define dimensions of the mattress, and the top layer comprises a length that is less than the length of the upper layer.
18. The mattress of claim 17, wherein the length of the upper layer is defined by a top edge and a bottom edge, and the length of the top layer is 75% or less than the length of the upper layer, wherein the top layer does not extend to the top edge or the bottom edge of the upper layer.
19. The mattress of claim 18, wherein the length of the top layer is 50% or less than the length of the upper layer and is positioned to include a region of the upper layer that corresponds to a position of a lumbar shoulder zone of the body supported on the mattress.
20. The mattress of claim 1, wherein the mattress reduces the core body temperature of the body supported thereon by at least 0.10° C., with respect to the standard mattress.
21. The mattress of claim 1, wherein the mattress increases time spent in slow wave sleep (SWS) of the body supported thereon by at least 5% with respect to the standard mattress.
22. The mattress of claim 1, wherein a surface temperature of a region of the mattress on which the body is supported is at least 1° C. lower than a surface temperature of the region on the standard mattress, measured after the body supported thereon has remained for a time period of at least 1 hour.
23. A method for improving sleep, the method comprising:
- providing the mattress according to claim 31 to a user.
24. A use of a high heat capacity mattress for sleep improvement, the use comprising:
- providing the high heat capacity mattress according to claim 1 for a user.
25. The use of claim 24, wherein the average surface heat capacity of the upper layer of the mattress is at least 25 kJ/° C.·m2.
26. The use of claim 24, wherein the high heat capacity mattress increases a time spent in slow wave sleep (SWS) of the user by at least 5% with respect to the standard mattress.
27. The use of claim 26, wherein the high heat capacity mattress increases the time spent in slow wave sleep (SWS) by at least 10% with respect to the standard mattress.
28. The use of claim 24, wherein the top layer has a specific heat capacity of at least 2.0 kJ/kg° C.
29. The use of claim 28, wherein the upper layer comprises a length and a width that define dimensions of the mattress, and the top layer comprises a length that is less than the length of the upper layer.
30. The use of claim 24, wherein a surface temperature of a region of the mattress on which the body is supported is at least 1° C. lower than a surface temperature of the region on the standard mattress, measured after the body supported thereon has remained for a time period of at least 1 hour.
31. A mattress for supporting at least a portion of a body thereon, the mattress comprising:
- an upper layer with a density of at least 500 kg/m3 for a thickness of 10 cm, and an average surface heat capacity of at least 20 kJ/° C.m2, the upper layer comprising a top layer having a plurality of projections that rise from a top surface of the top layer in a direction perpendicular to a planar surface of the top surface, the projections having lateral sides that are perpendicular to the planar surface of the top surface, and a three-dimensional shape configured so that an area of the top surface of the projections is greater than an area of the lateral sides along a parameter of the projections; and
- a base layer disposed below the upper layer,
- wherein the mattress is configured to reduce a core body temperature of the body supported thereon.
32. A mattress for supporting at least a portion of a body thereon, the mattress comprising:
- an upper layer with a density of at least 500 kg/m3 for a thickness of 10 cm, and an average surface heat capacity of at least 20 kJ/° C.·m2, and including a top layer disposed in the uppermost portion of the upper layer, the top layer having a thickness of 1.5 cm and consisting of a material having a density of at least 900 kg/m3 and comprising 75 wt. % to 95 wt. % of a polyurethane gel and 5 wt. % to 25 wt. % of a phase change material; and
- a base layer disposed below the upper layer,
- wherein the phase change material is finely dispersed in at least a portion of the support material, micro-encapsulated within a region of the support material, macro-encapsulated within a region of the support material, or a combination thereof, and
- wherein the mattress is configured to reduce a core body temperature of the body supported thereon.
33. The mattress of claim 1, wherein the top layer has a density of at least 900 kg/m3 for the thickness of 1 to 3 cm.
34. The mattress of claim 1, wherein the top layer has a plurality of projections that extend away from an upper planar surface of the mattress and have lateral sides that are perpendicular to a top surface of the projections.
35. The mattress of claim 34, wherein the projections have a three-dimensional shape configured so that an area of the top surface of the projections is greater than an area of the lateral sides along a perimeter of the projections.
36. The mattress of claim 31, wherein the top layer has a density of at least 900 kg/m3 for the thickness of 1 to 3 cm.
37. The mattress of claim 32, wherein the top layer has a plurality of projections that extend away from an upper planar surface of the mattress and have lateral sides that are perpendicular to a top surface of the projections.
Type: Application
Filed: Aug 4, 2017
Publication Date: Feb 7, 2019
Applicant: Technogel Italia S.r.I. (Pozzoleone VI)
Inventor: Matteo Mason (Limena (PD))
Application Number: 15/669,179
