Coated Polyurethane Foam

Abstract

Articles useful for bedding and other comfort applications include coated polyurethane foams. The coatings include an elastomeric polymer, a phase change material, and ceramic particles. The coatings provide desirable tactile properties, including a cool-feel characteristic that provides a refreshing feeling to the touch. The present invention also provides coating compositions and methods for producing such coatings.

Description

[Technical Field]

[0001] FIELD OF THE INVENTION The present invention relates to flexible polyurethane foams useful in cushioning applications, particularly so-called "comfort applications" such as bedding and pillows.

[0002] Polyurethane foams are used in great volume to make cushioning, particularly for bedding and seating. A growing category of these polyurethane foams is the low-resilience, slow-recovery type, sometimes known as "viscoelastic" or "memory" foam. The problem with these foams is that they do not conduct heat very effectively. Heat dissipated by the occupant is trapped by the foam in areas close to the occupant's body, resulting in localized temperature increases that are perceived as uncomfortable by the occupant.

[0003] To address this issue, so-called "gel technology" is used to impart a cooling sensation to the touch, which is important at the point of sale. "Gel technology" involves using phase change materials to impart a "cool to the touch" characteristic to foams. Phase change materials (or "gels") have a melting or phase transition temperature at about room temperature or slightly above. They effectively absorb body heat upon touch, as body heat causes the material to undergo its phase change. This causes a cooling sensation upon initial contact.

[0004] Phase change materials can be used as surface toppers or can be injected into foam. When used as surface toppers, phase change materials provide a "cool feel," but eventually begin to trap body heat due to the impermeability of the gel material. Large amounts of phase change material are required. Because the phase change material is encapsulated in a hard shell, the surface toppers can become hard and brittle.

[0005] WO 2017 / 210439 describes polyurethane foams with surface coatings containing encapsulated phase-change materials. The coatings are prepared from aqueous emulsions that are applied to the foam and allowed to dry. This approach offers many advantages. It provides a thin, flexible, soft coating layer with the desired "cool to the touch" characteristic. Nevertheless, further improvements in cooling are desirable. The coatings also tend to be somewhat tacky when the phase-change material is warm.

[0006] The present invention is an article comprising a flexible polyurethane foam and a cured coating of a solid, water-insoluble elastomeric polymer adhered to at least one surface of the flexible polyurethane foam, the cured coating having embedded therein (i) particles of an encapsulated phase change material, the phase change material having a melting temperature or glass transition temperature of 25-37°C, and (ii) ceramic particles having a particle size of up to 50 μm, wherein the encapsulated phase change material comprises 10-70 weight percent of the combined weight of the elastomeric polymer, the encapsulated phase change material particles, and the ceramic particles, and the ceramic particles comprise 2-25 weight percent of the combined weight of the elastomeric polymer, the encapsulated phase change material particles, and the ceramic particles.

[0007] The coating exhibits beneficial tactile properties that make the article particularly useful for bedding and other comfort applications. These include low microtexture roughness and coarseness, low adhesive tack, and good thermal cooling and heat retention properties that result in desirable "cool feel" attributes. Comfort applications include those in which the foam is exposed to the body heat of a human user or water vapor evaporating from the body during use. The foam or foam-containing article in such applications often supports at least a portion of the human user's weight and is compressed during use. Examples of such comfort applications include pillows, mattress toppers, mattresses, comforters, furniture and / or car seats, quilting, thermal clothing, and the like.

[0008] In another aspect, the invention is a coating composition useful for producing the aforementioned articles, the coating composition comprising a liquid phase containing water and / or one or more other compounds that are liquid at 23°C and have a boiling point of 40-100°C at standard pressure, a water-insoluble elastomeric polymer dispersed in the liquid phase in the form of particles or droplets, particles of an encapsulated phase change material dispersed in the liquid phase, and ceramic particles dispersed in the liquid phase, wherein the phase change material comprises 40-60 percent by weight of the elastomeric polymer, the encapsulated phase change material particles, and the ceramic particles, and the elastomeric particles comprise 8-20 percent by weight of the elastomeric polymer, the encapsulated phase change material particles, and the ceramic particles.

[0009] The present invention is also a method for preparing such a coating composition, which comprises: A. charging all or a portion of a liquid phase into a mixing vessel equipped with an agitation system including a motor, a shaft, a disperser impeller, and at least one pumping impeller, wherein the disperser impeller and the pumping impeller are mounted on the shaft, and the pumping impeller is positioned above the disperser impeller; B. agitating the liquid phase in the mixing vessel by rotating the disperser impeller to create a vortex on the surface of the liquid phase in the mixing vessel while maintaining the pumping impeller above the surface of the liquid phase in the mixing vessel; C. adding ceramic particles to the liquid phase while continuing to rotate the disperser impeller while maintaining the surface of the liquid phase in the mixing vessel under the pumping impeller; D. then adding the elastomeric polymer and optionally additional liquid phase to the liquid phase in the mixing vessel while positioning a pumping impeller below the surface of the liquid phase in the mixing vessel and agitating the liquid phase with both the disperser impeller and the pumping impeller to maintain a vortex on the surface of the liquid phase; E. Simultaneously with or after step D, adding the encapsulated phase change material to the liquid phase in the mixing vessel while continuing agitation with both the disperser impeller and the pumping impeller to maintain a vortex on the surface of the liquid phase. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a schematic diagram of an apparatus for preparing a coating composition useful in the present invention.

[0011] Flexible polyurethane foam (uncoated) has a compressive strength of, for example, at least 24 kg / m, as measured in accordance with ASTM D-3574. 3 , at least 32 kg / m 3 , at least 36 kg / m 3 , or at least 40 kg / m 3 The foam density may be, for example, up to 120 kg / m 3 , up to 104kg / m 3 , up to 92kg / m 3 , or up to 80 kg / m 3 The flexible polyurethane foam may exhibit an elongation at break of at least 50%, at least 75%, or at least 100%.

[0012] The flexible polyurethane foam (uncoated) may exhibit a compression force deflection (CFD) value at 40% compression of 0.4 to 15.0 kPa, more preferably 0.4 to 10 kPa, 0.4 to 5 kPa, 0.4 to 2.5 kPa, or 0.4 to 1.5 kPa, when measured according to ISO 3386-1.

[0013] The flexible polyurethane foam (uncoated) may exhibit a resilience of up to 70%, up to 60%, up to 50%, up to 25%, up to 20%, up to 15%, or up to 10% in the ASTM D-3574 ball rebound test.

[0014] Flexible polyurethane foam (uncoated) may exhibit a recovery time of at least 1 second or at least 2 seconds, and up to 15 seconds, preferably up to 10 seconds. For purposes of this invention, recovery time is measured by compressing a 2.0-inch (5.08 cm) thick piece of foam (4.0 x 4.0 x 2.0 inches, 10.16 x 10.16 x 5.08 cm) at room temperature to 24% of its original thickness, holding the foam under compression for 1 minute, and releasing the compression force. Recovery time is the time required for the foam to regain 90% of its original foam thickness after the compression force is released. Recovery time is conveniently measured using a viscoelastic foam testing device, such as a RESIMAT 150 device (with factory software) from Format Messtechnik GmbH.

[0015] The flexible polyurethane foam may exhibit an airflow of at least 0.8 L / sec when measured according to ASTM D3574 Test G. The airflow may be at least 1.2 L / sec or at least 1.4 L / sec, for example, at most 8 L / sec, at most 6 L / sec, or at most 4 L / sec.

[0016] In a preferred embodiment, the flexible polyurethane foam has a compressibility of 32 to 92 kg / m 3 a foam density of at most 20% or at most 10%, and a recovery time of at least 1 second or at least 2 seconds and at most 10 seconds.

[0017] In some embodiments, the foam exhibits a moisture wicking time of 5 seconds or less, preferably 4 seconds or less. Moisture wicking time is measured on a 5.08 x 5.08 x 2.54 cm skinless sample that has been dried to constant weight. 3 mL of room temperature water is slowly dispensed from a pipette onto the top surface of the foam sample to avoid splashing, and the time required for the foam to absorb the water is recorded as the moisture wicking time.

[0018] Polyurethane foams having the aforementioned properties can be prepared using the general methods as described, for example, in WO 2017 / 210439, U.S. Pat. Nos. 4,365,025, 6,479,433, 8,809,410, 9,814,187, and 9,840,575, U.S. Published Patent Applications Nos. 2004-0049980, 2006-0142529, and 2016-0115387, and International Application No. PCT / US2018 / 052323, among others.

[0019] Polyurethane foam must be at least 200cm 3 The polyurethane foam article may be in the form of an article having a volume (uncompressed) of at least 1 liter, at least 3 liters, or at least 5 liters, for example. The volume may be, for example, up to 10,000 liters or up to 1000 liters. The polyurethane foam article may be, for example, a pillow, a mattress, or a mattress topper. The article may be molded, i.e., prepared in a mold whose internal geometry is the same as the external geometry of the article. The article may be cut foam, made by producing a larger piece of foam relative to the final dimensions and geometry of the article.

[0020] The cured coating comprises an elastomeric polymer that is solid at room temperature (23°C) and insoluble in water. The elastomeric polymer itself (i.e., absent the phase change material and ceramic particles) preferably has a glass transition temperature of 0°C or less (as measured by differential scanning calorimetry and an elongation at break of at least 50%). An elastomeric polymer having these properties is considered to be an elastomer for purposes of the present invention. The elastomeric polymer itself may have a glass transition temperature of -15°C or less, -25°C or less, or -40°C or less. The elongation at break may be 100% or greater.

[0021] Examples of suitable elastomeric polymers include natural rubber and synthetic polymers such as homopolymers and copolymers of conjugated dienes such as butadiene and isoprene, homopolymers and copolymers of acrylate monomers such as methyl acrylate, ethyl acrylate, hydroxyethyl acrylate, butyl acrylate, homopolymers and copolymers of isobutylene, nitrile rubber, polysulfide rubber, silicone rubber, homopolymers and copolymers of neoprene, polyurethane rubber, and the like.

[0022] The cured coating has embedded therein (i) particles of an encapsulated phase change material and (ii) ceramic particles having a particle size of up to 50 μm.

[0023] The encapsulated phase change material includes a phase change material having a melting temperature or glass transition temperature of 25-37°C, which is contained within a shell. For purposes of the present invention, the weight of the phase change material includes the weight of the shell. The shell may, for example, comprise 5-25% of the total weight of the encapsulated phase change material, with the phase change material itself comprising the remaining amount, i.e., 75-95% by weight thereof.

[0024] The phase change material may be or contain any one or more of natural or synthetic waxes, such as polyethylene wax, beeswax, lanolin, carnauba wax, candelilla wax, ouricle wax, sugarcane wax, jojoba wax, epicuticular wax, coconut wax, petroleum wax, or paraffin wax. In some embodiments, the phase change material is an alkane having 14 to 30, particularly 14 to 24, or 16 to 22 carbon atoms, or a mixture of any two or more such alkanes. In particular embodiments, the phase change material includes octadecane and / or eicosane. The phase change material preferably has a melting temperature of 25 to 37°C, particularly 25 to 32°C, or 28 to 32°C.

[0025] The encapsulated phase change material may exhibit a heat of fusion of at least 50 Joules per gram (J / g), at least 100 J / g, or at least 150 J / g within a temperature range of 25-37° C., as measured by differential scanning calorimetry. The heat of fusion may be 300 J / g or greater, but is more typically up to 250 J / g or up to 200 J / g.

[0026] The shell material can be, for example, a polymeric material having a melting or decomposition temperature of at least 50° C., preferably at least 100° C. Examples of useful shell materials include crosslinked thermoset resins such as crosslinked melamine-formaldehyde, crosslinked melamine, crosslinked resorcinol urea formaldehyde, and gelatin.

[0027] The encapsulated phase change material is in the form of particles. The particles may have a particle size of 100 nm to 100 μm as measured by microscopy. In some embodiments, the particles have a particle size of at least 250 nm, at least 500 nm, at least 1 μm, or at least 5 μm, and at most 75 μm or at most 50 μm.

[0028] Suitable methods for preparing encapsulated phase change materials are described, for example, in US Pat. Nos. 10,221,323 and 10,005,059.

[0029] Suitable encapsulated phase change materials are available from Microtek Laboratories, Dayton, Ohio, US.

[0030] The phase change material comprises 10 to 70 weight percent of the combined weight of the elastomeric polymer, the encapsulated phase change material, and the ceramic particles. In some embodiments, the encapsulated phase change material comprises at least 25 weight percent, at least 40 weight percent, or at least 50 weight percent on the aforementioned basis, and up to 65 weight percent or up to 60 weight percent on the same basis.

[0031] Ceramic particles are generally characterized as non-metallic inorganic solids at 23°C and as having a melting temperature or decomposition temperature (where the ceramic particles decompose without melting) of at least 200°C. Ceramic materials are compounds of at least two chemical elements, at least one of which is non-metallic. Ceramic particles can be amorphous, semi-crystalline, or crystalline, but do not undergo a phase change in the temperature range of 0 to 50°C. Ceramic materials preferably have a thermal conductivity of at least 50 W / (m·K) in at least one direction, as measured according to ASTM C1470. Examples of useful ceramic particles include boron nitride, which can be amorphous or in hexagonal, cubic, and / or wurtzite forms, and silicon nitride.

[0032] The ceramic particles have a particle size of up to 50 μm. Particle size herein refers to the longest dimension of the primary (unagglomerated) particle as determined using microscopy. Preferred minimum particle sizes are at least 100 nm, at least 250 nm, or at least 500 nm. Preferred maximum particle sizes are up to 20 μm, up to 10 μm, or up to 5 μm.

[0033] The ceramic particles comprise 2 to 25 weight percent of the combined weight of the elastomeric polymer, encapsulated phase change material particles, and ceramic particles, hi some embodiments, the ceramic particles comprise at least 5 weight percent or at least 8 weight percent on the same basis, and again up to 20 weight percent or up to 15 weight percent on the same basis.

[0034] In some embodiments, the coating is produced by forming an emulsion and / or dispersion of an elastomeric polymer, an encapsulated phase change material, and ceramic particles, applying the emulsion or dispersion to the surface of a polyurethane foam, and curing the emulsion to produce a cured coating. "Cured" is used in this context simply to mean that the coating composition is formed into a solid coating by any mechanism or combination of mechanisms appropriate for the particular elastomeric polymer present. It is not necessary for any chemical reaction (e.g., polymerization, crosslinking, chain extension, etc.) to occur during the curing step, although in some cases such reactions may occur. Curing may simply involve drying the applied emulsion or dispersion to produce a solid coating.

[0035] The coating composition in the form of an emulsion or dispersion comprises a continuous liquid phase. The continuous liquid phase contains water and / or one or more other compounds that are liquid at room temperature (23°C) and have a boiling point at standard pressure between 40 and 100°C. Such materials may, for example, constitute 10 to 50% of the total weight of the coating composition. The elastomeric polymer is dispersed in the continuous liquid phase in the form of particles or droplets. Particles of encapsulated phase-change material and ceramic particles are also dispersed therein. The emulsion is preferably aqueous, i.e., the continuous liquid phase comprises water. Preferably, the emulsion or dispersion contains no more than 10% by weight, in particular no more than 5% by weight, or no more than 2% by weight, of room-temperature liquid organic compounds that have a boiling point at standard pressure between 40 and 100°C, based on the combined weight of such organic compounds and water.

[0036] The elastomeric polymer may be present in an emulsion produced in an emulsion polymerization process in which one or more monomers are dissolved or dispersed in a liquid phase and subjected to polymerization conditions until the polymer chains precipitate and are converted into solid polymer particles dispersed in the liquid phase. The liquid phase in such an emulsion polymerization process may form part or all of the liquid phase of the emulsion or dispersion used to coat the polyurethane foam according to the present invention.

[0037] Similarly, emulsions or dispersions of elastomeric polymers can be produced in a mechanical dispersion process in which molten elastomeric polymer is dispersed in a liquid phase, which can form part or all of the liquid phase of the emulsion or dispersion used to coat polyurethane foams according to the present invention.

[0038] In yet another suitable process, the elastomeric polymer may be ground or otherwise formed into small particles which are then dispersed in a liquid phase.

[0039] The coating composition, in the preferred form of an emulsion and / or dispersion, is conveniently formed by combining an emulsion or dispersion of the elastomeric polymer with the phase change particles and ceramic particles in the proportions described above.

[0040] Such coating compositions may include one or more optional materials in addition to those already described.

[0041] Among the useful optional materials are one or more hydrophilic polymers that are liquid at room temperature (23°C) and have a weight-average molecular weight of 350 to 8,000, particularly 350 to 1200, or 350 to 800 g / mol, as measured by gel permeation chromatography. The hydrophilic polymer is preferably water-soluble. Such hydrophilic polymers may contain at least 50% or at least 75% by weight of oxyethylene units, for example, homopolymers of ethylene oxide or copolymers (random and / or block) of ethylene oxide with one or other alkylene oxides, such as 1,2-propylene oxide. When present, such hydrophilic polymers may constitute 0.1 to 15 percent of the combined weight of the hydrophilic polymer, elastomeric polymer, encapsulated phase-change material, and ceramic particles. Preferred amounts are at least 1, at least 2, at least 4, or at least 5 weight percent, and up to 12, up to 10, or up to 8 weight percent, on the same basis.

[0042] Another useful optional material is one or more surfactants, which can perform one or more useful functions. Such surfactants can function as wetting agents to facilitate dispersion of the phase change material particles and / or ceramic particles into the remaining components of the coating composition. Surfactants can also function as antifoaming or degassing agents to reduce gas entrainment by the coating composition and reduce bubbles. Various silicone surfactants are useful for these purposes, as well as various non-silicone surfactants, such as sulfate esters, sulfonate esters, phosphate esters, ethoxylates, fatty acid esters, amine oxides, sulfoxides, and phosphine oxides. Surfactants can be nonionic, anionic, cationic, or zwitterionic. The one or more surfactants can comprise, for example, 0.1 to 5 weight percent based on the total weight of the coating composition.

[0043] Other useful ingredients include various rheology modifiers, such as various thickeners and thixotropic agents. Among these are fumed silica and various water-soluble or water-swellable polymers of acrylic acid containing free acid or carboxylate groups (e.g., alkali metal, ammonium (NH4), quaternary ammonium, or quaternary phosphonium carboxylates). Particularly useful rheology modifiers include aqueous emulsions of crosslinked acrylic acid polymers, such as those sold by DuPont under the Acrysol® trade name. Specific examples are Acrysol® ASE-60 and Acrysol ASE-95. When present, such rheology modifiers may comprise, for example, 0.01 to 5 weight percent, preferably 0.05 to 1 weight percent, of the coating composition.

[0044] Still other useful ingredients include one or more colorants, preservatives, antioxidants, and biocides.

[0045] The coating composition is conveniently prepared by mixing the aforementioned components. If the elastomeric polymer is provided in the form of an emulsion or dispersion, it is convenient to mix the remaining components into the elastomeric polymer emulsion or dispersion in any convenient order while mixing to produce a homogeneous dispersion.

[0046] A useful method for producing the coating composition of the present invention is to charge a portion of the liquid phase into a container. The hydrophilic polymer, if used, is mixed with this portion of the liquid phase in the absence of the elastomeric polymer. The ceramic particles are then combined with the portion of the liquid phase (and hydrophilic polymer, if used) in the container, after which the elastomeric polymer, encapsulated phase change material, and other ingredients, preferably in the form of an emulsion or dispersion, are added in any convenient order.

[0047] In certain embodiments, the coating composition is prepared using an apparatus as shown schematically in Figure 1. Apparatus 1 includes a mixing vessel 2 having a curved bottom and straight (vertical) sides. The curved bottom and straight sides meet at tangent line 17. The straight sides define an inner diameter Y. In some embodiments, mixing vessel 2 lacks internal baffles. Apparatus 1 as shown includes an agitation system including motor 7, shaft 5, disperser impeller 4, and impeller 6. Shaft 4 is preferably oriented vertically within mixing vessel 2 along a central vertical axis. Disperser impeller 4 and impeller 6 are preferably oriented horizontally.

[0048] The disperser impeller 4 can be, for example, a Cowles blade impeller or a Conn blade impeller. The disperser impeller 4 preferably has an overall length D in the range of 0.35 to 0.7Y, in particular 0.45 to 0.55Y. The disperser impeller 4 is preferably at the same height as the tangent line 17 or no more than 10 cm or no more than 5 cm above or below the tangent line 17.

[0049] The impeller 6 is a pumping impeller such as an A320 type impeller from Chemineer or a Pitch Blade Turbine (PBT) impeller. The impeller 6 is preferably located on the shaft 5 above the disperser impeller 4 by a distance of 0.5D to 0.75D during operation. The impeller 6 is variably positionable along the vertical length of the shaft 5 so that its vertical position relative to the disperser impeller 4 can be adjusted. The impeller 6 preferably has an overall length in the range of 0.35 to 0.7Y, especially 0.45 to 0.55Y.

[0050] In an alternative design, the impeller 6 is positioned below the disperser impeller 4, preferably by a distance of 0.5D to 1D, in particular 0.65 to 0.85D, and the second impeller 6 is positioned on the shaft 5 above the disperser impeller 4, also preferably by a distance of 0.5D to 1D, in particular 0.65 to 0.85D.

[0051] Apparatus 1 further includes a powder container 8 for holding ceramic particles, and a powder dispenser 9 for dispensing the ceramic particles from powder container 8 into container 2. Powder dispenser 2 preferably allows for a variable and controllable rate of dispensing the powder.

[0052] The illustrated apparatus 1 further includes an optional recirculation loop 10, which includes conduit 14, valve 11, pump 12, and rotor stator 13, as shown. Recirculation loop 10 removes material from the bottom of mixing vessel 10 and transports the removed material to the top of mixing vessel 10, where it is reintroduced into mixing vessel 10. Rotor stator 13 provides additional mixing as needed.

[0053] In a preferred mixing process, all or part of the liquid phase is filled inside the mixing vessel 2. This preferably includes at least some water and a hydrophilic polymer, if used. The impeller 6 is positioned above the fluid level during the first step of mixing. The disperser impeller 4 is positioned below the surface of the fluid in the mixing vessel 2. The disperser impeller 4 rotates to agitate the fluid and create a vortex 16 on the surface 15 of the fluid in the reaction vessel 2. The Froude number of the disperser impeller 4 in this step can be, for example, 0.12 to 0.5 to create the desired vortex. Next, while maintaining the fluid level below the impeller 6 and continuing the agitation without the impeller 6 participating in the mixing, ceramic particles are added continuously or intermittently from the powder container 8 to the power vessel 2 via the powder dispenser 9. The powder dispenser 9 preferably dispenses the ceramic particles near the vortex to prevent the ceramic particles from falling down the shaft. The resulting mixture of fluid and ceramic particles can be stirred for a period of time after all the ceramic particles have been added.

[0054] The impeller 6 is then positioned below the surface 15 of the contents of the mixing vessel 2. The elastomeric polymer is then added, preferably in the form of an emulsion or dispersion in the more fluid phase, followed by the phase change material. Optional ingredients are added before, during, or after the addition of the elastomeric polymer and phase change material. Agitation is maintained during this step to maintain a vortex 16. After all ingredients have been added, agitation can be continued for a period of time. If desired, recirculation of the material can be established during this step via the recirculation loop 10. The shear rate within the rotor stator 13 is preferably 1000 s to avoid disruption of the encapsulation of the PCM microspheres. -1 The finished coating composition is then discharged for packaging, storage, shipping, and / or use.

[0055] The coating composition can be applied to at least one outer surface of the polyurethane foam. The coating method is not particularly important. Rolling, brushing, spraying, dipping, or other coating methods are suitable.

[0056] Preferably, enough coating composition is applied to produce a cured coating having a thickness of 100 μm to 10 mm after curing. The coating thickness is preferably at least 250 μm or at least 350 μm, and up to 2,500 μm, up to 1500 μm, or up to 1000 μm.

[0057] The coating composition is cured on the surface of the polyurethane foam. The curing method may depend somewhat on the particular elastomeric polymer and / or physical form of the coating composition. Curing of a coating composition in emulsion form involves at least a drying step to remove water and / or one or more other compounds that are liquid at room temperature (23°C) and have a boiling point of 40-100°C at standard pressure, as may be present in the coating composition. Such a drying step may be carried out at about room temperature, such as 15-30°C, or at an elevated temperature, such as above 30°C to 100°C or higher.

[0058] When the curing involves a chemical reaction (e.g., polymerization, crosslinking, or chain extension, etc.), the conditions of the curing reaction, such as temperature, the presence of co-reactants, catalysts, initiators, etc. not otherwise present in the coating composition, etc., are selected to promote the chemical reaction to complete the cure.

[0059] In some embodiments, the coated foam exhibits a microtexture roughness value of up to 50, preferably 20-45, a microtexture roughness value of up to 20, preferably 8-18, a sticky tack value of up to 15, preferably 5-10, a heat cooling value of at least 8, preferably 9-15, and a heat persistence value of at least 8, preferably 10-15, when measured using a BioTac® Toccare instrument as described in the Examples below. In some embodiments, the coated foam exhibits a durometer hardness of up to 15 on the 00 scale when measured according to ASTM D2240.

[0060] The following examples are presented to illustrate the invention but are not intended to limit its scope. All parts and percentages are by weight unless otherwise indicated.

[0061] The degassing agent is a polyether siloxane copolymer with fumed silica sold by Evonik as Tego Airex 904W.

[0062] The emulsion is an acrylic latex polymer emulsion with 55% solids by weight. The latex particles are heated to a temperature of -50°C. g The emulsion is available as Rhoplex 3166 from The Dow Chemical Company.

[0063] PEG is a polyethylene glycol with an average nominal hydroxyl functionality of 2 and a number average molecular weight of about 600 g / mole.

[0064] The silicone surfactant is available from The Dow Chemical Company under the trade name DC-52.

[0065] RM (Rheology Modifier) ​​1 is an aqueous emulsion containing crosslinked acrylate polymer particles with acid groups. The solids content is 28%. When diluted with water and neutralized with base (NH4OH), the product functions as a thickener.

[0066] RM2 is an aqueous emulsion containing cross-linked acrylate polymer particles with acid groups. The solids content is 18%. When diluted with water and neutralized with base (NH4OH), the product functions as a thickener.

[0067] NH4OH is a 28-30% ammonium hydroxide solution for neutralizing RM1 and / or RM2.

[0068] BN is boron nitride (at least 98% pure) in the form of platelets having a longest dimension of about 1-3 μm, available from Wego Chemical.

[0069] PCM1 is a microencapsulated paraffin wax with particle sizes of 15-30 μm. The wax comprises 85-90% of the material's weight, and the polymer shell comprises the remainder of the product's weight. The phase change material has a melting point of approximately 28°C. The product has a melting enthalpy of 180-190 J / g. It is commercially available from Microtek Laboratories as MPCM 28D.

[0070] PCM2 is a microencapsulated paraffin wax with particle sizes of 15-30 μm. The wax comprises 85-90% of the material's weight, and the polymer shell comprises the remainder of the product's weight. The phase change material has a melting point of approximately 32°C. The product has a melting enthalpy of 160-170 J / g. It is commercially available from Microtek Laboratories as MPCM 32D.

[0071] PCM3 is a microencapsulated paraffin wax with particle sizes of 14-24 μm. The wax comprises 85-90% of the material's weight, and the polymer shell comprises the remainder of the product's weight. The phase change material has a melting point of approximately 28°C. The product has a melting enthalpy of 180-190 J / g. It is commercially available from Microtek Laboratories as Nextek 28D.

[0072] PCM4 is a microencapsulated paraffin wax with particle sizes of 15-30 μm. The wax comprises 85-90% of the material's weight, and the polymer shell comprises the remainder of the product's weight. The phase change material has a melting point of approximately 32°C. The product has an enthalpy of fusion of approximately 170 J / g. It is commercially available from Microtek Laboratories as Nextek 32D.

[0073] The coating composition is made from the ingredients listed in Table 1 by combining them and mixing them in a high speed laboratory mixer to produce a homogeneous mixture.

[0074] [Table 1] * It is not an embodiment of the present invention. 1 PCM and filler material based on the total weight of the elastomeric polymer. The filler is BN, Al, Cu, or graphite as indicated.

[0075] The coating composition is used to produce a coating on a viscoelastic polyurethane foam. A weighed amount of the coating composition is poured onto the top surface of the foam sample and spread using a roller brush to form a coating over an area of ​​approximately 316 cm. 2 The applied coating is cured by heating the coated foam at 80°C for 20 minutes, producing a coating with a thickness of approximately 500 µm.

[0076] The coating composition is such that the cured coating has a T of less than -15°C in each case in the absence of a phase change material and a filler. g It is formulated to have the following:

[0077] The microtexture roughness, microtexture roughness, adhesive tack, thermal cooling, and thermal persistence of the coated surface were evaluated using a BioTac® Toccare instrument (Suntouch, Montrose, CA), which reports the value of each attribute on a relative scale. For the intended bedding application, lower values ​​for microtexture roughness, microtexture roughness, and adhesive tack are preferred, while higher values ​​for thermal cooling and thermal persistence are preferred. In addition, the hardness (Durometer 00 scale) of the coating was measured using a durometer according to ASTM D2240. The results are shown in Table 2 below.

[0078] [Table 2] * It is not an embodiment of the present invention. 1 Rating on a relative scale generated by the testing device. ND = Not Determined.

[0079] Comparative Sample A, which does not contain boron nitride or other ceramics, exhibits good microtexture properties but is relatively tacky. It has acceptable thermal properties. Example 1 shows the effect of incorporating boron nitride particles into the coating composition of Comparative Sample A. It improves the microtexture properties and dramatically reduces tack. Thermal cooling and durability are each improved by 5-8%.

[0080] Examples 2 and 3 demonstrate the effect of removing PEG and surfactant, respectively, from the coating composition of Example 1. The adhesive tack remains low and the thermal properties are further improved. However, some loss of microtexture performance is observed, suggesting that including PEG and surfactant is preferable.

[0081] Example 4 is a repeat of Example 1, except that a different phase change material is used. This sample has excellent properties in all respects. The microtexture roughness and coarseness are very low, as is the adhesive tack, and the thermal properties are substantially improved compared to Example 1 and Comparative Sample A.

[0082] Comparative Samples B, C, and D demonstrate the effect of using alternative thermally conductive materials in place of boron nitride. Aluminum (Comparative B) provides very poor thermal properties. Copper (Comparative C) and graphite (Comparative D) each provide good tack and thermal properties, but their microtexture properties are much worse than those of Examples 1 and 2 (which, like Comparative C and Comparative D, contain PEG and silicone surfactants). In addition, Comparative Samples B, C, and D are all highly pigmented due to the incorporation of metal or graphite filler particles. Comparative Sample D is particularly black and cannot be colored through the use of other dyes or pigments. The present invention may include the following aspects. [1] An article comprising a flexible polyurethane foam and a cured coating of a solid, water-insoluble elastomeric polymer adhered to at least one surface of the flexible polyurethane foam, wherein the cured coating has embedded therein (i) particles of an encapsulated phase change material, the phase change material having a melting temperature or glass transition temperature of 25-37°C, and (ii) ceramic particles having a particle size of up to 50 μm, wherein the encapsulated phase change material comprises 10-70 weight percent of the combined weight of the cured coating, encapsulated phase change material particles, and ceramic particles, and the ceramic particles comprise 2-25 weight percent of the combined weight of the elastomeric polymer, encapsulated phase change material particles, and ceramic particles. [2] The article according to [1], wherein the cured coating has a thickness of 100 to 2500 μm. [3] The article of [1] or [2], wherein the phase change material comprises any one or more of natural or synthetic waxes such as polyethylene wax, beeswax, lanolin, carnauba wax, candelilla wax, ouricle wax, sugarcane wax, jojoba wax, epicuticular wax, coconut wax, petroleum wax, or paraffin wax. [4] The flexible polyurethane foam before coating has a compressive strength of 32 to 92 kg / m 3 The article according to any one of [1] to [3], having a density of 1 to 10 seconds and exhibiting an elasticity of less than 20%. [5] The article according to any one of [1] to [4], wherein the ceramic particles are boron nitride or silicon nitride particles having a particle size of 100 to 3000 μm. [6] The article according to any one of [1] to [5], wherein the phase change material comprises 40 to 60 percent of the total weight of the elastomeric polymer, encapsulated phase change material particles, and ceramic particles. [7] The article according to any one of [1] to [6], wherein the ceramic particles constitute 8 to 20 percent of the total weight of the elastomeric polymer, encapsulated phase change material particles, and ceramic particles. [8] The article of any one of [1] to [7], wherein the cured coating further contains a hydrophilic polymer that is liquid at 23°C and has a weight average molecular weight of 350 to 8000 g / mol, and the hydrophilic polymer constitutes 0.1 to 15 percent of the total weight of the elastomeric polymer, encapsulated phase change material particles, ceramic particles, and hydrophilic polymer. [9] A coating composition comprising: a liquid phase containing water and / or one or more other compounds that are liquid at 23°C and have a boiling point of 40-100°C at standard pressure; a water-insoluble elastomeric polymer dispersed in the liquid phase in the form of particles or droplets; particles of an encapsulated phase change material dispersed in the liquid phase; and ceramic particles dispersed in the liquid phase, wherein the phase change material constitutes 40-60 percent of the total weight of the elastomeric polymer, encapsulated phase change material particles, and ceramic particles, and the ceramic particles constitutes 8-20 percent of the total weight of the elastomeric polymer, encapsulated phase change material particles, and ceramic particles.

[10] The coating composition according to [9], wherein the phase change material comprises any one or more of natural or synthetic waxes such as polyethylene wax, beeswax, lanolin, carnauba wax, candelilla wax, ouricle wax, sugarcane wax, jojoba wax, epicuticular wax, coconut wax, petroleum wax, or paraffin wax, and the ceramic particles are boron nitride or silicon nitride particles having a particle size of 100 to 3000 μm.

[11] The coating composition according to [9] or

[10] , further comprising a hydrophilic polymer that is liquid at 23°C and has a weight-average molecular weight of 350 to 8000 g / mol, wherein the hydrophilic polymer constitutes 0.1 to 15 percent of the total weight of the elastomeric polymer, encapsulated phase-change material particles, ceramic particles, and hydrophilic polymer.

[12] A method for preparing the coating composition according to any one of [9] to

[11] , A. Charging all or a portion of the liquid phase inside a mixing vessel equipped with an agitation system including a motor, a shaft, a disperser impeller, and at least one pumping impeller. B. creating a vortex on the surface of the liquid phase while maintaining the pumping impeller above the surface of the liquid phase in the mixing vessel; C. adding said ceramic particles to said liquid phase. D. Adding the elastomeric polymer and an additional liquid phase to the liquid phase. E. Adding the encapsulated phase change material to the liquid phase. A method comprising:

Claims

1. 1. An article comprising: a flexible polyurethane foam; and a cured coating of a solid, water-insoluble elastomeric polymer adhered to at least one surface of the flexible polyurethane foam, wherein the cured coating has embedded therein (i) particles of an encapsulated phase change material, the phase change material having a melting temperature or glass transition temperature of 25-37°C; and (ii) boron nitride particles having a particle size of up to 50 μm, wherein the encapsulated phase change material comprises 10-70 weight percent of the combined weight of the cured coating, encapsulated phase change material particles, and boron nitride particles, and the boron nitride particles comprise 2-25 weight percent of the combined weight of the elastomeric polymer, encapsulated phase change material particles, and boron nitride particles.

2. The article of claim 1, wherein the cured coating has a thickness of from 100 to 2500 μm.

3. 3. The article of claim 1 or 2, wherein the phase change material comprises any one or more of natural or synthetic waxes selected from the group consisting of polyethylene wax, beeswax, lanolin, carnauba wax, candelilla wax, ouricle wax, sugarcane wax, jojoba wax, epicuticular wax, coconut wax, petroleum wax, and paraffin wax.

4. The flexible polyurethane foam before coating has a strength of 32 to 92 kg / m ３ 4. The article of claim 1, having a density of 0.1 to 0.5, and exhibiting a recovery time of 1 to 10 seconds and a resilience of less than 20%.

5. The article of any one of claims 1 to 4, wherein the boron nitride particles have a particle size of 100 to 3000 nm.

6. The article of any one of claims 1 to 5, wherein the phase change material comprises 40 to 60 percent of the total weight of the elastomeric polymer, encapsulated phase change material particles, and boron nitride particles.

7. The article of any one of claims 1 to 6, wherein the boron nitride particles comprise 8 to 20 percent of the total weight of the elastomeric polymer, encapsulated phase change material particles, and boron nitride particles.

8. 8. The article of any one of claims 1 to 7, wherein the cured coating further comprises a hydrophilic polymer that is liquid at 23°C and has a weight average molecular weight of 350 to 8000 g / mol, the hydrophilic polymer comprising 0.1 to 15 percent of the total weight of the elastomeric polymer, encapsulated phase change material particles, boron nitride particles, and hydrophilic polymer.

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