Polyurethane Foams for Comfort Applications

Abstract

Hydrophilic polyurethane foams, yet with low compression set, are made from a combination of MDI and TDI prepolymers, water, and polymer polyols. The foams are made by optionally incorporating a phase change material into the foam formulation. The phase change material does not require encapsulation.

Description

[Technical Field]

[0001] The present invention relates to flexible polyurethane foams useful in comfort applications such as pillows, mattresses, mattress toppers, and seat cushions.

[0002] Polyurethane foams are used in great volume to make cushioning, especially for bedding and seats. The problem with these foams is that they do not transfer heat very effectively. Thus, heat released by the user is trapped by the foam in areas closely adjacent to the user's body. This results in localized temperature increases that the user often finds uncomfortable.

[0003] Various approaches have been proposed to address this problem. Increasing the porosity of the foam significantly helps air to easily move in and out of the foam. Making the foam more hydrophilic allows it to wick moisture, such as sweat, away from the user's body more effectively, thus contributing to improved comfort. So-called "gel technology" is used to impart a cooling sensation, which is important in store.

[0004] None of these approaches have been entirely satisfactory. Foams that are highly porous and have high airflow are "breathable" but may lack the necessary load-bearing properties. Hydrophilic foams tend to have poor compression set, which results in permanent deformation, sagging, or the formation of depressions during normal use of the foam. Modification of the formulation to reduce compression set tends to reduce airflow. Hydrophilic foams also lack the "cool feel" characteristic desired in store.

[0005] Phase change materials or "gels" are often used to impart a "cool feel" characteristic. These materials have a melting or phase transition temperature that is about room temperature or slightly above room temperature. They effectively absorb body heat to the touch when the material undergoes its phase change. This causes a cooling sensation upon initial contact.

[0006] Gels are used as surface toppers or are injected into foam. Because gels are not breathable, they do not transfer heat effectively. When gels are heated to body temperature, they tend to trap heat rather than dissipate it. Because gels also tend to be sticky, they are usually encapsulated in polymer films, which further reduces their breathability and exacerbates the problem.

[0007] Polyurethane foams that exhibit good moisture absorption along with low compression set are desired for use in bedding and other comfort applications. Ideally, the foams also exhibit high airflow and a cool to the touch feel.

[0008] In one aspect, the present invention provides a flexible polyurethane foam, comprising: a) an isocyanate mixture, a-1) a first isocyanate-functional prepolymer, the first isocyanate-functional prepolymer being the reaction product of at least one hydroxyl-terminated polymer of ethylene oxide and optionally a hydroxyl-functional branching agent and / or a hydroxyl-functional chain extender, with an excess of diphenylmethane diisocyanate, wherein at least 50% by weight of the diphenylmethane diisocyanate is 4,4'-diphenylmethane diisocyanate; a-2) optionally diphenylmethane diisocyanate, wherein components a-1) and a-2) together have an isocyanate content of 5 to 15 weight percent and contain 30 to 75 weight percent oxyethylene units, based on the combined weight of components a-1) and a-2), and components a-1) and a-2) together constitute 40 to 60% of the total weight of the isocyanate mixture; a-3) a second isocyanate-functional prepolymer, the second isocyanate-functional prepolymer being the reaction product of at least one hydroxyl-terminated polymer of ethylene oxide and a hydroxy-functional branching agent having at least three hydroxyl groups per molecule and a hydroxyl equivalent weight of up to 250 g / eq, with an excess of toluene diisocyanate; a-4) optionally toluene diisocyanate, wherein a-3) and a-4) together have an isocyanate content of 5 to 15 weight percent, based on the combined weight of components a-3) and a-4), and contain 30 to 75 weight percent oxyethylene units and 2 to 5 weight percent residues from a hydroxyl-functional branching agent, based on the combined weight of components a-3) and a-4), wherein components a-3) and a-4) together constitute 40 to 60% of the total weight of the isocyanate mixture, and components a-1), a-2), a-3), and a-4) together constitute the entire weight of the isocyanate mixture; b) water; c) at least one polymer polyol comprising polymer particles dispersed in at least one base polyol, the base polyol being a polyether having at least 50% by weight of oxypropylene units and a hydroxyl equivalent weight of 500 to 3000 g / equivalent; d) optionally poly(ethylene oxide), wherein the poly(ethylene oxide) is a homopolymer of an ethylene oxide homopolymer or a random and / or block copolymer of at least 80% by weight ethylene oxide and up to 20% by weight of another alkylene oxide, the poly(ethylene oxide) having a number average molecular weight of 400 to 1200 g / mole; at least one of e) and f), wherein e) is at least one silicone surfactant and f) is at least one ethylene oxide / higher alkylene oxide block copolymer, the block copolymer containing 40 to 90% by weight of oxyethylene units and having a number average molecular weight of 1500 to 12,000 g / mole; and optionally, g) at least one phase change material having a melting temperature or glass transition temperature of 25-37°C and not containing isocyanate groups or isocyanate-reactive groups; i) the isocyanate mixture constitutes 40 to 65% of the total weight of components a to g; ii) water constitutes 15 to 41% of the total weight of components a to g; iii) at least one polymer polyol constitutes 8 to 20% of the total weight of components a to g, and polymer particles constitute 0.5 to 10% of the total weight of components a to g; iv) poly(ethylene oxide), when present, constitutes up to 5% by total weight of components a-g; v) at least one silicone surfactant comprises 0-3% of the total weight of components a-g; vi) at least one ethylene oxide / higher alkylene oxide block copolymer comprises 0-3% of the combined weight of components a-g; vii) at least one phase change material comprises up to 15% of the total weight of components a-g; viii) A flexible polyurethane foam, wherein components ag constitute at least 95% by weight of the reaction mixture.

[0009] The flexible polyurethane foams produced in accordance with the present invention possess a unique combination of properties that make them particularly desirable for use in bedding, sheeting, and other "comfort" applications where the foam is exposed to the body heat of a human occupant and / or water vapor evaporating therefrom. These properties include very low compression set, good moisture absorption behavior, and suitable density. In preferred embodiments, these properties also exhibit good airflow and / or a non-zero latent heat in the temperature range of 25-37°C. Good airflow and a non-zero latent heat each result in the foam's "cool feel" characteristics. The foam, or articles containing the foam, may support at least a portion of the weight of a human occupant in such applications.

[0010] The present invention also provides a method for making a flexible polyurethane foam, comprising the steps of: A. forming a reaction mixture, the reaction mixture comprising: a) an isocyanate mixture, a-1) a first isocyanate-functional prepolymer, the first isocyanate-functional prepolymer being the reaction product of at least one hydroxyl-terminated polymer of ethylene oxide and optionally a hydroxyl-functional branching agent and / or a hydroxyl-functional chain extender, with an excess of diphenylmethane diisocyanate, wherein at least 50% by weight of the diphenylmethane diisocyanate is 4,4'-diphenylmethane diisocyanate; a-2) optionally diphenylmethane diisocyanate, wherein components a-1) and a-2) together have an isocyanate content of 5 to 15 weight percent and contain 30 to 75 weight percent oxyethylene units, based on the combined weight of components a-1) and a-2), and components a-1) and a-2) together constitute 40 to 60% of the total weight of the isocyanate mixture; a-3) a second isocyanate-functional prepolymer, the second isocyanate-functional prepolymer being the reaction product of at least one hydroxyl-terminated polymer of ethylene oxide and a hydroxyl-functional branching agent having at least three hydroxyl groups per molecule and a hydroxyl equivalent weight of up to 250 g / eq, with an excess of toluene diisocyanate; a-4) optionally, an isocyanate mixture comprising toluene diisocyanate, wherein a-3) and a-4) together have an isocyanate content of 5 to 15 weight percent, based on the combined weight of components a-3) and a-4), and contain 30 to 75 weight percent oxyethylene units and 2 to 5 weight percent residues from a hydroxyl-functional branching agent, based on the combined weight of components a-3) and a-4), wherein components a-3) and a-4) together constitute 40 to 60% of the total weight of the isocyanate mixture, and components a-1), a-2), a-3), and a-4) together constitute the entire weight of the isocyanate mixture; b) water; c) at least one polymer polyol comprising polymer particles dispersed in at least one base polyol, the base polyol being a polyether having at least 50% by weight of oxypropylene units and a hydroxyl equivalent weight of 500 to 3000 g / equivalent; d) optionally, poly(ethylene oxide), wherein the poly(ethylene oxide) is a homopolymer of an ethylene oxide homopolymer or a random and / or block copolymer of at least 80% by weight ethylene oxide and up to 20% by weight of another alkylene oxide, the poly(ethylene oxide) having a number average molecular weight of 400 to 1200 g / mole; at least one of e) and f), wherein e) is at least one silicone surfactant and f) is at least one ethylene oxide / higher alkylene oxide block copolymer, the block copolymer containing 40 to 90% by weight of oxyethylene units and having a number average molecular weight of 1500 to 12,000 g / mole; and optionally, g) at least one phase change material having a melting temperature or glass transition temperature of 25-37°C and not containing isocyanate groups or isocyanate-reactive groups; i) the isocyanate mixture constitutes 40 to 65% of the total weight of components a to g; ii) water constitutes 15 to 41% of the total weight of components a to g; iii) at least one polymer polyol constitutes 8 to 20% of the total weight of components a to g, and polymer particles constitute 0.5 to 10% of the total weight of components a to g; iv) poly(ethylene oxide), when present, constitutes up to 5% by total weight of components a-g; v) at least one silicone surfactant comprises 0-3% of the total weight of components a-g; vi) at least one ethylene oxide / higher alkylene oxide block copolymer comprises 0-3% of the combined weight of components a-g; vii) at least one phase change material comprises up to 15% of the total weight of components a-g; viii) forming components a-g, wherein components a-g constitute at least 95% by weight of the reaction mixture; B. reacting the reaction mixture to produce a foam.

[0011] Component a-1) of the isocyanate mixture is a first isocyanate-terminated prepolymer that is the reaction product of at least one hydroxyl-terminated polymer of ethylene oxide and, optionally, a hydroxyl-containing branching agent and / or chain extender with an excess of diphenylmethane diisocyanate (MDI). At least 50% by weight of the MDI is the 4,4'-isomer. In some embodiments, the 4,4'-isomer constitutes at least 60 or at least 70% by weight of the diphenylmethane diisocyanate used to make the prepolymer. Up to 100% of the diphenylmethane diisocyanate can be the 4,4'-isomer. The 2,4'-isomer, if present, can constitute at least 5%, at least 10%, or at least 15% by weight of the diphenylmethane diisocyanate. The 2,2'-isomer, when present, may constitute up to 5%, or up to 2%, by weight of the diphenylmethane diisocyanate used to make the prepolymer.

[0012] The ethylene oxide polymer is conveniently a hydroxyl-terminated homopolymer of ethylene oxide or a hydroxyl-terminated random or block copolymer of ethylene oxide and 1,2-propylene oxide. The polyether may contain, for example, at least 50% or at least 60% by weight of oxyethylene groups, and as many as 100% by weight of oxyethylene groups. A particularly interesting polyether is a poly(ethylene oxide) homopolymer. Another is a random or block copolymer of ethylene oxide and 1,2-propylene oxide containing 50 to 99%, preferably 60 to 95%, of oxyethylene groups, and correspondingly 5 to 50%, preferably 5 to 40%, of methyloxyethylene (oxypropylene) groups.

[0013] The polyether may nominally contain, for example, a number average of 2 to 4 hydroxyl groups per molecule. A preferred nominal average hydroxyl functionality is 2 to 3, with a more preferred nominal average hydroxyl functionality being 2 to 2.5 or 2 to 2.25. Nominal functionality refers to the number of oxyalkylatable groups on the initiator compound used to produce the polyether. A primary amino group is considered to contain two oxyalkylatable sites for purposes of this invention.

[0014] The hydroxyl equivalent weight of the polyether is preferably at least 300 or at least 450, and can be, for example, up to 6000, up to 3000, or up to 2000 g / equivalent. A particularly preferred equivalent weight range is 500 to 1800 g / equivalent. All hydroxyl equivalent weights herein are determined by titration methods such as ASTM D4274-99.

[0015] A mixture of two or more of the polyethers described above may be used to make the first isocyanate-terminated prepolymer.

[0016] The first isocyanate-functional prepolymer is conveniently prepared by mixing MDI with a polyether and subjecting the mixture to conditions under which a portion of the isocyanate groups react with the hydroxyl groups of the polyether to form urethane linkages. A hydroxyl-containing branching agent and / or chain extender is optionally present when the first isocyanate-functional prepolymer is formed. Such branching agents or chain extenders may have a hydroxyl equivalent weight of up to 250 or up to 125, and may have at least 3 (preferably 3-8, 3-6, or 3-4) hydroxyl groups per molecule in the case of branching agents, and exactly 2 hydroxyl groups per molecule in the case of chain extenders. If present, they are suitably present in an amount of up to 5 parts by weight, preferably up to 2 parts by weight, per 100 parts by weight of polyether.

[0017] The prepolymer-forming reaction is conveniently carried out at elevated temperatures (e.g., 60-180°C), preferably under an inert atmosphere such as nitrogen, helium, or argon. An excess of isocyanate groups relative to hydroxyl groups is provided; in some embodiments, MDI, polyether, and optional branching and / or chain extender are combined in a ratio of 0.95 to 1.5, particularly 0.95 to 1.25, moles of polyisocyanate per equivalent of hydroxyl groups. The reaction is generally continued until the prepolymer reaches a constant isocyanate content, indicating that essentially all of the hydroxyl groups of the polyether have been consumed.

[0018] The first isocyanate-terminated prepolymer is preferably made substantially in the absence of a urethane catalyst, i.e., a catalyst that reacts isocyanate groups with hydroxyl groups to form a urethane. In particular, the reaction mixture for forming the first isocyanate-functional prepolymer preferably contains no more than 1 parts per million by weight of metals and no more than 100 parts per million by weight of amine compounds. Accordingly, the resulting first isocyanate-terminated prepolymer will similarly contain small amounts of such materials, if present at all. The polyether is preferably not amine-initiated and does not contain amine groups that would otherwise exhibit activity as a urethane catalyst.

[0019] The product of the prepolymer-forming reaction may contain some amount of unreacted MDI, which, if present, forms all or part of component a-2) of the isocyanate mixture. The MDI may be combined separately with the first isocyanate-functional prepolymer and / or with the other ingredients of the isocyanate mixture, if desired.

[0020] The first isocyanate-functional prepolymer and any free MDI in the isocyanate mixture together have an isocyanate content of 5 to 15%, based on the total weight of the first isocyanate-functional prepolymer and free MDI. The isocyanate content can be at least 6% or at least 7% by weight, for example, up to 12% or up to 10% by weight, on the same basis. The isocyanate content can be determined using well-known titration methods.

[0021] The first isocyanate-functional prepolymer and any free MDI in the isocyanate mixture together contain 30 to 70 weight percent oxyethylene units, based on the total weight of the first isocyanate-functional prepolymer and free MDI. The oxyethylene unit content can be at least 40 weight percent, at least 50 weight percent, or at least 55 weight percent and up to 70 weight percent or up to 65 weight percent on the same basis. The percentage of oxyethylene units is a calculated value determined using the following relationship:

[0022]

number

[0023] Component a-3) of the isocyanate mixture is a second isocyanate-terminated prepolymer, which is the reaction product of at least one hydroxyl-terminated polymer of ethylene oxide and a hydroxyl-containing branching agent with excess toluene diisocyanate (TDI). The TDI can be the 2,4-, 2,5-, or 2,6-isomer, or a mixture of any two or more thereof. In some embodiments, the TDI is a mixture of 50 to 85% 2,4-isomer and the remaining 2,6-isomer.

[0024] The hydroxyl-terminated polymer of ethylene oxide is as described above in connection with the first isocyanate-functional prepolymer.

[0025] The branching agent is generally as described with respect to the first isocyanate-functional prepolymer. The branching agent has at least three hydroxyl groups per molecule, and in some embodiments, 3 to 8, 3 to 6, or 3 to 4 hydroxyl groups per molecule. Its hydroxyl equivalent weight can be up to 250, up to 125, or up to 80. Examples include any one or more of the foregoing having the foregoing hydroxyl equivalent weights: glycerin, trimethylolpropane, trimethylolethane, sorbitol, mannitol, sucrose, pentaerythritol, erythritol, triethanolamine, and alkoxylates.

[0026] The amount of branching agent is selected so that the residues of the branching agent constitute 2-5%, preferably 3-5%, of the combined weight of components a-3) and a-4). The weight of the residues is calculated from the weights of the starting materials used in making components a-3) and a-4) as follows:

[0027]

number

[0028] The second isocyanate-functional prepolymer is conveniently prepared in a manner similar to that described above for making the first isocyanate-functional prepolymer, substituting TDI for MDI. The second isocyanate-terminated prepolymer is also preferably prepared substantially in the absence of a urethane catalyst, i.e., a catalyst for reacting isocyanate groups with hydroxyl groups to form urethanes. In particular, the reaction mixture for forming the second isocyanate-functional prepolymer preferably contains no more than 1 part per million by weight of metals and no more than 100 parts per million by weight of amine compounds. Accordingly, the resulting second isocyanate-functional prepolymer will similarly contain small amounts of such materials, if present at all. As previously mentioned, the polyether is preferably not amine-initiated and does not contain amine groups that would otherwise exhibit activity as a urethane catalyst.

[0029] The product of the prepolymer-forming reaction may contain some amount of unreacted TDI, which, if present, forms all or part of component a-4) of the isocyanate mixture. The TDI can be combined separately with the second isocyanate-functional prepolymer and / or with other ingredients of the isocyanate mixture, if desired.

[0030] The second isocyanate-functional prepolymer and any free TDI in the isocyanate mixture together have an isocyanate content of 5 to 15% based on the combined weight of the second isocyanate-functional prepolymer and free TDI. The isocyanate content can be at least 6% or at least 7% by weight, for example, up to 12% or up to 10% by weight, on the same basis.

[0031] The second isocyanate-functional prepolymer and any free TDI in the isocyanate mixture together contain 30 to 70 weight percent oxyethylene units, based on the total weight of the second isocyanate-functional prepolymer and free TDI. The oxyethylene unit content can be at least 40 weight percent or at least 50 weight percent on the same basis. The percentage of oxyethylene units is a calculation calculated in a manner similar to that described above, substituting the weight of TDI for the weight of MDI.

[0032] The isocyanate mixture comprises 40-65% of the combined weight of components a-g. In some embodiments, the isocyanate mixture comprises at least 45% of the combined weight of components a-g, and up to 62.5%, up to 60%, or up to 55% of the combined weight of components a-g.

[0033] Water (component b)) constitutes 15 to 41% of the combined weight of components a to g. Water may constitute at least 17%, at least 19%, or at least 20%, and may constitute up to 35% or up to 30%.

[0034] The polymer polyol (component c)) is a dispersion of polymer particles in a liquid base polyol, with the base polyol forming the continuous phase. Some or all of the polymer particles may be grafted to the base polyol. The polymer polyol may also contain one or more stabilizers to which some or all of the polymer particles may be grafted.

[0035] The base polyol is one or more polyethers having a hydroxyl equivalent weight of 500 to 3000 g / eq. The hydroxyl equivalent weight can be at least 800, at least 1000, or at least 1200, for example, up to 2500, up to 2000, or up to 1800 g / eq. The base polyol is a polymer or copolymer of propylene oxide containing at least 50% by weight of oxypropylene units. Homopolymers of propylene oxide and random and / or block copolymers of 50 to 99% by weight propylene oxide and 1 to 50% ethylene oxide are particularly useful base polyols.

[0036] The base polyol may have a nominal functionality of 2 to 6, particularly 2 to 4, and most preferably 2 to 3. The actual functionality may in some cases be somewhat lower than the nominal functionality.

[0037] A particularly preferred type of base polyol is made by homopolymerizing propylene oxide or randomly copolymerizing 75 to 99.9 weight percent propylene oxide with, correspondingly, 0.1 to 25 weight percent ethylene oxide over a difunctional or trifunctional initiator, and optionally capping the resulting polyether with up to 30 weight percent ethylene oxide (based on total product weight) to form a base polyol having predominantly primary hydroxyl groups.

[0038] The dispersed polymer particles may, for example, constitute at least 1, at least 5, or at least 10 percent of the total weight of the polymer polyol, and may, for example, constitute up to 60 percent, up to 50%, up to 40%, up to 30%, or up to 20% of its total weight.

[0039] In some embodiments, the dispersed polymer particles have a particle size of 100 nm to 25 μm, more typically 250 nm to 10 μm. Preferably, at least 90% by volume of the dispersed polymer particles have a size within these ranges. Particle size is taken as the diameter of a sphere having an equivalent volume. Particle size measurements can be obtained by laser diffraction techniques using an instrument such as a Beckman-Coulter LX13320 Laser Diffraction Particle Size Analyzer.

[0040] The dispersed polymer particles can be, for example, polyurea, polyurethane, and / or polyhydrazide, and / or polymers of one or more vinyl monomers. Useful vinyl monomers include, for example, various polyolefins (such as polymers and copolymers of ethylene), various polyesters, various polyamides, various polycarbonates, various polymers and copolymers of acrylic and / or methacrylic acid esters, homopolymers or copolymers of styrene, homopolymers or copolymers of acrylonitrile, and the like. In some embodiments, the dispersed particles are styrene-acrylonitrile copolymer particles.

[0041] At least a portion of the dispersed polymer particles are preferably grafted to at least a portion of the stabilizer and / or base polyol molecules that form the continuous phase.

[0042] Dispersions of polyurea particles can be prepared by reacting a primary or secondary amine with a polyisocyanate in the presence of a base polyol. Methods for producing polyurea dispersions are described, for example, in WO 2012 / 154831.

[0043] Dispersions of polyurethane particles can be prepared by reacting a low equivalent weight polyol or aminoalcohol with a polyisocyanate in the presence of a base polyol. Methods for producing such dispersions are described, for example, in U.S. Pat. No. 4,305,857, WO 94 / 20558, and WO 2012 / 154820.

[0044] Dispersions of polymerized vinyl monomers can be prepared by in situ polymerization of such monomers in a base polyol. Such methods are described, for example, in U.S. Pat. Nos. 4,513,124, 4,588,830, 4,640,935, and 5,854,386. Alternatively, dispersions of this type can be formed by a melt dispersion process in which a previously formed vinyl polymer is melted and dispersed in a base polyol. This type of process is described in U.S. Pat. No. 6,613,827 and WO 2009 / 155427.

[0045] The polymer polyol comprises at least 8 percent of the combined weight of components a-g. In some embodiments, the polymer polyol comprises at least 9 percent of that. The polymer polyol comprises up to 20% of the combined weight of components a-e, and may comprise up to 18%, up to 15%, or up to 12% of that.

[0046] The dispersed polymer particles constitute 0.5 to 10% of the combined weight of components a to g. The dispersed polymer particles may constitute at least 1%, at least 2%, or at least 4%, and up to 8%.

[0047] The polymer polyol preferably contains no more than 5 parts per million by weight or no more than 1 part per million by weight of metal and no more than 100 parts per million of amine compound. The base polyol is preferably not amine-initiated or does not contain amine groups that would otherwise be active as a urethane catalyst.

[0048] Poly(ethylene oxide) (component d)) is a homopolymer of ethylene oxide or a random and / or block copolymer of alkylene oxide, in which at least 80% by weight of the alkylene oxide is ethylene oxide and up to 20% by weight of one or more other alkylene oxides. The other alkylene oxide, if present, can include or be 1,2-propylene oxide. The poly(ethylene oxide) can have a molecular weight of 400 to 1200 g / mole by GPC. The poly(ethylene oxide) preferably contains at least one hydroxyl group per molecule. The poly(ethylene oxide) more preferably contains nominally at least two hydroxyl groups per molecule and up to six, four, or three hydroxyl groups per molecule.

[0049] Useful silicone surfactants (component e)) are self-dispersible and / or water-soluble. Useful silicone surfactants include block copolymers having at least one polysiloxane block and at least one polyether block. Such block copolymers can be, for example, AB or BAB type copolymers, where A represents a polysiloxane block and each B represents a polyether block. Such block copolymers can have a pendant graft structure in which multiple polyether blocks depend on the polysiloxane block. Each polyether block is preferably a homopolymer or copolymer of ethylene oxide. The copolymer of ethylene oxide can be a copolymer of ethylene oxide and propylene oxide.

[0050] The silicone surfactant may contain, for example, 20 to 80 wt% polysiloxane, 20 to 75 wt% polymerized ethylene oxide, and 0 to 50 wt% polymerized propylene oxide, based on the total weight of the silicone surfactant. A more preferred silicone surfactant contains 20 to 80 wt% polysiloxane, 20 to 75 wt% polymerized ethylene oxide, and 0 to 20 wt% polymerized propylene oxide. An even more preferred silicone surfactant contains 25 to 50 wt% polysiloxane, 50 to 75 wt% polymerized ethylene oxide, and 0 to 10 wt% polymerized propylene oxide.

[0051] Suitable silicone surfactants are commercially available and include, for example, the water-soluble surfactants sold by Momentive Performance Products under the Silwet® product name, including, for example, Silwet® L-7002, L-7200, L-7230, L-7600, L-7604, L-7605, and L7657 surfactants.

[0052] The silicone surfactant constitutes 0-3% of the combined weight of components a-g. The silicone surfactant may constitute at least 0.5%, at least 0.75%, or at least 1%, and may constitute up to 2.5% or 2%.

[0053] Block copolymers of ethylene oxide and higher alkylene oxide (component f)) contain one or more oxyethylene blocks and one or more blocks of polymerized higher alkylene oxide. The higher alkylene oxide can be, for example, 1,2-propylene oxide, 1,2-butylene oxide, or a mixture thereof. Such block copolymers can contain, for example, 40 to 90% by weight of oxyethylene units and have a number average molecular weight (by gel permeation chromatography versus polystyrene standards) of 1500 to 12,000 g / mol. Such block copolymers can have one or more hydroxyl groups, such as 1 to 4 hydroxyl groups or 2 to 4 hydroxyl groups. Examples of suitable block copolymers include those sold under the trade name Tergitol™ by The Dow Chemical Company and Pluronics™ by BASF.

[0054] The block copolymer of ethylene oxide and higher alkylene oxide preferably contains no more than 5 parts per million by weight or no more than 1 part per million by weight of metal and no more than 100 parts per million of amine compound. It is preferably not amine-initiated.

[0055] The block copolymer of ethylene oxide and higher alkylene oxide may constitute 0-3% of the combined weight of components a-g. It may constitute at least 0.5%, at least 0.75%, or at least 1%, and may constitute up to 2.5% or up to 2%.

[0056] The phase change material (component g)) is one or more materials that have a melting or glass transition temperature of 25-37°C and that do not contain isocyanate groups or isocyanate-reactive groups. The phase change material may be or contain any one or more of natural or synthetic waxes, such as, for example, polyethylene wax, beeswax, lanolin, carnauba wax, candelilla wax, ouricle wax, sugarcane wax, jojoba wax, epicuticular wax, coconut wax, petroleum wax, or paraffin wax. The phase change material preferably has a melting temperature of 25-32°C, particularly 28-32°C.

[0057] The phase change material is preferably not encapsulated, that is, not contained within a film or other container that forms a physical barrier between the phase change material and the remaining ingredients of the reaction mixture.

[0058] When present, the phase change material constitutes up to 15% of the combined weight of components a-g, in some embodiments the phase change material constitutes at least 1%, at least 2%, or at least 2.5%, and in some embodiments the phase change material constitutes up to 12.5% ​​or up to 10%.

[0059] The reaction mixture may contain one or more optional ingredients in addition to components a-g above, which, if present, together constitute 5% or less of the weight of the reaction mixture.

[0060] Suitable optional ingredients include one or more branching agents and / or chain extenders as described above in connection with the preparation of the quasi-prepolymer, although these may be omitted.

[0061] The reaction mixture may also contain various ingredients such as colorants, antioxidants, preservatives, biocides, flavorings, thickeners (such as xanthan gum, various water-soluble cellulose ethers or polyacrylamides), mixing aids, wetting agents (if fillers are present), etc. If present, these preferably constitute up to 10% or up to 5% of the total weight of the reaction mixture.

[0062] The reaction mixture for making polyurethane foams is preferably essentially devoid of a curing catalyst, i.e., a catalyst for the reaction of isocyanate groups with water and / or alcohol groups. In particular, the reaction mixture preferably contains no more than 5 parts per million by weight, preferably no more than 1 part per million by weight of a metal and no more than 100 parts per million by weight of an amine compound.

[0063] In addition to components a-g, the reaction mixture may contain one or more solid components such as fillers and reinforcing materials. Examples of fillers include clay, diatomaceous earth, calcium carbonate, wollastonite, ground polymer particles, wood flour, cork flour, glass or other ceramic particles, and various types of natural and synthetic fibers, which may be woven, knitted, or intertwined, if desired. Such solid components may constitute up to 75 percent of the total weight of the reaction mixture.

[0064] The polyurethane foam is made by combining the ingredients to form a reaction mixture and subjecting the resulting reaction mixture to conditions under which the isocyanate-functional quasi-prepolymer and one or more of components b-g react to form a flexible polyurethane foam.

[0065] Ingredients a-g can be combined in any order, but it is preferred to add the polyisocyanate mixture last or simultaneously with the other ingredients to avoid premature reaction before the remaining ingredients can be added. Thus, for example, components b-g can be combined first, followed by the polyisocyanate mixture. Alternatively, components a-g can be combined all at once. It is also possible to form components b-e into various subcombinations that are combined as the polyisocyanate mixture is added. Optional ingredients that are isocyanate-reactive or water-soluble can be added together with water or separately.

[0066] Curing occurs spontaneously upon mixing water with the polyisocyanate mixture, so a wide range of conditions are suitable for carrying out the reaction. Curing temperatures can be as low as 0°C or as high as, for example, 100°C. Temperatures close to or slightly above room temperature are entirely suitable and generally preferred. Thus, curing temperatures can be at least 15°C or at least 20°C and up to 50°C, 40°C, or 35°C. The curing reaction produces carbon dioxide gas, which forms cells and expands the reaction mixture as curing occurs.

[0067] The curing step can be carried out in an open vessel where the rising foam expands against the weight of the air and / or the weight of the film. Such a free-rise process can be carried out by dispensing the reaction mixture into a trough where it rises and hardens.

[0068] The curing process may alternatively be carried out in a closed container, such as a closed mold, where expansion is constrained by the internal dimensions of the cavity to produce a foam having a size and shape corresponding to the size and shape of the mold cavity.

[0069] The amount of water in the reaction mixture far exceeds the amount of isocyanate groups in the isocyanate mixture. For this reason, the cured foam often contains a significant amount of moisture, which may be in the form of a liquid at least partially contained within the cells of the foam. A drying step may be performed to remove some or all of this excess water.

[0070] Such drying may be carried out, for example, by passing a dry gas through the foam, by placing the foam under a dry atmosphere, and / or by heating the foam to a temperature of, for example, 50-150° C. Drying may be carried out until any desired moisture content is achieved. In some embodiments, drying is carried out until a constant foam weight is achieved, indicating that all residual water has been removed from the foam.

[0071] The foam of the present invention has a compressive strength of, for example, 40 to 144 kg / m when measured according to ASTM D3574. 3A significant advantage of the present invention is that the foam may have a post-drying foam density of 80 kg / m 3 In some embodiments, foam densities of 48 to 80 kg / m are readily achievable. 3 is.

[0072] Upon drying, the foams of the present invention exhibit low compression set in addition to low foam density. Compression set is measured on a 5 x 5 x 2.54 cm skinless specimen according to ASTM D-3774:D. The thickness of the specimen is measured with a micrometer. The specimen is then sandwiched between steel plates, compressed to 90% of its original thickness, and aged under compression at 70°C for 22 hours. The specimen is then removed from the testing apparatus and allowed to recover at room temperature for 30 minutes before its thickness is remeasured. Compression set is calculated as [100% x (original thickness - final thickness)] divided by the original thickness. Compression set is typically less than 10%. In preferred embodiments, the compression set can be 8% or less, 6% or less, or even 5% or less.

[0073] Foams of the present invention containing a phase change material (component g)), when dried to constant weight as described above, may exhibit a latent heat at 27°C of at least 2.5 J / g, as measured by differential scanning calorimetry. The latent heat may be at least 4 J / g, at least 8 J / g, at least 10 J / g, or at least 14 J / g at that temperature. In some embodiments, the latent heat may be 25 J / g or 30 J / g or more at that temperature.

[0074] The foams of the present invention 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, up to 5 L / sec or up to 4 L / sec.

[0075] In some embodiments, the foam exhibits a moisture absorption time of 5 seconds or less, preferably 4 seconds or less. Moisture absorption time is measured on a 5 x 5 x 2.54 cm skinless sample that has been dried to a constant weight. 3 mL of room temperature water is slowly dripped from a pipette onto the top surface of the foam sample, and the amount of time required for the foam to absorb the water is recorded as the moisture absorption time.

[0076] The foams of the present invention are useful in bedding, sheeting, and other "comfort" applications. 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 foams or articles containing the foams in such applications often support at least a portion of the body weight of a human user and are compressed during use. Examples of such comfort applications include pillows, mattress toppers, mattresses, comforters, furniture, and / or car seats; quilts; insulating clothing, and the like. Another intended use is padding for prosthetic limbs.

[0077] 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.

[0078] Polyisocyanate 1 is prepared by first preheating a mixture of 57.9 parts of a 1000 g / mole average molecular weight poly(ethylene oxide) homopolymer and 3.8 parts of trimethylolpropane to 80°C. Separately, 33.8 parts of an 80 / 20 mixture of 2,4- and 2,6-toluene diisocyanate (TDI) is heated to 40°C. 0.004 parts of benzoyl chloride is added to the TDI. The polyol mixture is added to the TDI, and the resulting reaction mixture is heated to 74°C until a constant isocyanate content of 8% is achieved. An additional 4.4 parts of TDI is mixed into the mixture. The resulting product is cooled to below 60°C. The isocyanate content is measured to be 9.45-10.3 wt% according to ASTM D5155. The viscosity is measured to be 18,000-21,000 mPa-s at 25°C according to ASTM D4065. Polyisocyanate 1 contains about 95.6 weight percent of a prepolymer of TDI and polyol, about 3.8 weight percent of the residue of a branching agent (trimethylolpropane), and about 4.4 weight percent of free TDI. Polyisocyanate 1 contains, by calculation, 57.9% oxyethylene units.

[0079] Polyisocyanate 2 is prepared by first preheating a mixture of 32 parts of a 1000 g / mole average molecular weight poly(ethylene oxide) homopolymer and 13 parts of a nominally trifunctional random copolymer of propylene oxide and ethylene oxide containing 75% oxyethylene units and having a number average molecular weight of 5000 g / mole to 80°C. Separately, 35 parts of a 79 / 21 mixture of 4,4'- and 2,4'-diphenylmethane diisocyanate (MDI) is heated to 55°C. 0.003 parts of benzoyl chloride is added to the MDI. The polyol mixture and MDI are combined, and the resulting reaction mixture is heated to 75°C until a constant isocyanate content is achieved. The resulting product is cooled to below 60°C. The isocyanate content is determined to be 7% by weight according to ASTM D5155. Polyisocyanate 2 contains a prepolymer of MDI and polyol, as well as a small amount of free MDI. Polyisocyanate 2 contains 61.75% oxyethylene units by calculation. The viscosity of Polyisocyanate 2 is approximately 20,000 cps at 25°C.

[0080] Polyisocyanate 3 is prepared by first preheating a mixture of 71.1 parts of a 1000 average molecular weight poly(ethylene oxide) homopolymer and 1.1 parts of trimethylolpropane to 80°C. Separately, 27.8 parts of an 80 / 20 mixture of 2,4- and 2,6-toluene diisocyanate (TDI) is heated to 40°C. 0.007 parts of benzoyl chloride is added to the TDI. The polyol mixture is added to the TDI, and the resulting reaction mixture is heated to 74°C until a constant isocyanate content of 6.25% is achieved. The resulting product is cooled to below 60°C. Polyisocyanate 3 contains a prepolymer of TDI and polyol. A small amount of free TDI may be present. Polyisocyanate 3 contains 66.2% oxyethylene units and approximately 1.1 weight percent residues of a branching agent.

[0081] Polyisocyanate 4 is prepared by first preheating a mixture of 66.2 parts of a 1000 average molecular weight poly(ethylene oxide) homopolymer and 2.4 parts of trimethylolpropane to 80°C. Separately, 30.4 parts of an 80 / 20 mixture of 2,4- and 2,6-toluene diisocyanate (TDI) is heated to 40°C. 0.05 parts of benzo-4,4-thiobis(6-tert-butyl-m-cresol) are added to the TDI. The polyol mixture is added to the TDI, and the resulting reaction mixture is heated to 74°C until a constant isocyanate content is achieved. 1 part of dicyclohexylmethane-4,4'-diisocyanate is mixed therein. The resulting product is cooled to below 60°C. The isocyanate content is determined to be 6.8% by weight according to ASTM D5155. Polyisocyanate 3 contains a prepolymer of TDI and polyol and may contain small amounts of free TDI and / or small amounts of free dicyclohexylmethane-4-4'-diisocyanate. Polyisocyanate 4 contains about 66.2% by weight of oxyethylene units and about 2.4% residues from a branching agent.

[0082] Polyisocyanate 5 is made by first preheating a 1000 equivalent weight nominally difunctional propylene oxide homopolymer to 80°C. Separately, 35 parts of a 69 / 31 mixture of 4,4'- and 2,4'-diphenylmethane diisocyanate (MDI) is heated to 55°C. 0.003 parts of benzoyl chloride is added to the MDI. The polyol mixture and MDI are combined, and the resulting reaction mixture is heated to 75°C until a constant isocyanate content of 7% is achieved. The resulting product is cooled to below 60°C. Polyisocyanate 5 contains a prepolymer of MDI and polyol, as well as free MDI. Polyisocyanate 5 does not contain oxyethylene units.

[0083] Surfactant A is an organosilicone surfactant sold by Momentive Performance Materials under the trade name Silwet®.

[0084] Surfactant B is an ethylene oxide / propylene oxide / ethylene oxide triblock copolymer. The central poly(propylene oxide) block of the copolymer has a molecular weight of 1750. The outer poly(ethylene oxide) blocks comprise 80% of the total weight of the copolymer. The copolymer has a nominal hydroxyl functionality of 2.

[0085] The PCM (phase change material) is a non-encapsulated paraffin wax with a melting temperature of 28°C.

[0086] CPP is a polymer polyol with a hydroxyl number of about 22. The base polyol is a nominally trifunctional 36.5 hydroxyl number copolymer of propylene oxide and ethylene oxide, and the oxyethylene content of the base polyol is about 20% by weight. The dispersed phase is styrene-acrylonitrile particles. The solids content (weight of styrene-acrylonitrile particles) is about 40% by weight.

[0087] Poly(EO) is a glycerin-initiated, nominally trifunctional ethylene oxide homopolymer with a hydroxyl number of 270 mg KOH / g and a number average molecular weight of 624 g / mole.

[0088] Polyurethane foams are made using the ingredients shown in Tables 1-4 below. The polyisocyanate in each case is combined with the remaining ingredients in a high-speed laboratory mixer for 20 seconds at room temperature. The resulting reaction mixture is poured into an open mold lined with polyethylene sheeting. The foam rises and hardens within the mold. When dimensionally stable, the foam is demolded and allowed to cure under ambient conditions for at least 24 hours. The skin is removed from the foam before samples are taken for property testing.

[0089] Moisture absorption time is measured on a 5 x 5 x 2.54 cm skinless specimen that has been dried to a constant weight. 3 mL of room temperature water is slowly dispensed from a pipette onto the top surface of the foam specimen, and the volume is measured.

[0090] Foam density is measured according to ASTM D3574A.

[0091] Compression set is determined using three 2 inch x 2 inch x 1 inch (5.08 cm x 5.08 cm x 2.54 cm) core specimens. The samples are measured for thickness with a Litematic micrometer and placed between steel plates with 0.1 inch (2.54 mm) spacers to measure 90% deflection. The foams are aged in a 70°C oven for 22 hours. After 22 hours, the specimens are removed and allowed to recover for 30 minutes before final measurements are made according to ASTM D3574:D.

[0092] Airflow is measured on crushed foam samples according to ASTM D3574:G.

[0093] The latent heat is measured by differential scanning calorimetry.

[0094] K-factor is measured using a laser comparison heat flow meter at the average test temperature of 75°F and 40°F test temperature difference.

[0095] Comparison samples A to E Comparative Samples A to E are made from the recipes set forth in Table 1. The results of foam testing of these samples are as shown in Table 1.

[0096] [Table 1] * It is not an embodiment of the present invention.

[0097] These foams were made without a phase change material, simplifying the formulation and isolating the effect of the various polyisocyanate compositions. The zero latent heat at 27°C in each case reflects the absence of a phase change material. As the data in Table 1 show, foam properties are highly dependent on the choice of polyisocyanate in unpredictable ways.

[0098] Polyisocyanate 2 (Comparative A) by itself produces a foam with a very high compression set. When Polyisocyanates 1 and 2 are used together in a 30 / 70 ratio (Comparative B), the compression set improves, but the compression set of 31.2% is far too high for this foam to be useful in bedding applications.

[0099] A 50 / 50 blend of Polyisocyanate 2 with either Polyisocyanate 3 (Comparative C) or Polyisocyanate 4 (Comparative D) results in high compression set and also reduced airflow for Comparative D. A 50 / 50 blend of Polyisocyanate 1 with Polyisocyanate 5 (Comparative E) results in very low compression set. Taken together, these results demonstrate the large variability in foaming properties due to the change in polyisocyanate, and neither polyisocyanate is useful for achieving low compression set.

[0100] Examples 1 to 3 Comparative Samples 1 to 3 are made from the recipes set forth in Table 2. The results of the foam testing of these samples are as shown in Table 2.

[0101] [Table 2]

[0102] These results show the effect of using a 50 / 50 mixture of Polyisocyanates 1 and 2 with three different surfactant packages. Example 1 is a direct comparison with Comparative Sample C (Table 1), the difference being the higher level of branching in the TDI prepolymer of Example 1 (Prepolymer 1, 3.8 wt. % branching agent) compared to the TDI prepolymer of Comparative Sample C (Prepolymer 3, 1.1 wt. % branching agent). The more highly branched Prepolymer 1 results in a dramatic reduction in compression set (9.7% vs. 84.6% for Comparative Sample C).

[0103] Example 1 compared to Comparative Sample B demonstrates the effect of the ratio of components a-1)+a-2) to components a-3)+a-4). Too much components a-3)+a-4) results in a large increase in compression set (31.2% for Comparative Sample B vs. only 9.7% for Example 1).

[0104] Examples 2 and 3 show the effect of using only one of surfactants A and B; very low compression set is obtained in all of Examples 1-3, but the airflow is much lower when only one of the surfactants is present, as in Examples 2 and 3. The latent heat at 27°C is zero due to the absence of phase change material.

[0105] Comparative samples F and G Comparative samples F and G are made from the recipes set forth in Table 3. The results of foam testing of these samples are shown in Table 3.

[0106] [Table 3] * It is not an embodiment of the present invention.

[0107] Comparative Examples F and G illustrate the effect of increasing (Comparative F) or decreasing (Comparative G) the amount of polymer polyol combined with a 50 / 50 blend of Polyisocyanates 1 and 2 compared to Example 1 (Table 2). Compression set increases somewhat for Comparative Sample F. Even at this moderate increase level, the compression set is higher than desired for bedding applications. Compression set is very high in Comparative Sample G. Again, the latent heat is zero in all cases due to the lack of phase change material.

[0108] Examples 4 to 8 Examples 4-8 are made from the recipes set forth in Table 4. The results of foam testing of these samples are shown in Table 4.

[0109] [Table 4] * It is not an embodiment of the present invention.

[0110] Examples 4-8 all exhibit very low compression set.

[0111] The presence of the phase change material in Example 4 has three effects, as shown by comparison with Example 1: The compression set is even lower than in Example 1, and a positive latent heat is observed at 27°C. Some loss of airflow is observed.

[0112] Example 5 shows the effect of including component f) in the reaction mixture in the absence of a phase change material. Compared to Example 1, the compression set is significantly lower and higher airflow is obtained. The latent heat at 27°C is zero due to the absence of a phase change material.

[0113] Examples 6-8 demonstrate the effect of including both component f) and a phase change material. Relative to Example 4, which has a phase change material but no component f), compression set is very low and airflow is improved. This is seen even at very high levels of phase change material (Example 7). The airflow of Examples 6 and 8 is comparable to or higher than that of Example 1, regardless of the presence of a phase change material. The present application also relates to the following aspects: (1) A flexible polyurethane foam, a) an isocyanate mixture, a-1) a first isocyanate-functional prepolymer, said first isocyanate-functional prepolymer being the reaction product of at least one hydroxyl-terminated polymer of ethylene oxide and optionally a hydroxyl-functional branching agent and / or a hydroxyl-functional chain extender, with an excess of diphenylmethane diisocyanate, wherein at least 50% by weight of the diphenylmethane diisocyanate is 4,4'-diphenylmethane diisocyanate; a-2) optionally diphenylmethane diisocyanate, wherein components a-1) and a-2) together have an isocyanate content of 5 to 15 weight percent and contain 30 to 75 weight percent oxyethylene units, based on the combined weight of components a-1) and a-2), and components a-1) and a-2) together constitute 40 to 60% of the total weight of the isocyanate mixture; a-3) a second isocyanate-functional prepolymer, said second isocyanate-functional prepolymer being the reaction product of at least one hydroxyl-terminated polymer of ethylene oxide and a hydroxy-functional branching agent having at least three hydroxyl groups per molecule and a hydroxyl equivalent weight of up to 250 g / eq, with an excess of toluene diisocyanate; a-4) optionally, toluene diisocyanate, wherein a-3) and a-4) together have an isocyanate content of 5 to 15 weight percent, based on the combined weight of components a-3) and a-4), and contain 30 to 75 weight percent oxyethylene units and 2 to 5 weight percent residues from the hydroxyl-functional branching agent, based on the combined weight of components a-3) and a-4), wherein components a-3) and a-4) together constitute 40 to 60% of the total weight of the isocyanate mixture, and components a-1), a-2), a-3), and a-4) together constitute the entire weight of the isocyanate mixture; b) water; c) at least one polymer polyol comprising polymer particles dispersed in at least one base polyol, said base polyol being a polyether having at least 50% by weight of oxypropylene units and a hydroxyl equivalent weight of 500 to 3000 g / equivalent; d) optionally, poly(ethylene oxide), wherein the poly(ethylene oxide) is a homopolymer of an ethylene oxide homopolymer or a random and / or block copolymer of at least 80% by weight ethylene oxide and up to 20% by weight of another alkylene oxide, the poly(ethylene oxide) having a number average molecular weight of 400 to 1200 g / mole; and At least one of e) and f), wherein e) is at least one silicone surfactant and f) is at least one ethylene oxide / higher alkylene oxide block copolymer, said block copolymer containing 40 to 90% by weight of oxyethylene units and having a number average molecular weight of 1500 to 12,000 g / mole; e) and / or f), and optionally at least one of g) at least one phase change material having a melting temperature or glass transition temperature of 25-37°C and not containing isocyanate groups or isocyanate-reactive groups; i) the isocyanate mixture constitutes 40 to 65% of the total weight of components a to g; ii) water constitutes 15 to 41% of the total weight of components a to g; iii) the at least one polymer polyol constitutes 8 to 20% of the total weight of components a to g, and the polymer particles constitute 0.5 to 10% of the total weight of components a to g; iv) the poly(ethylene oxide), when present, constitutes up to 5% by weight of the total of components a-g; v) the at least one silicone surfactant comprises 0 to 3% of the total weight of components a to g; vi) the at least one ethylene oxide / higher alkylene oxide block copolymer comprises 0-3% of the combined weight of components a-g; vii) the at least one phase change material comprises up to 15% of the total weight of components a-g; viii) A flexible polyurethane foam, wherein components a-g comprise at least 95% by weight of the reaction mixture. (2) The flexible polyurethane foam according to (1), wherein the phase change material comprises 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. (3) The flexible polyurethane foam according to (1) or (2) above, wherein the phase change material constitutes 2.5 to 10 percent of the total weight of components a to g. (4) The flexible polyurethane foam according to any one of (1) to (3) above, wherein components a-1) and a-2) together constitute 45 to 55% by weight of the isocyanate mixture, and components a-3) and a-4) together constitute 55 to 45% by weight of the isocyanate mixture, correspondingly. (5) The flexible polyurethane foam according to any one of (1) to (4) above, wherein the silicone surfactant and the ethylene oxide / higher alkylene oxide block copolymer each constitute 0.5 to 3% of the total weight of components a to g. (6) The flexible polyurethane foam according to any one of (1) to (5), wherein the silicone surfactant contains 25 to 70% by weight of polysiloxane, 10 to 75% by weight of polymerized ethylene oxide, and 0 to 10% by weight of polymerized propylene oxide, based on the weight of the silicone surfactant. (7) The flexible polyurethane foam according to any one of (1) to (6) above, wherein the ethylene oxide / higher alkylene oxide block copolymer contains 40 to 90% of oxyethylene units and has a number average molecular weight of 1,500 to 12,000. (8) The flexible polyurethane foam according to any one of (1) to (7) above, wherein the poly(ethylene oxide) constitutes 0.5 to 5% by weight of the total weight of components a to g. (9) 1. A method for making a flexible polyurethane foam, comprising: A. forming a reaction mixture, said reaction mixture comprising: a) an isocyanate mixture, a-1) a first isocyanate-functional prepolymer, said first isocyanate-functional prepolymer being the reaction product of at least one hydroxyl-terminated polymer of ethylene oxide and, optionally, a hydroxyl-functional branching agent and / or a hydroxyl-functional chain extender, with an excess of diphenylmethane diisocyanate, wherein at least 50% by weight of the diphenylmethane diisocyanate is 4,4'-diphenylmethane diisocyanate; a-2) optionally diphenylmethane diisocyanate, wherein components a-1) and a-2) together have an isocyanate content of 5 to 15 weight percent and contain 30 to 75 weight percent oxyethylene units, based on the combined weight of components a-1) and a-2), and components a-1) and a-2) together constitute 40 to 60% of the total weight of the isocyanate mixture; a-3) a second isocyanate-functional prepolymer, said second isocyanate-functional prepolymer comprising at least one hydroxyl-terminated polymer of ethylene oxide and a hydroxy-functional branching agent having at least three hydroxyl groups per molecule and a hydroxyl equivalent weight of up to 250 g / eq; excess toluene diisocyanate; a second isocyanate-functional prepolymer which is the reaction product of a-4) optionally, toluene diisocyanate, wherein a-3) and a-4) together have an isocyanate content of 5 to 15 weight percent, based on the combined weight of components a-3) and a-4), and contain 30 to 75 weight percent oxyethylene units and 2 to 5 weight percent residues from the hydroxyl-functional branching agent, based on the combined weight of components a-3) and a-4), wherein components a-3) and a-4) together constitute 40 to 60% of the total weight of the isocyanate mixture, and components a-1), a-2), a-3), and a-4) together constitute the entire weight of the isocyanate mixture; b) water; c) at least one polymer polyol comprising polymer particles dispersed in at least one base polyol, said base polyol being a polyether having at least 50% by weight of oxypropylene units and a hydroxyl equivalent weight of 500 to 3000 g / equivalent; d) optionally, poly(ethylene oxide), wherein the poly(ethylene oxide) is a homopolymer of an ethylene oxide homopolymer or a random and / or block copolymer of at least 80% by weight ethylene oxide and up to 20% by weight of another alkylene oxide, the poly(ethylene oxide) having a number average molecular weight of 400 to 1200 g / mole; and At least one of e) and f), wherein e) is at least one silicone surfactant and f) is at least one ethylene oxide / higher alkylene oxide block copolymer, said block copolymer containing 40 to 90% by weight of oxyethylene units and having a number average molecular weight of 1500 to 12,000 g / mole; e) and / or f), and optionally at least one of g) at least one phase change material having a melting temperature or glass transition temperature of 25-37°C and not containing isocyanate groups or isocyanate-reactive groups; i) the isocyanate mixture constitutes 40 to 65% of the total weight of components a to g; ii) water constitutes 15 to 41% of the total weight of components a to g; iii) the at least one polymer polyol constitutes 8 to 20% of the total weight of components a to g, and the polymer particles constitute 0.5 to 10% of the total weight of components a to g; iv) the poly(ethylene oxide), when present, constitutes up to 5% by weight of the total of components a-g; v) the at least one silicone surfactant comprises 0 to 3% of the total weight of components a to g; vi) the at least one ethylene oxide / higher alkylene oxide block copolymer comprises 0-3% of the combined weight of components a-g; vii) the at least one phase change material comprises up to 15% of the total weight of components a-g; viii) forming components a-g, wherein components a-g constitute at least 95% by weight of the reaction mixture; B. reacting said reaction mixture to produce said foam. (10) 10. The method of claim 9, wherein the phase change material comprises 2.5 to 10 percent of the total weight of components a to g, and 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. (11) The method according to (9) or (10), wherein the silicone surfactant and the ethylene oxide / higher alkylene oxide block copolymer each constitute 0.5 to 3% of the total weight of components a to g, the silicone surfactant contains 25 to 70% by weight of polysiloxane, 10 to 75% by weight of polymerized ethylene oxide, and 0 to 10% by weight of polymerized propylene oxide, based on the weight of the silicone surfactant, and the ethylene oxide / higher alkylene oxide block copolymer contains 40 to 90% oxyethylene units and has a number average molecular weight of 1,500 to 12,000. (12) A cushion comprising the flexible polyurethane foam according to any one of (1) to (8) above. (13) The cushion according to (12) above, which is a pillow, a mattress topper, a mattress, a comforter, a seat or backrest of furniture, a seat or backrest of an automobile, a quilt or article of insulating clothing, or a pad for a prosthetic limb. (14) The cushion according to (12) or (13), wherein the soft polyurethane foam has a density of 48 to 80 kg / m3 and a compression set of 10% or less when dried to a certain weight. (15) The cushion according to any one of (12) to (14), wherein the flexible polyurethane foam, when dried to a constant weight, exhibits a latent heat of at least 2.5 J / g at 27°K and a moisture absorption time of 5 seconds or less.

Claims

1. A flexible polyurethane foam, a) an isocyanate mixture, a-1) a first isocyanate-functional prepolymer, said first isocyanate-functional prepolymer being the reaction product of at least one hydroxyl-terminated polymer of ethylene oxide and optionally a hydroxyl-functional branching agent and / or a hydroxyl-functional chain extender, with an excess of diphenylmethane diisocyanate, wherein at least 50% by weight of the diphenylmethane diisocyanate is 4,4'-diphenylmethane diisocyanate; a-2) optionally diphenylmethane diisocyanate, wherein components a-1) and a-2) together have an isocyanate content of 5 to 15 weight percent and contain 30 to 75 weight percent oxyethylene units, based on the combined weight of components a-1) and a-2), and components a-1) and a-2) together constitute 40 to 60% of the total weight of the isocyanate mixture; a-3) a second isocyanate-functional prepolymer, said second isocyanate-functional prepolymer being the reaction product of at least one hydroxyl-terminated polymer of ethylene oxide and a hydroxy-functional branching agent having at least three hydroxyl groups per molecule and a hydroxyl equivalent weight of up to 250 g / eq, and an excess of toluene diisocyanate; a-4) optionally, an isocyanate mixture comprising toluene diisocyanate, wherein a-3) and a-4) together have an isocyanate content of 5 to 15 weight percent, based on the combined weight of components a-3) and a-4), and contain 30 to 75 weight percent oxyethylene units and 2 to 5 weight percent residues from said hydroxyl functional branching agent, based on the combined weight of components a-3) and a-4), wherein components a-3) and a-4) together constitute 40 to 60% of the total weight of the isocyanate mixture, and components a-1), a-2), a-3), and a-4) together constitute the entire weight of the isocyanate mixture; b) water; and c) at least one polymer polyol comprising polymer particles dispersed in at least one base polyol, said base polyol being a polyether having at least 50% by weight of oxypropylene units and a hydroxyl equivalent weight of 500 to 3000 g / equivalent; d) optionally, poly(ethylene oxide), wherein the poly(ethylene oxide) is a homopolymer of an ethylene oxide homopolymer or a random and / or block copolymer of at least 80% by weight ethylene oxide and up to 20% by weight of another alkylene oxide, the poly(ethylene oxide) having a number average molecular weight of 400 to 1200 g / mol; At least one of e) and f), wherein e) is at least one silicone surfactant and f) is at least one ethylene oxide / higher alkylene oxide block copolymer, said block copolymer containing 40 to 90 weight percent oxyethylene units and having a number average molecular weight of 1500 to 12,000 g / mol; e) and / or f), and optionally, g) at least one phase change material having a melting temperature or glass transition temperature of 25-37°C and not containing isocyanate groups or isocyanate-reactive groups; i) the isocyanate mixture comprises 40 to 65% of the combined weight of components a through g; ii) water constitutes 15 to 41% of the combined weight of components a to g; iii) the at least one polymer polyol comprises 8 to 20% of the combined weight of components a to g, and the polymer particles comprise 0.5 to 10% of the combined weight of components a to g; iv) the poly(ethylene oxide), when present, constitutes up to 5% by total weight of components a-g; v) the at least one silicone surfactant comprises 0 to 3% of the combined weight of components a through g; vi) the at least one ethylene oxide / higher alkylene oxide block copolymer comprises 0 to 3% of the combined weight of components a through g; vii) the at least one phase change material comprises up to 15% of the combined weight of components a-g; viii) A flexible polyurethane foam wherein components a-g comprise at least 95% by weight of said reaction mixture.

2. 10. The flexible polyurethane foam of claim 1, 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, or paraffin wax.

3. 3. The flexible polyurethane foam of claim 1, wherein the phase change material comprises 2.5 to 10 percent of the total weight of components a to g.

4. 4. The flexible polyurethane foam according to claim 1, wherein components a-1) and a-2) together constitute 45 to 55% by weight of the isocyanate mixture, and components a-3) and a-4) together constitute, correspondingly, 55 to 45% by weight of the isocyanate mixture.

5. 5. The flexible polyurethane foam according to claim 1, wherein the silicone surfactant and the ethylene oxide / higher alkylene oxide block copolymer each constitute 0.5 to 3% of the combined weight of components a to g.

6. 6. The flexible polyurethane foam according to claim 1, wherein the silicone surfactant contains 25 to 70% by weight of polysiloxane, 10 to 75% by weight of polymerized ethylene oxide, and 0 to 10% by weight of polymerized propylene oxide, based on the weight of the silicone surfactant.

7. 7. The flexible polyurethane foam according to claim 1, wherein the ethylene oxide / higher alkylene oxide block copolymer contains 40 to 90% oxyethylene units and has a number average molecular weight of 1,500 to 12,000.

8. 8. The flexible polyurethane foam according to claim 1, wherein the poly(ethylene oxide) comprises 0.5 to 5% of the combined weight of components a to g.

9. 1. A method for making a flexible polyurethane foam, comprising: A. forming a reaction mixture, said reaction mixture comprising: a) an isocyanate mixture, a-1) a first isocyanate-functional prepolymer, said first isocyanate-functional prepolymer being the reaction product of at least one hydroxyl-terminated polymer of ethylene oxide and optionally a hydroxyl-functional branching agent and / or a hydroxyl-functional chain extender, with an excess of diphenylmethane diisocyanate, wherein at least 50% by weight of the diphenylmethane diisocyanate is 4,4'-diphenylmethane diisocyanate; a-2) optionally diphenylmethane diisocyanate, wherein components a-1) and a-2) together have an isocyanate content of 5 to 15 weight percent and contain 30 to 75 weight percent oxyethylene units, based on the combined weight of components a-1) and a-2), and components a-1) and a-2) together constitute 40 to 60% of the total weight of the isocyanate mixture; a-3) a second isocyanate-functional prepolymer, said second isocyanate-functional prepolymer being the reaction product of at least one hydroxyl-terminated polymer of ethylene oxide and a hydroxy-functional branching agent having at least three hydroxyl groups per molecule and a hydroxyl equivalent weight of up to 250 g / eq, and an excess of toluene diisocyanate; a-4) optionally, an isocyanate mixture comprising toluene diisocyanate, wherein a-3) and a-4) together have an isocyanate content of 5 to 15 weight percent, based on the combined weight of components a-3) and a-4), and contain 30 to 75 weight percent oxyethylene units and 2 to 5 weight percent residues from said hydroxyl functional branching agent, based on the combined weight of components a-3) and a-4), wherein components a-3) and a-4) together constitute 40 to 60% of the total weight of the isocyanate mixture, and components a-1), a-2), a-3), and a-4) together constitute the entire weight of the isocyanate mixture; b) water; and c) at least one polymer polyol comprising polymer particles dispersed in at least one base polyol, said base polyol being a polyether having at least 50% by weight of oxypropylene units and a hydroxyl equivalent weight of 500 to 3000 g / equivalent; d) optionally, poly(ethylene oxide), wherein the poly(ethylene oxide) is a homopolymer of an ethylene oxide homopolymer or a random and / or block copolymer of at least 80% by weight ethylene oxide and up to 20% by weight of another alkylene oxide, the poly(ethylene oxide) having a number average molecular weight of 400 to 1200 g / mol; At least one of e) and f), wherein e) is at least one silicone surfactant and f) is at least one ethylene oxide / higher alkylene oxide block copolymer, said block copolymer containing 40 to 90 weight percent oxyethylene units and having a number average molecular weight of 1500 to 12,000 g / mol; e) and / or f), and optionally, g) at least one phase change material having a melting temperature or glass transition temperature of 25-37°C and not containing isocyanate or isocyanate-reactive groups; i) the isocyanate mixture comprises 40 to 65% of the combined weight of components a through g; ii) water constitutes 15 to 41% of the combined weight of components a to g; iii) the at least one polymer polyol comprises 8 to 20% of the combined weight of components a to g, and the polymer particles comprise 0.5 to 10% of the combined weight of components a to g; iv) the poly(ethylene oxide), when present, constitutes up to 5% by total weight of components a-g; v) the at least one silicone surfactant comprises 0 to 3% of the combined weight of components a through g; vi) the at least one ethylene oxide / higher alkylene oxide block copolymer comprises 0 to 3% of the combined weight of components a through g; vii) the at least one phase change material comprises up to 15% of the combined weight of components a-g; viii) forming components a-g, wherein components a-g comprise at least 95% by weight of the reaction mixture; B. reacting the reaction mixture to produce the foam.

10. 10. The method of claim 9, wherein the phase change material comprises 2.5 to 10 percent of the total weight of components a-g, and 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, or paraffin wax.

11. 11. The method of claim 9 or 10, wherein the silicone surfactant and the ethylene oxide / higher alkylene oxide block copolymer each constitute 0.5 to 3% of the combined weight of components a through g, the silicone surfactant contains 25 to 70% by weight polysiloxane, 10 to 75% by weight polymerized ethylene oxide, and 0 to 10% by weight polymerized propylene oxide, based on the weight of the silicone surfactant, and the ethylene oxide / higher alkylene oxide block copolymer contains 40 to 90% oxyethylene units and has a number average molecular weight of 1,500 to 12,000.

12. A cushion comprising the flexible polyurethane foam according to any one of claims 1 to 8.

13. 13. The cushion of claim 12 which is a pillow, a mattress topper, a mattress, a comforter, a furniture seat or back, an automobile seat or back, a quilt or article of insulating clothing, or a pad for a prosthetic limb.

14. When the flexible polyurethane foam is dried to a constant weight, it has a viscosity of 48 to 80 kg / m ３ 14. The cushion of claim 12 or 13, having a density of 0.15 or less and a compression set of 10% or less.

15. 15. The cushion of any one of claims 12 to 14, wherein the flexible polyurethane foam, when dried to a constant weight, exhibits a latent heat of at least 2.5 J / g at 27°C and a moisture absorption time of 5 seconds or less.

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