Soft, slow-recovery, washable polyurethane foam

Abstract

A very soft, washable polyurethane foam for pillows and other bedding applications is made using a quasi-prepolymer of diphenylmethane diisocyanate and a polyether polyol having a high oxyethylene content. The quasi-prepolymer is reacted with an isocyanate-reactive component that includes certain monoalcohols but is devoid or nearly devoid of a polyether polyol having a high oxyethylene content.

Description

[Technical Field]

[0001] FIELD OF THE INVENTION The present invention relates to slow recovery polyurethane foams that are useful in bedding and other cushioning applications.

[0002] Slow recovery polyurethane foams have gained a significant share of the bedding market in recent years. These foams, often referred to as "viscoelastic" or "memory" foams, are generally characterized by their low resilience and slow recovery of their original dimensions after compression. These attributes contribute to the perceived comfort of the human user.

[0003] Pillow foams have certain special requirements that present manufacturing challenges. In particular, pillow foam must be very soft in addition to being slow to recover. Unlike many other foam bedding products, pillows are washed frequently. Unfortunately, very soft viscoelastic foams tend to stiffen after washing. They are also prone to damage, often tearing during the washing process. A very soft viscoelastic foam that exhibits minimal change in properties after washing is desired.

[0004] The present invention provides a polyurethane foam produced by a process comprising: A) combining ingredients including an isocyanate-reactive component, a polyisocyanate component, at least one foam-stabilizing surfactant, and at least one urethane and / or urea catalyst at an Isocyanate Index of 65 to 95 to form a reaction mixture; and B) curing the reaction mixture to form a polyurethane foam, The isocyanate-reactive component is a-1) 40 to 60 weight percent, based on the total weight of all isocyanate-reactive components, of one or more first polyether polyols having a hydroxyl number of 112 to 280 mg KOH / g, a nominal hydroxyl functionality of 2 to 4, and an oxyethylene content of 45 to 70 weight percent; a-2) 0 to 25 wt. % of one or more second polyether polyols having a hydroxyl number of 20 to 70 mg KOH / g, a nominal hydroxyl functionality of 2 to 4, and an oxyethylene content of 0 to 25 wt. %, based on the weight of all isocyanate-reactive components; a-3) 5 to 25 wt. % of one or more third polyether polyols having a hydroxyl number of 112 to 280 mg KOH / g, a nominal hydroxyl functionality of 2 to 4, and an oxyethylene content of 0 to 25 wt. %, based on the weight of all isocyanate-reactive components; a-4) 3 to 12 wt. % of one or more polyethermonols having a hydroxyl number of 50 to 200 mg KOH / g and an oxyethylene content of at least 40 wt. %, based on the weight of all isocyanate-reactive components; a-5) 2 to 6 wt. % water, based on the weight of all isocyanate-reactive components; further, i) a-1), a-2), a-3), a-4), and a-5) together constitute at least 95% by weight of the isocyanate-reactive component; and ii) the isocyanate-reactive component comprises 0 to 2% by weight, based on the weight of all isocyanate-reactive components, of one or more fourth polyether polyols having a hydroxyl number of up to 56 mg KOH / g, a nominal hydroxyl functionality of 2 or greater, and an oxyethylene content of at least 70%; Further, the polyisocyanate component is a quasi-prepolymer of diphenylmethane diisocyanate and a polyether polyol having a hydroxyl number of 15 to 56 mg KOH / g, a nominal hydroxyl functionality of 2 to 4, and an oxyethylene content of at least 70 wt.%, wherein the quasi-prepolymer has an isocyanate content of 25 to 31 wt.%.

[0005] The polyurethane foams of the present invention are characterized by foam density and hardness suitable for use as pillows, as well as slow recovery times. The foams also show little or no change in these properties after washing.

[0006] The isocyanate-reactive components of the reaction mixture include all components having an isocyanate-reactive group. The isocyanate-reactive components include at least components a-1), a-3), a-4), and a-5.

[0007] Component a-1) is one or more first polyether polyols having a hydroxyl number of 112 to 280 mg KOH / g, a nominal hydroxyl functionality of 2 to 4, and an oxyethylene content of 45 to 70 wt. %. In some embodiments, the hydroxyl number is 125 to 200 mg KOH / g, the nominal hydroxyl functionality is 2.5 to 3.5, and the oxyethylene content is 50 to 65 wt. %. In some embodiments, at least 50% of the hydroxyl groups in component a-1) are primary hydroxyl groups, with the remainder being secondary hydroxyl groups.

[0008] The weight of component a-1) that is not an oxyethylene unit is preferably an oxypropylene unit, and is the weight of the residue of the starting compound. In some embodiments, component a-1) is a random and / or block copolymer of ethylene oxide and propylene oxide.

[0009] Component a-1) comprises 40 to 60% of the total weight of all isocyanate-reactive components.

[0010] Component a-2) is one or more second polyether polyols having a hydroxyl number of 20 to 70 mg KOH / g, a nominal hydroxyl functionality of 2 to 4, and an oxyethylene content of 0 to 25 wt%. In some embodiments, the hydroxyl number is 30 to 60 mg KOH / g, the nominal hydroxyl functionality is 2.5 to 3.5, and the oxyethylene content is 0 to 20 wt%, 5 to 20 wt%, or 8 to 15 wt%. In some embodiments, up to 25% or up to 15% of the hydroxyl groups in component a-2) are primary hydroxyl groups, with the remainder being secondary hydroxyl groups.

[0011] The weight of component a-2) that is not an oxyethylene unit is preferably an oxypropylene unit, and is the weight of the residue of the starting compound. In some embodiments, component a-2) is a homopolymer of propylene oxide or a random and / or block copolymer of ethylene oxide and propylene oxide.

[0012] Component a-2) comprises 0-25% of the total weight of all isocyanate-reactive components, in some embodiments, component a-2) comprises at least 5%, at least 10%, or at least 12.5%, and up to 20% or up to 18% of the weight of all isocyanate-reactive components.

[0013] Component a-3) is one or more third polyether polyols having a hydroxyl number of 112 to 280 mg KOH / g, a nominal hydroxyl functionality of 2 to 4, and an oxyethylene content of 0 to 25 wt. In some embodiments, the hydroxyl number is at least 150 or at least 200 mg KOH / g, the nominal hydroxyl functionality is 2.5 to 3.5, and the oxyethylene content is 0 to 20 wt. %, 0 to 10 wt. %, or 0 to 5 wt. In some embodiments, up to 25%, up to 15%, or up to 10% of the hydroxyl groups in component a-3) are primary hydroxyl groups, with the remainder being secondary hydroxyl groups.

[0014] The weight of component a-3) that is not an oxyethylene unit is preferably an oxypropylene unit, and is the weight of the residue of the starting compound. In some embodiments, component a-3) is a homopolymer of propylene oxide or a random and / or block copolymer of ethylene oxide and propylene oxide.

[0015] Component a-3) constitutes 5 to 25% of the total weight of all isocyanate-reactive components, in some embodiments, component a-3) constitutes at least 10% or at least 12.5% ​​of the weight of all isocyanate-reactive components, and up to 20% or up to 18% thereof.

[0016] Component a-4) is one or more polyether monols having a hydroxyl number of 50 to 200 mg KOH / g, a number average molecular weight of up to 1000, and an oxyethylene content of at least 40% by weight. In some embodiments, the hydroxyl number is at least 60 or at least 75, up to 150, or up to 125 mg KOH / g, and the oxyethylene content is 70% to 100%, or 80% to 100% by weight. In some embodiments, at least 75% of the hydroxyl groups in component a-4) are primary hydroxyl groups, with the remainder being secondary hydroxyl groups.

[0017] The weight of component a-4) that is not an oxyethylene unit is preferably an oxypropylene unit, and is the weight of the residue of the starting compound. In some embodiments, component a-4) is a homopolymer of ethylene oxide or a random and / or block copolymer of ethylene oxide and propylene oxide.

[0018] Component a-4) comprises 3 to 12% of the total weight of all isocyanate-reactive components, in some embodiments, component a-4) comprises at least 5% or at least 6%, and up to 10%, of the weight of all isocyanate-reactive components.

[0019] Component a-5) is water, which comprises 2-6% of the total weight of all isocyanate-reactive components. Water may comprise at least 3% and at most 5%, at most 4.5%, at most 4%, or at most 3.75% of the total weight of all isocyanate-reactive components.

[0020] Components a-1), a-2), a-3), a-4), and a-5) together constitute at least 95% by weight of all isocyanate-reactive components. In some embodiments, they together constitute at least 96%, at least 97%, or at least 98%, and may constitute 100% by weight. The weight of monofunctional impurities in any of components a-1), a-2), and a-3), if present, is counted relative to the weight of the respective component.

[0021] The isocyanate-reactive component comprises up to 2 wt. % of one or more fourth polyether polyols having a hydroxyl number of up to 56 mg KOH / g, a nominal hydroxyl functionality of 2 or greater, and an oxyethylene content of at least 70%, based on the weight of all isocyanate-reactive components. The fourth polyether polyol may be absent, and when present, in some embodiments, constitutes up to 1 wt. % or up to 0.5 wt. % of the fourth polyether polyol.

[0022] Other isocyanate-functional components that may be present include, for example, i) hydroxyl and / or amine-functional crosslinkers and chain extenders such as glycerin, trimethylolpropane, trimethylolethane, triethanolamine, diethanolamine, monoethanolamine, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, and cyclohexanedimethanol; ii) polyethers other than those mentioned above; iii) polyester polyols; and iv) amine-terminated polyethers.

[0023] The polyisocyanate component is a quasi-prepolymer of diphenylmethane diisocyanate and a polyether polyol having a hydroxyl number of 15 to 56 mg KOH / g, a nominal hydroxyl functionality of 2 to 4, and an oxyethylene content of at least 70% by weight, the quasi-prepolymer having an isocyanate content of 25 to 31% by weight.

[0024] The diphenylmethane diisocyanate may be either the 4,4'-, 2,4'-, or 2,2'-isomer, or any mixture of two or more thereof. Preferred diphenylmethane diisocyanates contain at least 50% by weight of the 4,4'-isomer.

[0025] In some embodiments, the polyether polyol used in making the prepolymer has a nominal hydroxyl functionality of 2.5 to 3.5, a hydroxyl number of 25 to 45 mg KOH / g, and an oxyethylene content of 75% to 100% by weight.

[0026] The quasi-prepolymer is prepared by combining some or all of the diphenylmethane diisocyanate with a polyether polyol to provide at least two moles of isocyanate groups per mole of hydroxyl groups. The resulting reaction mixture is then reacted to consume the hydroxyl groups. The reaction is continued until the hydroxyl groups are consumed, as indicated by a constant isocyanate content. If less than all of the diphenylmethane diisocyanate is present in the reaction, the remainder can be added subsequently. The reaction of diphenylmethane diisocyanate with a polyether produces a compound having urethane groups and terminal isocyanate groups. The quasi-prepolymer contains a mixture of such compounds and free (unreacted) diphenylmethane diisocyanate.

[0027] Foam-stabilizing surfactants help stabilize the bubbles formed during the foaming process until the polymer cures. A wide variety of silicone surfactants are useful, including silicone oils and organosilicone-polyether copolymers, such as polydimethylsiloxane and polydimethylsiloxane-polyoxyalkylene block copolymers. Examples of such silicone surfactants are commercially available under the trade names Tegostab™ (Evonik Corporation), Niax™ (Momentive Performance Materials), and Dabco™ (Evonik Corporation). The foam-stabilizing surfactant may comprise, for example, 0.1 to 2 percent by weight of the total reaction mixture. Silicone surfactants, even if they contain isocyanate-reactive groups, are not counted toward the weight of the isocyanate-reactive material.

[0028] The reaction is carried out in the presence of one or more catalysts. The catalyst(s) catalyze either or both the water-isocyanate reaction and the alcohol-isocyanate reaction. Suitable catalysts include, for example, tertiary amines, cyclic amidines, tertiary phosphines, various metal chelates, acidic metal salts, strong bases, various metal alcoholates and phenolates, and metal salts of organic acids. Examples of metal-containing catalysts are salts of tin, bismuth, cobalt, and zinc. The most important catalysts are tertiary amine catalysts, cyclic amidines, zinc catalysts, and tin catalysts. Examples of tertiary amine catalysts include trimethylamine, triethylamine, N-methylmorpholine, N-ethylmorpholine, N,N-dimethylbenzylamine, N,N-dimethylethanolamine, N,N,N',N'-tetramethyl-1,4-butanediamine, N,N-dimethylpiperazine, 1,4-diazobicyclo-2,2,2-octane, bis(dimethylaminoethyl)ether, triethylenediamine, and dimethylalkylamines in which the alkyl group contains 4 to 18 carbon atoms. Mixtures of these tertiary amine catalysts are often used.

[0029] A reactive amine catalyst such as DMEA (dimethylethanolamine) or DMAPA (dimethylaminopropylamine), or an amine-initiated polyol. If the catalyst is reactive towards isocyanate groups, it counts towards the weight of the isocyanate-reactive material in the reaction mixture.

[0030] Tin catalysts include stannic chloride, stannous chloride, stannous octoate, stannous oleate, dimethyltin dilaurate, dibutyltin dilaurate, stannous ricinoleate, and tin catalysts of the formula SnR n (OR) 4-n (wherein R is alkyl or aryl having up to 18 carbon atoms, and n is 0 to 4), and other tin compounds. When used, zinc and tin catalysts are generally used in conjunction with one or more tertiary amine catalysts.

[0031] Catalysts are typically used in small amounts, for example, each catalyst is utilized in an amount of from about 0.0015 to about 5, or 0.1 to 0.5 parts by weight per 100 parts by weight of the polyol mixture.

[0032] The reaction mixture may contain a variety of optional components, including one or more flame retardants, such as phosphorus-containing flame retardants, halogenated flame retardants, and melamine, physical blowing agents, one or more pigments and / or colorants, one or more biocides, one or more preservatives, one or more antioxidants, and the like.

[0033] The foam is produced by combining the above-described ingredients to form a reaction mixture which is then foamed and cured. The order of mixing is generally not important, but it is preferred to combine the quasi-prepolymer with the other ingredients last, or at least simultaneously with the mixing of the other ingredients.

[0034] The proportions of starting materials are selected to provide an isocyanate index of 65 to 95. The isocyanate index refers to the ratio of isocyanate groups to isocyanate-reactive groups provided in the reaction mixture times 100. An advantage of the present invention is that very soft foams can be produced without using very low isocyanate indices. Preferred isocyanate indices are at least 72 or at least 75 and up to 90 or up to 85.

[0035] The process of the present invention does not require special foaming conditions; therefore, foaming conditions and equipment described in the art for producing flexible polyurethane foams are fully suitable. Generally, isocyanate compounds react spontaneously with water and polyols even at room temperature (23°C); therefore, in some embodiments, curing is achieved without heating to elevated temperatures (apart from the temperature increase associated with the reaction exotherm that occurs during curing). If necessary, heat can be applied to the reaction mixture to accelerate the curing reaction. This can be done by heating some or all of the ingredients before combining them, by applying heat as the reaction mixture cures, or by some combination of each. If heat is applied, a suitable elevated temperature is 40 to 80°C. Curing is continued until the reaction mixture has expanded and cured sufficiently to form a stable foam.

[0036] In some embodiments, the curing step is carried out in a closed mold. In such a process, the reactive mixture is either formed within the mold itself or formed outside the mold and then injected into the mold and cured there. Thus, the expansion of the reactive mixture as it cures is limited by the interior surfaces of the mold, as well as the size and shape of the molded part. Sufficient reactive mixture is introduced into the mold so that the resulting foam achieves the desired density when it expands to fill the mold.

[0037] In other embodiments, the curing step is carried out in a free-rise (or slabstock) process. In a free-rise process, the reaction mixture is poured into an open container so that expansion occurs in at least one direction (usually perpendicular) against the atmosphere or a lightweight surface (such as a film) that offers little resistance to the expansion of the foam. In a free-rise process, the reaction mixture expands essentially unrestrained in at least one direction, except by its own weight. A free-rise process may be carried out by forming the reaction mixture and dispensing it into a trough or onto a conveyor, where the reaction mixture expands and hardens.

[0038] The resulting foam may have a foam density, for example, of at least 24 g / L, at least 32 g / L, or at least 36 g / L, as measured by ASTM D3574, Test A. The foam density may also be up to 64 g / L, up to 56 g / L, up to 48 g / L, up to 46 g / L, or up to 43 g / L. These density ranges tend to produce foams with the flexibility desired for pillow applications. A particularly preferred density is 37-43 g / L.

[0039] The flexibility (or conversely, hardness) of a foam is conveniently determined by a Compression Force Deflection (CFD) method such as ISO 3386-1. For these applications, a CFD value of 0.4 to 1.0 kPa, more preferably 0.4 to 0.85 kPa at 40% compression is preferred.

[0040] The foam preferably exhibits a recovery time of at least 2 seconds, or at least 3 seconds, and up to 15 seconds, more preferably up to 10 seconds. Recovery time, for purposes of the present invention, 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) to 24% of its original thickness at room temperature, holding the foam under compression for 1 minute, and releasing the compression force. After releasing the compression force, the time required for the foam to recover to 90% of its original foam thickness is the recovery time. Recovery time is conveniently measured using a viscoelastic foam testing device, such as a RESIMAT 150 device (with factory software) manufactured by Format Messtechnik GmbH.

[0041] An important advantage of the present invention is that the foam exhibits little or no change in properties when washed. In particular, the foam exhibits at most a slight increase in CFD upon washing, such as 0-8% or even 0-6% of the CFD value at 40% compression before washing. Weight loss is also minimal, typically 5% or less of the pre-wash weight. This is a very important advantage when the foam is used as pillows or other bedding, because it can be washed without damage when soiled and then reused with little or no loss of tactile properties.

[0042] Thus, the foams of the present invention are useful as pillow foams and other cushioning and comfort applications. The foams may be molded or cut to the shape of a pillow or other device. The foams may be covered with fabric or other sheet materials that can serve decorative and / or tactile functions.

[0043] 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.

[0044] Examples 1-2 and Comparative Samples A-F The polyurethane foam pillow is made from the ingredients as shown in Table 1 below. All ingredients except the polyisocyanate are combined using a high-speed laboratory mixer. The polyisocyanate is then added, and the resulting reaction mixture is poured into a mold (30 cm x 30 cm x 10 cm), which is then closed. The reaction mixture is allowed to rise and cure in the mold without heating for about 12 hours or 5 minutes in a heated mold (about 50°C).

[0045] Polyol a-1) is a random copolymer of ethylene oxide and propylene oxide, having a hydroxyl number of 167 mg KOH / g, a nominal hydroxyl functionality of 3, and an oxyethylene content of 60% by weight. Polyol a-2) is a random copolymer of ethylene oxide and propylene oxide, having a hydroxyl number of 47.5 mg KOH / g, a nominal hydroxyl functionality of 3, and an oxyethylene content of 11% by weight. Polyol a-3) is a homopolymer of propylene oxide having a hydroxyl number of 237 mg KOH / g, a nominal hydroxyl functionality of 3, and an oxyethylene content of 0 wt. %. Monol a-4) is a homopolymer of ethylene oxide. It has a hydroxyl number of 102 mg KOH / g and an oxyethylene content of 100%. Polyol 4 is a random copolymer of ethylene oxide and propylene oxide with a hydroxyl number of 37 mg KOH / g, a nominal hydroxyl functionality of 3, and an oxyethylene content of 78%. QP-1 is a quasi-prepolymer made by reacting 100 parts of a mixture of 98% 4,4'-MDI and 2% 2,4'-MDI with approximately 9.5 parts of Polyol 4 until the hydroxyl groups are consumed. QP-1 has an isocyanate content of 29.5%. PMDI is a polymeric MDI product with an isocyanate content of 32.4%. The MDI fraction of this product contains approximately 75% of the 4,4'-isomer and 25% of the 2,4'-isomer. Polyol 5 is a homopolymer of propylene oxide. It has a hydroxyl number of about 56, a nominal hydroxyl functionality of 3, and an oxyethylene content of 0%. Polyol 6 is a nominally trifunctional homopolymer of propylene oxide. It has a hydroxyl number of about 170. Polyol 7 is a homopolymer of ethylene oxide. It has a hydroxyl number of about 187 and is nominally difunctional. Monol B is a monofunctional homopolymer of ethylene oxide with a hydroxyl number of about 160. Surfactants A and B are silicone foam stabilizing surfactants. Catalysts A and B are each a mixture of a gelling catalyst and a blowing catalyst.

[0046] [Table 1] * It is not an embodiment of the present invention.

[0047] The foam density in each case is measured according to ASTM D3574, Test A. Recovery time is determined according to the method described above. CFD measurements at 40% compression are performed according to ISO 3386-1 or equivalent method, both before and after washing the pillows. Washing is performed in a machine using a water temperature of 40°C and a spin cycle of 1600 rpm, followed by drying in a tumble dryer at 55-60°C for 2 hours. The test results are shown in Table 2.

[0048] [Table 2] * It is not an embodiment of the present invention.

[0049] Comparative Sample B represents the baseline case in this series of examples. The formulation is the same as Examples 1 and 2, except that polymeric MDI is used instead of the quasi-prepolymer of Examples 1 and 2. Comparative Example B has desirable density and exhibits slow recovery time. The foam hardness before washing is only slightly higher than required for pillow applications, but increases quite substantially upon washing. Thus, the polyol and monol combination according to the present invention, when used with polymeric MDI at a 75 index, exhibits marginal properties for pillow applications even before washing. It then becomes too hard.

[0050] Comparative Sample A is another foam made using polymeric MDI, in this case with an isocyanate index of only 70. 6 parts of Polyol 4 are added to the formulation. These changes result in a softer, lower density foam. However, this foam performs very poorly upon washing, as a very significant increase in hardness is observed along with a weight loss of over 7%. The good flexibility before washing is attributed to the lower isocyanate index and the presence of Polyol 4; unfortunately, these factors are also believed to contribute to the much poorer performance after washing.

[0051] The presence of Polyol 4 is also believed to contribute to the poor post-wash performance of Comparative Foams C and D, respectively. Quasi-prepolymer is used at a 70 index to make Comparative Sample C. Although very low hardness is obtained, both weight loss and hardness gain after washing are high. In Comparative Sample D, the quasi-prepolymer is replaced with polymeric MDI at an 80 index, which produces a foam with less property change upon washing. Unfortunately, this results in a much harder foam that is unsuitable for pillow applications. The use of polymeric MDI requires a lower index to achieve the desired foam flexibility, but as a comparative example, Samples A and B demonstrate that lowering the isocyanate index also results in greater property loss after washing.

[0052] Examples 1 and 2 exhibit desirable foam density, low hardness, and slow recovery time, even at an Isocyanate Index of 75 or 80. Furthermore, these foams exhibit only slight changes in hardness and weight after washing.

[0053] Comparative Samples E and F are made substantially according to U.S. Patent Application Publication No. 2013 / 0159476. The foam made at 100 index (Comparative Sample E) is at least three times stiffer than desired for pillow applications. Sample F, made at 80 index, is sufficiently soft but does not exhibit the desired slow recovery and shows large property changes after washing. The present application also relates to the following aspects: 〔1〕 1. A polyurethane foam produced by a process comprising: A) combining ingredients including an isocyanate-reactive component, a polyisocyanate component, at least one foam-stabilizing surfactant, and at least one urethane and / or urea catalyst at an Isocyanate Index of 65 to 95 to form a reaction mixture; and B) curing the reaction mixture to form a polyurethane foam, the isocyanate-reactive component is a-1) 40 to 60 weight percent, based on the total weight of all isocyanate-reactive components, of one or more first polyether polyols having a hydroxyl number of 112 to 280 mg KOH / g, a nominal hydroxyl functionality of 2 to 4, and an oxyethylene content of 45 to 70 weight percent; a-2) 0 to 25 wt. % of one or more second polyether polyols having a hydroxyl number of 20 to 70 mg KOH / g, a nominal hydroxyl functionality of 2 to 4, and an oxyethylene content of 0 to 25 wt. %, based on the weight of all isocyanate-reactive components; a-3) 5 to 25 wt. % of one or more third polyether polyols having a hydroxyl number of 112 to 280 mg KOH / g, a nominal hydroxyl functionality of 2 to 4, and an oxyethylene content of 0 to 25 wt. %, based on the weight of all isocyanate-reactive components; a-4) 3 to 12 wt. % of one or more polyethermonols having a hydroxyl number of 50 to 200 mg KOH / g, a number average molecular weight of up to 1000, and an oxyethylene content of at least 40 wt. %, based on the weight of all isocyanate-reactive components; a-5) 2 to 6 wt. % water, based on the weight of all isocyanate-reactive components; further, i) a-1), a-2), a-3), a-4), and a-5) together constitute at least 95% by weight of the isocyanate-reactive component; and ii) the isocyanate-reactive component comprises 0 to 2% by weight, based on the weight of all isocyanate-reactive components, of one or more fourth polyether polyols having a hydroxyl number of up to 56 mg KOH / g, a nominal hydroxyl functionality of 2 or greater, and an oxyethylene content of at least 70%; Further, the polyurethane foam, wherein the polyisocyanate component is a quasi-prepolymer of diphenylmethane diisocyanate and a polyether polyol having a hydroxyl number of 15 to 56 mg KOH / g, a nominal hydroxyl functionality of 2 to 4, and an oxyethylene content of at least 70 wt.%, the quasi-prepolymer having an isocyanate content of 25 to 31 wt. 〔2〕 The polyurethane foam according to the above [1], wherein a-2) constitutes 5 to 25% by weight of the total weight of all isocyanate-reactive components. 〔3〕 The polyurethane foam according to the above [1] or [2], wherein a-2) has a hydroxyl number of 30 to 60, an average hydroxyl functionality of 2.5 to 3.5, and contains 8 to 15% by weight of oxyethylene units. 〔4〕 The polyurethane foam according to any one of the above [1] to [4], wherein water constitutes 2 to 4.5% by weight of the total weight of all isocyanate-reactive components. 〔5〕 The polyurethane foam according to any one of the above [1] to [3], wherein a-3) has a hydroxyl number of at least 200, an average hydroxyl functionality of 2.5 to 3.5, and contains 0 to 20% by weight of oxyethylene units. 〔6〕 The polyurethane foam according to any one of the above [1] to [3], wherein a-3) constitutes 10 to 20% by weight of the total weight of all isocyanate-reactive components. 〔7〕 The polyurethane foam according to any one of the above [1] to [4], wherein the polyisocyanate component is a quasi-prepolymer of diphenylmethane diisocyanate and a polyether polyol having a hydroxyl number of 25 to 45 mg KOH / g, a nominal hydroxyl functionality of 2.5 to 3.5, and an oxyethylene content of 75 to 100 wt.%. 〔8〕 The polyurethane foam according to any one of the above [1] to [7], which has an isocyanate index of 72 to 90. 〔9〕 The polyurethane foam according to any one of the above [1] to [8], which has a density of 37 to 43 g / L, a 40% compressive force deflection value of 0.4 to 1.0 kPa, and a recovery time of at least 2 seconds. 〔10〕 The polyurethane foam according to any one of the above [1] to [9], which is a molded pillow. 〔11〕 1. A process for producing a polyurethane foam, comprising: A) combining ingredients including an isocyanate-reactive component, a polyisocyanate component, at least one foam-stabilizing surfactant, and at least one urethane and / or urea catalyst at an Isocyanate Index of 65 to 95 to form a reaction mixture; and B) curing the reaction mixture to form the polyurethane foam; the isocyanate-reactive component is a-1) 40 to 60 weight percent, based on the total weight of all isocyanate-reactive components, of one or more first polyether polyols having a hydroxyl number of 112 to 280 mg KOH / g, a nominal hydroxyl functionality of 2 to 4, and an oxyethylene content of 45 to 70 weight percent; a-2) 0 to 25 wt. % of one or more second polyether polyols having a hydroxyl number of 20 to 70 mg KOH / g, a nominal hydroxyl functionality of 2 to 4, and an oxyethylene content of 0 to 25 wt. %, based on the weight of all isocyanate-reactive components; a-3) 5 to 25 wt. % of one or more third polyether polyols having a hydroxyl number of 112 to 280 mg KOH / g, a nominal hydroxyl functionality of 2 to 4, and an oxyethylene content of 0 to 25 wt. %, based on the weight of all isocyanate-reactive components; a-4) 3 to 12 wt. % of one or more polyethermonols having a hydroxyl number of 50 to 200 mg KOH / g, a number average molecular weight of up to 1000, and an oxyethylene content of at least 40 wt. %, based on the weight of all isocyanate-reactive components; a-5) 2 to 6 wt. % water, based on the weight of all isocyanate-reactive components; further, i) a-1), a-2), a-3), a-4), and a-5) together constitute at least 95% by weight of the isocyanate-reactive component; and ii) the isocyanate-reactive component comprises 0 to 2% by weight, based on the weight of all isocyanate-reactive components, of one or more fourth polyether polyols having a hydroxyl number of up to 56 mg KOH / g, a nominal hydroxyl functionality of 2 or greater, and an oxyethylene content of at least 70%; and wherein the polyisocyanate component is a quasi-prepolymer of diphenylmethane diisocyanate and a polyether polyol having a hydroxyl number of 15 to 56 mg KOH / g, a nominal hydroxyl functionality of 2 to 4, and an oxyethylene content of at least 70 wt.%, the quasi-prepolymer having an isocyanate content of 25 to 31 wt.%.

Claims

1. 1. A polyurethane foam produced by a process comprising: A) combining ingredients including an isocyanate-reactive component, a polyisocyanate component, at least one foam-stabilizing surfactant, and at least one urethane and / or urea catalyst at an Isocyanate Index of 65 to 95 to form a reaction mixture; and B) curing the reaction mixture to form a polyurethane foam, the isocyanate-reactive component is a-1) 40 to 60 weight percent, based on the total weight of all isocyanate-reactive components, of one or more first polyether polyols having a hydroxyl number of 112 to 280 mg KOH / g, a nominal hydroxyl functionality of 2 to 4, and an oxyethylene content of 45 to 70 weight percent; a-2) 5 to 25 weight percent, based on the weight of all isocyanate-reactive components, of one or more second polyether polyols having a hydroxyl number of 20 to 70 mg KOH / g, a nominal hydroxyl functionality of 2 to 4, and an oxyethylene content of 0 to 25 weight percent; a-3) 5 to 25 weight percent, based on the weight of all isocyanate-reactive components, of one or more third polyether polyols having a hydroxyl number of 112 to 280 mg KOH / g, a nominal hydroxyl functionality of 2 to 4, and an oxyethylene content of 0 to 25 weight percent; a-4) 3 to 12 wt. % based on the weight of all isocyanate-reactive components of one or more polyether monools having a hydroxyl number of 50 to 200 mg KOH / g, a number average molecular weight of up to 1000, and an oxyethylene content of at least 40 wt. %; a-5) 2 to 6 wt. % water, based on the weight of all isocyanate-reactive components; further, i) a-1), a-2), a-3), a-4), and a-5) together constitute at least 95% by weight of the isocyanate-reactive component; and ii) the isocyanate-reactive component comprises 0 to 2% by weight, based on the weight of all isocyanate-reactive components, of one or more fourth polyether polyols having a hydroxyl number of up to 56 mg KOH / g, a nominal hydroxyl functionality of 2 or greater, and an oxyethylene content of at least 70%; Further, the polyisocyanate component is a quasi-prepolymer of diphenylmethane diisocyanate and a polyether polyol having a hydroxyl number of 15 to 56 mg KOH / g, a nominal hydroxyl functionality of 2 to 4, and an oxyethylene content of at least 70 weight percent, the quasi-prepolymer having an isocyanate content of 25 to 31 weight percent.

2. 2. The polyurethane foam of claim 1, wherein a-2) contains a hydroxyl number of 30 to 60 mg KOH / g, an average hydroxyl functionality of 2.5 to 3.5, and 8 to 15 wt. % of oxyethylene units.

3. 3. The polyurethane foam of claim 1, wherein water comprises 2 to 4.5% of the total weight of all isocyanate-reactive components.

4. 3. The polyurethane foam of claim 1, wherein a-3) contains a hydroxyl number of at least 200 mg KOH / g, an average hydroxyl functionality of 2.5 to 3.5, and 0 to 20 wt. % of oxyethylene units.

5. The polyurethane foam of claim 1 or 2, wherein a-3) comprises 10 to 20% of the total weight of all isocyanate-reactive components.

6. 4. The polyurethane foam according to claim 1, wherein the polyisocyanate component is a quasi-prepolymer of diphenylmethane diisocyanate and a polyether polyol having a hydroxyl number of 25 to 45 mg KOH / g, a nominal hydroxyl functionality of 2.5 to 3.5, and an oxyethylene content of 75 to 100 wt.%.

7. The polyurethane foam according to any one of claims 1 to 6, having an isocyanate index of 72 to 90.

8. The polyurethane foam according to any one of claims 1 to 7, having a density of 37 to 43 g / L, a 40% compressive force deflection value of 0.4 to 1.0 kPa, and a recovery time of at least 2 seconds.

9. The polyurethane foam according to any one of claims 1 to 8, which is a molded pillow.

10. 1. A process for producing a polyurethane foam, comprising: A) combining ingredients including an isocyanate-reactive component, a polyisocyanate component, at least one foam-stabilizing surfactant, and at least one urethane and / or urea catalyst at an Isocyanate Index of 65 to 95 to form a reaction mixture; and B) curing the reaction mixture to form the polyurethane foam; the isocyanate-reactive component is a-1) 40 to 60 weight percent, based on the total weight of all isocyanate-reactive components, of one or more first polyether polyols having a hydroxyl number of 112 to 280 mg KOH / g, a nominal hydroxyl functionality of 2 to 4, and an oxyethylene content of 45 to 70 weight percent; a-2) 5 to 25 weight percent, based on the weight of all isocyanate-reactive components, of one or more second polyether polyols having a hydroxyl number of 20 to 70 mg KOH / g, a nominal hydroxyl functionality of 2 to 4, and an oxyethylene content of 0 to 25 weight percent; a-3) 5 to 25 weight percent, based on the weight of all isocyanate-reactive components, of one or more third polyether polyols having a hydroxyl number of 112 to 280 mg KOH / g, a nominal hydroxyl functionality of 2 to 4, and an oxyethylene content of 0 to 25 weight percent; a-4) 3 to 12 wt. % based on the weight of all isocyanate-reactive components of one or more polyether monools having a hydroxyl number of 50 to 200 mg KOH / g, a number average molecular weight of up to 1000, and an oxyethylene content of at least 40 wt. %; a-5) 2 to 6 wt. % water, based on the weight of all isocyanate-reactive components; Furthermore, i) a-1), a-2), a-3), a-4), and a-5) together comprise at least 95% by weight of the isocyanate-reactive components; ii) the isocyanate-reactive component comprises 0 to 2 wt. %, based on the weight of all isocyanate-reactive components, of one or more fourth polyether polyols having a hydroxyl number of up to 56 mg KOH / g, a nominal hydroxyl functionality of 2 or greater, and an oxyethylene content of at least 70%; and wherein the polyisocyanate component is a quasi-prepolymer of diphenylmethane diisocyanate and a polyether polyol having a hydroxyl number of 15 to 56 mg KOH / g, a nominal hydroxyl functionality of 2 to 4, and an oxyethylene content of at least 70 weight percent, the quasi-prepolymer having an isocyanate content of 25 to 31 weight percent.

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