Compatibilized blends of terephthalate polyols and hydrocarbon blowing agents.

Abstract

The compounded polyol composition includes a terephthalic acid-based polyester polyol, a C4-7 hydrocarbon blowing agent, and a nonionic surfactant having a hydrophilic-lipophilic balance greater than 13 and up to 18.5. The compounded polyol composition exhibits surprisingly good storage stability and resistance to stratification. The composition is useful for making rigid polyurethane and / or polyisocyanurate foams. The good compatibility of the blowing agents leads to improved cell structure of the foam.

Description

[Technical field]

[0001] The present invention relates to blends of terephthalate polyols and hydrocarbon blowing agents, and rigid foams made from such blends. Summary of the Invention [Problem to be solved by the invention]

[0002] Rigid polyurethane / polyisocyanurate foams are commonly used for insulation in building interiors and other applications. The foams are made commercially by reacting one or more polyols with one or more isocyanates in the presence of a blowing agent. Polyester polyols are preferred for these applications because they offer better foaming properties. Commonly available polyester polyols used in these applications include those based on orthophthalic or terephthalic acid (or their respective anhydrides).

[0003] Hydrocarbons are commonly used as blowing agents, either alone or in combination with water, to react with isocyanate groups to produce carbon dioxide.

[0004] Typically, foams are produced by forming a compounded polyol component which is then preferably reacted with a polyisocyanate. The compounded polyol component includes a polyester polyol and a hydrocarbon blowing agent, and typically includes water (if used), a foam stabilizing surfactant, and a catalyst.

[0005] The compounded polyol component may be stored for a significant period of time before being processed into a foam, and therefore, in such cases, the mixture of polyol and blowing agent is required to be storage stable, specifically, the components of the compounded polyol component are required to form a composition that remains homogeneous over a period of time ranging from several hours to several days or longer.

[0006] Compatibility is important even if the blowing agent is not mixed with the polyol until the foam is prepared. If the blowing agent and polyol are insufficiently compatible, a homogeneous reaction mixture will not be produced. A homogeneous mixture is necessary to ensure a homogeneous foam and good processing.

[0007] Unfortunately, hydrocarbon blowing agents have limited solubility in polyester polyols: they do not dissolve readily in polyester polyols, and even when they do, the polyol / hydrocarbon mixture tends to stratify and separate.

[0008] Poor compatibility of the blowing agent with the polyol can lead to defects in the foam. The blowing agent tends to phase separate as the foam-forming reaction occurs, which can lead to the formation of large pores. This leads to localized high concentrations of blowing agent, which creates large pores. These large pores are unacceptable from both a performance and appearance standpoint.

[0009] To address these problems, it has been proposed to include various additives in the formulated polyol component to aid in compatibilizing various types of polyols with the hydrocarbon blowing agents and / or to modify the polyester polyols.

[0010] U.S. Patent No. 5,922,779 describes this problem. As described therein, mixtures of phthalic anhydride / diethylene glycol polyester polyol blends and pentane separate after a short time. Addition of non-ionic surfactants does not solve the problem. The solution proposed in U.S. Patent No. 5,922,799 is to modify the polyester with hydrophobic groups in addition to incorporating certain non-ionic surfactants into the polyol formulation.

[0011] WO2007 / 094780 describes blends of polyols, hydrocarbon blowing agents, and certain non-ionic surfactants. As shown in the examples of this reference, large amounts of surfactant are required to compatibilize even n-pentane with hydrophobically modified phthalate-based polyols.

[0012] US Patent No. 6,245,826 describes the use of fatty alcohol ethoxylates having an HLB of 7 to 12 to compatibilize phthalic anhydride-initiated polyester polyols with hydrocarbon blowing agents. US Patent No. 5,464,562 describes a similar approach.

[0013] In certain applications, terephthalic acid-based polyols are preferred over orthophthalic acid-based polyols. Terephthalic acid-based polyols have different solubility properties than orthophthalic acid-based polyols. Strategies for compatibilizing orthophthalic acid-based polyols with hydrocarbon blowing agents have not been successful when the polyols are replaced with terephthalic acid-based polyols.

[0014] What is desired is a polyol composition comprising a terephthalic acid-based polyol and a hydrocarbon blowing agent, where the hydrocarbon blowing agent has good compatibility with the polyol.

[0015] The present invention, in one aspect, comprises: a) at least one polyester polyol containing one or more terephthalic acid ester groups, the polyester polyol having a number average of at least 1.5 hydroxyl groups per molecule and a hydroxyl value of 150 to 350, or a mixture of at least 50% by weight of the polyester polyol and up to 50% by weight of one or more other polyols having a number average of at least 1.5 hydroxyl groups per molecule and a hydroxyl value of 150 to 350, based on the weight of the mixture; b) 5 to 30 parts by weight per 100 parts by weight of component a) of one or more aliphatic hydrocarbons having 4 to 7 carbon atoms; and c) 0.25 to 20 parts by weight per 100 parts by weight of component a) one or more nonionic surfactants having a hydrophilic-lipophilic balance (HLB) of greater than 13 and up to 18.5.

[0016] The present invention also provides a method of making a polymer foam, comprising the steps of: A) a) at least one polyester polyol containing one or more terephthalate ester groups, the polyester polyol having a number average of at least 1.5 hydroxyl groups per molecule and a hydroxyl number of from 150 to 350, or a mixture, the mixture being at least 50% by weight, based on the weight of the mixture, of the polyester polyol with one or more other polyols having a number average of at least 1.5 hydroxyl groups per molecule and a hydroxyl number of from 150 to 350; b) 5 to 30 parts by weight per 100 parts by weight of component a) of one or more aliphatic hydrocarbons having 4 to 7 carbon atoms; c) 0.25 to 20 parts by weight per 100 parts by weight of component a) of one or more nonionic surfactants having a hydrophilic-lipophilic balance (HLB) of greater than 13 and up to 18.5; d) one or more foam stabilizing surfactants; and e) one or more urethane and / or isocyanate trimerization catalysts; f) forming a reaction mixture comprising at least one organic polyisocyanate in an amount sufficient to provide an Isocyanate Index of at least 90; B) curing the reaction mixture under conditions such that component b) volatilizes and components a) and f) react to form a polymer foam.

[0017] The present invention is also a polymer foam made in the above process.

[0018] It has been believed that surfactants capable of compatibilizing orthophthalic polyester polyols with hydrocarbon blowing agents are ineffective when orthophthalic polyesters are replaced with terephthalic polyesters. Surprisingly, the selection of high HLB surfactants provides excellent compatibility between terephthalic polyester polyols and hydrocarbon blowing agents. These results are obtained even when the terephthalic polyester polyols do not contain hydrophobic chains. This allows the use of simple and inexpensive terephthalic polyester polyols. The compounded polyol composition of the present invention produces more uniform foam products during foam processing because it is slow to layer, if at all.

[0019] Component a) of the blended polyol composition is a polyester polyol containing one or more terephthalic acid ester groups, the polyester polyol having at least two hydroxyl groups per molecule and a hydroxyl number of 150 to 350. For convenience, the polyester polyol may be referred to herein as "terephthalic acid-based." A terephthalate group is represented by the following structure: [ka]

[0020] Here, each of the terminal oxygen atoms is bonded to a different carbon atom (not shown).

[0021] Terephthalic acid-based polyester polyols, in some embodiments, are the reaction products of reactants including terephthalic acid and / or terephthalic anhydride with one or more aliphatic polyols having a hydroxyl equivalent weight of up to 125, preferably up to 100, up to 75, or up to 60. The polyols can contain from 2 to 8 hydroxyl groups, but preferably contain no more than 3 hydroxyl groups. Particularly preferred polyols are diols or mixtures of diols and triols. Examples of such polyols include, for example, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 2-methyl-1,3-propanediol, glycerin, trimethylolpropane, trimethylolethane, pentaerythritol, erythritol, mannitol, sucrose, sorbitol, and the like, as well as alkoxylates of any of the foregoing having a hydroxyl equivalent weight up to 125. The polyol is used in excess to produce a polyester having terminal hydroxyl groups and little, if any, residual carboxyl groups.

[0022] Terephthalic acid-based polyester polyols can be modified, such as by the methods described in U.S. Patent No. 6,359,022, to introduce pendant aliphatic hydrocarbyl groups containing 6 or more carbon atoms in a linear or branched chain. However, an advantage of the present invention is that such modifications are not required to obtain adequate compatibilization of the terephthalic acid-based polyester polyols with hydrocarbons. Thus, in a preferred embodiment, the terephthalic acid-based polyester polyols do not contain such pendant aliphatic hydrocarbon groups of 6 or more carbon atoms.

[0023] The terephthalic acid-based polyester polyols in some embodiments have a hydroxyl functionality (average number of hydroxyl groups per molecule) of 1.5 to 2.5 and a hydroxyl number of 200 to 330, especially 200 to 275. In a particularly preferred embodiment, the terephthalic acid-based polyester polyols are the reaction products of terephthalic acid and / or terephthalic anhydride with ethylene glycol and / or diethylene glycol and / or higher polyethylene glycol.

[0024] The terephthalic acid-based polyester polyol is composed of at least 50% by weight of all polyols having a functionality of at least 2 and a hydroxyl number of 150 to 350. It may comprise at least 60%, at least 75%, at least 85% or at least 90% of them, and may comprise up to 100% of them or up to 95% of them.

[0025] Other polyols having a hydroxyl number of 150 to 350 may be present in component a). Examples of these include polyols having a hydroxyl equivalent weight of up to 125 and other polyester polyols such as phthalic acid-based polyester polyols formed by reaction of phthalic acid and / or phthalic anhydride, optionally with fatty acids or vegetable oils. Other polyols that may be present include polyether polyols, polyether carbonates, other polyester polyols, etc., in each case having a hydroxyl number of 150 to 350 and at least two hydroxyl groups per molecule.

[0026] Component b) is one or more hydrocarbons having 4 to 7 carbon atoms. The hydrocarbon is preferably aliphatic. The hydrocarbon may be linear, branched, and / or cyclic. Examples include n-butane, isobutane, n-pentane, isopentane, neopentane, cyclopentane, methylcyclopentane, n-hexane, 2- and / or 3-methylpentane, cyclohexane, n-heptane, 2-, 3- and / or 4-methylhexane, methylcyclohexane, 1-butene, 2-butene, 1-pentene, 2-pentene, 1-hexene, 2-hexene, 1-heptene, 2-heptene, 3-heptene, and the like, as well as mixtures of any two or more thereof. Preferred hydrocarbons include at least 50 weight percent, preferably at least 80, at least 95% or at least 98% weight percent of one or more pentane isomers.

[0027] The hydrocarbon is present in an amount of 5 to 30, in particular 10 to 30 or 15 to 25 parts by weight per 100 parts by weight of component a).

[0028] Component c) is a non-ionic surfactant with an HLB of greater than 13 and up to 18.5. The HLB is preferably at least 13.5, at least 14, at least 14.5, or at least 15. In some embodiments, the HLB is up to 18.3 or up to 18. The HLB is 20×M h / M, where M h is the weight of the hydrophilic portion of the surfactant molecule and M is the total mass of the surfactant molecule.

[0029] The nonionic surfactant may be a liquid, solid, or waxy material at room temperature (23° C.). It may have, for example, a molecular weight of at least 600 or at least 1000, and up to 20,000 or up to 10,000.

[0030] Nonionic surfactants can have one or more hydroxyl groups per molecule, but preferably have no more than three or no more than two hydroxyl groups. In such cases, their hydroxyl equivalent weight is preferably at least 600.

[0031] Nonionic surfactants typically contain at least one poly(oxyethylene) block, with the poly(oxyethylene) block(s) constituting at least 65% of the total weight of the surfactant. The poly(oxyethylene) block(s) generally constitute the hydrophilic portion of the surfactant molecule.

[0032] The nonionic surfactant further comprises at least one hydrophobic block, the hydrophobic block(s) constituting 7.5-35% of the total weight of the surfactant molecule. The hydrophobic block(s) may be, for example, a hydrocarbon block containing at least 6, at least 8, at least 10, or at least 12 carbon atoms. Such a hydrocarbon block may be, for example, a linear or branched aliphatic hydrocarbon block, an aromatic group, an aralkyl group, an alkaryl group, etc. The hydrophobic block may alternatively be, for example, a polyether block in which the repeating ether groups have 3 or more carbon atoms (e.g., a poly(propylene oxide), poly(butylene oxide) and / or poly(tetramethylene glycol) block).

[0033] The non-ionic surfactant preferably lacks terephthalic acid or phthalate ester groups.

[0034] Examples of useful nonionic surfactants include ethoxylates of fatty alcohols and / or fatty acids, block copolymers of propylene oxide and / or butylene oxide and ethylene oxide, including diblock and triblock copolymers, ethoxylates of polyethylene oligomers, and the like.

[0035] Suitable commercially available surfactants include Pluronic™ PE10400 and Pluronic™ L-68LF, each available from BASF, Tergitol 15-S-15 and Tergitol 15-S-40, each available from The Dow Chemical Company, and PE-PEG MW 2250 available from Merck.

[0036] The formulated polyol composition comprises 0.25 to 20 parts by weight of a surfactant per 100 parts by weight of component a), in some embodiments the formulated polyol composition may comprise at least 0.5 parts by weight or at least 0.75 parts by weight of a surfactant, and up to 15 parts by weight, up to 12.5 parts by weight, up to 10 parts by weight, up to 7.5 parts by weight, up to 6.5 parts by weight, up to 6 parts by weight, up to 5.5 parts by weight of a surfactant, on the same basis.

[0037] The compounded polyol composition may contain other compounded ingredients in addition to components a), b) and c).

[0038] Among the optional formulation ingredients are d) foam stabilizing surfactants. Foam stabilizing surfactants are materials that help stabilize the bubbles formed by the blowing agent during the foaming process until the polymer cures. A wide variety of silicone surfactants, such as those typically used in making polyurethane foams, can be used in the present invention. Silicone surfactants can include polyether chains, such as poly(ethylene oxide), poly(propylene oxide), or random or block chains of copolymerized ethylene oxide and propylene oxide. Examples of such silicone surfactants are commercially available under the trade names Tegostab™ (Evonik Industries AG), Niax™ (Momentive Performance Materials), and Dabco™ (Air Products and Chemicals).

[0039] The silicone foam stabilizing surfactant may comprise, for example, 0.01 to 5 weight percent of component a).

[0040] Another optional compounding component of the compounded polyol composition is e) a urethane and / or isocyanate trimerization catalyst. For the purposes of the present invention, a urethane catalyst is a catalyst for the reaction of isocyanate groups with alcohol and / or water. 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. Examples of tertiary amine catalysts include triethylamine, N-methylmorpholine, N-ethylmorpholine, N,N-dimethylbenzylamine, N,N-dimethylethanolamine, N,N,N',N'-tetramethyl-1,4-butanediamine, pentamethyldiethylenetriamine, N,N-dimethylcyclohexylamine, 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.

[0041] Reactive amine catalysts such as DMEA (dimethylethanolamine), DMAPA (dimethylaminopropylamine), or amine-initiated polyols different from component a) may also be used.

[0042] Tin catalysts include stannic chloride, stannous chloride, stannous octoate, stannous oleate, dimethyltin dilaurate, dibutyltin dilaurate, stannous ricinoleate, and stannous mercury compounds represented by the formula SnR n (OR) 4-n (wherein R is alkyl or aryl and n is 0-4), dialkyltin mercaptides, dialkyl tin thioglycolates, etc. Zinc and tin catalysts, if used at all, are generally used in conjunction with one or more tertiary amine catalysts.

[0043] Urethane catalysts are typically used in small amounts, with the combined amount of all catalysts preferably comprising 0.0015 to 4.5 percent of the total weight of components b) through e). Preferred amounts are up to 2 percent, up to 1.5 percent, or up to 1.0 percent on the same basis. Zinc and tin catalysts are typically used in very small amounts within this range, such as 0.0015 to 0.25 weight percent on the same basis.

[0044] Isocyanate trimerization catalysts are materials that promote the reaction of isocyanate groups with other isocyanate groups to form isocyanurate rings. Useful isocyanate trimerization catalysts include strong bases such as alkali metal phenolates, alkali metal alkoxides, alkali metal carboxylates, and quaternary ammonium salts. The alkali metal is preferably sodium or potassium. Specific examples of such trimerization catalysts include sodium p-nonylphenolate, sodium p-octylphenolate, sodium p-tert-butylphenolate, sodium acetate, sodium 2-ethylhexanoate, sodium propionate, sodium butyrate, potassium analogs of any of the foregoing, trimethyl-2-hydroxypropylammonium carboxylate salts, and the like. The isocyanate trimerization catalyst may be present in catalytic amounts such as 0.05 to 10 parts by weight per 100 parts by weight of component a). In certain embodiments, the catalyst may be present in an amount of at least 0.1, 0.25, 0.5, or 1 part by weight per 100 parts by weight of component a), and may be present in an amount of up to 7.5, up to 5, or up to 2.5 parts by weight per 100 parts by weight of component a).

[0045] The blended polyol formulation of the present invention may include g) one or more other polyols in addition to component a). When present, these polyols may, for example, constitute up to 25%, up to 10%, or up to 5% of the combined weight of components a) and g). Examples of such other polyols include one or more polyols having a hydroxyl value of less than 150, such as, for example, 20-150 or 30-150. Such polyols may be, for example, polyether polyols, polyester polyols, natural oil polyols such as castor oil, soybean "blown" oil, and the like. Component g) may include, for example, one or more polyols having a hydroxyl value greater than 350, such as glycerin, trimethylolpropane, triethanolamine, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, penterythritol, erythritol, sorbitol, sucrose, or any one or more alkoxylates of the foregoing having a hydroxyl value greater than 350.

[0046] In addition to the aforementioned components, the reaction mixture may include, for example, one or more fillers and / or reinforcing agents, such as glass fiber, carbon fiber, glass flake, mica, talc, melamine, and calcium carbonate, one or more pigments and / or colorants, such as titanium dioxide, iron oxide, chromium oxide, azo / diazo dyes, phthalocyanines, dioxazines, and carbon black, one or more biocides, one or more preservatives, one or more antioxidants, one or more flame retardants, and the like.

[0047] The compounded polyol composition of the present invention can be made by simple mixing of components a)-c) and, optionally, one or more of components d)-e) (and g) described below, if used). If component c) or other compounding ingredients (other than fillers, reinforcing agents or pigments) are solid at room temperature, it is preferred to heat such ingredients to melt or soften them before combining with component a), and to cool the resulting mixture before adding the hydrocarbon blowing agent. The hydrocarbon blowing agent must be combined with the other compounding ingredients at a temperature below its boiling point. Once all compounding ingredients are mixed, the compounded polyol composition must be stored at a temperature below the boiling point of the hydrocarbon blowing agent and / or in a pressurized container to prevent the hydrocarbon from volatilizing.

[0048] Foams are made in accordance with the present invention by combining components a)-e) as described above (and g) as described below, if present, with component f) at least one organic polyisocyanate to form a reaction mixture, and then curing under conditions such that component b) volatilizes and components a) and f) (and g) if present) react to form a polymeric foam. The isocyanate index (100 times the ratio of isocyanate groups to isocyanate reactive groups provided in the reaction mixture) is at least 90, preferably at least 100 or at least 110. When polyurethane-isocyanurate foams are desired, the isocyanate index is preferably at least 200, at least 250, or at least 300. In some embodiments, the isocyanate index can be up to 1000, up to 600, up to 500, or up to 450.

[0049] Any two or more of components a)-e) may be formed into a formulated polyol composition as described above prior to combination with an organic polyisocyanate to produce a foam. In a preferred embodiment, a formulated polyol composition including at least components a)-c) (and optionally any one or more of components d), e) and g)) is first prepared, and the preformed polyol composition is combined with the polyisocyanate to form a reaction mixture. However, it is within the scope of the present invention to form the reaction mixture by combining various components at once or in various subcombinations. In particular, the hydrocarbon blowing agent may be mixed with the polyol and other components at the time the reaction mixture is prepared and the foam is made.

[0050] The organic polyisocyanate may have an isocyanate equivalent weight of 80 to 500, with a preferred equivalent weight being 120 to 250 or 125 to 150. The organic isocyanate may contain an average of at least 2 to about 4 isocyanate groups per molecule. Examples of useful aromatic polyisocyanates include, for example, m-phenylene diisocyanate, toluene-2,4-diisocyanate, toluene-2,6-diisocyanate, naphthylene-1,5-diisocyanate, methoxyphenyl-2,4-diisocyanate, diphenylmethane-4,4'-diisocyanate, diphenylmethane-2,4'-diisocyanate, diphenylmethane-2,2'-diisocyanate, 4,4'-biphenylene diisocyanate, 3,3'-dimethoxy-4,4'-biphenyl diisocyanate, 3,3'-dimethyl ... Examples of aromatic isocyanates include 4,4',4"-triphenylmethane triisocyanate, polymethylene polyphenylisocyanate (PMDI) with three or more phenylisocyanate groups, toluene-2,4,6-triisocyanate, and 4,4'-dimethyldiphenylmethane-2,2',5,5'-tetraisocyanate. Any of the foregoing aromatic isocyanates can be modified to contain one or more urethane, urea, allophanate, biuret, carbodiimide or uretonimine linkages, or any combination of any two or more thereof.

[0051] Preferably, the polyisocyanate is diphenylmethane-4,4'-diisocyanate, diphenylmethane-2,4'-diisocyanate, diphenylmethane-2,2'-diisocyanate, PMDI, or a mixture of any two or more thereof. Diphenylmethane-4,4'-diisocyanate, diphenylmethane-2,4'-diisocyanate, and diphenylmethane-2,2'-diisocyanate, as well as mixtures thereof, are collectively referred to as MDI, and all of them can be used. As for the "polymeric MDI" which is a mixture of PMDI and MDI, a polymeric MDI containing 70% by weight or less of MDI, particularly 50 to 70% by weight of MDI, can be particularly used.

[0052] In some embodiments, the polyisocyanate is a polymeric MDI having an isocyanate equivalent weight of 126 to 150 and an average isocyanate functionality of 2.2 to 3.5.

[0053] The curing conditions are selected such that the blowing agent volatilizes and components a) and f) (and g), if present) react to produce a polymer foam. The conditions typically include a temperature above the boiling point of the hydrocarbon blowing agent at the pressure used. Components a) and f) usually react spontaneously when mixed, even at ambient temperature, and the exothermic heat of reaction is often sufficient to produce the temperature required to volatilize the hydrocarbon blowing agent. Thus, in many cases, it is only necessary to form the reaction mixture at or near ambient temperature, such as 10-35°C, and the curing reaction can proceed without the addition of further heat. However, if desired, the components can be heated at or before forming the reaction mixture, and / or the reaction mixture can be heated to an elevated temperature to accelerate the curing reaction.

[0054] In some embodiments, foams are produced by introducing a reactive mixture into a cavity or defined space where expansion and curing occurs. The cavity or defined space can be, for example, an insulating panel or wall, such as the wall of a refrigerator, freezer, or cooler. The cavity can be the space between opposing layers, as in producing sandwich panels for the construction or transportation industries. In such embodiments, the expansion of the reactive mixture is limited by the shape of the cavity, and the cured form assumes the shape defined by the interior surface of the cavity.

[0055] In other embodiments, the foam is produced in a continuous process by continuously dispensing the reactive mixture onto a moving belt or substrate. The substrate is an opposing sheet or panel, and a second layer of the opposing sheet or panel may be continuously placed on top of the reactive mixture to form a sandwich structure. The reactive mixture cures to form a foam that adheres to the substrate.

[0056] Alternatively, the foam can be produced in a free rise process in which the foam formulation is dispensed into an open area and allowed to rise freely vertically to produce bunstock.

[0057] The polymer foam of the present invention has a melting point of, for example, 20 to 120 kg / m 3 or 30~80kg / m 3 The foam density may be

[0058] The following examples are provided to illustrate the present invention, but are not intended to limit the scope of the invention. All parts and percentages are by weight unless otherwise indicated. All molecular weights are number averages by gel permeation chromatography.

[0059] The compatibility of each of the three polyester polyols with n-pentane is evaluated by mixing 15 parts n-pentane with 100 parts polyol in a high speed laboratory mixer at ambient temperature for 1 minute. The resulting mixture is weighed and the amount of pentane absorbed by the polyol is determined (and by subtracting the amount of pentane volatilized during the mixing process). An additional amount of n-pentane equal to the amount of n-pentane volatilized is added to the polyol / pentane mixture while mixing for 1 minute, again at ambient temperature. The mixture is again weighed. The weight of n-pentane in the mixture is determined. The retained n-pentane is calculated as the weight of n-pentane in the polyol / pentane mixture divided by the combined weight of the two additions of n-pentane.

[0060] In either case, the mixture is allowed to stand at room temperature for 24 hours and then visually inspected for phase separation. The volume of the upper n-pentane rich phase is measured as a percentage of the total volume of the mixture.

[0061] The polyester polyols evaluated were: Polyol A: A terephthalic acid / diethylene glycol polyester polyol having a hydroxyl functionality of 2 and a hydroxyl number of 215. Polyol A corresponds to component a) of the present invention. It does not contain pendant hydrocarbon chains.

[0062] Polyol B: An orthophthalic anhydride / diethylene glycol polyester polyol having a hydroxyl functionality of 2 and a hydroxyl number of 320. It does not contain any pendant hydrocarbon chains.

[0063] Polyol C: A hydrophobically modified phthalic anhydride / diethylene glycol polyester polyol having a hydroxyl functionality of 1.5-2 and a hydroxyl number of 234 made according to US Pat. No. 6,345,022.

[0064] The results are shown in Table 1. [Table 1]

[0065] These results indicate the significantly different solubility properties of orthophthalic and terephthalic polyester polyols, as well as the effect of hydrophobic modification of the phthalic polyol. The terephthalic esters retain much less n-pentane and have a greater tendency to stratify into an n-pentane-rich upper layer and one or more relatively n-pentane-poor lower layers. Hydrophobic modification of the orthophthalic polyester polyol increases the amount of n-pentane retained.

[0066] Examples 1 and 2 and Comparative Sample A Blends of Polyol A with various surfactants at various surfactant concentrations are evaluated for n-pentane retention and upper phase volume % by the methods described above. The solid surfactants are melted prior to blending with the polyol. The surfactants are as follows:

[0067] Comparative sample A: Oligoethylene block-poly(ethylene glycol) containing 67% oxyethylene units. The molecular weight of this surfactant is 642 g / mol and the HLB is 12.6 (Surfactant A). It is a liquid at room temperature.

[0068] Example 1: Block copolymer of ethylene oxide and propylene oxide (Surfactant B) with molecular weight of 5900 and HLB of 15. This surfactant is a waxy solid at room temperature.

[0069] Example 2: Oligoethylene block-poly(ethylene glycol) containing 90% oxyethylene units. This surfactant is a room temperature solid with a molecular weight of 1960 g / mol and an HLB of 18 (Surfactant C).

[0070] The test results are as shown in Table 2. [Table 2]

[0071] The data shows the effect of surfactant HLB on compatibility. A surfactant with an HLB of 12.6 (Comparative Sample A) is less effective even at high concentrations of 5-10%. Mixtures containing that surfactant stratify easily on standing.

[0072] In Example 1, the presence of 5% surfactant at HLB 15 results in very high retention of n-pentane and no stratification. Surfactant levels as low as 1% improve retention of n-pentane over Comparative Sample A, which has a surfactant of HLB 12.6, at 5%.

[0073] In Example 2, the HLB 18 surfactant, at levels as low as 0.25%, is at least as effective at retaining n-pentane and preventing stratification as the 5% HLB 12.6 surfactant, Comparative Sample A. At 0.5% surfactant level, no stratification is observed, and at 1% surfactant level, the retained n-pentane is as high as that seen with the 5% surfactant of Comparative Sample A.

[0074] Examples 3 to 4 and Comparative Samples B to C Polyol A and various surfactant blends are evaluated for n-pentane retention and overlayer volume % as described above. The surfactant amounts and test results are shown in Table 3.

[0075] The surfactants used in the various experiments were as follows: Comparative Sample B: A liquid triblock copolymer with a central poly(propylene oxide) block and terminal poly(ethylene oxide) blocks. The surfactant has a molecular weight of 2900 and an HLB of 8 (Surfactant D).

[0076] Comparative Sample C: A solid (at room temperature) triblock copolymer having a central poly(propylene oxide) block and terminal poly(ethylene oxide) blocks. The surfactant has a molecular weight of 2000 and an HLB of 10 (Surfactant E).

[0077] Comparative Sample D: A liquid oligoethylene block poly(ethylene glycol) having a molecular weight of 420 and an HLB of 11 (Surfactant F).

[0078] Example 3: PO-EO-PO triblock copolymer (surfactant G) having a molecular weight of 8,400 and an HLB of 16, which is solid at room temperature.

[0079] Example 4: A solid polyethylene / polyethylene glycol block copolymer at room temperature, with a molecular weight of 2250 and an HLB of 16 (Surfactant H). [Table 3]

[0080] The higher amount of retained n-pentane and the smaller upper phase volume of the inventive examples are clear indications of improved compatibilization of the blowing agent and the terephthalic acid-based polyester polyol.

[0081] A sandwich panel having metal surface layers on the outside and a foam layer in the middle is prepared using the following standard foam formulation. All of the formulation ingredients except the polyisocyanate are formed into a polyol composition. The polyol composition is then combined with the polyisocyanate to produce a reaction mixture that is applied to one of the metal surface layers to form a layer. The other surface layer is brought into position above the polyol composition layer. The polyol composition rises and cures in contact with the surface layer to form a urethane modified polyisocyanurate foam having a thickness of 10 mm and a foam density as shown in Table 4. The amount and type of surfactant are also as shown in Table 4. [Table 4]

[0082] The tensile adhesion strength is measured on the resulting panels. Pieces of 50 mm x 50 mm x 10 mm (thickness of foam) are cut. A tensile force is applied perpendicular to the plane of the metal surfaces and the force required to separate the foam from one metal surface is measured.

[0083] Surface smoothness is evaluated as an indication of how well the blowing agent has been compatibilized in the polyol formulation. The exposed foam surface obtained after removing the metal surface layer is painted black with a roller. A photograph of the painted surface is taken. The image is processed using IMAGEJ version 1.52A software by selecting Process / Binary / Operation and checking the "Black Background" box, so that pixels with a value of 0 are displayed in black and pixels set to 255 are displayed in white. Use the threshold tool, select Image / Adjust / Threshold and check the "Dark Background" box. Adjust the lower threshold to a value that highlights most pixels in red and select "Apply" to obtain a binary image. Select Edit / Select / Create and select only the white pixels. By selecting Analyze / Measure an area value is generated that represents the white pixels indicating surface smoothness.

[0084] The test results are as shown in Table 4. [Table 5]

[0085] As shown in Table 4, foams made with surfactants with HLB between 15 and 18 have much smoother surfaces than foams made with lower HLB surfactants. The improved surface smoothness indicates better compatibility of the pentane blowing agent with the terephthalic acid-based polyester polyols. Adhesion to metal surface panels remains good and foam density is essentially unchanged. It should be noted that the present invention includes the following aspects. [Aspect 1] a) at least one polyester polyol containing one or more terephthalic acid ester groups, the polyester polyol having a number average of at least 1.5 hydroxyl groups per molecule and a hydroxyl value of from 150 to 350, or a mixture of at least 50% by weight of the polyester polyol, based on the weight of the mixture, with up to 50% by weight of one or more other polyols having a number average of at least 1.5 hydroxyl groups per molecule and a hydroxyl value of from 150 to 350; b) 5 to 30 parts by weight per 100 parts by weight of component a) of one or more aliphatic hydrocarbons having 4 to 7 carbon atoms; and c) 0.25 to 20 parts by weight per 100 parts by weight of component a) one or more nonionic surfactants having a hydrophilic-lipophilic balance (HLB) of greater than 13 and up to 18.5. [Aspect 2] 2. The blended polyol composition of embodiment 1, wherein the nonionic surfactant is selected from the group consisting of ethoxylates of fatty alcohols and / or fatty acids, block copolymers of propylene oxide and / or butylene oxide and ethylene oxide, and ethoxylates of polyethylene oligomers, and the nonionic surfactant has an HLB of 14 to 18. [Aspect 3] 3. The formulated polyol composition of any one of the preceding claims, comprising 0.5 to 10 parts by weight of the nonionic surfactant per 100 parts by weight of component a). [Aspect 4] The blended polyol composition of any one of the preceding aspects, wherein the polyester polyol containing one or more terephthalate ester groups has a number average of 2 to 2.5 hydroxyl groups per molecule and a hydroxyl number of 200 to 275. [Aspect 5] The blended polyol composition of any one of the preceding aspects, wherein the polyester polyol containing one or more terephthalate ester groups does not contain a pendant aliphatic hydrocarbon group having 6 or more carbon atoms. [Aspect 6] The blended polyol composition of any one of the preceding aspects, wherein the polyester polyol containing one or more terephthalate ester groups constitutes at least 85% by weight of component a). [Aspect 7] The blended polyol composition of any one of the preceding aspects, wherein component c) comprises at least 95% by weight of one or more pentane isomers. [Aspect 8] The formulated polyol composition of any one of the preceding aspects, further comprising d) one or more foam stabilizing surfactants, and e) one or more urethane and / or isocyanate trimerization catalysts. [Aspect 9] 1. A method of making a polymer foam, comprising the steps of: A) a) at least one polyester polyol containing one or more terephthalic acid ester groups, the polyester polyol having a number average of at least 1.5 hydroxyl groups per molecule and a hydroxyl value of from 150 to 350, or a mixture of at least 50% by weight of the polyester polyol, based on the weight of the mixture, with up to 50% by weight of one or more other polyols having a number average of at least 1.5 hydroxyl groups per molecule and a hydroxyl value of from 150 to 350; b) 5 to 30 parts by weight per 100 parts by weight of component a) of one or more aliphatic hydrocarbons having 4 to 7 carbon atoms; c) 0.5 to 20 parts by weight per 100 parts by weight of component a) of one or more nonionic surfactants having a hydrophilic-lipophilic balance (HLB) of greater than 13 and up to 18.5; d) one or more foam stabilizing surfactants; and e) one or more urethane and / or trimerization catalysts; f) forming a reaction mixture comprising at least one organic polyisocyanate in an amount sufficient to provide an Isocyanate Index of at least 90; B) curing the reaction mixture under conditions such that component b) volatilizes and components a) and f) react to form the polymer foam. [Aspect 10] 10. The method of claim 9, wherein the nonionic surfactant is selected from the group consisting of ethoxylates of fatty alcohols and / or fatty acids, block copolymers of propylene oxide and / or butylene oxide and ethylene oxide, and ethoxylates of polyethylene oligomers, and the nonionic surfactant has an HLB of 14 to 18. [Aspect 11] 11. The method of claim 9 or 10, wherein component a) comprises 0.5 to 10 parts by weight of said nonionic surfactant per 100 parts by weight. [Aspect 12] The method of any one of aspects 9 to 11, wherein the polyester polyol containing one or more terephthalate ester groups has a number average of 2 to 2.5 hydroxyl groups per molecule and a hydroxyl number of 200 to 275. [Aspect 13] The method of any one of aspects 9-12, wherein the polyester polyol containing one or more terephthalate ester groups does not contain any pendant aliphatic hydrocarbon groups having six or more carbon atoms. [Aspect 14] The method of any one of aspects 9 to 13, wherein the polyester polyol containing one or more terephthalate ester groups constitutes at least 85% by weight of component a). [Aspect 15] The method of any one of aspects 9-14, wherein component c) comprises at least 95% by weight of one or more pentane isomers.

Claims

1. a) at least one polyester polyol containing one or more terephthalate ester groups, the polyester polyol having a number average of at least 1.5 hydroxyl groups per molecule and a hydroxyl value of from 150 to 350, or a mixture of at least 50% by weight of the polyester polyol, based on the weight of the mixture, with up to 50% by weight of one or more other polyols having a number average of at least 1.5 hydroxyl groups per molecule and a hydroxyl value of from 150 to 350; b) 5 to 30 parts by weight per 100 parts by weight of component a) of one or more aliphatic hydrocarbons having 4 to 7 carbon atoms; c) 0.25 to 20 parts by weight per 100 parts by weight of component a) of one or more nonionic surfactants having a hydrophilic-lipophilic balance (HLB) of 15 to 18.5; Including, A compounded polyol composition for producing rigid polyurethane and / or polyisocyanurate foams, wherein the nonionic surfactant is selected from the group consisting of ethoxylates of fatty alcohols and / or fatty acids; block copolymers of propylene oxide and / or butylene oxide with ethylene oxide; and ethoxylates of polyethylene oligomers.

2. 10. The compounded polyol composition of claim 1, wherein said nonionic surfactant has an HLB of 15-18.

3. 3. The blended polyol composition of claim 1 or 2, comprising 0.5 to 10 parts by weight of said nonionic surfactant per 100 parts by weight of component a).

4. The blended polyol composition of any one of claims 1 to 3, wherein the polyester polyol containing one or more terephthalate groups has a number average of 2 to 2.5 hydroxyl groups per molecule and a hydroxyl number of 200 to 275.

5. 5. The blended polyol composition of claim 1, wherein the polyester polyol containing one or more terephthalate ester groups does not contain any pendant aliphatic hydrocarbon groups having 6 or more carbon atoms.

6. The blended polyol composition of any one of claims 1 to 5, wherein the polyester polyol containing one or more terephthalate ester groups constitutes at least 85% by weight of component a).

7. The blended polyol composition of any one of claims 1 to 6, wherein component c) comprises at least 95% by weight of one or more pentane isomers.

8. 8. The formulated polyol composition of claim 1, further comprising: d) one or more foam stabilizing surfactants; and e) one or more urethane catalysts and / or isocyanate trimerization catalysts, wherein the foam stabilizing surfactants are silicone surfactants.

9. 1. A method of making a polymer foam, comprising the steps of: A) a) at least one polyester polyol containing one or more terephthalate ester groups, the polyester polyol having a number average of at least 1.5 hydroxyl groups per molecule and a hydroxyl value of from 150 to 350, or a mixture of at least 50% by weight of the polyester polyol, based on the weight of the mixture, with up to 50% by weight of one or more other polyols having a number average of at least 1.5 hydroxyl groups per molecule and a hydroxyl value of from 150 to 350; b) 5 to 30 parts by weight per 100 parts by weight of component a) of one or more aliphatic hydrocarbons having 4 to 7 carbon atoms; c) 0.5 to 20 parts by weight per 100 parts by weight of component a) one or more nonionic surfactants having a hydrophilic-lipophilic balance (HLB) of 15 to 18.5, wherein said nonionic surfactants are selected from the group consisting of ethoxylates of fatty alcohols and / or fatty acids; block copolymers of propylene oxide and / or butylene oxide with ethylene oxide; and ethoxylates of polyethylene oligomers; d) one or more foam stabilizing surfactants, wherein said foam stabilizing surfactants are silicone surfactants; e) one or more urethane catalysts and / or isocyanate trimerization catalysts; f) forming a reaction mixture comprising at least one organic polyisocyanate in an amount sufficient to provide an Isocyanate Index of at least 90; B) curing the reaction mixture under conditions such that component b) volatilizes and components a) and f) react to form the polymer foam.

10. The method of claim 9, wherein the nonionic surfactant has an HLB of 15-18.

11. 11. The method of claim 9 or 10, comprising 0.5 to 10 parts by weight of said nonionic surfactant per 100 parts by weight of component a).

12. The method of any one of claims 9 to 11, wherein the polyester polyol containing one or more terephthalate groups has a number average of 2 to 2.5 hydroxyl groups per molecule and a hydroxyl number of 200 to 275.

13. The method of any one of claims 9 to 12, wherein the polyester polyol containing one or more terephthalate ester groups does not contain any pendant aliphatic hydrocarbon groups having six or more carbon atoms.

14. The method of any one of claims 9 to 13, wherein the polyester polyol containing one or more terephthalate ester groups constitutes at least 85% by weight of component a).

15. 15. The process according to any one of claims 9 to 14, wherein component c) comprises at least 95% by weight of one or more pentane isomers.

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