Isocyanate reactive components with enhanced hydrocarbon compatibility

Abstract

The present disclosure relates to an isocyanate-reactive component comprising a soybean oil-modified aromatic polyester polyol, a terephthalic acid-based polyester polyol, a first EO / PO block copolymer nonionic surfactant, a phosphorus-based flame retardant, a C1-C3 carboxylic acid (e.g., a 1, 3, 4-trimethyl-1, 3, 4-trimethyl-1, 3, 4-trimethyl-1, 3, 4-trimethyl-1, 3, 4-trimethyl-1, 3, 4-trimethyl-1, 3, 4-trimethyl-1, 3-trimethyl-1 formic acid), a silicon-based surfactant, a foaming / gelling catalyst and a trimerization catalyst.

Description

Technical Field

[0001] Embodiments of the present disclosure relate to isocyanate-reactive components for forming rigid polyurethane (PU) foams, and more particularly to isocyanate-reactive components having enhanced hydrocarbon compatibility for rigid PU foams. Background Art

[0002] Rigid polyurethane (PU) foams are commonly used as thermal insulators in building products such as preformed building panels. Rigid PU foams are typically produced by the reaction of an isocyanate with a polyol component, where the reaction mixture is expanded with a blowing agent to provide the foam for the rigid PU foam. The isocyanate, polyol component, and blowing agent are contacted together with a catalyst and other optional components at a dispensing head that dispenses the rigid PU foam formulation. The blowing agent is typically dissolved or emulsified in the polyol component and volatilizes at or above its boiling point during the exothermic reaction between the polyol and the isocyanate compound to produce the pores or honeycomb structure of the foam.

[0003] In forming rigid PU foams, the isocyanate is provided in the so-called "A-side" stream of the reagents, while the polyol component is provided in the "B-side" stream of the reagents. In addition to the polyol component, the B-side also contains a blowing agent that is mixed into the polyol component. Among many blowing agents, some are preferred due to their lower ozone depletion characteristics. Such blowing agents include pentane isomers such as n-pentane, isopentane, and cyclopentane. n-Pentane and isopentane are the cheapest isomers, but they also have the least solubility in the polyol component. Cyclopentane is relatively soluble in the polyol component, but it is expensive, and the PU foam boards produced with it can exhibit poor dimensional stability in colder environments. Therefore, blends of these different pentane isomers are often used.

[0004] The pentane isomers have other problems. For example, at least one problem with using pentane isomers is the tendency for rapid phase separation in the B-side. This can be problematic when the blowing agent is mixed with the B-side and then added to the dispensing tank of the polyurethane foaming equipment and the mixture is left idle in the tank. For example, this can occur when operations are suspended between work shifts (e.g., at night) or on weekends. Once separated, the B-side and the phase-separated blowing agent (e.g., pentane isomers) need to be removed from the storage tank and associated supply lines to allow for the use of a properly mixed B-side and blowing agent in forming the PU foam.

[0005] Accordingly, there is a need in the art for a polyol component that provides enhanced compatibility (e.g., no phase separation) with hydrocarbon-based blowing agents such as pentane isomers used in the production of rigid PU foams. Summary of the Invention

[0006] The present disclosure provides an isocyanate-reactive component that provides enhanced compatibility with hydrocarbon-based blowing agents such as pentane isomers for the production of rigid PU foams. Specifically, the present disclosure provides an isocyanate-reactive component that comprises (i) 5 wt% to 20 wt% of a soybean oil-modified aromatic polyester polyol having a hydroxyl value of 250 mg KOH / g to 270 mg KOH / g and a functionality of at least about 1.8; (ii) 30 wt% to 65 wt% of a terephthalic acid-based polyester polyol having a hydroxyl value of 200 mg KOH / g to 340 mg KOH / g and a functionality of at least about 2; (iii) 1 wt% to 5 wt% of a first EO / PO block copolymer nonionic surfactant having a weight average molecular weight of 2000 g / mol to 3000 g / mol; (iv) 10 wt% to 20 wt% of a phosphorus-based flame retardant; (v) 2 wt% to 5 wt% of a C1-C3 carboxylic acid; (vi) 1 wt% to 5 wt% of a silicone-based surfactant; (vii) 0.1 wt% to 3 wt% of a blowing / gelling catalyst; and (viii) 0.5 wt% to 5 wt% of a trimerization catalyst; wherein the percentages of (i) to (viii) are based on the total weight of the isocyanate-reactive component and the total weight of (i) to (viii) does not exceed 100%. Detailed Description

[0007] The present disclosure provides an isocyanate-reactive component that provides enhanced compatibility with hydrocarbon-based blowing agents such as pentane isomers for the production of rigid polyurethane (PU) foams. Specifically, the present disclosure provides an isocyanate-reactive component that can be used to form rigid PU foams for insulation applications, such as products like steel-faced building panels. Surprisingly, when mixed with hydrocarbon-based blowing agents known in the art, the isocyanate-reactive component exhibits enhanced solubility and stability for rapid separation from the so-called "B-side". As discussed herein, such blowing agents include, but are not limited to, pentane isomers. Thus, the isocyanate-reactive component of the present disclosure can be used in rigid PU foam processes where, due to the formation of rigid PU foams in a discontinuous process, the isocyanate-reactive component may be idle (e.g., operations are paused overnight between work shifts or on weekends).

[0008] For various embodiments, the isocyanate-reactive component particularly includes a soybean oil-modified aromatic polyester polyol having a phthalic acid backbone of dicarboxylic acid, and a first ethylene oxide / propylene oxide (EO / PO) block copolymer nonionic surfactant, both of which contribute to providing enhanced solubility and stability to the blowing agent in the isocyanate-reactive component. Additional components in the isocyanate-reactive component particularly include C1-C3 carboxylic acids (e.g., formic acid) and water, which also play a role in enhancing the solubility and stability of the blowing agent in the isocyanate-reactive component. Additionally, it is recognized that formic acid can also contribute to improving the aesthetic properties of the rigid PU foam formed in a discontinuous injection molding process. It has also been surprisingly found that the isocyanate-reactive component containing both the soybean oil-modified aromatic polyester polyol and the first EO / PO block copolymer nonionic surfactant has a significant effect on the fire resistance of the rigid PU foam formed according to the present disclosure.

[0009] The above advantages of the present disclosure are surprisingly achieved using an isocyanate-reactive component comprising: (i) 5 wt% to 20 wt% of a soybean oil-modified aromatic polyester polyol having a hydroxyl value of 250 mg KOH / g to 270 mg KOH / g and a functionality of at least about 1.8; (ii) 30 wt% to 65 wt% of a terephthalic acid-based polyester polyol having a hydroxyl value of 200 mg KOH / g to 340 mg KOH / g and a functionality of at least about 2; (iii) 1 wt% to 5 wt% of a first EO / PO block copolymer nonionic surfactant having a weight average molecular weight of 2000 g / mol to 3000 g / mol; (iv) 10 wt% to 20 wt% of a phosphorus-based flame retardant; (v) 2 wt% to 5 wt% of a C1-C3 carboxylic acid (e.g., formic acid); (vi) 1 wt% to 5 wt% of a silicon-based surfactant; (vii) 0.1 wt% to 3 wt% of a blowing / gelling catalyst; and (viii) 0.5 wt% to 5 wt% of a trimerization catalyst; wherein the percentages of (i) to (viii) are based on the total weight of the isocyanate-reactive component and the total weight of (i) to (viii) does not exceed 100%.

[0010] The present disclosure further provides a rigid PU foam formed from a reaction mixture comprising (A) an isocyanate component having a functionality of 2.7 to 2.9; (B) an isocyanate-reactive component as provided herein; and (C) at least one hydrocarbon blowing agent; wherein the stoichiometric index of the isocyanate component to the isocyanate-reactive component is 1.0 to 3.0.

[0011] Each of the above components of the isocyanate-reactive component and other optional components are discussed below. For various embodiments, the hydroxyl value (OH value, as KOH) can be determined by ASTM D4274, where ASTM D 1957 and ASTM E222-10 also describe methods for determining the hydroxyl value provided herein; the acid value (as KOH) is determined by ASTM D4662. The weight percentage (wt.%) values provided for the isocyanate-reactive components (e.g., (i) to (xii)) are based on the total weight of the isocyanate-reactive components, where the total weight percentage never exceeds 100 wt.%.

[0012] (i) - Aromatic polyester polyol modified with soybean oil

[0013] The isocyanate-reactive component comprises (i) 5 wt.% to 20 wt.% of a soybean oil-modified aromatic polyester polyol having a hydroxyl value of 250 mg KOH / g to 270 mg KOH / g and a functionality of at least about 1.8. As used herein, functionality is the number of chemically reactive atoms or groups (e.g., -H, -OH, -NCO) per molecule for the reaction under consideration. This is used as the average value for the soybean oil-modified aromatic polyester polyol.

[0014] The soybean oil-modified aromatic polyester polyol is the reaction product of phthalic anhydride (a phthalic acid-based polyester) or phthalic acid, diethylene glycol (DEG), and soybean oil. The soybean oil-modified aromatic polyester polyol contains greater than 0 wt.% to 11 wt.%, inclusive, of soybean oil. The soybean oil-modified aromatic polyester polyol can have a hydroxyl equivalent weight of 208 g / eq to 224 g / eq. As used herein, hydroxyl equivalent weight is the weight of the compound per reactive site and is calculated according to the following equation: equivalent weight = (56.1 x 1000) / number of OHs. All individual values and subranges between 208 g / eq and 224 g / eq are included herein; for example, the soybean oil-modified aromatic polyester polyol can have a hydroxyl equivalent weight with a lower limit of 208 g / eq, 210 g / eq, 212 g / eq, or 214 g / eq to an upper limit of 224 g / eq, 222 g / eq, 220 g / eq, or 218 g / eq.

[0015] Known equipment and reaction conditions can be used to prepare soybean oil-modified aromatic polyester polyols. Additionally, methods for forming soybean oil-modified aromatic polyester polyols are provided in the Examples section. Briefly, soybean oil-modified aromatic polyester polyols are produced by mixing 30 wt.% to 40 wt.% phthalic anhydride and 45 wt.% to 55 wt.% diethylene glycol in a stirred reactor (e.g., a glass reactor with stirring) under an internal environment (e.g., a nitrogen atmosphere). The mixture is heated to a temperature of 100 °C - 130 °C and stirred until a homogeneous mixture is obtained. Then, a titanium acetylacetonate catalyst (0.01 wt.% to 0.05 wt.%) is added, and the mixture is further heated to 210 °C and stirred until an acid value of 3 mg KOH / g to 5 mg KOH / g is reached. Then, 1 wt.% to 11 wt.% of refined soybean oil is added to the reaction mixture and allowed to react until an acid value of less than 1 mg KOH / g is reached. The wt.% values are based on the total weight of the reaction mixture of the soybean oil-modified aromatic polyester polyol.

[0016] According to the method in Table 2 of the following Examples section, the progress of the conversion is monitored by acid value measurement. Then the product is cooled to 50 °C to 60 °C and filtered through a 25 μm filter before use. The final product has an acid value of 0.30 to 0.40, a hydroxyl value of 250 mg KOH / g to 270 mg KOH / g, and a functionality of at least about 1.8. The functionality of the product is calculated by multiplying the functionality of each structural unit by its weight percentage in the formulation, as f = 2x wt.% phthalic anhydride + 2x wt.% DEG + 0x wt.% soybean oil = functionality.

[0017] The soybean oil-modified aromatic polyester polyol has a functionality of at least about 1.8. For various embodiments, the functionality of the soybean oil-modified aromatic polyester polyol can be from about 1.8 to 2.0. All individual values and subranges of 1.8 to 2.0 including the functionality of the soybean oil-modified aromatic polyester polyol are included; for example, the soybean oil-modified aromatic polyester polyol can have a functionality of 1.8 or a value of 1.85 up to 2.0, 1.95 or an upper limit value of 1.95 (e.g., 1.8 to 2.0). It should also be understood that higher-functional diols, such as glycerol, can produce a higher functionality with the same amount of soybean oil.

[0018] For various embodiments, the isocyanate-reactive component comprises from 5 wt% to 20 wt% of a soybean oil-modified aromatic polyester polyol. This document includes all individual values and sub-ranges from 5 wt.% to 20 wt.% of the soybean oil-modified aromatic polyester polyol; for example, the soybean oil-modified aromatic polyester polyol can be present in the isocyanate-reactive component in an amount from a lower limit of 5 wt.% or 6 wt.% to an upper limit of 20 wt.%, 17 wt.%, 15 wt.%, 12 wt.%, 10 wt.%, or 7 wt.% of the total weight of the isocyanate-reactive component. For example, based on the total weight of the isocyanate-reactive component, the soybean oil-modified aromatic polyester polyol can be from 5 wt.% to 15 wt.%; from 5 wt.% to 10 wt.%, from 5 wt.% to 7 wt.%, or from 6 wt.% to 7 wt.% of the soybean oil-modified aromatic polyester polyol.

[0019] It is understood that, by way of example, soybean oil is a natural product that includes a mixture of different fatty acids (e.g., linoleic acid, oleic acid), which are also present in other naturally occurring oils such as sunflower oil and safflower oil. Thus, the recitation of soybean oil can and does include those other natural oils that share such overlap with the fatty acids found in soybean oil.

[0020] (ii) - Polyester polyol based on terephthalic acid

[0021] The isocyanate-reactive component comprises (ii) from 30 wt% to 65 wt% of a terephthalic acid-based polyester polyol having a hydroxyl value of from 200 mg KOH / g to 340 mg KOH / g and a functionality of at least about 2. As discussed, functionality is the number of chemically reactive atoms or groups per molecule for the reaction under consideration, where this is an average value for the terephthalic acid-based polyester polyol.

[0022] The terephthalic acid-based polyester polyol can have a hydroxyl equivalent weight of from 165 g / eq to 280 g / eq, where the hydroxyl equivalent weight is calculated as described herein. This document includes all individual values and sub-ranges from 165 g / eq to 280 g / eq; for example, the terephthalic acid-based polyester polyol can have a hydroxyl equivalent weight from a lower limit of 165 g / eq, 175 g / eq, 185 g / eq, 195 g / eq, or 205 g / eq to an upper limit of 280 g / eq, 270 g / eq, 260 g / eq, or 250 g / eq.

[0023] The terephthalic acid-based polyester polyol has a functionality of at least about 2. For various embodiments, the functionality of the terephthalic acid-based polyester polyol can be from 2 to 2.7. This document includes all individual values and subranges from 2 to 2.7 of the functionality of the terephthalic acid-based polyester polyol; for example, the terephthalic acid-based polyester polyol can have a functionality with a value of 2.0 or 2.2 up to 2.7, 2.5, or an upper limit value of 2.3.

[0024] The terephthalic acid-based polyester polyol can have a hydroxyl value of from 200 mg KOH / g to 340 mg KOH / g. This document includes all individual values and subranges from 200 mg KOH / g to 340 mg KOH / g; for example, the terephthalic acid-based polyester polyol can have a hydroxyl value with a lower limit of 200 mg KOH / g, 220 mg KOH / g, 240 mg KOH / g, or 250 mg KOH / g up to an upper limit of 340 mg KOH / g, 320 mg KOH / g, 300 mg KOH / g, or 280 mg KOH / g. Preferably, the terephthalic acid-based polyester polyol is a polyester polyol derived from an aromatic terephthalic acid diacid or diester and a diol or polyol, and is produced according to known techniques. For example, the terephthalic acid-based polyester polyol can be prepared by reacting an aromatic polyester polyol that includes at least one acid component (e.g., terephthalic acid) and at least one diol, glycerol, and / or polyol component (e.g., ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, 3-methyl-1,5-pentanediol, 3,3-dihydroxymethylheptane, diethylene glycol, dipropylene glycol, neopentyl glycol, diethylene glycol, dipropylene glycol, cyclohexane-1,4-diol, cyclohexane-1,4-dimethanol, dimer acid diol, ethylene oxide and propylene oxide of bisphenol A). Preferably, the terephthalic acid-based polyester polyol is a polyester polyol derived from an aliphatic or aromatic terephthalic acid diacid, diethylene glycol, and polyethylene glycol, and is produced via a polycondensation reaction according to known techniques. An esterification catalyst can be present in the reaction, and such a reaction can be carried out in an atmosphere of an inert gas (e.g., nitrogen, carbon monoxide, helium, argon, etc.) at a temperature of 150 °C to 280 °C, optionally under reduced pressure, to a desired acid value.

[0025] For various embodiments, the isocyanate-reactive component comprises 30 wt% to 65 wt% of a terephthalic acid-based polyester polyol. This includes all individual values and subranges of 30 wt.% to 65 wt.% of the terephthalic acid-based polyester polyol; for example, the terephthalic acid-based polyester polyol can account for from a lower limit of 30 wt.%, 35 wt.%, or 40 wt.% to an upper limit of 65 wt.%, 60 wt.%, 55 wt.%, 50 wt.%, or 45 wt.% of the total weight of the isocyanate-reactive component. For example, based on the total weight of the isocyanate-reactive component, the terephthalic acid-based polyester polyol can be 35 wt.% to 65 wt.%; 35 wt.% to 55 wt.%; 35 wt.% to 45 wt.% or 40 wt.% to 45 wt.% of the terephthalic acid-based polyester polyol.

[0026] (iii) - First EO / PO block copolymer non-ionic surfactant

[0027] The isocyanate-reactive component comprises (iii) 1 wt% to 5 wt% of a first EO / PO block copolymer nonionic surfactant having a weight average molecular weight of 2000 g / mol to 3000 g / mol. Examples of the first EO / PO block copolymer nonionic surfactant include products commercially available under the trade names Tergitol TM L-61 and Tergitol TM L-64, Tergitol TM L-81 and combinations thereof.

[0028] For various embodiments, the isocyanate-reactive component comprises 1 wt% to 5 wt% of a first EO / PO block copolymer nonionic surfactant. This includes all individual values and subranges of 1 wt.% to 5 wt.% of the first EO / PO block copolymer nonionic surfactant; for example, the first EO / PO block copolymer nonionic surfactant can account for from a lower limit of 1 wt.%, 1.5 wt.%, or 2 wt.% to an upper limit of 5 wt.%, 4 wt.%, or 3 wt.% of the total weight of the isocyanate-reactive component. For example, based on the total weight of the isocyanate-reactive component, the first EO / PO block copolymer nonionic surfactant can be 1 wt.% to 4 wt.%; 1.5 wt.% to 4 wt.% or 2 wt.% to 4 wt.% of the first EO / PO block copolymer nonionic surfactant.

[0029] Preferably, the isocyanate-reactive component of the present disclosure can comprise 5 wt% to 15 wt% of a soybean oil-modified aromatic polyester polyol and 2 wt% to 4 wt% of a first EO / PO block copolymer nonionic surfactant.

[0030] (iv) - Phosphorus-based flame retardant

[0031] The isocyanate-reactive component comprises (iv) from 10 wt% to 20 wt% of a phosphorus-based flame retardant. For the embodiments provided herein, the phosphorus-based flame retardant is selected from the group consisting of phosphate esters, phosphonate esters, phosphinate esters, and combinations thereof. Examples of phosphate ester-based flame retardants include trialkyl phosphates, triaryl phosphates, phosphate esters, and resorcinol bis(diphenyl phosphate). As used herein, a trialkyl phosphate has at least one alkyl group having 2 to 12 carbon atoms and optionally a halogen atom. The other two alkyl groups of the trialkyl phosphate may independently be the same as or different from the first alkyl group and contain 1 to 8 carbon atoms, including straight-chain or branched-chain alkyl groups, cyclic alkyl groups, alkoxyethyl, hydroxyalkyl, hydroxyalkoxyalkyl groups, and straight-chain or branched-chain alkylene groups. Examples of the other two alkyl groups of the trialkyl phosphate include, for example, methyl, ethyl, propyl, butyl, n-propyl, isopropyl, N-butyl, isobutyl, sec-butyl, tert-butyl, butoxyethyl, isopentyl, neopentyl, isohexyl, isoheptyl, cyclohexyl, propylene, 2-methylpropylene, neopentylene, hydroxymethyl, hydroxyethyl, hydroxypropyl, or hydroxybutyl. Blends of different trialkyl phosphates may also be used. The three alkyl groups of the trialkyl phosphate may be the same. The trialkyl phosphate may be tris(2-chloro-1-methylethyl) phosphate (TCPP), tris[2-chloro-1-(chloromethyl)ethyl] phosphate (TDCP), tris(p-tert-butylphenyl) phosphate (TBPP), and tris(2-chloroethyl) phosphate (TCEP). The trialkyl phosphate is desirably triethyl phosphate (TEP).

[0032] Examples of phosphonate esters include diethyl (hydroxymethyl)phosphonate, dimethyl methylphosphonate, and diethyl ethylphosphonate. Examples of phosphinate esters include metal salts of organic phosphinates such as aluminum methyl ethylphosphinate, aluminum diethylphosphinate, zinc methyl ethylphosphinate, and zinc diethylphosphinate. Examples of additional halogen-free flame retardant compounds include resorcinol diphosphate, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, ammonium polyphosphate, and combinations thereof.

[0033] For various embodiments, the isocyanate-reactive component comprises from 10 wt% to 20 wt% of a phosphorus-based flame retardant. This includes all individual values and subranges from 10 wt.% to 20 wt.% of the phosphorus-based flame retardant; for example, the phosphorus-based flame retardant can be from a lower limit of 10 wt.%, 12 wt.%, or 13 wt.% to an upper limit of 20 wt.%, 18 wt.%, or 15 wt.% of the total weight of the isocyanate-reactive component. For example, based on the total weight of the isocyanate-reactive component, the phosphorus-based flame retardant can be from 10 wt.% to 18 wt.%; from 12 wt.% to 18 wt.% or from 13 wt.% to 15 wt.% of the phosphorus-based flame retardant.

[0034] (v) - C1-C3 carboxylic acid

[0035] The isocyanate-reactive component comprises (v) from 2 wt% to 5 wt% of a C1-C3 carboxylic acid (i.e., formic acid, acetic acid, and / or lactic acid). For various embodiments, the isocyanate-reactive component comprises from 2 wt% to 5 wt% of a C1-C3 carboxylic acid. This includes all individual values and subranges from 2 wt.% to 5 wt.% of the C1-C3 carboxylic acid; for example, the C1-C3 carboxylic acid can be from a lower limit of 2 wt.%, 2.5 wt.%, or 2.8 wt.% to an upper limit of 5 wt.%, 4.5 wt.%, or 4 wt.% of the total weight of the isocyanate-reactive component. For example, based on the total weight of the isocyanate-reactive component, the C1-C3 carboxylic acid can be from 2 wt% to 4.5 wt.%; from 2.5 wt.% to 4 wt.% or from 2.8 wt.% to 4 wt.% of the C1-C3 carboxylic acid. Preferably, the C1-C3 carboxylic acid is formic acid.

[0036] (vi) - Silicon-based surfactant

[0037] The isocyanate-reactive component comprises (vi) from 1 wt% to 5 wt% of a silicone-based surfactant. The silicone-based surfactant can help provide stability during the polyurethane reaction to avoid cell collapse, especially for low-density rigid PU foams. For example, the surfactant can help stabilize the bubbles formed by the blowing agent during the foaming process until the polymer cures. Examples of suitable surfactants include silicone-based surfactants such as polyether polysiloxanes, including polysiloxane polyoxyalkylene block copolymers and organic-based surfactants containing polyoxyethylene-polyoxybutylene block copolymers. Examples of such silicone surfactants can be trademarked (Evonik Industries AG), (Momentive), and (Obtained commercially from The Dow Chemical Company). Specific examples of useful surfactants include DC 193, RF 5374, DC 5604, SF 2937, DC 5098, 504, B8418, B 8491, B 8421, B 8461 and B 8462, L-6988, L-6642 and L-6633 surfactants.

[0038] For various embodiments, the isocyanate-reactive component comprises from 1 wt.% to 5 wt.% of a silicone-based surfactant. All individual values and subranges from 1 wt.% to 5 wt.% of the silicone-based surfactant are included herein; for example, the silicone-based surfactant can be from a lower limit of 1 wt.%, 1.5 wt.%, or 2 wt.% to an upper limit of 5 wt.%, 4 wt.%, or 3 wt.% of the total weight of the isocyanate-reactive component. For example, based on the total weight of the isocyanate-reactive component, the silicone-based surfactant can be from 1 wt.% to 4 wt.%; from 1.5 wt.% to 4 wt.% or from 2 wt.% to 3 wt.% of the silicone-based surfactant.

[0039] (vii) - Foaming / gelling catalyst

[0040] The isocyanate-reactive component comprises (vii) from 0.1 wt.% to 3 wt.% of a blowing / gelling catalyst. As used herein, blowing catalysts and gelling catalysts can be distinguished by their tendency to favor the urea (blowing) reaction in the case of blowing catalysts or the urethane (gelling) reaction in the case of gelling catalysts. For various embodiments, the blowing / gelling catalyst can include one or more of the blowing catalysts and / or gelling catalysts as provided herein or as known in the art.

[0041] Examples of blowing catalysts (e.g., catalysts that can tend to favor the blowing reaction) include, but are not limited to, short-chain tertiary amines or oxygen-containing tertiary amines. For example, blowing catalysts include bis-(2-dimethylaminoethyl) ether; pentamethyldiethylenetriamine, triethylamine, tributylamine, N,N-dimethylaminopropylamine, dimethylethanolamine, N,N,N',N'-tetramethylethylenediamine, and combinations thereof, etc.

[0042] Examples of gelling catalysts (e.g., catalysts that may tend to favor the gel reaction) include, but are not limited to, organometallic compounds, cyclic tertiary amines, and / or long-chain amines (e.g., containing several nitrogen atoms), and combinations thereof. Organometallic compounds include organotin compounds, such as tin(II) salts of organic carboxylic acids, e.g., tin(II) diacetate, tin(II) dioctanoate, tin(II) diethylhexanoate, and tin(II) dilaurate, and dialkyltin(IV) salts of organic carboxylic acids, e.g., dibutyltin diacetate, dibutyltin dilaurate, dibutyltin maleate, and dioctyltin diacetate. Bismuth salts of organic carboxylic acids can also be used as gelling catalysts, e.g., bismuth octanoate. Cyclic tertiary amines and / or long-chain amines include dimethylbenzylamine, N,N,N',N'-tetramethylbutanediamine, N,N-dimethylcyclohexylamine, triethylenediamine, and combinations thereof.

[0043] For various embodiments, the isocyanate-reactive component comprises from 0.1 wt.% to 3 wt.% of a blowing / gelling catalyst. This document includes all individual values and subranges of 0.1 wt.% to 3 wt.% of the blowing / gelling catalyst; e.g., the blowing / gelling catalyst can range from a lower limit of 0.1 wt.%, 0.12 wt.%, or 0.14 wt.% to an upper limit of 3 wt.%, 2 wt.%, or 1.6 wt.% of the total weight of the isocyanate-reactive component. For example, based on the total weight of the isocyanate-reactive component, the blowing / gelling catalyst silicone can be from 0.12 wt.% to 3 wt.%; 0.12 wt.% to 2 wt.% or 0.14 wt.% to 1.6 wt.% of the blowing / gelling catalyst.

[0044] (viii) - Trimerization catalyst

[0045] The isocyanate-reactive component comprises (viii) from 0.5 wt.% to 5 wt.% of a trimerization catalyst. A trimerization catalyst is a material that promotes the reaction of isocyanate groups with other isocyanate groups to form an isocyanurate ring. Useful trimerization catalysts include strong bases, such as alkali metal phenolates, alkali metal alkoxides, alkali metal hydroxides, alkali metal carboxylates, quaternary ammonium salts, etc. The alkali metal can be sodium or potassium. Examples of trimerization catalysts include tris(dialkylaminopropyl)-s-hexahydrotriazines, such as 1,3,5-tris(N,N-dimethylaminopropyl)-s-hexahydrotriazine; [2,4,6-tris(dimethylaminomethyl)phenol]; N-(2-hydroxypropyl)-N-trimethylformammonium acetate, potassium octanoate; tetraalkylammonium hydroxides, such as tetramethylammonium hydroxide; alkali metal hydroxides, such as sodium hydroxide; alkali metal alkoxides, such as sodium methoxide and potassium isopropoxide; and alkali metal salts of long-chain fatty acids having from 10 to 20 carbon atoms, and combinations thereof. Some commercially available trimerization catalysts include TMR, TMR-2, TMR-30, K 2097; K15, 41, 43 and 46 etc.

[0046] For various embodiments, the isocyanate-reactive component comprises from 0.5 wt% to 5 wt% of a trimerization catalyst. This document includes all individual values and sub-ranges from 0.5 wt.% to 5 wt.% of the trimerization catalyst; for example, the trimerization catalyst can be present in the isocyanate-reactive component in an amount from a lower limit of 0.5 wt.%, 1 wt.%, 1.2 wt.% or 1.4 wt.% to an upper limit of 5 wt.%, 3 wt.% or 2 wt.% of the total weight of the isocyanate-reactive component. For example, based on the total weight of the isocyanate-reactive component, the trimerization catalyst can be from 0.5 wt.% to 3 wt.%; from 1 wt.% to 2 wt.% or from 1.2 wt.% to 2 wt.% of the trimerization catalyst.

[0047] For various embodiments, the percentages of (i) to (viii) are based on the total weight of the isocyanate-reactive component and the total weight of (i) to (viii) does not exceed 100%. In one embodiment, the isocyanate-reactive component can comprise components (i) to (viii). In another embodiment, the isocyanate-reactive component can consist essentially of components (i) to (viii). In a further embodiment, the isocyanate-reactive component can consist of components (i) to (viii). The isocyanate-reactive components of the present disclosure can also comprise other components, such as components (ix) to (xii) discussed herein. For various embodiments, when other components are present together with (i) to (viii) (e.g., (ix) to (xii) as provided herein), the percentages of the components (e.g., (i) to (xii)) are based on the total weight of the isocyanate-reactive component and the total weight of (i) to (xii) does not exceed 100%.

[0048] (ix) - Second EO / PO block copolymer non-ionic surfactant

[0049] The isocyanate-reactive component may optionally include (ix) from 0.5 wt% to 1.5 wt% of a second EO / PO block copolymer nonionic surfactant having a weight average molecular weight greater than 3000 g / mol to 5000 g / mol. For various embodiments, the second EO / PO block copolymer nonionic surfactant is different from (i.e., not the same as) the first EO / PO block copolymer nonionic surfactant. Examples of the second EO / PO block copolymer type nonionic surfactant include linear EO / PO block copolymers. The second EO / PO block copolymer nonionic surfactant can act as an anti-foaming / de-foaming agent and a low-foaming surfactant. Examples of commercially available second EO / PO block copolymer nonionic surfactants include, but are not limited to, DOWFAX TM 92N40.

[0050] For various embodiments, the isocyanate-reactive component can include from 0.5 wt% to 1.5 wt% of a second EO / PO block copolymer nonionic surfactant. This document includes all individual values and subranges from 0.5 wt.% to 1.5 wt.% of the second EO / PO block copolymer nonionic surfactant; for example, the second EO / PO block copolymer nonionic surfactant can account for from 0.5 wt.%, 0.55 wt.%, or 0.6 wt.% of the total weight of the isocyanate-reactive component as a lower limit to 1.5 wt.%, 1.3 wt.%, or 1 wt.% as an upper limit. For example, based on the total weight of the isocyanate-reactive component, the second EO / PO block copolymer nonionic surfactant can be from 0.5 wt.% to 1.3 wt.%; from 0.5 wt.% to 1 wt.%, or from 6 wt.% to 1 wt.% of the second EO / PO block copolymer nonionic surfactant.

[0051] (x) - Polyoxypropylene-polyoxyethylene polyol initiated by aromatic resin

[0052] The isocyanate-reactive component may also optionally include up to 25 wt% of (x) an aromatic resin-initiated polyoxypropylene-polyoxyethylene polyol having a hydroxyl value of 195 mg KOH / g, an equivalent weight of 286 g / mol, and an average functionality of 3.3 (as defined herein). In one embodiment, the aromatic resin-initiated polyoxypropylene-polyoxyethylene polyol can be a novolak-type polyol, and suitable commercial examples can include those available from The Dow Chemical Company IP 585.

[0053] For various embodiments, the isocyanate-reactive component can comprise up to 25 wt% of an aromatic resin-initiated polyoxypropylene-polyoxyethylene polyol. This includes all individual values and subranges of up to 25 wt.% of the aromatic resin-initiated polyoxypropylene-polyoxyethylene polyol; for example, the aromatic resin-initiated polyoxypropylene-polyoxyethylene polyol can be 5 wt%, 10 wt%, 15 wt%, or 20 wt% of the total weight of the isocyanate-reactive component, with a lower limit of 25 wt% or 23 wt% as the upper limit. For example, based on the total weight of the isocyanate-reactive component, the aromatic resin-initiated polyoxypropylene-polyoxyethylene polyol can be 10 wt% to 25 wt%; 15 wt% to 25 wt% or 20 wt% to 23 wt% of the blowing / gelling catalyst.

[0054] (xi) - Glycerol propoxylated polyether triol

[0055] The isocyanate-reactive component also optionally comprises from 1 wt% to 7 wt% of (xi) glycerol propoxylated polyether triol having an average molecular weight of 1000 g / mol. The glycerol propoxylated polyether triol is a glycerol-initiated polyether triol prepared using known equipment and reaction conditions, having a hydroxyl value of 165 mg KOH / g and a functionality of 3 (as defined herein). Suitable commercially available polyether polyols include VORANOL available from The Dow Chemical Company TM 220 - 110, VORATEC TM SD301, VORANOL TM CP 260, VORANOL TM CP 450, VORANOL TM CP 755, VORANOL TM CP 1000, VORANOL TM CP 1050 and VORANOL TM CP 1055.

[0056] For various embodiments, the isocyanate-reactive component can comprise from 1 wt% to 7 wt% of the glycerol propoxylated polyether triol. This includes all individual values and subranges of 1 wt% to 7 wt% of the glycerol propoxylated polyether triol; for example, the glycerol propoxylated polyether triol can be 1 wt%, 2 wt%, or 3 wt% of the total weight of the isocyanate-reactive component, with a lower limit of 7 wt%, 6 wt%, or 5 wt% as the upper limit. For example, based on the total weight of the isocyanate-reactive component, the glycerol propoxylated polyether triol can be 2 wt% to 7 wt%; 2 wt% to 6 wt% or 3 wt% to 5 wt% of the trimerization catalyst.

[0057] (xii) - Water

[0058] The isocyanate-reactive component may further comprise from 0.2 wt% to 1 wt% of (xii) water. This document includes all individual values and subranges from 0.2 wt.% to 1 wt.% of water; for example, water may account for from 0.2 wt.%, 0.4 wt.%, or 0.6 wt.% of the total weight of the isocyanate-reactive component to 1 wt.%, 0.9 wt.%, or 0.8 wt.% of the upper limit. For example, based on the total weight of the isocyanate-reactive component, water may be from 0.2 wt.% to 1 wt.%; from 0.4 wt.% to 0.9 wt.% or from 0.6 wt.% to 0.8 wt.% of water.

[0059] (xiii) - Hydrocarbon blowing agent

[0060] The isocyanate-reactive component of the present disclosure may further comprise from 1 part by weight to 15 parts by weight of (xiii) a hydrocarbon blowing agent. For various embodiments, the hydrocarbon blowing agent may be selected from the group consisting of alkanes such as butane, isobutane, 2,3-dimethylbutane, pentane isomers such as n-pentane and isopentane, hexane isomers, heptane isomers; cycloalkanes such as cyclopentane, cyclohexane, cycloheptane; HFC-245fa (1,1,1,3,3-pentafluoropropane), HFC-365mfc (1,1,1,3,3-pentafluorobutane), HFC-227ea (1,1,1,2,3,3,3-heptafluoropropane), HFC-134a (1,1,1,2-tetrafluoroethane), trans-1-chloro-3,3,3-trifluoropropene or at least one of their combinations.

[0061] Embodiments of the present disclosure provide that, relative to the weight of the isocyanate-reactive system, the isocyanate-reactive system further comprises from 1 part by weight to 15 parts by weight of a hydrocarbon blowing agent. This document includes all individual values and subranges from 1 part by weight to 15 parts by weight of the hydrocarbon blowing agent; for example, relative to the weight of the isocyanate-reactive system, the hydrocarbon blowing agent may account for from 1 part by weight, 3 parts by weight, or 5 parts by weight of the lower limit to 15 parts by weight, 12 parts by weight, or 10 parts by weight of the upper limit.

[0062] Embodiments of the present disclosure include an isocyanate-reactive component which, in addition to the embodiments provided herein, also has the following embodiments. The isocyanate-reactive component has (i) 6 wt% to 15 wt% of the soybean oil-modified aromatic polyester polyol provided herein; (ii) 35 wt% to 62 wt% of a terephthalic acid-based polyester polyol; (iii) 2 wt% to 4 wt% of a first EO / PO block copolymer nonionic surfactant; (iv) 12 wt% to 16 wt% of a phosphorus-based flame retardant; (v) 2 wt% to 5 wt% of a C1-C3 carboxylic acid (e.g., formic acid); (vi) 2 wt% to 3 wt% of a silicon-based surfactant; (vii) 0.1 wt% to 1 wt% of a blowing / gelling catalyst; and (viii) 1 wt% to 3 wt% of a trimerization catalyst; wherein the percentages of (i) to (viii) are based on the total weight of the isocyanate-reactive component and the total weight of (i) to (viii) does not exceed 100%. Embodiments of the present invention may also optionally include the following components (ix) to (xiii): 0 wt% or 0.7 wt% to 1 wt% of (ix) a second EO / PO block copolymer nonionic surfactant; 0 wt% or 20 wt% to 25 wt% of (x) an aromatic resin-initiated polyoxypropylene-polyoxyethylene polyol; 0 wt% or 1 wt% to 7 wt% of (xi) a glycerol propoxylated polyether triol; 0 wt% or 0.6 wt% to 0.9 wt% of (xii) water; and 1 part by weight to 15 parts by weight of (xiii) a hydrocarbon blowing agent. The percentages of (i) to (xii) are based on the total weight of the isocyanate-reactive component and the total weight of (i) to (xii) does not exceed 100%.

[0063] The isocyanate-reactive component has (i) 6 wt% to 7 wt% of the soybean oil-modified aromatic polyester polyol provided herein; (ii) 40 wt% to 62 wt% of a terephthalic acid-based polyester polyol; (iii) 2 wt% to 4 wt% of a first EO / PO block copolymer nonionic surfactant; (iv) 12 wt% to 16 wt% of a phosphorus-based flame retardant; (v) 2 wt% to 5 wt% of a C1-C3 carboxylic acid (e.g., formic acid); (vi) 2 wt% to 3 wt% of a silicon-based surfactant; (vii) 0.1 wt% to 0.5 wt% of a blowing / gelling catalyst; and (viii) 1 wt% to 2 wt% of a trimerization catalyst; wherein the percentages of (i) to (viii) are based on the total weight of the isocyanate-reactive component and the total weight of (i) to (viii) does not exceed 100%. Embodiments of the present invention may optionally further include the following components (ix) to (xiii): 0 wt% or 0.7 wt% to 1 wt% of (ix) a second EO / PO block copolymer nonionic surfactant; 0 wt% or 20 wt% to 25 wt% of (x) an aromatic resin-initiated polyoxypropylene-polyoxyethylene polyol; 0 wt% or 1 wt% to 7 wt% of (xi) a glycerol propoxylated polyether triol; 0 wt% or 0.6 wt% to 0.9 wt% of (xii) water; and 1 part by weight to 15 parts by weight of (xiii) a hydrocarbon blowing agent. The percentages of (i) to (xii) are based on the total weight of the isocyanate-reactive component and the total weight of (i) to (xii) does not exceed 100%.

[0064] The present disclosure further provides a rigid PU foam formed from a reaction mixture comprising (A) an isocyanate component having a functionality of 2.7 to 2.9; (B) an isocyanate-reactive component; and (C) at least one hydrocarbon blowing agent; wherein the stoichiometric index of the isocyanate component to the isocyanate-reactive component is 1.0 to 3.0. For various embodiments, the (B) isocyanate-reactive component and the (C) at least one hydrocarbon blowing agent are as described above and herein. For various embodiments, the reaction mixture can be mixed at a temperature of 15°C to 90°C, preferably 20°C to 60°C, and particularly 20°C to 35°C, and introduced onto a workpiece (e.g., a steel plate), into an open mold, or optionally into a closed mold under elevated pressure. The mixing can be carried out mechanically by a stirrer or a mixing screw. Once dispensed, the reaction temperature of the reaction mixture can be 20°C to 110°C, preferably 30°C to 70°C, and particularly 40°C to 60°C.

[0065] For various embodiments, the isocyanate component includes at least one polyisocyanate. As used herein, "polyisocyanate" refers to a molecule having an average of greater than 1.0 isocyanate groups / molecule, e.g., an average functionality greater than 1.0. For example, the isocyanate component can be an aliphatic polyisocyanate, cycloaliphatic polyisocyanate, araliphatic polyisocyanate, aromatic polyisocyanate, or a combination thereof. Examples of isocyanates include, but are not limited to, toluene 2,4- / 2,6-diisocyanate (TDI), methylene diphenyl diisocyanate (MDI), polymeric MDI, triisocyanatononane (TIN), naphthyl diisocyanate (NDI), 4,4'-diisocyanatodicyclohexylmethane, 3-isocyanatomethyl-3,3,5-trimethylcyclohexyl isocyanate (isophorone diisocyanate IIPDI), tetramethylene diisocyanate, hexamethylene diisocyanate (HDI), 2-methylpentamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate (THDI), dodecamethylene diisocyanate, 1,4-diisocyanatocyclohexane, 4,4'-diisocyanato-3,3'-dimethyl dicyclohexylmethane, 4,4'-diisocyanato-2,2-dicyclohexylpropane, 3-isocyanatomethyl-1-methyl-1-isocyanatocyclohexane (MCI), 1,3-diisocyanato-4-methylcyclohexane, 1,3-diisocyanato-2-methylcyclohexane, and combinations thereof. In addition to the isocyanates mentioned above, partially modified polyisocyanates can be utilized, including uretdione, isocyanurate, carbodiimide, uretonimine, urethane, or biuret structures and combinations thereof, etc.

[0066] The isocyanate component can be polymeric. As used herein, when describing the isocyanate component, "polymeric" refers to homologues and / or isomers having a relatively high molecular weight. For example, polymeric methylene diphenyl isocyanate refers to homologues and / or isomers of methylene diphenyl isocyanate having a relatively high molecular weight.

[0067] For various embodiments, the stoichiometric index of the isocyanate component to the isocyanate-reactive component is from 1.0 to 3.0. As is known in the art, when the number of isocyanate groups in the isocyanate component is equal to the number of hydroxyl groups in the isocyanate-reactive component, the result is that the stoichiometric index of the isocyanate component to the isocyanate-reactive component is 1.0. When the number of isocyanate groups in the isocyanate component is greater than the number of hydroxyl groups in the isocyanate-reactive component (e.g., three times more), the result is that the stoichiometric index of the isocyanate component to the isocyanate-reactive component is greater than 1.0 (e.g., 3.0 for this example).

[0068] The isocyanate component may have an isocyanate equivalent weight of from 130 g / eq to 140 g / eq. All individual values and sub-ranges from 130 g / eq to 140 g / eq are included herein; for example, the isocyanate component may have an isocyanate equivalent weight with a lower limit of 130 g / eq or 132 g / eq to an upper limit of 140 g / eq, 138 g / eq or 136 g / eq.

[0069] The isocyanate component can be prepared by known methods. For example, it can be prepared by phosgenating the corresponding polyamine and forming a polycarbamoyl chloride and thermally decomposing it to provide a polyisocyanate and hydrogen chloride or by a phosgene-free method, such as by reacting the corresponding polyamine with urea and an alcohol to obtain a polyurethane and thermally decomposing it to obtain a polyisocyanate and an alcohol to prepare the polyisocyanate.

[0070] The isocyanate component can be commercially obtained. Examples of commercial isocyanates include (but are not limited to) those commercially available under the trade name VORANATE TM such as VORANATE TM M 220 and PAPI TM such as PAPI TM 27 polyisocyanates, and other commercial isocyanates.

[0071] The isocyanate component can be utilized such that the composition for producing a rigid PU foam has an isocyanate index in the range of 100 to 300. The isocyanate index can be determined as the quotient of the actual amount of isocyanate utilized and the theoretical amount of isocyanate required for complete reaction of all the active hydrogen groups present in the isocyanate-reactive system multiplied by one hundred. All individual values and sub-ranges from 100 to 300 are included herein; for example, the foam formulation can have an isocyanate index with a lower limit of 100, 120 or 150 to an upper limit of 300, 250 or 200.

[0072] The composition for producing the rigid PU foam disclosed herein can be cured to form a rigid PU foam having a core density greater than 30 kg / m 3 As used herein, the core density of the PU foam is determined as the mass per unit volume of the middle internal part of the molded foam. The foam core density is generally lower than the apparent density calculated by dividing the foam mass by its total volume, due to the density variation from the skin to the core in the molded foam. The rigid PU foam can be prepared by using known methods and conditions, which can vary for different applications. One or more embodiments of the present disclosure provide a method for forming a rigid polyurethane foam product. The method includes curing the reaction mixture disclosed herein. The method can utilize known equipment and conditions, such as the one shot process, etc.

[0073] One or more embodiments of the present disclosure provide that the composition for producing rigid PU foam may comprise one or more additional components. Different additional components and / or different amounts of additional components can be utilized for various applications. Examples of additional components include pigments, colorants, additional flame retardants known in the art, crosslinking agents, chain extenders, antioxidants, biological blockers, and combinations thereof, etc.

[0074] Examples

[0075] The examples below are provided for illustration only and are not intended to limit or restrict the embodiments in any way. Unless otherwise specified, all compounds were purchased from Sigma - Aldrich. In the examples of the present invention (EX) and comparative examples (CE), various terms and names of materials were used, and these terms and names include, for example, the following:

[0076] Table 1. Materials

[0077]

[0078] Preparation of Polyester Polyol 2.

[0079] Polyester polyol 2 was prepared as follows. Phthalic anhydride (3755.3 g, 37.6 wt.%) and diethylene glycol (5144.7 g, 51.4 wt.%) were weighed into a glass reactor equipped with a mechanical stirrer, thermocouple, nitrogen inlet, and distillation bridge under a nitrogen atmosphere. The reactor was brought to a temperature range of 110 °C - 120 °C and stirred until a homogeneous mixture was obtained. Thereafter, titanium acetylacetonate catalyst (Tyzor AA - 105 from Dorf Ketal) (3.00 g, 0.03 wt.%) was added, and the mixture was further heated to 210 °C and stirred until an acid value of 3 mg KOH / g to 5 mg KOH / g was reached. Then refined soybean oil (1100.0 g, 11.0 wt.%) was added to the reaction mixture and allowed to react until an acid value of < 1 mg KOH / g was reached. The progress of the conversion was monitored by acid value measurement according to the method in Table 2. Then the product was cooled to 50 °C - 60 °C and filtered through a 25 μm filter before use. The final product had an acid value of 0.37 and a hydroxyl value of 262.5 mg KOH / g. The functionality of the product was calculated by multiplying the functionality of each structural unit by its weight percentage in the formulation, such as f = 2 x 37.6% (for phthalic anhydride) + 2 x 51.4% (for DEG) + 0 x 11.0% (for soybean oil) = 1.8.

[0080] Table 2 - Analytical methods used in polyester polyol synthesis and results of Polyester Polyol 2

[0081]

[0082] Testing

[0083] The NBS smoke chamber test (optical density of smoke) was carried out in accordance with ASTM E 662. The flame spread test was carried out in accordance with DIN 4102-1.

[0084] Sample

[0085] The polyurethane examples (EX) and comparative examples (CE) were formed as follows. Rigid foamed foams were manufactured by reacting a formulated polyol containing a hydrocarbon blowing agent with a polymeric isocyanate (both maintained at 20 °C). The two components were uniformly mixed by a suitable device operating at 2500 revolutions per minute and poured into a 20 cm x 20 cm x 8 cm mold maintained at 50 °C. Demolding occurred after 20 minutes. Then the foam samples were cut into the required sizes for the fire test methods.

[0086] Table 2A

[0087]

[0088]

[0089] Table 2B

[0090]

[0091]

[0092] CE A to CE D each showed phase separation. In contrast, each of the examples showed a fully formulated blend as a clear liquid (i.e., was homogeneous and did not separate) and provided unexpected and beneficial fire performance as shown in EX.8 (Table 2B). It is believed that the combination of non-ionic surfactant 2 and the soybean oil derivative promoted unexpected results once compared with other examples containing the same type and amount of hydrocarbon blowing agent, the last being used in the amount for the pre-formulated polyol mixture.

Claims

1. An isocyanate-reactive component, the isocyanate-reactive component comprising: (i) 5 wt% to 20 wt% of a soybean oil-modified aromatic polyester polyol having a hydroxyl value of 250 mg KOH / g to 270 mg KOH / g and a functionality of at least about 1.8; (ii) 30 wt% to 65 wt% of a terephthalic acid-based polyester polyol having a hydroxyl value of 200 mg KOH / g to 340 mg KOH / g and a functionality of at least about 2; (iii) 1 wt% to 5 wt% of a first EO / PO block copolymer nonionic surfactant having a weight average molecular weight of 2000 g / mol to 3000 g / mol; (iv) 10 wt% to 20 wt% of a phosphorus-based flame retardant; (v) 2 wt% to 5 wt% of a C1-C3 carboxylic acid; (vi) 1 wt% to 5 wt% of a silicon-based surfactant; (vii) 0.1 wt% to 3 wt% of a foaming / gelling catalyst; and (viii) 0.5 wt% to 5 wt% of a trimerization catalyst; wherein the percentages of (i) to (viii) are based on the total weight of the isocyanate-reactive component and the total weight of (i) to (viii) does not exceed 100%.

2. The isocyanate-reactive component according to claim 1, the isocyanate-reactive component further comprising (ix) 0.5 wt% to 1.5 wt% of a second EO / PO block copolymer nonionic surfactant having a weight average molecular weight greater than 3000 g / mol to 5000 g / mol, wherein the second EO / PO block copolymer nonionic surfactant is different from the first EO / PO block copolymer nonionic surfactant, and wherein the percentages of (i) to (ix) are based on the total weight of the isocyanate-reactive component and the total weight of (i) to (ix) does not exceed 100%.

3. The isocyanate-reactive component according to any one of claims 1 to 2, the isocyanate-reactive component further comprising up to 25 wt% of (x) an aromatic resin-initiated polyoxypropylene-polyoxyethylene polyol having a hydroxyl value of 195 mg KOH / g, an equivalent weight of 286, and an average functionality of 3.

3.

4. The isocyanate-reactive component according to any one of claims 1 to 3, the isocyanate-reactive component further comprising 1 wt% to 7 wt% of (xi) a glycerol propoxylated polyether triol having an average molecular weight of 1000.

5. The isocyanate-reactive component according to any one of claims 1 to 4, the isocyanate-reactive component further comprising 0.2 wt% to 1 wt% of (xii) water.

6. The isocyanate-reactive component according to any one of claims 1 to 5, wherein the soybean oil-modified aromatic polyester polyol is a reaction product of phthalic anhydride, diethylene glycol, and soybean oil.

7. The isocyanate-reactive component according to claim 6, wherein the soybean oil-modified aromatic polyester polyol contains at most 11% by weight of soybean oil.

8. The isocyanate-reactive component according to any one of claims 1 to 7, the isocyanate-reactive component further comprising a hydrocarbon blowing agent selected from the group consisting of butane, isobutane, 2,3-dimethylbutane, n-pentane, isopentane, hexane isomers, heptane isomers, cyclopentane, cyclohexane, cycloheptane, HFC-245fa (1,1,1,3,3-pentafluoropropane), HFC-365mfc (1,1,1,3,3-pentafluorobutane), HFC-227ea (1,1,1,2,3,3,3-heptafluoropropane), HFC-134a (1,1,1,2-tetrafluoroethane), trans-1-chloro-3,3,3-trifluoropropene, or a combination thereof.

9. The isocyanate-reactive component according to any one of claims 1 to 8, wherein the isocyanate-reactive component contains 5% to 15% by weight of the soybean oil-modified aromatic polyester polyol and 2% to 4% by weight of the first EO / PO block copolymer nonionic surfactant.

10. A rigid polyurethane foam formed from a reaction mixture comprising: (A) an isocyanate component having a functionality of 2.7 to 2.9; (B) the isocyanate-reactive component according to any one of claims 1 to 9; and (C) at least one hydrocarbon blowing agent; wherein the stoichiometric index of the isocyanate component to the isocyanate-reactive component is 1.0 to 3.0.

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