Stable polyurethane catalysts

Abstract

Catalysts stable in the presence of a hydrohaloolefin (HFO) blowing agent useful for the preparation of polyurethane foams. Also described are methods for manufacturing polyurethane foams and compositions useful in the preparation of polyurethane foams.

Description

Cross Reference to Related Applications

[01] This application claims priority to U.S. Provisional Patent Application Serial Number 63 / 643,010 filed May 6, 2024. The noted application is incorporated herein by reference. Background

[02] Polyurethane foams are typically prepared by reacting an isocyanate and a premix which consists of isocyanate-reactive components such as a polyol, and optionally other components such as blowing agents, catalysts, flame retardants, water, and foam-stabilizing surfactants.

[03] Examples of blowing agents in the premix useful in the production of polyurethane foam include but are not limited to, hydrohalocarbons, e.g., hydrofluorocarbons (HFCs), hydrohaloolefins, e.g., hydrofluoroolefins (HFOs), hydrofluorochloroolefins (HFCOs), and hydrochlorofluorocarbons (HCFCs), formates, ketones, and hydrocarbons. Unlike HFCs, HFOs have zero ODP (Ozone Depletion Potential) and low gloabal warming potential (GWP), making them a more environmentally-friendly option than HFCs. Nowadays HFOs are widely applied, since they are safe, very efficient, and environmentally friendly blowing agents with a much lower global warming potential (GWP). However, HFOs may react with widely used amine catalysts in a polyol premix formulation, resulting in reduced storage stability and compromised amine catalyst activity.

[04] WO2019050970A1, which is hereby incorporated by reference in its entirety, discloses a catalyst system comprising 2,2'- dimorpholinodiethyl ether, N,N-dimethylcyclohexylamine, and a hydroxyl-containing compound selected from a diol (e.g., ethylene glycol) and / or an alkanolamine (e.g., methyldiethanolamine) is capable of stabilizing a polyol premix containing a hydrohaloolefin blowing agent while improving the front-end reactivity of the polyol premix over comparable catalysts / polyol premixes when contacted with an isocyanate.

[05] EP 4253442 A2, which is hereby incorporated by reference in its entirety, describes an amine composition useful for making stable polyurethane foam systems.

[06] U.S. Pat. Appl. No. 20120313035A1, which is hereby incorporated by reference in its entirety, describes a foamable composition comprising a hydrohaloolefin blowing agent and an amine catalyst that produce a stable polyol premix. The method includes the use of 1,2-dimethylimidazole, N-methylmorpholine, and other hindered tertiary amines such as diisopropylethylamine catalysts. These catalysts suffer from the drawback that they do not contain isocyanate-reactive groups and thus are emissive from the final polyurethane foam. Additionally, it is demonstrated that reactive amine catalysts such as dimethylaminoethoxy ethanol and 2-[N-(dimethylaminoethoxyethyl)]-N-methylamino)ethanol result in an unstable polyol premix in the presence of a hydrohaloolefin.

[07] U.S. Pat. Appl. No. 2013019415A1, which is incorporated herein in its entirety, describes a foamable composition comprising a non-emissive catalyst and a tetraalkyl guanidine catalyst. Specifically, the non-emissive catalyst can include 2-[N-(dimethylaminoethoxyethyl)-N-methylamino]ethanol and dimethylaminoethoxyethanol, and the tetraalkyl guanidine can be tetramethylguanidine. The drawback being that the blowing agent composition is water, and will not produce a closed-cell insulating foam with the same insulation value as a foamable composition utilizing a halogenated blowing agent containing a hydrohaloolefin.

[08] WO2013116416A1, which is hereby incorporated by reference in its entirety, describes a foamable composition comprising an encapsulated amine catalyst and a hydrohaloolefin blowing agent. The drawback being that the amine catalyst is encapsulated in a solid thermoplastic polymer which must be dispersed in the polyol premix. Object of the Disclosure

[09] There is therefore a need to provide a catalyst for making polyurethane foam using low GWP blowing agents such as hydrohaloolefins that can provide sufficient kinetics after ageing of the polyol premix systems. The catalysts presented in this present disclosure can offer the right balance for making foam even in applications where high foam speed rise is needed (spray foam, for example) without sacrificing the shelf life of the hydrohaloolefin-polyol premix system. Detailed Description

[010] Unless otherwise defined, all terms used in disclosing the present disclosure, including technical and scientific terms, have the meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. By means of further guidance, term definitions are included to better appreciate the teaching of the present disclosure.

[011] It is to be noticed that the term “comprising”, as used in the claims and the present disclosure, should not be interpreted as being restricted to the means listed thereafter; it does not exclude other elements or steps. It is thus to be interpreted as specifying the presence of the stated features, steps or components as referred to, but does not preclude the presence or addition of one or more other features, steps or components, or groups thereof. Thus, the scope of the expression “a compound comprising components X and Y” should not be limited to compounds consisting only of components X and Y. It means that with respect to the present disclosure, the only relevant components of the compound are X and Y.

[012] Throughout this specification, reference to “one embodiment” or “an embodiment” are made. Such references indicate that a particular feature, described in relation to the embodiment is included in at least one embodiment of the present disclosure. Thus, appearances of the phrases “in one embodiment” or “in an embodiment” in various places throughout this specification do not necessarily all referring to the same embodiment, though they could. Furthermore, the particular features or characteristics may be combined in any suitable manner in one or more embodiments, as would be apparent to one of ordinary skill in the art.

[013] The terms “preferred” and “preferably” as used herein refer to embodiments that may afford certain benefits, under certain circumstances. However, other embodiments may also be preferred, under the same or other circumstances. Furthermore, the recitation of one or more preferred embodiments does not imply that other embodiments are not useful and is not intended to exclude other embodiments from the scope of the present disclosure.

[014] Where substituent groups are specified by their conventional chemical formula, written from left to right, they equally encompass the chemically identical substituents that would result from writing the structure from right to left, for example, -CH2O- is equivalent to -OCH2-.

[015] The term “optional” or “optionally” as used herein means that the subsequently described event or circumstance may or may not occur, and that the description includes instances where said event or circumstance occurs and instances where it does not.

[016] Throughout this disclosure, the term “about” as used herein indicates that a value includes the inherent variation of error for the quantifying device, mechanism, or method, or the inherent variation that exists among the subject(s) to be measured. For example, but not by way of limitation, when the term “about” is used, the designated value to which it refers may vary by plus or minus ten percent, or nine percent, or eight percent, or seven percent, or six percent, or five percent, or four percent, or three percent, or two percent, or one percent, or one or more fractions therebetween.

[017] The phrases “or combinations thereof’ and “and combinations thereof’ as used herein refers to all permutations and combinations of the listed items preceding the term. For example, “A, B, C, or combinations thereof’ is intended to include at least one of: A, B, C, AB, AC, BC, or ABC and, if order is important in a particular context, also BA, CA, CB, CBA, BCA, ACB, BAC, or CAB. Continuing with this example, expressly included are combinations that contain repeats of one or more items or terms such as BB, AAA, CC, AABB, AACC, ABCCCC, CBBAAA, CABBB, and so forth. The skilled artisan will understand that typically there is no limit on the number of items or terms in any combination, unless otherwise apparent from the context. In the same light, the terms “or combinations thereof’ and “and combinations thereof’ when used with the phrases “selected from” or “selected from the group consisting of’ refers to all permutations and combinations of the listed items preceding the phrase.

[018] Unless otherwise stated the term “a” or “an” and “the” as used herein include both singular and plural referents unless the context clearly dictates otherwise. By way of example, “an isocyanate group” as used herein means one isocyanate group or more than one isocyanate group.

[019] The term “aromatic” as used herein refers to a hydrocarbyl radical having 6 to 50 carbon atoms that contains at least one ring with delocalised pi electrons, such as a benzene ring.

[020] The term “aliphatic” as used herein refers to a hydrocarbyl radical having 6 to 50 carbon atoms that does not contain a delocalized pi electron system.

[021] The term "ambient temperature" as used herein refers to the temperature of the surrounding work environment (e.g., the temperature of the area, building or room where the composition is used), exclusive of any temperature changes that occur as a result of the direct application of heat to the composition to facilitate curing. The ambient temperature may be within a range from about 10°C to about 30°C, more specifically from about 15°C to about 25°C.

[022] “Isocyanate index” or “NCO index” or “index” as used herein refers to the ratio of NCO-groups over isocyanate-reactive hydrogen atoms present in a formulation, given as a percentage: [NCO]xl00 / [active hydrogen] (%). In other words, the NCO-index expresses the percentage of isocyanate actually used in a formulation with respect to the amount of isocyanate theoretically required for reacting with the amount of isocyanate reactive hydrogens used in a formulation. It should be observed that the isocyanate index as used herein is considered from the point of view of the actual reaction process involving the isocyanate ingredients and the isocyanate-reactive ingredients. Any isocyanate groups consumed in a preliminary step to produce modified polyisocyanates (including such isocyanate derivatives referred to in the art as prepolymers) or any active hydrogens consumed in a preliminary step (e.g., reacted with isocyanate to produce modified polyols or polyamines) are not taken into account in the calculation of the isocyanate index. Only the free isocyanate groups and the free isocyanate-reactive hydrogens (including those of the water) present at the actual reaction stage are taken into account.

[023] The mass average molar mass (Mw) is sometimes referred to herein as weight average molecular weight. It can be measured using any technique known to the skilled person, for example, using small-angle laser light scattering.

[024] The number average molar mass (Mn) is sometimes referred to herein as the number average molecular weight. It can be measured using any technique known to the skilled person, for example, using osmometry.

[025] All references cited in the present specification are hereby incorporated by reference in their entirety. In particular, the teachings of all references herein specifically referred to are incorporated by reference.

[026] In a first aspect the present disclosure relates to a catalyst of formula (I): (I)

[027] wherein x is 1, 2, 3, or 4.

[028] R is selected from the group consisting of alkyl, cycloalkyl, and aryl optionally substituted with 1 to 4 -OH groups. Preferably R is a Ci-6 straight or branched alkyl which is optionally substituted with 1 to 4 -OH groups.

[029] When used herein, the term “alkyl” refers to a saturated hydrocarbon with the general formula -CnH2n+i, wherein one or more of the ‘H’ atoms may be replaced with a substituent. When used herein, the term “cycloalkyl” refers to a cycloalkane by removal of a hydrogen atom from a ring and has the general formula -CnH2n-i, wherein one or more of the ‘H’ atoms may be replaced with a substituent. When used herein, the term “aryl” refers to an arene by removal of a hydrogen atom from the ring and has the general formula -CnHn, wherein one or more of the ‘H’ atoms may be replaced with a substituent.

[030] Ri is independently an optionally C1-3 straight or branched alkyl. Preferably Ri is unsubstituted.

[031] The skilled person would understand that any substituent may be present, insofar as it does not interfere with the action of the catalyst. Examples of suitable substituents include but are not limited to an alkyl, alkenyl, alkoxy, hydroxyalkyl, alkoxyalkyl, cycloalkyl, aryl or aryl alkyl group, a hydroxyl group, a nitro group, a halogen atom, a halo or perhaloalkyl group, a formyl group, an acyl group containing from 2 to 6 carbon atoms, a carboxylic group, an amino or an amido group.

[032] If the Ri group is too large the catalyst may be too sterically hindered and have poor activity.

[033] R2 is independently an optionally substituted C1-3 linear or branched alkyl, preferably R2 is CH3. The skilled person would understand that any substituent may be present, insofar as it does not interfere with the action of the catalyst. Examples of suitable substituents include but are not limited to an alkyl, alkenyl, alkoxy, hydroxyalkyl, alkoxyalkyl, cycloalkyl, aryl or andalkyl group, a hydroxyl group, a nitro group, a halogen atom, a halo or perhaloalkyl group, a formyl group, an acyl group containing from 2 to 6 carbon atoms, a carboxylic group, an amino or amido group.

[034] R3 is independently an optionally substituted C1-3 linear or branched alkyl, preferably R3 is CH3. The skilled person would understand that any substituent may be present, insofar as it does not interfere with the action of the catalyst. Examples of suitable substituents include but are not limited to an alkyl, alkenyl, alkoxy, hydroxyalkyl, alkoxyalkyl, cycloalkyl, aryl or arylalkyl group, a hydroxyl group, a nitro group, a halogen atom, a halo or perhaloalkyl group, a formyl group, an acyl group containing from 2 to 6 carbon atoms; a carboxylic group, an amino or amido group.

[035] n is independently 1-10, preferably n is 1-4. As the value for n increases, the catalyst may become increasingly viscous and harder to handle.

[036] The Ri, R2 and R3 groups may be the same or different. Similarly, the value for ‘n’ may be the same or different for each substituent on R.

[037] The catalyst described above provides excellent reaction kinetics for the formation of a polyurethane without sacrificing the shelflife of any hydrohaloolefin blowing agent present in a composition comprising the catalyst.

[038] In some embodiments, the catalyst has the formula (II) below: wherein R, Ri, R2, R3, and n are as defined above.

[039] In some embodiments the catalyst has the structure of formula (IIA): (IIA), wherein n is 1, R is -CH3, R2 is -CH3, R3 is -CH3 and Ri is -C2H5.

[040] In some embodiments, the catalyst has the formula (III) wherein R, Ri, R2, R3, and n are as defined above, m is 1-10, preferably 1-4.

[041] In some embodiments, the catalyst has the structure of formula (IIIA), (IIIB), or (IIIC): (IIIA), wherein n is 1, m is 1, R is -C2H5, R2 is -CH3, R3 is -CH3 and Ri is -CH3, (HIB) wherein n is 1, m is 1, R is -C2H5, R2 is -CH3, R3 is -CH3 and Ri is -C2H5, (IIIC) wherein n is 2, m is 1, R is -C2H5, R2 is -CH3, R3 is -CH3 and Ri is -C2H5.

[042] In some embodiments, the catalyst has the structure of formula (IV): m L              _h (IV)

[043] wherein R, Ri, R2, R3, n, and m are as defined above. 0 is 1-10, preferably 1-4.

[044] In some embodiments, at least one of the Ri groups is -CH3 and at least one of the Ri group is selected from the group consisting of -C2H5, -C3H7 and CH(CH3)2.

[045] In some embodiments, at least of the Ri groups is -CH3 and at least one Ri group is -C2H5. Such an arrangement provides a good compromise between activity and stability. Furthermore, this arrangement provides low cost starting materials.

[046] In some embodiments, the catalyst has the structure of formula (IVA): wherein n is 1, m is 1, o is 1, R is -C3H6, R2 is -CH3, R3 is -CH3 and Ri is -C2H5,

[047] In some embodiments, the catalyst has the structure of formula (V) shown below: (V) wherein R, Ri, R2, R3, n, m, and o, are as defined above, p is 1-10, preferably 1-4.

[048] In an aspect there is provided a use of the catalyst described above in the preparation of a polyurethane foam.

[049] Polyurethane foam is a specialist material used for thermal insulation and other applications. It is a solid polymeric foam formed by the reaction of an isocyanate and an isocyanate reactive compound (usually a polyol) in the presence of at least one blowing agent.

[050] The catalyst of the present disclosure may be used in the production of any suitable polyurethane foam.

[051] In one embodiment, the blowing agent is a hydrohaloolefin blowing agent. For example, the at least one hydrohaloolefin blowing agent may be a hydrofluoroolefm, hydrochlorofluoroolefm, or a combination thereof.

[052] Non-limiting examples of the at least one hydrohaloolefin blowing agent include hydrofluoroolefin (HFO) blowing agents containing 3, 4, 5, or 6 carbons, and further include, for example but without limitation, pentafluoropropenes; tetrafluoropropenes such as 1,3,3,3-tetrafluoropropene (HFO 1234ze, E and Z isomers), 2,3,3,3-tetrafluoropropene (HFO 1234yf),l,2,3,3-tetrafluoropropene (HFO 1234ye); trifluoropropenes such as 3,3,3-trifluoropropene (1243zf); tetrafluorobutenes such as HFO 1354; pentafluorobutene isomers such as HFO1345; hexafluorobutene isomers such as HFO 1336 (e.g. z-1336mzz); heptafluorobutene isomers such as HFO 1327; heptafluoropentene isomers such as HFO 1447; octafluoropentene isomers such as HFO 1438; nonafluoropentene isomers such as HFO 1429; hydrochlorofluoroolefm (HCFO) blowing agents such as 1 -chi oro-3,3,3- trifluoropropene (HCFO-123 3 zd), 2-chloro-3,3,3-trifluoropropene (HCFO 1233xf), HCFO 1223,1,2-dichloro-1,2-difluoroethene (E and Z isomers), 3,3-dichioro-3-fluoropropene,2-chloro-1,1,1,4,4,4-hexafluorobutene-2 (E and Z isomers), and 2-chloro-l,l,l,3,4,4,4-heptafluorobutene-2 (E and Z isomers).

[053] The at least one hydrohaloolefin blowing agent can be used alone or in combination with other blowing agents including, but not limited to: (a) hydrofluorocarbons including, for example, difluoromethane (HFC-32); 1,1,1,2,2- pentafluoroethane (HFC-125); 1,1,1 -trifluoroethane (HFC143a); 1,1,2,2-tetrafluorothane (HFC-134); 1,1,1,2-tetrafluoroethane (HFC-134a); 1,1-difluoroethane (HFC-152a); 1,1,1,2,3,3,3-heptafluoropropane (HFC-227ea); 1,1,1,3,3-pentafluopropane (HFC-245fa); 1,1,1,3,3-pentafluobutane (HFC-365mfc) and 1,1,1,2,2,3,4,5,5,5-decafluoropentane (HFC-4310mee); (b) hydrocarbons including, for example, pentane isomers (iso-pentane, n-pentane, cyclo-pentane) and butane isomers; (c) hydrofluoroethers (HFE), including, for example, C4F9OCH3 (HFE-7100), C4F9OC2H5 (HFE-7200), CF3CF2OCH3 (HFE-245cb2), CF3CH2CHF2 (HFE-245fa), CF3CH2OCF3 (HFE-236fa), C3F7OCH3 (HFE-7000), 2-trifluoromethyl-3-ethoxydodecofluorohexane (HFE-7500), 1,1,1,2,3 -hexafluoro-4-( 1,1,2,3,3,3 -hexafluoropropoxy)-pentane                 (HFE-7600), l,l,l,2,2,3,5,5,5-decafluoro-3-methoxy-4-(trifluoromethyl)pentane (HFE-7300), ethyl nonafluoroisobutyl ether / ethyl nonafluorobutyl ether (HFE-8200), CHF2OCHF2, CHF2OCH2F, CH2FOCH2F, CH2FOCH3, cyclo-CF2CH2CF2O, cyclo-CF2CF2CH2O, CHF2CF2CHF2, CF3CF2OCH2F, CHF2OCHFCF3, CHF2OCF2CHF2, CH2FOCF2CHF, CF3OCF2CH3, CHF2CHFOCHF2, CF3OCHFCH2F, CF3CHFOCH2F, CF3OCH2CHF2, CHF2OCH2CF3, CH2FCF2OCH2F, CHF2OCF2CH3, CHF2CF2OCH3(HFE254 pc), CH2FOCHFCH2F, CHF2CHFOCH2F, CF3OCHFCH3, CF3CHFOCH3, CHF2OCH2CHF2, CF3OCH2CH2F, CF3CH2OCH2F, CF2HCF2CF2OCH3, CF3CHFCF2OCH3, CHF2CF2CF2OCH3, CHF2CF2CH2OCHF2, CF3CF2CH2OCH3, CHF2CF2OCH2CH3, (CF3)2CFOCH3, (CF3)2CHOCHF, (CF3)2CHOCH3, and mixture thereof; (d) Cl to C5 alcohols, Cl to C4 aldehydes, Cl to C4 ketones, Cl to C4 ethers and di ethers, Cl to C6 hydrocarbons; (e) water, (f) carbon dioxide; (g) trans-1,2-dichloroethylene; and (h) methylformate, methylacetate, ethyl formate, dichloromethane, and dimethoxymethane.

[054] In some embodiments, the polyisocyanate reactive component may be a polyol.

[055] The polyol can be one or more polyols which react in a known fashion with an isocyanate in the preparation of a polyurethane (PUR) and / or polyisocyanurate (PIR) foam. In one embodiment, the polyol component includes polyols typically used for making rigid PIR and / or PUR foam.

[056] In one embodiment, the polyol comprises one or more polyether polyols. Non-limiting examples of the polyether polyols include poly(alkylene oxide) polymers, such as, poly(ethylene oxide), poly(propylene oxide), and / or copolymers with terminal hydroxyl groups derived from polyhydric compounds (for example, diols, triols, tetranols, pentanols, and the like); polyhydroxy-terminated acetal resin; hydroxy- terminated amine; hydroxyl-terminated polyamine; or combinations thereof.

[057] In another embodiment, the polyol component includes amine polyether polyols that can be prepared when an amine, such as ethylenediamine, diethylenetriamine, tolylenediamine, diphenylmethanediamine, triethanolamine, or the like, is reacted with ethylene oxide or propylene oxide.

[058] In yet another embodiment, the polyol component may include a polyester polyol produced when a dicarboxylic acid is reacted with an excess of a diol, for example, terephthalic acid, adipic acid, phthalic acid, phthalic anhydride with ethylene glycol, diethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, polypropylene glycol or butanediol, or when a lactone is reacted with an excess of a diol, such as, caprolactone with propylene glycol.

[059] In another embodiment, the polyol is, or includes, polyalkylene carbonate-based polyols, phosphate-based polyols, or combinations thereof.

[060] In still another embodiment, the polyol may be or may include a natural oil polyol. Suitable examples of natural oil polyol include triglycerides of saturated and / or unsaturated acids having a carbon chain length between 12 and 24. The saturated acids may be lauric acid, myristic acid, palmitic acid, steric acid, arachidic acid, lignoceric acid, or a combination thereof. The unsaturated acids may be mono-unsaturated (for example, palmitoleic acid, oleic acid, or a combination thereof) and / or poly-unsaturated (for example, linoleic acid, linolenic acid, arachidonic acid, or a combination thereof).

[061] Any polyisocyanate can be employed as the at least one isocyanate, inclusive of aliphatic and aromatic polyisocyanates. Suitable organic polyisocyanates include aliphatic, cycloaliphatic, araliphatic, aromatic, and heterocyclic isocyanates which are well known in the field of polyurethane chemistry.

[062] Non-limiting examples of the polyisocyanates that can be used as the at least one isocyanate include those represented by the formula Q(NCO)a where a is a number from 2-5, preferably 2-3 and Q is an aliphatic hydrocarbon group containing 2-18 carbon atoms, a cycloaliphatic hydrocarbon group containing 5-10 carbon atoms, an araliphatic hydrocarbon group containing 8-13 carbon atoms, or an aromatic hydrocarbon group containing 6-15 carbon atoms.

[063] Additional examples of polyisocyanates include, but are not limited to, ethylene diisocyanate; 1,4-tetram ethylene diisocyanate; 1,6-hexamethylene diisocyanate; 1,12-dodecane diisocyanate; cyclobutane-l,3-diisocyanate; cyclohexane-1,3- and 1,4-diisocyanate, and mixtures of these isomers; isophorone diisocyanate; 2,4- and 2,6-hexahydrotoluene diisocyanate and mixtures of these isomers; dicyclohexylmethane-4,4'-diisocyanate (hydrogenated MDI, or HMDI); 1,3- and 1,4-phenylene diisocyanate; 2,4- and 2,6-toluene diisocyanate and mixtures of these isomers (TDI); diphenylmethane-2,4'- and / or -4,4'-diisocyanate (MDI); naphthylene-1,5-diisocyanate; triphenylmethane-4,4',4"-triisocyanate; polyphenyl- polymethylene-polyisocyanates of the type which may be obtained by condensing aniline with formaldehyde, followed by phosgenation (crude MDI); norbornane diisocyanates; m- and p-isocyanatophenyl sulfonyl isocyanates; perchlorinated aryl polyisocyanates; modified polyisocyanates containing carbodiimide groups, urethane groups, allophanate groups, isocyanurate groups, urea groups, or biuret groups; polyisocyanates obtained by telomerization reactions; polyisocyanates containing ester groups; and polyisocyanates containing polymeric fatty acid groups. Those skilled in the art will recognize that it is also possible to use mixtures of the polyisocyanates described above.

[064] In some embodiments, the polyol premix and the at least one isocyanate may be contacted by mixing a stream of the at least one isocyanate (A side) and a stream of the polyol premix (B side). The mixing can be carried out in a spray apparatus, a mixhead with or without a static mixer for combining the polyol component and blowing agent, or a vessel, and then spraying or otherwise depositing the reacting mixture onto a substrate. This substrate may be, for example, a rigid or flexible facing sheet made of foil or another material, including another layer of similar or dissimilar polyurethane which is conveyed, continuously or discontinuously, along a production line, or directly onto a conveyor belt.

[065] Alternatively, the at least one isocyanate and the polyol premix may be contacted by being mixed and poured into an open mold or distributed via laydown equipment into an open mold or simply deposited at or into a location for which it is desired, i.e., a pour-in-place application, such as between the interior and exterior walls of a structure. In the case of deposition on a facing sheet, a second sheet may be applied on top of the deposited mixture. In other embodiments, the polyol premix and at least one isocyanate may be mixed and injected into a closed mold, with or without vacuum assistance for cavity-filling. If a mold is employed, it is most typically heated.

[066] In general, such applications may be accomplished using the known one-shot, prepolymer or semi-prepolymer techniques used together with conventional mixing methods. The mixture, on reacting, takes the shape of the mold or adheres to the substrate to produce a polyurethane polymer or a more-or-less predefined structure, which is then allowed to cure in place or in the mold, either partially or fully. Optimum cure conditions will depend upon the particular components, including catalysts and quantities used in preparing the polymer and also the size and shape of the article manufactured.

[067] The result may be a rigid foam in the form of slabstock, a molding, a filled cavity, including but not limited to a pipe or insulated wall or hull structure, a sprayed foam, a frothed foam, or a continuously- or discontinuously-manufactured laminate product, including but not limited to a laminate or laminated product formed with other materials such as hardboard, plasterboard, plastics, paper, metal, or a combination thereof.

[068] In an aspect of the disclosure is provided a composition comprising: a) one or more polyisocyanate compounds as defined above, also referred to herein as the A-side; and b) a polyol pre-mix, also referred to herein as the B-side, wherein the B-side comprises at least one polyisocyanate reactive compound as defined above, at least one blowing agent as defined above, and at least one catalyst as defined above.

[069] In some embodiments, the polyol pre-mix may also comprise water, a surfactant(s), a flame retardant(s), and other foam processing additives known to those familiar in the art of preparing polyurethane foams.

[070] The skilled person will know the amount of catalyst to include in the B-side. In some embodiments, the amount of catalyst in the composition can range from about 0.5 weight percent (wt%) to about 10 wt %, based on the total weight of the composition. For example, from about 1 wt %, from about 2 wt%, from about 3 wt%, from about 4 wt%, from about 5 wt%, from about 6 wt%, from about 7 wt%, from about 8 wt%, or from about 9 wt%. For example, up to about 9 wt%, up to about 8 wt%, up to about 7 wt%, up to about 6 wt%, up to about 5 wt%, up to about 4 wt%, up to about 3 wt%, up to about 2 wt%, or up to about 1 wt%.

[071] The skilled person will know the amount of polyisocyanate reactive compound to include in the B-side. In some embodiments, the amount of polyisocyanate reactive compound in the composition can range from about 5 wt% to about 55 wt%. For example, from about 10 wt %, from about 15 wt%, from about 20 wt%, from about 25 wt%, from about 30 wt%, from about 35 wt%, from about 40 wt%, from about 45 wt%, or from about 50 wt%. For example, up to about 50 wt%, up to about 45 wt%, up to about 40 wt%, up to about 35 wt%, up to about 30 wt%, up to about 25 wt%, up to about 20 wt%, or up to about 15 wt %.

[072] The skilled person would know how much blowing agent to include in the B-side composition. In some embodiments, the amount of blowing agent in the B-side composition can range from about 1 wt% to about 20 wt%. For example, from about 3 wt%, from about 4 wt%, from about 5 wt%, from about 6 wt%, from about 7 wt%, from about 8 wt%, from about 9 wt%, from about 10 wt%, from about 11 wt%, from about 12 wt%, from about 13 wt%, from about 14 wt%, from about 15 wt%, from about 16 wt%, from about 17 wt%, from about 18 wt%, or from about 19 wt%. For example, up to about 19 wt%, up to about 18 wt%, up to about 17 wt%, up to about 16 wt%, up to about 15 wt%, up to about 14 wt%, up to about 13 wt%, up to about 12 wt%, up to about 11 wt%, up to about 10 wt%, up to about 9 wt%, up to about 8 wt%, up to about 7 wt%, up to about 6 wt%, up to about 5 wt%, up to about 4 wt%, up to about 3 wt%, or up to about 2 wt%.

[073] In a further aspect, the disclosure provides a method for preparing a polyurethane foam, said method comprising providing the composition described above, mixing the A and B side, and curing.

[074] The ratio of B side to polyisocyanate A side can be any suitable ratio. For example, the ratio of composition to polyisocyanate can range from 4:3 to about 2:0.9.

[075] The skilled person will appreciate the time and temperature needed to cure a polyurethane foam. For example, the composition may be cured at a temperature ranging from about 0°C to about 100°C for a time ranging from about 10 seconds to about 1 hour.

[076] In a further aspect, there is provided a foam produced by the method described above. Examples

[077] More details and advantages of the present disclosure will become obvious from the following examples.

[078] All materials were obtained from Huntsman International LLC unless otherwise specified. Example 1

[079] A polyether amine with structure below (Denoted as D-190, Huntsman) was alkylated with two methyl groups on each nitrogen. In this case all four reactive hydrogens on nitrogen were replaced with four methyl groups to obtain the desired catalyst. methylated D 190                   methylated D-190 is the stable catalyst derived from D-190.

[080] First, hydrogen was pushed through a fixed bed reactor packed with 150 ml of propriate catalyst at 72 liters / hour. A mixture comprising of 50 wt.% D-190 and 50 wt.% methanol was fed into the fixed-bed reactor at a rate of 120 grams / hour. At the same time methyl formcel (55% in methanol and water) was fed into the fixed bed reactor at a rate of 88 grams / hour. The fixed-bed reactor was kept at a temperature of 110°C and under pressure of 2000 psig. The effluent was collected for stripping and distillation.

[081] The effluent from the above fixed bed reactor was stripped to remove most of lights such as methanol, water, and possible methyl formcel. The effluent was loaded into a flask with a condenser and a cold trap and connected to a vacuum system. The vacuum was kept at 100 mmHg and the flask was gradually heated up to 130°C and held at 130°C for 4 hours. All the lights collected in the cold trap and overhead was about 50% of total material charged. Then the bottom product was undergoing distillation.

[082] The product was charged into a flask equipped with a 1”ID and 24” high packed column, a water-cooling condenser and a cold trap and connected to a vacuum system. The entire system was gradually pulled vacuum to 10-15 mmHg and the flask was gradually heated up to 150160°C. The reflux ratio was kept at 4:2 and different fractions were collected. The different fractions were analyzed using GC-MS and GC to confirm their compositions. A composite with a purity more than 99.0% of compound 1 was collected for spray foam performance test. Example 2

[083] A polyether amine with structure below (Denoted as XTJ-568, Huntsman) was alkylated with two methyl groups on each nitrogen. In this case all four reactive hydrogens on nitrogen were replaced with four methyl groups to obtain the desired catalyst. NH2 nh2 XTJ-568 derived from XTJ-568. Methylated stable catalyst

[084] First, hydrogen was pushed through a fixed bed reactor packed with 150 ml of propriate catalyst at 39 liters / hour. A mixture comprising of 33.3 wt.% XTJ-568 and 66.7 wt.% methanol was fed into the above fixed-bed reactor at a rate of 90 grams / hour. At the same time methyl formcel (55% in methanol and water) was fed into the above fixed bed reactor at a rate of 38 grams / hour. The fixed-bed reactor was kept at a temperature of 110°C and under pressure of 2000 psig. The effluent was collected for stripping and distillation.

[085] The effluent from the above fixed bed reactor was stripped to remove most of lights such as methanol, water, and possibly methyl formcel. The effluent was loaded into a flask with a condenser and a cold trap and connected to a vacuum system. The vacuum was kept at 100 mmHg and the flask was gradually heated up to 130°C and held at 130°C for 4 hours. All the lights collected in the cold trap and overhead was about 58% of total material charged. Then the bottom product was undergoing distillation.

[086] The product was charged into a flask equipped with a 1”ID and 24” high packed column, a water-cooling condenser and a cold trap and connected to a vacuum system. The entire system was gradually pulled vacuum to 10-15 mmHg and the flask was gradually heated up to 150160°C. The reflux ratio was kept at 4:2 and different fractions were collected in overhead. Different fractions were analyzed using GC-MS and GC to confirm their compositions. A composite with a purity of 96.3% compound 2 was collected for spray foam performance test. Example 3

[087] A polyether amine with structure below (Denoted as XTJ-998, Huntsman) was alkylated with two methyl groups on the nitrogen and distilled to get an HFO stable polyurethane catalyst. The structure of the resulting stable catalyst is shown below: XTJ-998 Methylated stable catalyst derived from XTJ-998

[088] First, hydrogen was pushed through a fixed bed reactor packed with 150 ml of propriate catalyst at 11 Liters / hour. A mixture comprising of 24.1 wt.% XTJ-998, and 37.4 wt.% methanol and 38.5 wt.% methyl formcel (55% in methanol and water) was fed into the above fixed-bed reactor at a rate of 175 grams / hour. The fixed-bed reactor was kept at a temperature of 110°C and under pressure of 2000 psig. The effluent was collected for stripping and distillation.

[089] The effluent from the above fixed bed reactor was stripped to remove most of lights such as methanol, water, and possibly methyl formcel. The effluent was loaded into a flask with a condenser and a cold trap. Under atmospheric pressure the flask was gradually heated up to 135°C. All the fractions in the cold trap and overhead were collected as lights until overhead temperature 101 °C. Then the bottom product was undergoing distillation.

[090] The bottom product was charged into a flask equipped with a 1 ” ID and 24” high packed column, a water-cooling condenser and a cold trap. The entire system was kept at atmospheric pressure and the flask was gradually heated up to 150-160°C. The reflux ratio was kept at 8:2 and different fractions were collected in overhead and analysed using GC-MS and GC to confirm their compositions. Two cuts from this distillation were tested for efficacy in the spray foam cup performance tests. The bottom cut, having lower purity, was compared to the overhead cut, which was -91% purity and contained 7.24% water. The water content of the overheads sample is accounted for in the analysis below. Analysis of Examples 1 and 2 Initial Reactivity Comparison

[091] The catalysts produced in Examples 1 and 2 were tested and the results are provided together with a commercially available reference catalyst JEFFCAT® ZF-20 (bis-(2-dimethylaminoethyl)ether)). All 3 catalysts were tested using the same procedure and same formulation in parallel.

[092] For all the tests, a pre-blended masterbatch with the formulation shown in Table 1 was prepared without water and in the absence of catalyst. Pre-blended masterbatch was added into a 4oz jar with appropriate amount of water and testing catalysts and then mixed on a sample roller for 20 minutes. This mixture is known as the resin mixture and is commonly referred to as the B-side pre-mix, or simply B-side. Table 1 Component Percent Supplier TEROL® 925 (Aromative polyester polyol, Huntsman) 52.32 Huntsman International LLC JEFFOL® R-425-X (Reactive Aromatic Amine Polyol) 10 Huntsman International LLC JEFFOL® SG-522 (Polyether polyol) 7.88 Huntsman International LLC PHT4-Diol (Flame Retardant) 6.8 Lanxess TCPP (Flame Retardant) 11 Isochem Vorasurf™ DC-193 (Silicone Surfactant) 1 Dow Chemical Forane® FBAHFO 1233zd’E’ 11 Arkema Total 100

[093] After mixing, the resin mixtures were placed into a 22°C water-bath for 30 minutes. Then 50g of the resin mixture was poured into a 32 oz cup followed by adding 50 g of isocyanate (Polymeric MDI). The two components were then mixed using a high shear mixer for 5 seconds. The reactivity profile of the foam was then recorded. This profile consisted of measuring the cream, top of cup, string gel, tack free, and end of rise time. The protocols are described below.

[094] To obtain a similar string gel in all catalyst tests, the masterbatch amount and the catalyst load was adjusted. The string gel component of the reactivity profile was the determining factor for matching the reactivity profile for all other catalysts being tested. To obtain a similar string gel for all catalysts being tested, the catalyst level was adjusted for each test until a matching string gel was achieved, with a target of ± 1.5 seconds. The water level was maintained at 1.8% for each resin mixture. The pre-blended masterbatch was reduced by the same percentage that the catalyst load was increased by, and vice versa, to maintain 100% composition for each resin mixture. The final compositions of each sample tested is shown in Table 2 below. All wt% are based on the total weight of the resin side composition (also referred to herein as the resin mixture or B-side). Table 2 Resin Side Composition Test Catalyst Catalyst load level (wt%) Water loaded (wt%) Masterbatch Added (wt%) 1 JEFFCAT® ZF-20 0.6 1.8 97.6 2 Example 2 1.8 1.8 96.4 3 Example 1 1.5 1.8 96.7

[095] Descriptions of how these times are determined are as follows. Once the Resin mixture (B-side) and the isocyanate (A-side) portions are added together into the cup, the cup is lifted into place beneath the high shear mixer. The timer is started at the same time as the mixer blade is activated. At 5 seconds, the cup is lowered from the blade and sat on the benchtop to visualize the timing for the reactivity times listed below. The timer is not stopped until the foaming is complete. Each part of the reactivity profile time is noted during the rise. All times are measured in seconds. a. Cream: Time it takes from the start of mixing the A and B sides together until the mixture first starts to show upward movement inside the cup. b. Top of Cup: Time it takes for the dome of the rising foam to breach the top of the cup and be visible at eye level with the top of the cup. c. String Gel: Time it takes for the foam to gel enough for a wooden tongue depressor or other stick held on its side to form unbreakable strings when pulled away from the foam. d. Tack-Free: Time it takes for the top of the foam to stop being sticky when touched with a gloved finger or wooden stick. e. End of Rise: Time it takes for the foam to stop moving. String gel reactivity measurement

[096] For the initial day of the stability comparison, it was necessary to obtain a day 0 reactivity profile for each of the catalysts being tested. 930g of each resin mixture was prepared in a IL glass jar using the same resin side compositions as listed in Table 2 above. The samples were placed on the sample roller and mixed for 30 minutes before placing in a 22°C water bath to equilibrate for 30 minutes and then tested. The initial reactivity was tested on day 0 before heating. The day 0 reactivities are shown in Table 3 below. The wt% of the catalyst is based on the total amount of the resin composition: Table 3 Initial String Gel Reactivity Test Catalyst Load Level (wt%) Cream Time (s) Top of Cup (s) String Gel (s) Tack-Free Time (s) End of Rise (s) 1 JEFFCAT® ZF-20 0.6 6.8 18.3 33.8 45.8 61.1 2 Example 2 1.8 8.6 25.0 33.0 40.8 57.6 3 Example 1 1.5 8.0 24.0 33.1 42.0 60.3

[097] The results in Table 3 demonstrate that the initial string gel formation time was roughly the same for all compositions. Catalyst stability comparison

[098] Following string gel testing, the samples were sealed well with electrical tape to limit any HFO loss, and then placed into the oven maintained at a constant temperature of 50°C for six weeks.

[099] After six weeks, the samples were removed from the oven and shaken thoroughly to remix the contents. They were then allowed to sit at room temperature for five hours, before placing them into a 22°C water bath and allowed to equilibrate for 30 minutes before testing the stability. The final reactivity at the end of the 6 weeks is shown in Table 4 below. The wt% of the catalyst is based on the total amount of the resin composition: Table 4 String Gel Reactivity after Six Weeks at 50 °C Test Catalyst Load Level (wt%) Cream Time (s) Top of Cup (s) String Gel (s) Tack-Free Time (s) End of Rise (s) 1 JEFFCAT® ZF-20 0.6 49.9 149.1 180.1 352.9 353.0 2 Example 2 1.8 14.0 38.3 49.1 63.5 87.3 3 Example 1 1.5 17.6 65.9 80.7 115.6 145.3

[0100] The stability of a sample is a measure of the reactivity drift observed over the duration of the testing. Table 5 shows the percentage of loss of string gel time after the 6 weeks. Table 5 String Gel Drift Time after Six Weeks at 50 °C Test Catalyst Catalyst load level (wt% based on total weight of resin side) String Gel loss (%) 1 JEFFCAT® ZF-20 0.6 434 2 Example 2 1.8 49 3 Example 1 1.5 144

[0101] Table 5 illustrates that the conventional catalyst in Test 1 suffers from a substantial loss in string gel time after six weeks, when it mixes with HFO blowing agent in the pre-mix polyol side. On the contrary, the catalysts of Examples 1 and 2 as described in the present disclosure showed significantly less string gel time loss when compared to the commercial catalyst. As such, the test results concludes that the catalysts of Examples 1 and 2 as described in the present disclosure dramatically improved the composition stability in HFO blowing agent existing premix polyol composite. Analysis of Example 3

[0102] The catalysts produced in Example 3 was tested and the results are provided together with a commercially available reference catalyst, JEFFCAT® ZF-20 (bis-(2-dimethylaminoethyl)ether)). The catalysts were tested using the same procedure and same masterbatch formulation in parallel. The process for generating a pre-blended masterbatch with the formulation was prepared in the same method as described above.

[0103] The reactivity profile of the foam was tested in the manner described above then recorded. This profile consisted of measuring the cream, top of cup, string gel, tack free, and end of rise time.

[0104] The final compositions of each sample tested are shown in Table 6 below. All wt% are based on the total weight of the composition.

[0105] Example 3 was distilled to produce both an overhead and a bottoms sample. The overhead sample provides a higher purity, both samples were evaluated in the same manner and the corresponding results are provided. Table 6 Resin Side Composition Catalyst Catalyst load level (wt%) Water loaded (wt%) Masterbatch Added (wt%) JEFFCAT® ZF-20 0.6 1.8 97.60 Example 3 (Overhead) 3.50 1.55 94.95 Example 3 (Bottoms) 4.00 1.80 94.20 String gel reactivity measurement

[0106] For the initial day of the stability comparison, it was necessary to obtain a day 0 reactivity profile for each of the catalysts being tested. 930g of each resin mixture was prepared in a IL glass jar using the same resin side compositions as listed in Table 6 above. The procedure for testing is the same as described above. The day 0 reactivities are shown in Table 7 below. The wt% of the catalyst is based on the total amount of the resin composition: Table 7 Initial String Gel Reactivity Catalyst Load Level (wt%) Cream Time (s) Top of Cup (s) String Gel (s) Tack-Free Time (s) End of Rise (s) JEFFCAT® ZF-20 0.60 6.8 18.3 33.8 45.8 61.1 Example 3 (Overhead) 3.50 9.2 27.1 39.8 60.4 73.9 Example 3 (Bottoms) 4.00 10.4 25.3 34.5 50.5 63.6

[0107] The results in Table 7 demonstrate that the initial string gel formation time was roughly the same for all compositions. Catalyst stability comparison

[0108] Following string gel testing, the samples were sealed well with electrical tape to limit any HFO loss, then placed into the oven maintained at a constant temperature of 50°C for three weeks.

[0109] After three weeks, the samples were process in the same manner as described above. The final reactivity at the end of the three weeks is shown in Table 8 below. The wt% of the catalyst is based on the total amount of the resin composition: Table 8 String Gel Reactivity after Three Weeks Catalyst Load Level (wt%) Cream Time (s) Top of Cup (s) String Gel (s) Tack-Free Time (s) End of Rise (s) JEFFCAT® ZF-20 0.6 30.3 41.9 106.1 127.8 214.4 Example 3 (Overhead*) 3.50 11.2 31.1 42.9 67.4 79.2 Example 3 (Bottoms) 4.00 11.2 28.7 38.3 57.2 73.2

[0110] The stability of a sample is a measure of the reactivity drift observed over the duration of the testing. Table 9 shows the percentage of loss of string gel time after the three weeks. Table 9 String Gel Drift Time after Three Weeks at 50 °C Catalyst Catalyst load level (wt% based on total weight of the resin side) String Gel loss (%) JEFFCAT® ZF-20 0.60 214 Example 3 (Overhead) 3.50 8 Example 3 (Bottoms) 4.00 11

[0111] Table 9 shows the conventional catalyst suffered a substantial loss in string gel time after three weeks when mixed with HFO blowing agents in the pre-mix polyol side. On the contrary, the catalyst of Example 3 clearly demonstrates significantly less string gel time loss. The catalyst of Example 3, described in the present disclosure, dramatically improves the composition stability in HFO blowing agent existing pre-mix polyol composite. Improvement is shown for both Example 3 overhead and bottoms samples, the bottoms sample provides a lower cost option while maintaining improvement.

[0112] It is to be understood that although preferred embodiments and / or materials have been discussed for providing embodiments according to the present disclosure, various modifications or changes may be made without departing from the spirit and scope of the disclosure described herein.

Claims

What is claimed:

1. A catalyst of formula (I):(I)wherein x is 1, 2, 3, or 4;R is selected from the group consisting of alkyl, cycloalkyl, and aryl optionally substituted with 1 to 4 -OH groups;Ri is independently an optionally substituted C1-3 straight or branched alkyl;R2 is independently an optionally substituted C1-3 linear or branched alkyl;R3 is independently an optionally substituted C1-3 linear or branched alkyl; andn is independently 1-10.

2. The catalyst of claim 1, wherein R is a C1-6 straight or branched alkyl optionally substituted with 1 to 4 -OH groups.

3. The catalyst of claim 1 or claim 2, wherein Ri is an unsubstituted a C1-3 alkyl.

4. The catalyst of any preceding claim, wherein R2 is -CH3.

5. The catalyst of any preceding claim, wherein R3 is -CH3.

6. The catalyst of any preceding claim, wherein n is 1-4.

7. The catalyst of any preceding claim, wherein the catalyst has the formula (II):(II).

8. The catalyst of claim 7, wherein the catalyst has the structure of formula (IIA):

9. The catalyst of any one of claims 1 to 6, wherein the catalyst has the formula (III):

10. The catalyst of claim 9, wherein m is 1-4.

11. The catalyst of claim 9 or claim 10, wherein the catalyst has the structure of formula(niA), (IIIB), or (me):(niA),T1(HIB),(IV)wherein o is 1-10.

13. The catalyst of claim 12, wherein o is 1 - 4.

14. The catalyst of claim 12 or claim 13, wherein at least one of the Ri groups is -CH3 and at least one Ri group is selected from the group consisting of -C2H5, -C3H7 and CH(CH3)2.

15. The catalyst of any one of claims 12 to 14, wherein the catalyst has the structure formula(IVA):(IVA).

16. The catalyst of any one of claims 12 to 14, wherein at least one Ri group is -CH3 and at least one Ri group is -C2H5.

17. The catalyst of any one of claims 1 to 6, wherein the catalyst has the formula (V) shown below:(V)wherein p is 1-10.

18. The catalyst of claim 17, wherein p is 1-4.

19. The catalyst of claim 17 or claim 18, wherein the catalyst has the structure of formula(VA):(VA).

20. The catalyst of any preceding claim for use in the preparation of a polyurethane foam.

21. A composition comprising:a)     one or more polyisocyanate compounds; andb)     a polyol pre-mix,wherein the polyol pre-mix comprises at least one polyisocyanate reactive compound, at least one blowing agent, and at least one catalyst as defined in any one of claims 1 to 19.

22. The composition of claim 21, wherein the at least one blowing agent is a hydrofluoroolefin, hydrochlorofluoroolefin, or a combination thereof.

23. The composition of claim 21 or claim 22, wherein the polyisocyanate reactive compound is a polyol.

24. The composition of claim 23, wherein the polyol is a polyether polyol, a polyester polyol, a polyalkylene carbonate-based polyol, a phosphate-based polyol, or a combination thereof.

25. The composition of any one of claims 21 to 24, wherein the polyisocyanate is an aliphatic isocyanate, a cycloaliphatic isocyanate, an araliphatic isocyanate, an aromatic isocyanate, a heterocyclic isocyanate, or a combination thereof.

26. The composition of any one of claims 21 to 25, wherein the polyol pre-mix further comprises at least one component selected from water, a surfactant, and a flame retardant.

27. The composition of any one of claims 21 to 26, wherein the amount of catalyst in the polyol pre-mix comprises from about 0.5 wt% to about 10 wt % based on the weight of the polyol pre-mix.

28. The composition of any one of claims 21 to 27, wherein the amount of polyisocyanate reactive compound is from about 5 wt% to about 55 wt% based on the weight of the polyol pre-mix.

29. The composition of any one of claims 21 to 28, wherein the amount of blowing agent in the polyol pre-mix is from about 1 wt% to about 20 wt% based on the weight of the polyol pre-mix.

30. A method for preparing a polyurethane foam, said method comprising:i) providing the composition of any one of claims 21 to 29;ii)    mixing components a) and b); andiii)     curing.

31. The method of claim 30, wherein the ratio of component a) to component b) ranges from 4:3 to about 2:0.9.

32. The method of claim 30 or claim 31, wherein the curing takes place at a temperature ranging from about 0°C to about 100°C for a time ranging from about 10 seconds to about 1 hour.

33. The method of any one of claims 30 to 32, wherein the polyol premix and the one or more polyisocyanate compounds are contacted by mixing a stream of the one or more polyisocyanate compounds and a stream of the polyol premix.

34. A polyurethane foam produced by the method of any one of claims 30 to 33.

35. The polyurethane foam of claim 34 which in the form of slabstock, a molding, or a filled cavity.