Formulation for producing a polyisocyanurate foam, polyisocyanurate foam, and article comprising the polyisocyanurate foam

Abstract

There is provided a formulation for producing a polyisocyanurate foam, comprising: a polyisocyanate component; optionally, an isocyanate-reactive component; and a quaternary ammonium salt trimerization catalyst of specific formula, wherein the isocyanate index of the formulation is at least 850.

Description

1 EU-51177FORMULATION FOR PRODUCING A POLYISOCYANURATE FOAM, POLYISOCYANURATE FOAM, AND ARTICLE COMPRISING THE POLYISOCYANURATE FOAMFIELD OF INVENTION

[0001] The present disclosure relates to a formulation for producing a polyisocyanurate foam, a polyisocyanurate foam obtainable by reacting the formulation, an article comprising the polyisocyanurate foam, and the use of a quaternary ammonium salt trimerization catalyst in the production of the polyisocyanurate foam from the formulation. The polyisocyanurate foams produced from the formulation described herein have superior temperature resistance relative to alternative polyisocyanurate foams already on the market.BACKGROUND

[0002] Polyisocyanurate foams are widely used in construction for insulation, prefabricated sandwich panels, spray foam for in-situ application, pre-insulated pipes and one- component froth as sealants. One reason polyisocyanurate foams are useful is because of the thermal properties inherent in the polyisocyanurate foam. Polyisocyanurate foams are typically produced by reacting a polyisocyanate and optionally an isocyanatereactive compound (such as polyol), in the presence of a conventional trimerization catalyst.

[0003] However, polyisocyanurate foams which are made in the presence of the conventional trimerization catalysts often significantly decompose in the temperature range of 250°C to 450°C, which limits their application. There is thus a need to further improve the temperature resistance (or temperature stability) of the polyisocyanurate foams, so that their application extends even further.

[0004] The present disclosure addresses the problems and needs mentioned above, by providing a formulation for a polyisocyanurate foam which contains an effective trimerization catalyst and thus gives the obtained foam an improved temperature resistance.SUMMARY

[0005] In a first aspect, there is provided a formulation for producing a polyisocyanurate foam, comprising: a polyisocyanate component; optionally, an isocyanate-reactive component; and a quaternary ammonium salt trimerization catalyst of Formula 1 :2 EU-51177wherein Ri to R4 are each independently an unsubstituted or a substituted alkyl group, with the proviso that at least one of Ri to R4 is an alkyl group substituted with any one of -OH, -COOH, -SH, -NH2, -NCO, an epoxide and -NHR wherein R is an alkyl group; and X' is a counter-ion, wherein the isocyanate index of the formulation is at least 850.

[0006] A polyisocyanurate foam produced from such a formulation has excellent temperature resistance, compared to a polyisocyanurate foam produced from an identical formulation which differs only in that a conventional trimerization catalyst is used instead of a catalyst according to Formula 1. This is evidenced by Example 1 when compared to Comparative Example 1 (see also Figure 1), which shows that the polyisocyanurate foam according to the present disclosure is more stable at a given temperature than a conventionally produced polyisocyanurate foam (i.e., retains a higher weight% of the foam at a given temperature). Thus, the polyisocyanurate foam of the present disclosure is particularly useful when a highly temperature resistant polyisocyanurate foam is required, such as in composite panels, spray foams, pipe-in- pipe insulation or insulation boards for construction.

[0007] In a second aspect, there is provided a polyisocyanurate foam obtainable by reacting the formulation as defined herein.

[0008] In a third aspect, there is provided an article comprising the polyisocyanurate foam as defined herein, wherein the article is a composite panel, spray foam or an insulation board.

[0009] In a fourth aspect, there is provided the use of a quaternary ammonium salt trimerization catalyst of Formula 1 as a catalyst in the production of a polyisocyanurate foam from a formulation, wherein the formulation comprises a polyisocyanate component, optionally an isocyanate-reactive component and the quaternary ammonium salt trimerization catalyst of Formula 1.

[0010] The embodiments described should not be read to limit or otherwise narrow the scope of any inventive concepts otherwise provided by the present disclosure. While multiple embodiments are disclosed, other embodiments will become apparent to those skilled in3 EU-51177 the art from the following description and figure. Accordingly, the description and figure are to be regarded as illustrative rather than restrictive.BRIEF DESCRIPTION OF THE FIGURES

[0011] Figure 1 shows the temperature resistance of the foam of Example 1 compared to the foam of Comparative Example 1, as determined by thermogravimetric analysis (TGA) under nitrogen.DETAILED DESCRIPTION

[0012] As used herein, the term “formulation” refers to a mixture of components for producing the polyisocyanurate foam. The components of the formulation may be kept separate from each other until the production of a foam is desired, or the components may be mixed together.

[0013] [Polyisocyanate component]

[0014] The polyisocyanate component comprises one or more polyisocyanate compounds. As used herein, the phrase “polyisocyanate compound” or “polyisocyanate” refers to a molecule which has two or more isocyanate functional groups in the molecule.

[0015] The polyisocyanate compound is not particularly limited, and any polyisocyanate compound known in the art may be used. The polyisocyanate compound may comprise an aliphatic polyisocyanate (including alicyclic polyisocyanates), an aromatic polyisocyanate, a prepolymer of a polyisocyanate, or a combination thereof. In one embodiment, the polyisocyanate compound is an aromatic polyisocyanate compound, and is preferably methylene diphenyl diisocyanate (MDI), polymeric MDI or a mixture thereof, and most preferably polymeric MDI. In one embodiment, the polyisocyanate compound is an aromatic diisocyanate compound. In a preferred embodiment, the polyisocyanate component comprises MDI or polymeric MDI.

[0016] According to an embodiment, the polyisocyanate component may comprise at least 50 weight%, or at least 75 weight%, or at least 80 weight%, or at least 85 weight%, or at least 90 weight%, or at least 95 weight%, or about 100 weight%, of an aromatic diisocyanate, such as MDI (preferably, 4,4'-diphenylmethane diisocyanate), polymeric MDI or a mixture thereof, based upon the total weight of the polyisocyanate component.

[0017] Examples of aliphatic polyisocyanates suitable for use include, but are not limited to, hexamethylene diisocyanate (HDI), tetraalkyl xylene diisocyanate, cyclohexane diisocyanate, 1,12-dodecane diisocyanate, 1,4-tetram ethylene diisocyanate, 1,3- and 1,4-cyclohexane diisocyanate, l-isocyanato-3,3,5-trimethyl-5-isocyanatomethyl-4 EU-51177 cyclohexane (isophorone diisocyanate), 4,4'-, 2,2'- or 2,4'-dicyclohexyl-methane diisocyanate, as well as the corresponding isomer mixtures.

[0018] Examples of aromatic polyisocyanates suitable for use include, but are not limited to, m-phenylene diisocyanate, p-phenylene diisocyanate, 4,4'- or 2,4'- or 2,2'-methylene diphenyl diisocyanate (MDI), polymeric MDI, 2,4- or 2,6-toluene diisocyanate (TDI), dianisidine diisocyanate, bitolylene diisocyanate, naphthal ene-l,4-diisocyanate and diphenylene 4,4'-diisocyanate.

[0019] A prepolymer of the polyisocyanate and a polyol may be prepared by pre-reacting the polyol with the polyisocyanate.

[0020] In one embodiment, the polyisocyanate component may be present in the formulation in an amount of at least 50 weight%, or at least 60 weight%, or at least 70 weight%, or at least 75 weight%, or at least 80 weight%, or at least 85 weight%, or at least 90 weight%, based upon the total weight of the formulation.

[0021] [Isocyanate-reactive component]

[0022] The isocyanate-reactive component is an optional component of the formulation and may not be present in the formulation.

[0023] The isocyanate-reactive component may comprise one or more polyol compounds, one or more polyamine compounds, one or more chain extenders, one or more crosslinker compounds, or a mixture thereof. The isocyanate-reactive component may be deliberately added to the formulation or may be added as an impurity when adding another component. The phrase “polyol compound” refers to a molecule which has two or more hydroxyl functional groups in the molecule. More than one type of polyol compound may be present in the isocyanate-reactive component. The phrase “polyamine compound” refers to a molecule which has two or more amine functional groups in the molecule. More than one type of polyamine compound may be present in the isocyanate-reactive component.

[0024] The polyol compound is not particularly limited, and any polyol compound known in the art may be used. The polyol compound may be a poly ether polyol, a polyester polyol, a polyester-polyether polyol, a polycarbonate polyol, a polycaprolactone polyol, other polyol which may be used either individually or in combinations of two or more, or combinations thereof.

[0025] Examples of polyether polyols include, but are not limited to, polyethylene glycol, polypropylene glycol, polypropylene glycol-ethylene glycol copolymer, polytetramethylene ether glycol, polytetramethylene glycol, polyhexamethylene glycol,5 EU-51177 polyheptamethylene glycol, polydecamethylene glycol, and polyether polyols obtained by ring-opening co-polymerization of alkylene oxides, such as ethylene oxide and / or propylene oxide and / or butylene oxide, with isocyanate-reactive initiators having functionality from 2 to 8.

[0026] The polyether polyol may be made by the addition of alkylene oxides to initiators, which may contain from 2 to 8 active hydrogen atoms per molecule. In some embodiments, the initiators may include glycols, glycerol, trimethylolpropane, triethanolamine, pentaerythritol, sorbitol, sucrose, ethylenediamine, ethanolamine, diethanolamine, aniline, toluenediamines (e.g., 2,4- and 2,6- toluenediamines), polymethylene polyphenylene polyamines, N-alkylphenylene-diamines, o-chloro- aniline, p-aminoaniline, diaminonaphthalene, or a combination thereof. Suitable alkylene oxides that may be used to form the polyether polyols include ethylene oxide (EO), propylene oxide (PO), butylene oxide, or a combination thereof. In one embodiment, the polyol compound may be an ethylene oxide / propylene oxide polyether polyol, obtained by reacting ethylene oxide and propylene oxide with a suitable initiator having functionality from 2 to 8.

[0027] Examples of polyester polyols include, but are not limited to, those which may be obtained by reacting a diol and a polybasic acid. Examples of diols include ethylene glycol, polyethylene glycol, tetramethylene glycol, polytetramethylene glycol, 1,6- hexanediol, 3-methyl-l,5-pentanediol, 1,9-nonanediol and 2-m ethyl- 1,8 -octanediol. Examples of polybasic acids include phthalic acid, dimer acid, isophthalic acid, terephthalic acid, maleic acid, fumaric acid, adipic acid and sebacic acid. In a preferred embodiment, the isocyanate-reactive component, if present, comprises an aromatic polyester polyol. Suitable aromatic polyester polyols are those made from aromatic polybasic acids, such as phthalic acid, isophthalic acid and terephthalic acid.

[0028] Examples of polycarbonate polyols include, but are not limited to, aliphatic polycarbonate diols, for example those based upon alkylene glycols, ether glycols, alicyclic glycols or mixtures thereof. In some embodiments, the alkylene groups for preparing the polycarbonate polyol can comprise from 5 to 10 carbon atoms and can be a straight chain, cycloalkylene or combinations thereof. Nonlimiting examples of such alkylene groups include hexylene, octylene, decylene, cyclohexylene and cyclohexyldimethylene. The polycarbonate polyols can be prepared, in non-limiting examples, by reacting the alkylene glycol with a dialkyl carbonate, such as methyl, ethyl, n-propyl or n-butyl carbonate, or diaryl carbonate, such as diphenyl or6 EU-51177 dinaphthyl carbonate, or by reacting a hydroxy -terminated alkylene diol with phosgene or bischloroformate, in a manner well known to those skilled in the art.

[0029] Examples of polycaprolactone polyols include, but are not limited to, those prepared by condensing caprolactone in the presence of an initiator such as water, ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, dipropylene glycol, 1,3- propylene glycol, polyethylene glycol, polypropylene glycol, poly(oxyethylene- oxypropylene)glycols and similar polyalkylene glycols, either blocked or capped containing up to about 40 or more alkyleneoxy units in the molecule, 3-methyl-l,5- pentanediol, cyclohexanediol, 4,4'-methylene-bis-cyclohexanol, 4,4'-isopropylidene bis-cyclohexanol, xylenediol, 2-(4-hydroxymethylphenyl)ethanol, 1,4-butanediol, glycerol, trimethylolpropane, 1,2,6-hexanetriol, triethanolamine, triisopropanolamine, erythritol, pentaerythritol and N,N,N',N'-tetrakis-(2-hydroxyethyl)ethylene diamine. The caprolactone reacted with the initiator can be caprolactone itself or a substituted caprolactone as described in US Pat. No. 3169945.

[0030] Examples of suitable polyamines, chain extenders and crosslinkers are known in the art, and any may be used in the formulation, if desired.

[0031] In one embodiment, the isocyanate-reactive component may be present in the formulation in an amount of 20 weight% or less, or 15 weight% or less, or 10 weight% or less, or 5 weight% or less, or 3 weight% or less, or 2 weight% or less, or 1 weight% or less, based upon the total weight of the formulation.

[0032] In one embodiment, the amount of isocyanate-reactive component in the formulation is less than 20 weight%, or less than 15 weight%, or less than 10 weight%, or less than 5 weight%, or substantially none, based upon the total weight of the isocyanate-reactive component and polyisocyanate component.

[0033] [Quaternary ammonium salt trimerization catalyst]

[0034] The quaternary ammonium salt trimerization catalyst catalyses the trimerization of the polyisocyanate compounds to form an isocyanurate group. The quaternary ammonium salt trimerization catalyst has a structure corresponding to Formula 1 :7 EU-51177 wherein Ri to R4 are each independently an unsubstituted or a substituted alkyl group, with the proviso that at least one of Ri to R4 is an alkyl group substituted with any one of -OH, -COOH, -SH, -NH2, -NCO, an epoxide and -NHR wherein R is an alkyl group; and X' is a counter-ion.

[0035] The alkyl group may be linear, branched or cyclic. The substituent on the alkyl group may be any one of -OH, -COOH, -SH, -NH2, -NCO, an epoxide and -NHR wherein R is an alkyl group.

[0036] In one embodiment, the alkyl group contains from 1 to 20 carbon atoms, or from 1 to 15 carbon atoms, or from 1 to 10 carbon atoms, or from 1 to 7 carbon atom, or from 1 to 5 carbon atoms, or from 1 to 3 carbon atoms.

[0037] In one embodiment, one, two, three or all four of the Ri to R4 groups is an alkyl group substituted with any one of -OH, -COOH, -SH, -NH2, -NCO, an epoxide and -NHR wherein R is an alkyl group. Preferably, only one of Ri to R4 is an alkyl group substituted with any one of -OH, -COOH, -SH, -NH2, -NCO, an epoxide and -NHR wherein R is an alkyl group. R may contain from 1 to 5 carbon atoms, or from 1 to 3 carbon atoms.

[0038] In one embodiment, one of Ri to R4 is substituted with -OH, and the remaining Ri to R4 groups are unsubstituted. In one embodiment, Ri, R3 and R4 are each independently an unsubstituted alkyl group containing from 1 to 5 carbon atoms, and R2 is an alkyl group which contains from 1 to 5 carbon atoms wherein one of those carbon atoms is substituted with -OH. In one embodiment, Ri, R3 and R4 are each independently an unsubstituted alkyl group containing from 1 to 3 carbon atoms, and R2 is an alkyl group which contains from 1 to 3 carbon atoms wherein one of those carbon atoms is substituted with -OH.

[0039] In one embodiment, the quaternary ammonium salt trimerization catalyst of Formula 1 is represented by Formula la:8 EU-51177 wherein Ri, R3 and R4 are each independently a substituted or unsubstituted alkyl group (or as defined herein with respect to Formula 1); RA is an unsubstituted alkyl group; RB is -OH or -COOH; and X~ is a counter-ion.

[0040] In one embodiment, in Formula la, Ri, R3 and R4 are each independently a substituted or unsubstituted alkyl group containing from 1 to 5 carbon atoms; RA is an unsubstituted alkyl group containing from 1 to 5 carbon atoms; RB is -OH; and X~ is a counter-ion. In another embodiment, in Formula la, Ri, R3 and R4 are each independently an unsubstituted alkyl group containing from 1 to 3 carbon atoms; RA is an unsubstituted alkyl group containing from 1 to 3 carbon atoms; RB is -OH; and X~ is a counter-ion. In another embodiment, in Formula la, Ri, R3 and R4 are each independently an unsubstituted alkyl group containing from 1 to 2 carbon atoms; RA is an unsubstituted alkyl group containing from 1 to 2 carbon atoms; RB is -OH; and X~ is a counter-ion.

[0041] In one embodiment, the quaternary ammonium salt trimerization catalyst of Formula 1 is represented by Formula lb:wherein X' is a counter-ion.

[0042] In one embodiment, X' is any suitable counter-ion and is not particularly limited. Suitable counter-ions include a halide anion, hydroxide, a phosphate anion, a carbonate anion, and a carboxylate anion. In one embodiment, X~ is a carboxylate anion derived from a carboxylic acid containing from 1-15 carbon atoms, or preferably a carboxylate anion derived from a carboxylic acid containing from 1-10 carbon atoms. In one embodiment, the carboxylate anion is octoate.

[0043] In one embodiment, the quaternary ammonium salt trimerization catalyst of Formula 1 may be present in the formulation in an amount of 10 weight% or less, or 5 weight% or less, or 4 weight% or less, or 3 weight% or less, or 2 weight% or less, or 1 weight% or less, or from 0.01 weight% to 5 weight%, or from 0.1 weight% to 3 weight%, or from 0.5 weight% to 1.5 weight%, based upon the total weight of the formulation.

[0044] Without being limited by theory, it is believed that the presence of a substituent group on one of Ri to R4 allows for the thermal degradation of the catalyst once the foam is9 EU-51177 exposed to raised temperatures. Since the catalyst is degraded at raised temperatures, the catalyst cannot act to catalyse the breakdown of the foam, thus improving its temperature resistance. On the contrary, conventional catalysts are stable until higher temperatures than the catalyst as defined herein, and thus may catalyse the breakdown of the foam at raised temperatures.

[0045] [Additives]

[0046] The formulation may further comprise additives such as blowing agents, surfactants and the like.

[0047] In one embodiment, the formulation comprises a blowing agent. Physical and chemical blowing agents are suitable for use in the present disclosure.

[0048] Any physical blowing agent known in the art can be used as the blowing agent. For example, suitable blowing agent compounds include hydrocarbons, hydrochlorofluorocarbons, hydrofluorocarbons, hydrohaloolefins, or combinations thereof.

[0049] Examples of hydrocarbon blowing agents that may be used include lower aliphatic or cyclic, linear, or branched hydrocarbons (e.g., alkanes, alkenes and cycloalkanes, preferably those compounds having from 4 to 8 carbon atoms). Specific examples of suitable blowing agent compounds include n-butane, iso-butane, 2,3 -dimethylbutane, cyclobutane, n-pentane, iso-pentane, technical grade pentane mixtures, cyclopentane, methylcyclopentane, neopentane, n-hexane, iso-hexane, n-heptane, iso-heptane, cyclohexane, methylcyclohexane, 1 -pentene, 2-m ethylbutene, 3 -methylbutene, 1- hexene, or combinations thereof.

[0050] Examples of suitable hydrochlorofluorocarbons include l-chloro-l,2-difhioroethane, 1- chl oro-2, 2-difluoroethane, 1 -chloro- 1 , 1 -difluoroethane, 1 , 1 -di chloro- 1 -fluoroethane, monochlorodifluoromethane, or combinations thereof.

[0051] Examples of suitable hydrofluorocarbons include 1,1,1,2-tetrafluoroethane (HFC 134a),1.1.2.2-tetrafluoroethane, trifluoromethane, heptafluoropropane, 1,1,1 -trifluoroethane,1.1.2- trifluoroethane, 1,1,1,2,2-pentafhioropropane, 1,1, 1,3 -tetrafluoropropane, 1,1,1,3,3-pentafhioropropane (HFC 245fa), 1,1,3,3,3-pentafhioropropane, 1, 1,1, 3,3- pentafluoro-n-butane (HFC 365mfc), 1,1,1,4,4,4-hexafhioro-n-butane, 1, 1,1, 2, 3,3,3- heptafluoropropane (HFC 227ea), or combinations thereof.

[0052] Examples of suitable hydrohaloolefins are trans-l-chloro-3,3,3-fluoropropene (HFO 1233zd), trans-l,3,3,3-tetrafhioropropene (HFO 1234ze), cis- and trans- 1, 1,1, 4,4,4- hexafluoro-2-butene (HFO 1336mzz), or combinations thereof.10 EU-51177

[0053] Chemical blowing agents, such as water, mono-carboxylic acid (e.g., formic acid), and polycarboxylic acid, can also be used as the sole blowing agent. Alternatively, these chemical blowing agents can also be used in combination with the physical blowing agents described above as a co-blowing agent.

[0054] In one embodiment, the blowing agent is present in the formulation in an amount of less than about 25 weight%, or less than about 20 weight%, or less than about 15 weight%, or less than about 10 weight%, or less than about 5 weight%, or from about 0.1 weight% to about 25 weight%, or from about 0.1 weight% to about 20 weight%, or from about 0.1 weight% to about 15 weight%, based upon the total weight of the formulation.

[0055] In one embodiment, the formulation comprises a surfactant. In one embodiment, the surfactant comprises a silicone-based surfactant. Suitable surfactants include commercially available surfactants such as Tegostab B8494, Tegostab B8905, Tegostab B8993, Tegostab B8948, Tegostab B8017, Tegostab B8930, Tegostab B8950, Tegostab B8960, DABCO DC193, Vorasurf DC198, Vorasurf 5382, Niax L1500, Niax L1550, Niax LI 542, Niax UAX 7061, Niax UAX 6897, Niax UAX 6639, Niax UAX 7061, Tegostab B8466 and Tegostab B8416. In one embodiment, the surfactant is present in the formulation in an amount of less than about 5 weight%, or less than about 3 weight%, or less than about 2 weight%, or less than about 1 weight%, or from about 0.1 weight% to about 5 weight%, based upon the total weight of the formulation.

[0056] In addition to the trimerization catalyst, the formulation may comprise gelling catalyst and / or blowing catalyst. Any suitable gelling catalyst and blowing catalyst known in the art may be used.

[0057] The formulation may also comprise one or more of flame retardants (such as expandable graphite, tri ethyl phosphate, TCPP or APP) , fillers (such as calcium carbonate), release agents, diluents, flow aids and the like, as desired.

[0058] In one embodiment, the formulation may comprise a flame retardant selected from expandable graphite, triethyl phosphate, tris(chloropropyl)phopshate (TCPP), ammonium polyphosphate (APP), or a combinaton thereof. In one embodiment, the flame retardant is present in the formulation in an amount of less than about 5 weight%, or less than about 4 weight%, or less than about 3 weight%, or from about 0.1 weight% to about 5 weight%, based upon the total weight of the formulation.

[0059] [Polyisocyanurate foam]

[0060] The polyisocyanurate foam is obtainable by reacting the formulation as defined herein in the presence of a blowing agent. Any known process to obtain the foam may be used.11 EU-51177The blowing agent may be a part of the formulation. The foam may be made in a free rise process or in a moulded process. The foam may be made in a continuous or a discontinuous process.

[0061] The isocyanate index of the formulation used to obtain the polyisocyanurate foam is at least 850. In one embodiment, the isocyanate index of the formulation is at least 1000, or at least 1250, or at least 1500, or at least 1750, or at least 2000, or at least 3000, or at least 4000, or at least 5000, or from 850 to 10,000, or from 1000 to 7500, or from 1250 to 7500, or from 1500 to 7000.

[0062] As used herein, the isocyanate index refers to the ratio of isocyanate groups (NCO- groups) over isocyanate-reactive hydrogen atoms present in a composition or formulation:[NCO] x 100[active hydrogen]It should be observed that the isocyanate index as used herein is considered from the point of view of the actual polymerisation process preparing the material involving the isocyanate ingredient 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 water, if used) present at the actual polymerisation stage are taken into account.

[0063] In one embodiment, the density of the polyisocyanurate foam is less than 300 kg / m3, or less than 200 kg / m3, or less than 100 kg / m3, or less than 60 kg / m3, or from 10 kg / m3to 300 kg / m3, or from 10 kg / m3to 100 kg / m3, or from 20 kg / m3to 60 kg / m3, or from 20 kg / m3to 50 kg / m3. The density may be measured according to ISO 845.

[0064] In one embodiment, the polyisocyanurate foam has a closed cell content of more than 50%, or more than 60%, or more than 70%, or more than 80%, or more than 90%, or more than 95%, as measured with a gas pycnometer. “Closed cell content” of a foam is measured using a pycnometer according to ISO 4590-2016. In one embodiment, the polyisocyanurate foam has a substantially fully closed cell structure.

[0065] In one embodiment, the lambda value at 10°C of the polyisocyanurate foam is less than 35 mW / m.K, or less than 30 mW / m.K, or less than 25 mW / m.K, or less than 2012 EU-51177 mW / m.K. The lambda value measurement is carried out at 10°C according to ISO 8301- 2010, using a Heat Flow Meter (HFM) apparatus. “Lambda value” as used herein refers to the thermal conductivity of a material, expressed in mW / m.K. The lower the lambda value, the better the thermal insulation performance.

[0066] In one embodiment, the residual weight (%) of the polyisocyanurate foam, when heated to 750°C under nitrogen atmosphere, is at least 45%, or at least 47%, or at least 50%, based upon the total weight of the foam before heating occurs. The residual weight may be measured by thermogravimetric analysis (TGA), using a TA instruments Q5000 analyser with a 20°C / min heating ramp applied under nitrogen atmosphere.

[0067] [Article]

[0068] The present disclosure provides an article comprising the polyisocyanurate foam as defined herein, wherein the article is a composite panel, spray foam, or an insulation board.

[0069] In one embodiment, the article is a composite panel, such as a sandwich panel. Sandwich panels typically comprise an overlayer, a foam layer and another overlayer, in that order. Polyisocyanurate foams are particularly useful in construction sandwich panels due to the excellent temperature resistance.

[0070] [Use of the quaternary ammonium salt trimerization catalyst]

[0071] The present disclosure also provides a use of the quaternary ammonium salt trimerization catalyst of Formula 1 as a catalyst in the production of a polyisocyanurate foam from the formulation as described herein.

[0072] [Non-limiting embodiments]

[0073] In an embodiment of the present disclosure, there is provided a formulation for producing a polyisocyanurate foam, comprising: a polyisocyanate component; optionally, an isocyanate-reactive component; and a quaternary ammonium salt trimerization catalyst of Formula 1 :13 EU-51177 wherein Ri to R4 are each independently an unsubstituted alkyl group, with the proviso that at least one of Ri to R4 is an alkyl group substituted with any one of -OH or -COOH; and X' is a counter-ion, wherein the isocyanate index of the formulation is at least 850.

[0074] In an embodiment of the present disclosure, there is provided a formulation for producing a polyisocyanurate foam, comprising: a polyisocyanate component; optionally, an isocyanate-reactive component; and a quaternary ammonium salt trimerization catalyst of Formula 1 :wherein Ri to R4 are each independently an unsubstituted alkyl group containing from 1 to 5 carbon atoms, with the proviso that at least one of Ri to R4 is an alkyl group substituted with any one of -OH or -COOH; and X' is a counter-ion, wherein the isocyanate index of the formulation is at least 1000.

[0075] In an embodiment of the present disclosure, there is provided a formulation for producing a polyisocyanurate foam, comprising: a polyisocyanate component; optionally, an isocyanate-reactive component; and a quaternary ammonium salt trimerization catalyst of Formula 1 :wherein Ri to R4 are each independently an unsubstituted alkyl group containing from 1 to 3 carbon atoms, with the proviso that at least one of Ri to R4 is an alkyl group substituted with -OH; and X~ is a counter-ion, wherein the isocyanate index of the formulation is at least 1250.

[0076] In an embodiment of the present disclosure, there is provided a formulation for producing a polyisocyanurate foam, comprising: a polyisocyanate component; optionally, an isocyanate-reactive component; and a quaternary ammonium salt trimerization catalyst of Formula 1 :14 EU-51177wherein Ri to R4 are each independently an unsubstituted alkyl group containing from 1 to 3 carbon atoms, with the proviso that at least one of Ri to R4 is an alkyl group substituted with -OH; and X' is a counter-ion, wherein the isocyanate index of the formulation is at least 1250, wherein the amount of quaternary ammonium salt trimerization catalyst of Formula 1 in the formulation is from 0.1 weight% to 3 weight%, based upon the total weight of the formulation, wherein the amount of polyisocyanate component in the formulation is at least 75 weight%, based upon the total weight of the formulation, and wherein the amount of isocyanate-reactive component in the formulation is less than 10 weight%, based upon the total weight of the isocyanate-reactive component and polyisocyanate component.

[0077] In an embodiment of the present disclosure, there is provided a formulation for producing a polyisocyanurate foam, comprising: a polyisocyanate component; optionally, an isocyanate-reactive component; a blowing agent; and a quaternary ammonium salt trimerization catalyst of Formula lb:wherein X' is a counter-ion, wherein the isocyanate index of the formulation is at least 1250, wherein the amount of quaternary ammonium salt trimerization catalyst of Formula lb in the formulation is from 0.1 weight% to 3 weight%, based upon the total weight of the formulation, wherein the amount of polyisocyanate component in the formulation is at least 75 weight%, based upon the total weight of the formulation, and15 EU-51177 wherein the amount of isocyanate-reactive component in the formulation is less than 10 weight%, based upon the total weight of the isocyanate-reactive component and polyisocyanate component.

[0078] [Examples]

[0079] The present disclosure will be described in more detail with reference to the Examples. The present disclosure is not limited to the following Examples.

[0080] Measurement methods used in the examples:Density: foam density was measured on samples (4x4x2.5 cm3) by dividing the mass by the volume and expressing it in kg / m3, as described in ISO 845 norm.Therm ogravimetric analysis (TGA): Thermograms were recorded on a TA Instruments Q5000 analyser with a 20°C / min heating ramp applied under nitrogen environment.

[0081] Chemicals used in the examples:DABCO DC 193: Silicon surfactant from Evonik (OH value: 75 mg KOH / g)Catalyst LB: Potassium acetate in di ethylene glycol - Trimerization catalyst from HuntsmanDABCO TMR: Trimerization catalyst from Evonik (OH value: 463 mg KOH / g) (according to Formula lb)Triethyl phosphate (TEP): Fire retardant from Akzo Nobel Suprasec®2085: Polymeric MDI from Huntsman (NCO value: 30.50 %) Solstice LBA: Blowing agent from Honeywell

[0082] Example 1:

[0083] A rigid polyisocyanurate foam was produced under free rise conditions in a 400 mL paper cup by mixing under high shear with a Heidolph Mixer (-3000 rpm) the formulation indicated in Table 1 for 10 seconds. The foam was stored in the fumehood overnight before being cut and characterized by thermogravimetric analysis.Table 1. Formulation of Example 116 EU-51177

[0084] Comparative Example 1:

[0085] A rigid polyisocyanurate foam was produced under free rise conditions in a 400 mL paper cup by mixing under high shear with a Heidolph Mixer (~3000rpm) the formulation indicated in Table 2 for 10 seconds. The foam was stored in the fumehood overnight before being cut and characterized by thermogravimetric analysis.Table 2. Formulation of Comparative Example 1

[0086] Results discussion:

[0087] Superior temperature resistance of the foam of Example 1 compared to the foam of Comparative Example 1 was evidenced by TGA analysis under nitrogen (see Table 3 below and Figure 1). Table 3 indicates that the foam of Example 1 was more temperature resistant because of the higher temperatures required to obtain a specific percentage weight of the foam, and because the residual weight at 750°C was higher (both indicate less foam decomposition at a given temperature).Table 3. TGA results17 EU-51177

[0088] All ranges described herein are exemplary in nature and include any and all values in between. The terms “substantially”, “approximately” and “about” used herein are interchangeable and refer to a measurement that includes the stated measurement and any measurements reasonably close to the stated measurement. Measurements that are reasonably close to the stated measurement deviate from the stated measurement by a reasonably small amount as understood and readily ascertained by individuals having ordinary skill in the relevant art. Such deviations may be attributable to measurement error, differences in measurement and / or manufacturing equipment calibrations, human error in reading and / or setting measurements, minor adjustments made to optimize performance and / or structural parameters in view of differences in measurement associated with other components, particular implementation scenarios, imprecise adjustment and / or manipulation of objects by a person or machine. In the event it is determined that individuals having ordinary skill in the relevant art would not readily ascertain values for such reasonably small differences, the terms “about” and “approximately” can be understood to mean plus or minus 10% of the stated value.

[0089] Throughout the description and claims, the terms take the meanings explicitly defined herein, unless the context clearly dictates otherwise.

[0090] The phrases “in one embodiment”, “in an embodiment” and “in some embodiments” etc. as used herein do not necessarily refer to the same embodiment s), though they may. Furthermore, the phrases “in another embodiment” and “in some other embodiments” as used herein do not necessarily refer to a different embodiment, though they may. All embodiments of the present disclosure are intended to be combinable.

[0091] The terms “comprises” and “comprising” mean to include but not limited to, such that further features may be present. The terms may also mean to consist of or consist essentially of.

[0092] All references and test methods cited herein are incorporated by reference in their entireties.

Claims

18 EU-51177CLAIMS1. A formulation for producing a polyisocyanurate foam, comprising: i) a polyisocyanate component; ii) optionally, an isocyanate-reactive component; and iii) a quaternary ammonium salt trimerization catalyst of Formula 1 :wherein Ri to R4 are each independently an unsubstituted or a substituted alkyl group, with the proviso that at least one of Ri to R4 is an alkyl group substituted with any one of -OH, -COOH, -SH, -NH2, -NCO, an epoxide and -NHR wherein R is an alkyl group; and X' is a counter-ion, wherein the isocyanate index of the formulation is at least 850.

2. A formulation according to Claim 1, wherein one of Ri to R4 is substituted with -OH.

3. A formulation according to Claim 1, wherein Ri, R3 and R4 are each independently an unsubstituted alkyl group containing from 1 to 5 carbon atoms, and R2is an alkyl group which contains from 1 to 5 carbon atoms wherein one of those carbon atoms is substituted with -OH.

4. A formulation according to Claim 1, wherein the quaternary ammonium salt trimerization catalyst of Formula 1 is represented by Formula la:wherein Ri, R3 and R4 are each independently a substituted or unsubstituted alkyl group; RA is an unsubstituted alkyl group; RB is -OH or -COOH; and X' is a counter-ion.19 EU-511775. A formulation according to Claim 4, wherein Ri, R3 and R4 are each independently an unsubstituted alkyl group containing from 1 to 5 carbon atoms; RA is an unsubstituted alkyl group containing from 1 to 3 carbon atoms; RB is -OH; and X' is a counter-ion.

6. A formulation according to any preceding claim, wherein the quaternary ammonium salt trimerization catalyst of Formula 1 is represented by Formula lb:wherein X' is a counter-ion.

7. A formulation according to any preceding claim, wherein the isocyanate index of the formulation is at least 1250.

8. A formulation according to any preceding claim, wherein the polyisocyanate component comprises an aromatic polyisocyanate, preferably polymeric methylene diphenyl diisocyanate (pMDI).

9. A formulation according to any preceding claim, wherein the amount of isocyanatereactive component in the formulation is less than 10 weight%, based upon the total weight of the isocyanate-reactive component and polyisocyanate component.

10. A formulation according to any preceding claim, wherein, if present, the isocyanatereactive component comprises an aromatic polyester polyol.

11. Polyisocyanurate foam obtainable by reacting the formulation as defined in any of Claims 1-10 in the presence of a blowing agent.20 EU-5117712. A polyisocyanurate foam according to Claim 11, wherein the foam has a closed cell content of above 90%, as measured with a gas pycnometer.

13. A polyisocyanurate foam according to Claim 11 or Claim 12, wherein the lambda value at 10°C of the foam is less than 35 mW / m.K.

14. An article comprising the polyisocyanurate foam as defined in any of Claims 11 to 13, wherein the article is a composite panel, spray foam, or an insulation board.

15. Use of a quaternary ammonium salt trimerization catalyst of Formula 1 as a catalyst in the production of a polyisocyanurate foam from a formulation, wherein the formulation comprises a polyisocyanate component, optionally an isocyanate-reactive component and the quaternary ammonium salt trimerization catalyst of Formula 1 :wherein Ri to R4 are each independently an unsubstituted or a substituted alkyl group, with the proviso that at least one of Ri to R4 is an alkyl group substituted with any one of -OH, -COOH, -SH, -NH2, -NCO, an epoxide and -NHR wherein R is an alkyl group; and X' is a counter-ion, wherein the isocyanate index of the formulation is at least 850.

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