EP3230333A1

EP3230333A1 - Catalysts for producing isocyanurates from isocyanates

Info

Publication number: EP3230333A1
Application number: EP15807926.9A
Authority: EP
Inventors: Thomas Ernst Müller; Torsten Hagen; Bolko Raffel; Christoph Gürtler; Henning Vogt; Abdulghani AL NABULSI; Burkhard KÖHLER; Walter Leitner
Original assignee: Covestro Deutschland AG
Current assignee: Covestro Deutschland AG
Priority date: 2014-12-11
Filing date: 2015-12-10
Publication date: 2017-10-18
Also published as: US20180001310A1; WO2016092018A1; CN107001562A

Abstract

The invention relates to a method for producing isocyanurates and isocyanurate-containing polyurethanes, comprising the step of reacting an isocyanate in the presence of a catalyst. Said method is characterized in that the catalyst comprises the product of the reaction of a carboxylic acid containing thiol groups with an alkali-metal, alkaline-earth-metal, scandium-group, or lanthanoid base, wherein the reaction is performed in the absence of compounds containing tin and/or lead, wherein the degree of deprotonation of the catalyst is > 50% to ≤ 100% and the H atoms present in carboxyl groups, the carboxylate groups, the H atoms present in thiol groups, and the thiolate groups are also taken into account in the calculation of the degree of deprotonation. The catalyst is preferably a dipotassium salt of 2-mercaptoacetic acid, 3-mercaptopropionic acid, 4-mercaptobutyric acid, and/or thiosalicylic acid. Even at low temperatures, isocyanurates and/or isocyanurate units and in particular mixtures of isocyanurates and/or isocyanurate units and carbamates and/or urethane units, which are present in isocyanurate-containing polyurethanes (PUR/PIR systems), are obtained at a higher reaction speed than in the case of comparable methods in which catalysts that do not contain mercapto groups, such as potassium acetate, are used.

Description

Catalysts for the production of isocvanurates from isocvanates

The present invention describes a process for the preparation of isocyanurates and isocyanurate-containing polyurethanes using isocyanates in the presence of a catalyst, the catalyst comprising the product of the reaction of a thiol group-containing carboxylic acid with an alkali metal and / or alkaline earth metal base.

Isocyanurates play an important role in the production of polyurethane foams. They may result from the trimerization of the isocyanates used in the preparation of the polyurethane foam and give the resulting foam advantageous properties, e.g. a high rigidity, a high chemical resistance and in particular a favorable fire behavior.

In the production of isocyanurate-containing polyurethane foams from di- or polyisocyanates and di- or polyalcohols two reactions play an essential role: the urethanization reaction of one isocyanate group and one alcohol group to urethane units (hereinafter also interchangeable as Carbamate units referred to) and the trimerization reaction of three isocyanate groups to isocyanurate units (hereinafter also referred to interchangeably as trimer units).

Due to the exothermic nature of the chemical reaction of di- or polyisocyanates and di- or polyalcohols during adiabatic or polytropic foam formation, the foam formed heats up to temperatures of up to 180 ° C. The urethanization reaction usually starts already at moderate temperatures in an early stage of foaming. The also desirable formation of isocyanurate units from the isocyanates used typically starts only in a higher temperature range and thus with a time delay, when the urethanization reaction has already largely expired. As a result of the progressive formation of polyurethane, the viscosity of the foam increases during foam formation, so that due to the increasing inflexibility of the surrounding medium, the meeting of the remaining isocyanate groups to form isocyanurates is difficult.

A particular problem may arise during polyurethane foam formation in the edge regions of the foam. These usually have a significantly lower temperature than the foam core, since the foam edges are in contact with the cooler environment or in production plants with colder system parts. At the temperatures prevailing there during foaming, which are lower compared to the foam core, a lower proportion of isocyanurate units is formed. As a result, an inhomogeneous foam is obtained. For the targeted formation of isocyanurate units in the polyurethane foam, special catalysts, such as, for example, potassium acetate or potassium 2-ethylhexanoate, are frequently used.

Methods for achieving an advantageous concentration of isocyanurate structures even at lower temperatures or in the edge regions of the polyurethane foam are the subject of research. Thus, WO2010054311, WO2010054313, WO2010054315, WO2010054317 describe the use of various phosphorus- or nitrogen-containing catalysts which have an activation temperature of ≦ 73 ° C. for the isocyanurate formation reaction and are intended to increase the yield of isocyanurate structures in the edge region. However, the catalysts used here also show a marked drop in the isocyanurate structures in the edge region of the polyurethane foam (for example WO2010054317 A2, diagram last page).

The catalysts commonly used have a low activity at temperatures below 70 ° C. This requires that in the industrial production of isocyanurate-containing polyurethane foams typically the highest possible processing temperatures are required to ensure a sufficiently high rate of formation of the isocyanurate-containing polyurethane foam and a sufficient isocyanurate content. In the case of rigid foam sandwich panels this requires a high temperature of the double conveyor belt (belt temperature), which is often in the range of 70 ° C. However, a high strip temperature results in an increased energy requirement for heating the production plant. In the search for new Isocyanurafbildungskatalysatoren sulfur compounds have been observed in connection with PUR / PIR systems so far only in certain aspects. In many cases, sulfur compounds are described as additives or reaction components. For example, in Applied Polymer Science (2014) 131 (13), 40402 / 1-40401 / 11 or Progress in Organic Coatings (2009) 64 (2-3), 238-246 thiols for regulating elasticity in crosslinked urethane acrylates or pentaerythritol tetrakis (3-mercaptopropionate) and comparable compounds described as reactants for the thiol-ene addition.

DE 2422647 AI describes elemental sulfur as a flame retardant additive in isocyanurate urethane foam mixtures.

Furthermore, sulfur-containing ligands for tin and lead catalysts are disclosed in the prior art: dibutyltin bis (ethoxybutyl-3-mercaptopropionate) (WO 2008/089163 Al), dimethyltin bis (3-mercaptopropionate) (EP 0651017 A1), dibutyltin mercaptopropionate (EP 0075130 AI), Dimethylzinndilaurylmercaptid (WO 2009/143198 AI), tin sulfides and Zinnthiolate (US 6,613,865) and Triphenylbleithioacetat (US 3,474,075). No. 4,173,692 A describes mixtures of carboxylates which may also contain mercapto groups Tin catalysts, however, the mixtures are also heavy metal-containing and the reaction rate and selectivity to the trimer formation is not sufficient for some applications. A mixture of carboxylates, heavy metal compounds and specific amines is described in WO 2013/117541 Al as a catalyst system. It is claimed an improved flame retardancy, but the foaming takes place from a prepolymer, which requires an upstream reaction step.

A heavy metal-free sulfur-containing catalysis in the PUR / PIR range is described in DD 121 461 A3. This document relates to a process for the preparation of polyisocyanurate-polycarbodiimide molding materials including -foams with increased temperature resistance and flame retardancy whose carbodiimidgruppenhaltige isocyanate prepolymers are stable as intermediates by reacting polyisocyanates with organic oxygen-containing sulfur compounds which cause a pro-rata formation of carbodiimide groups, and subsequent trimerization , As the carbodiimide group-causing catalyst, dialkyl sulfide, dialkyl sulfate or dialkyl sulfite is used. EP 0,476,337 AI describes a heavy metal-free catalyst system of carboxylates and Trisdialkylaminoalkyl- hexahydrotriazines. However, this system is sulfur-free, which has a negative effect on the flame resistance.

There remains a need for improved manufacturing processes for PUR / PIR foams which are less energy intensive. Particular attention is paid to the temperature at which the reaction to the PUR / PIR foam is carried out. Furthermore, the improvement of the fire behavior of PUR / PIR foams is desirable. Also, the catalyst or catalyst system should be free of heavy metals such as tin or lead.

The object of the present invention has been found to provide a process for the preparation of isocyanurates, which can be carried out at lower temperatures than hitherto conventional and foams with better fire performance provides.

According to the invention, the object is achieved by a process for the preparation of isocyanurates and isocyanurate-containing polyurethanes, comprising the step of reacting an isocyanate in the presence of a catalyst, wherein the catalyst is the product of the reaction of a thiol-containing carboxylic acid with an alkali metal, alkaline earth metal, scandium groups or lanthanide base, wherein the reaction is carried out in the absence of tin and / or lead-containing compounds, wherein the Deprotonierungsgrad of the catalyst> 50% to ≤ 100% and present in carboxyl groups H atoms and the carboxylate groups and the H atoms present in thiol groups and the thiolate groups are taken into account in the calculation of the degree of deprotonation. The Erftndungsgemäße method has the advantage that isocyanate or isocyanate units and in particular mixtures of isocyanurates or isocyanurate units and carbamates or urethane units, such as those in isocyanurate-containing polyurethanes (PUR / PIR systems) present lower temperatures are obtained at a higher reaction rate than in comparable processes in which catalysts are used which do not contain mercapto groups, such as potassium acetate.

The catalysts selected according to the invention furthermore offer the advantage that at low temperatures, for example in a range around 40 ° C., there is an increased activity in the conversion of isocyanate groups in comparison with potassium acetate. This increased activity means that even at an early stage of the reaction of isocyanates and alcohols or of di- or polyisocyanates and di- or polyalcohols larger amounts of isocyanurate or isocyanurate units are formed. In this way, polyurethane foams having an increased isocyanurate content, in particular in the edge regions of the foam, can also be obtained even at the strip running temperatures commonly used, such as, for example, 70.degree. In addition, for example, observed at 70 ° C, a higher relative reactivity (formation of trimer / formation of carbamate) in comparison to potassium acetate

Due to the high activity of the catalysts of the invention with respect to the formation of carbamal / isocyanurate mixtures or PUR / PIR systems at low temperatures (for example in the range of 40 ° C to 70 ° C), the inventive method allows the production of isocyanurate-containing polyurethane Foams at lower strip running temperatures (in the case of block foam or panels), for example in the range of 40 ° C to 70 ° C. This means that isocyanurate-containing polyurethane foams can be produced over conventional processes while saving energy, which is needed for heating the production line. Regardless of the temperature, a higher activity of the catalysts according to the invention with regard to formation of carbamate / isocyanurate mixtures or PUR / PIR systems leads to the fact that polyurethane foams having a suitable isocyanurate content can be produced at lower reaction times and thus a higher productivity of the production plant is guaranteed. An increased relative activity of the catalysts of the invention with respect to the formation of isocyanurate units (as opposed to the formation of carbamate or urethane units), especially at low temperatures (for example in the range of 40 ° C to 70 ° C), also allows the Production of PUR / PIR systems with an increased proportion of isocyanurate and thus improved fire behavior. The catalyst is considered to be the reaction product of a thiol group-containing carboxylic acid with an alkali metal, alkaline earth metal, scandium group or lanthanide base.

Depending on the charge of the alkali metal, alkaline earth metal, scandium group or lanthanide base, alkali metal, alkaline earth metal, scandium group or lanthanide cations (base cations), valence of the alkali metal, alkaline earth metal, scandium group or lanthanide cations. Base or, more generally, the total number of positive charges present, alkali metal, alkaline earth metal, scandium group or lanthanide base strength and number of protons bonded and thus cleaved in COOH and SH groups can be exemplified by dianion of the thiol group-containing carboxylic acid having two bases Monocations or a dianion of the thiol-containing carboxylic acid with a base dication in the catalyst.

It is also possible that mixtures of the aforementioned combinations are present. It is also possible that the thiol group-containing carboxylic acid with the alkali metal or alkaline earth metal base is in a protomeration ZDeprotomerungs equilibrium. The thiol-containing carboxylic acid may be, for example, an aliphatic or aromatic carboxylic acid which is linked via the aliphatic or aromatic radical with at least one thiol group. There may be several carboxyl groups and / or several thiol groups in the molecule.

The alkali metal or alkaline earth metal base can consist of the combination of a base anion B ^n- with a suitable number of alkali metal or alkaline earth metal cations Μ ™ ⁺ and usually has the composition (M ^m4 ) b (B ^{+ +} ) _m , where m is In the alkali metal or alkaline earth metal base of the above composition, the cations M ™ * may be proportionally replaced by protons H *, the total charge of the cations of the total charge to be replaced being 1 or 2 and b being 1, 2 or 3 and valency corresponds to the replacing proton and in the alkali metal or alkaline earth metal base at least one cation M ^{m + is} included.

The cations M ™ * can be selected from the group of alkali metals, in particular lithium, sodium, potassium, rubidium, cesium, from the group of alkaline earth metals, in particular magnesium, calcium, strontium, barium, from the scandium group, in particular scandium, yttrium or the group of lanthanides, in particular lanthanum, europium, gadolinium, ytterbium, lutetium.

The base anions B ^13- can, for example, monovalent base anions such as H, OH, OOH, SH, CIO, CN, alcoholates, thiolates, amides, carboxylates, carbanions or bivalent Base anions such as O ^2- , CO3 ^2- , SO3 ^2- , HPO4 ^2- , or trivalent base anions such as PO4 ^3- be.

The alkali metal, alkaline earth metal, scandium group or lanthanide base may further be an elemental alkali metal, alkaline earth metal, scandium group metal or lanthanide metal. It is provided according to the invention that the reaction is carried out in the absence of tin or lead-containing compounds. Compounds to be avoided are, in particular, dibutyltin dilaurate (DBTL), dibutyltin bis (ethoxybutyl-3-mercaptopropionate), dimethyltin bis (3-mercaptopropionate), dibutyltin mercaptopropionate, dimethyltin dilaurylmercaptide, tin sulfide and tin thiolates, and triphenyl lead thioacetate. Preferably, bismuth-containing compounds are also excluded, for example bismuth trioctoate.

It is further provided according to the invention that the degree of deprotonation of the catalyst is> 50% to ≦ 100%, whereby the H atoms present in carboxyl groups and the carboxylate groups and the H atoms present in thiol groups and the thiolate groups are taken into account in the calculation of the deprotonation degree become. The Deprotonierungsgrad can be derived from the amounts of thiol-containing carboxylic acids and alkali metal, alkaline earth metal, Scandiumgruppen- or lanthanide base. In general, the proton bonded to the COOH group will be more acidic than the proton attached to the thiol group and will first react with the base. Only then will the proton bound to the SH group react. The degree of deprotonation is the percentage of Zerivitinoff-active protons removed from the acid underlying the catalyst molecule. As Zerivitinoff- active protons are those which react with the Grignard reagent methylmagnesium iodide to form one molecule of methane per active proton.

Under this premise, a degree of deprotonation of 50% indicates that when a carboxylic acid containing thiol groups in which the number of carboxyl groups present is equal to the number of thiol groups present, all carboxyl groups are present in deprotonated form and all thiol groups in protonated form.

A degree of deprotonation of 100% accordingly states that all the carboxyl and thiol groups present in the thiol-containing carboxylic acid are present in deprotonated form.

The degree of deprotonation can be determined by analyzing the ratio of alkali metal, alkaline earth metal, scandium group or lanthanide cations and sulfur by means of Determine elemental analysis. The degree of deprotonation is then given by the following equation 1,

where m is the charge of the alkali metal, alkaline earth metal, scandium group or lanthanide cation, M / S for the determined by elemental analysis molar ratio of alkali metal, alkaline earth metal, Scandiumgruppenmetall or Lanthanoidmetall M to sulfur, and ncooH / nsH for the ratio from carboxyl groups to thiol groups in the thiol group-containing carboxylic acid.

Embodiments and further aspects of the invention are described below. They can be combined with one another as long as the context does not undoubtedly lead to the opposite.

In the process according to the invention further catalysts, e.g. Urethanisierungskatalysatoren be used. Examples of such urethanization catalysts are aminic catalysts, in particular those selected from the group triethylenediamine, Ν, Ν-dimethylcyclohexylamine, dicyclohexylmethylamine, tetramethylenediamine, 1-methyl-4-dimethylaminoethylpiperazine, triethylamine, tributylamine, N, N-dimemylbenzylamine, N, N ', N' Tris (dimethylammopropyl) hexahydrotriazine, tris

(dimethylaminopropyl) amine, tris (dimethylaminomethyl) phenol, dimethylaminopropylformamide, N, N, N'N'-tetramethylethylene (diamine, Ν, Ν, Ν'Ν'-tetramethylbutanediamine, tetramethylenediamine, pentamethyldiethylenetriamine, pentamethyldipropylenetriamine, tetramethyldiaminoethyl ether, dimethylpiperazine, 1, 2-dimethylimidazole, 1-

Azabicyclo [3.3.0] octane, 1,4-diazabicyclo [2.2.2] octane, bis (dimethylaminopropyl) urea, N-methylmorpholine, N-ethylmorpholine, N-cyclohexylmorpholine, 2,3-dimethyl-3,4, 5,6-tetrahydropyrimidine, triethanolamine, diethanolamine, triisopropanolamine, N-methyldiethanolamine, N-ethyldiethanolamine and / or dimethylethanolamine.

In a further embodiment of the present invention, the thiol group-containing carboxylic acid comprises a thiol group and a carboxyl group.

In a further embodiment of the present invention, the thiol group-containing carboxylic acid comprises a thiol group and a carboxyl group, and the thiol group is bridged with the carboxyl group by not more than 3 carbon atoms, among "bridging carbon atoms" the chain having the least number of carbon atoms between Carboxyl group and thiol group in the molecule is understood and the carbon atom contained in the carboxyl group is not taken into account. Examples of thiol-containing carboxylic acids of this embodiment are 2-mercaptoacetic acid, 3-mercaptopropionic acid, 4-mercapto butyric acid, wherein the carbon atoms in the bridging alkylene chain independently of each other with further radicals such as linear or branched, saturated or mono- or polyunsaturated, optionally Heteroatom-containing C 1 - to C 20 -alkyl, cycloalkyl, aryl, alkylaryl or arylalkyl groups, fluorine, chlorine or bromine atoms, nitrile groups and / or nitro groups, and different radicals can be linked to one another in this way, that they form mono-, bi- or polycyclic ring systems, and thiosalicylic acid, wherein the aromatic carbon atoms which are not bonded to the thiol group or to the carboxyl group, independently of one another in each case with further radicals such as linear or branched, saturated or mono- or polysubstituted unsaturated, given lls heteroatom-containing C 1 - to C 20 -alkyl, cycloalkyl, aryl, alkylaryl or arylalkyl groups, fluorine, chlorine or bromine atoms, nitrile groups and / or nitro groups may be connected and / or condensed to higher ring systems , Preferred thiol-containing carboxylic acids in this embodiment are 2-mercaptoacetic acid, 2-mercaptopropionic acid, 4-mercaptobutyric acid and thiosalicylic acid.

In a further embodiment of the present invention, the thiol group-containing carboxylic acid comprises a thiol group and a carboxyl group, and the thiol group is bridged with the carboxyl group through 2 or 3 carbon atoms, with "bridging carbon atoms" being the chain having the least number of carbon atoms between carboxyl group and thiol group Examples of thiol group-containing carboxylic acids of this embodiment are 3-mercaptopropionic acid, 4-mercaptobutyric acid, wherein the carbon atoms in the bridging alkylene chain independently of each other with further radicals such as linear or branched, saturated or mono- or polyunsaturated, optionally heteroatom-containing C 1 - to C 20 -alkyl, cycloalkyl, aryl, alkylaryl or arylalkyl groups, fluorine, chlorine or bromine atoms, nitrile-G groups and / or nitro groups may be connected and various radicals may be linked together to form mono-, bi- or polycyclic ring systems, and thiosalicylic acid, wherein the aromatic carbon atoms which are not bound to the thiol group or to the carboxyl group, independently each with other radicals such as linear or branched, saturated or mono- or polyunsaturated, optionally containing heteroatoms C 1 - to C 20 -alkyl, cycloalkyl, aryl, alkylaryl or arylalkyl groups, fluorine, chlorine or bromine atoms , Nitrile groups and / or nitro groups and / or may be condensed to higher ring systems. preferred Thiol-containing carboxylic acids in this embodiment are 2-mercaptopropionic acid, 4-mercaptobutyric acid and thiosalicylsävire.

In another embodiment of the present invention, the thiol-containing carboxylic acid is 2-mercaptoacetic acid, 3-mercaptopropionic acid, 4-mercaptobutyric acid and / or thiosalicylic acid. Preferred catalysts are the dipotassium salts of said acids.

In a further embodiment of the present invention, the degree of deprotonation of the catalyst is 70 70% to ≦ 100%, whereby the H atoms present in carboxyl groups and the carboxylate groups and the H atoms present in thiol clusters and the thiolate clusters are taken into account in the calculation of the degree of deprotonation become. The calculation of the degree of deprotonation is carried out as already described above. The degree of deprotonation is preferably 80 80% to ≦ 100%, more preferably 90 90% to ≦ 100%, and particularly preferably 95 95% to ≦ 100%.

In another embodiment, the base for deprotonating the catalyst precursor is an alkali metal, alkaline earth metal, scandium or lanthanide hydride, an alkali metal, alkaline earth metal, scandium or lanthanide alkoxide, or an alkali metal, alkaline earth metal, Scandium clump or lanthanoid alkyl.

The advantage of using hydrides as the base is that gaseous hydrogen escapes as a by-product and thus no neutralization products such as water are present in the reaction mixture. Preference is given to lithium hydride, sodium hydride, potassium hydride, magnesium hydride and / or calcium hydride.

The alkali metal, alkaline earth metal, Scandiumgrappen- or lanthanoid alkoxides, for example, by reacting a suitable alkali metal or alkaline earth metal base, in particular an alkali metal, alkaline earth metal, Scandiumgrappen- or lanthanide hydride or an elemental alkali metal, alkaline earth metal, Scandiumgrappenmetalls or Lanthanoidmetalls with the corresponding alcohol. Examples of alcohols which can be reacted with alkali metal, alkaline earth metal, Scandiumgrappen- or lanthanide bases to give suitable alkoxides are methanol, ethanol, n-propanol, isopropanol, "-butanol, isobutanol, tert-butanol, n-pentanol, tert-pentanol, neopentyl alcohol, cyclopentanol, hexanol, cyclohexanol, heptanol, octanol, 2-ethylhexanol, nonanol, decanol, undecanol, dodecanol and their higher homologs, monomeric, oligomeric or polymeric diols, especially alkylene, oligoalkylene or polyalkylene glycols such as ethylene glycol , Diethylene glycol, triethylene glycol, polyethylene glycol, dipropylene glycol, tripropylene glycol, polypropylene glycol, tetramethylene glycol, di (tetramethylene glycol), poly (tetramethylene glycol), and monoalkyl ethers, especially monomethyl, monoethyl, monopropyl and Monobutyl ether, of monomeric, oligomeric or polymeric diols. Preferred alcohols for this purpose are methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, tert-butanol, n-pentanol, tert-pentanol, neopentyl alcohol, diethylene glycol, diethylene glycol monomethyl ether or a polyalkylene glycol or its monomethyl ether. The alkali metal, alkaline earth metal, scandium group or lanthanide alkoxide can be present dissolved in a solvent, for example in one of the abovementioned alcohols.

The advantage of using carbanions as base is that as a by-product chemically inert compounds are formed and so there are no neutralization products such as water in the reaction mixture. Preference is given to methyllimium, ethylurium, methylsodium, ethylsodium, methylpotassium, ethylpotassium and / or methylmagnesium chloride.

In a further embodiment of the present invention, the catalyst is dissolved or suspended in a solvent prior to the beginning of the reaction. The solvent is preferably monoethylene glycol, diethylene glycol, diethylene glycol monomethyl ether or a polyalkylene glycol, N-methylpyrrolidone, N-ethylpyrrolidone or dimethyl sulfoxide or mixtures thereof. In addition, the catalyst formulations may contain other ingredients, e.g. monofunctional alcohols. Without wishing to be bound by theory, it is believed that said compounds exert at least labile ligands on the catalytic system of the invention.

In a further embodiment of the present invention, the reaction is carried out at a temperature of ≥20 ° C to ≤90 ° C. Preferred reaction temperatures are ≥ 30 ° C to ≤ 80 ° C, more preferably ≥ 40 ° C to ≤ 70 ° C.

In a further embodiment of the present invention, the reaction is carried out in a non-constant temperature range, but at the beginning of the reaction a temperature of ≥20 ° C to ≤90 ° C, preferably ≥30 ° C to ≤80 ° C, especially preferably ≥ 40 ° C to ≤ 70 ° C prevails. Typically, in this embodiment, after the onset of the reaction, a temperature rise is observed in the reaction system, so that the maximum temperature of the reaction system is ≥ 80 ° C to ≤ 250 ° C, preferably ≥ 100 ° C to ≤ 220 ° C, more preferably ≥ 140 ° C can be up to ≤ 200 ° C. Such an adiabatic temperature profile is usually observed in particular in PUR / PIR systems, ie in the reaction of diisocyanates and / or polyisocyanates with diols and / or polyols. In the case of block foam or panels, the temperature at the beginning of the reaction is the strip running temperature. Feedstocks such as isocyanates, alcohols, catalyst solution and other components of the foam formulation can be pre-heated to this temperature or a lower temperature prior to mixing at the beginning of the reaction. In one embodiment of the present invention, the isocyanate is a monoisocyanate. When monoisocyanates are used, monomeric isocyanurates are obtained. Examples of monoisocyanates are methyl isocyanate, ethyl isocyanate, n-propyl isocyanate, isopropyl isocyanate, n-butyl isocyanate, isobutyl isocyanate, tert-butyl isocyanate, n-pentyl isocyanate, n-hexyl isocyanate, cyclohexyl isocyanate, ω-chlorohexamethylene isocyanate, n-heptyl isocyanate, n-octyl isocyanate, isooctyl isocyanate, 2- Ethylhexyl isocyanate, 2-norbornylmethyl isocyanate, nonyl isocyanate, 2,3,4-trimethylcyclohexyl isocyanate, 3,3,5-trimethylcyclohexyl isocyanate, decyl isocyanate,

Undecyl isocyanate, dodecyl isocyanate, tridecyl isocyanate, tetradecyl isocyanate, pentadecyl isocyanate, hexadecyl isocyanate, octadecyl isocyanate, stearyl isocyanate, 3-butoxypropyl isocyanate, 3- (2-ethylhexyloxy) propyl isocyanate, 6-chlorohexyl isocyanate, benzyl isocyanate, phenyl isocyanate, ortho-, meta-, /> ara-toluyl isocyanate, dimethyl phenyl isocyanate (technical mixtures are individual isomers), 4-pentylphenyl isocyanate, 4-cyclohexylphenyl isocyanate, 4-dodecylphenyl isocyanate, ortho-, meta-, /> ara-methoxyphenyl isocyanate, chlorophenyl isocyanate (2,3,4-isomer), the various dichlorophenyl isocyanate isomers, 4 Nitrophenyl isocyanate, 3-trifluoromethylphenyl isocyanate, 1-naphthyl isocyanate. Preferred monoisocyanates are benzyl isocyanate, phenyl isocyanate, ortho-, meta-, /? Ara-toluyl isocyanate, dimethylphenyl isocyanate (technical mixtures and individual isomers), 4-cyclohexylphenyl isocyanate and ortho-, meta-, /> ara-methoxyphenyl isocyanate. A particularly preferred monoisocyanate is para-toluyl isocyanate. In another embodiment of the present invention, the isocyanate is a polyisocyanate. These are customary in the PUR / PIR area isocyanates having an NCO functionality of 2 or more. Aliphatic, cycloaliphatic, arylaliphatic and aromatic polyhydric polyisocyanates are generally suitable. Examples of such suitable polyisocyanates are 1,4-butylene diisocyanate, 1,5-pentane diisocyanate, 1,6-hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), 2,2,4- and / or 2,4,4-trimethylhexamethylene diisocyanate, the isomers Bis (4,4'-isocyanatocyclohexyl) methanes or mixtures thereof of any isomer content, 1,4-cyclohexylene diisocyanate, 1,4-phenylene diisocyanate, 2,4- and / or 2,6-toluene diisocyanate (TDI), 1,5-naphthylene diisocyanate, 2,2 ^l and / or 2,4 'and / or 4,4'-diphenylmethane diisocyanate (MDI) or a higher homologue or mixtures thereof (polymeric MDI), 1,3- and / or 1,4-bis - (2-isocyanato-prop-2-yl) -benzene (TMXDI), l, 3-bis (isocyanatomethyl) benzene (XDI), as well as alkyl-2,6-diisocyanatohexanoate (lysine diisocyanates) with Ci to Ce-alkyl groups. Preference is given here to an isocyanate from the diphenylmethane diisocyanate series.

It is also possible to use NCO-terminated prepolymers as the polyisocyanate, which are obtained, for example, from the reaction of one of the abovementioned polyisocyanates with polyols, in particular Polyalkylene glycols emerge.

In addition to the abovementioned polyisocyanates, modified diisocyanates with uretdione, isocyanuric, urethane, carbodiimide, uretonimine, allophanate, biuret, iminooxadiazinedione, or oxadiazinetrione structure and also unmodified polyisocyanate having more than 2 NCO groups per molecule may be proportionally added such as 4-isocyanatomethyl-l, 8-octane diisocyanate (nonane triisocyanate), tris-4-isocyanatophenyl-thiophosphate or triphenylmethane-4,4 ', 4 "- triisocyanate with.

In a further embodiment, the reaction is further carried out in the presence of a monoalcohol. When monoisocyanates are used, mixtures of monomeric isocyanurates with carbamates resulting from the reaction of the monoisocyanate with the alcohol can thus be obtained. The composition of the mixture is dependent on the type of monoisocyanate and the monoalcohol, the ratio of isocyanate groups to hydroxyl groups in the alcohol, the type and concentration of the catalyst and the reaction conditions such as temperature, solvent and reaction. Examples of monoalcohols are methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, tert-butanol, n-pentanol, tert-pentanol, neopentyl alcohol, cyclopentanol, hexanol, cyclohexanol, heptanol, octanol, 2-ethylhexanol, nonanol, Decanol, undecanol, dodecanol and their higher homologs, monoalkyl ethers of monomeric, oligomeric or polymeric diols such as Ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol monopropyl ether, triethylene glycol monobutyl ether, polyethylene glycol. Monomethyl ether, polyethylene glycol monoethyl ether, polyethylene glycol monopropyl ether, polyethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether,

Propylene glycol monopropyl ether, propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monopropyl ether, dipropylene glycol monobutyl ether, tripropylene glycol monomethyl ether, tripropylene glycol monoethyl ether, tripropylene glycol monopropyl ether, tripropylene glycol monobutyl ether, polypropylene glycol monomethyl ether, polypropylene glycol monoethyl ether, polypropylene glycol Monopropyl ether, polypropylene glycol monobutyl ether, tetramethylene glycol monomethyl ether, tetramethylene glycol monoethyl ether, tetramethylene glycol monopropyl ether, tetramethylene glycol monobutyl ether, di (tetramethylene glycol) monomethyl ether, di (tetramethylene glycol) monoethyl ether, di (tetramethylene glycol) monopropyl ether, di (tetramethylene glycol) monobutyl ether, poly (tetramethylene glycol) monomethyl ether, Poly (tetramethylene glycol) monoethyl ether, poly (tetramethylene glycol) monopropyl ether, poly (tetramethylene glycol) monobutyl ether.

Preferred monoalcohols are primary alcohols, e.g. Methanol, ethanol, n-butanol, n-pentanol, tert-pentanol, neopentyl alcohol, n-hexanol, n-octanol, 2-ethylhexanol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, Diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol monopropyl ether, triethylene glycol monobutyl ether, polyethylene glycol monomethyl ether, polyethylene glycol monoethyl ether, polyethylene glycol monopropyl ether, polyethylene glycol monobutyl ether. Particularly preferred monoalcohols are monoalkyl ethers of diols, in particular ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol Monopropyl ether, triethylene glycol monobutyl ether, polyethylene glycol monomethyl ether, polyethylene glycol monoethyl ether, polyethylene glycol monopropyl ether, polyethylene glycol monobutyl ether.

In a preferred embodiment, the reaction is further carried out in the presence of a polyol. The polyols which can be used according to the invention can have, for example, a number-average molecular weight M _{n of} 60 60 g / mol to ≦ 8000 g / mol, preferably from 90 90 g / mol to ≦ 5000 g / mol and more preferably from 92 92 g / mol to ≦ 1000 g / mol. The OH number of the polyols indicates the OH number in the case of a single polyol added. In the case of mixtures, the average OH number is given. This value can be determined using DIN 53240. The average OH functionality of said polyols is 1,5 1.5 and is, for example, in a range of 1,5 1.5 to ≦ 6, preferably ≥ 1.6 to ≦ 5, and more preferably ≥ 1.8 to ≦ 4.

Polyether polyols which can be used according to the invention are, for example

Polytetramethylene glycol polyethers obtainable by polymerization of tetrahydrofuran by cationic ring opening.

Also suitable polyether polyols are addition products of styrene oxide, ethylene oxide, propylene oxide, butylene oxides and / or epichlorohydrin to di- or polyfunctional starter molecules.

Suitable starter molecules are, for example, water, ethylene glycol, diethylene glycol, Butyl diglycol, glycerol, diethylene glycol, trimethylolpropane, propylene glycol, pentaerythritol, sorbitol, sucrose, ethylenediamine, toluenediamine, triethanolamine, 1,4-butanediol, 1,6-hexanediol and low molecular weight, hydroxyl-containing esters of such polyols with dicarboxylic acids. Polyester polyols which can be used according to the invention include, among others, polycondensates of di- and also tri- and tetraols and di- and also tri- and tetracarboxylic acids or hydroxycarboxylic acids or lactones. Instead of the free polycarboxylic acids, it is also possible to use the corresponding polycarboxylic acid anhydrides or corresponding polycarboxylic acid esters of lower alcohols for the preparation of the polyesters. Examples of suitable diols are ethylene glycol, butylene glycol, diethylene glycol, triethylene glycol, polyalkylene glycols such as polyethylene glycol, furthermore 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 1,6-hexanediol and isomers, Neopentyl glycol or hydroxypivalic acid neopentyl glycol ester. In addition, it is also possible to use polyols, such as trimethylolpropane, glycerol, erythritol, pentaerythritol, trimethylolbenzene or trishydroxyethyl isocyanurate.

Examples of suitable polycarboxylic acids are phthalic acid, isophthalic acid, terephthalic acid, tetrahydrophthalic acid, hexahydrophthalic acid, cyclohexanedicarboxylic acid, adipic acid, azelaic acid, sebacic acid, glutaric acid, tetrachlorophthalic acid, maleic acid, fumaric acid, itaconic acid, malonic acid, suberic acid, 2-methylsuccinic acid, 3,3-diethylglutaric acid, 2 2-dimethyl succinic acid, dodecanedioic acid,

Endomethylenetetrahydrophthalic acid, dimer fatty acid, trimer fatty acid, citric acid, or trimellitic acid. The acid source used may also be the corresponding anhydrides.

In addition, aromatic monocarboxylic acids such as e.g. Benzoic acid and / or aliphatic saturated or unsaturated monocarboxylic acids, e.g. Fatty acids or mixtures thereof are used.

Hydroxycarboxylic acids which can be co-used as reactants in the preparation of a hydroxyl-terminated polyester polyol include, for example, hydroxycaproic acid, hydroxybutyric acid, hydroxydecanoic acid, hydroxystearic acid, and the like. Suitable lactones include caprolactone, butyrolactone and homologs.

Polycarbonate polyols which can be used according to the invention are hydroxyl-containing polycarbonates, for example polycarbonate diols. These are by reaction of carbonic acid derivatives, such as diphenyl carbonate, dimethyl carbonate or phosgene, with polyols, preferably diols, available.

Examples of such diols are ethylene glycol, 1,2-pentane-1,3-propanediol, 1,3-pentene-1, 4-butanediol, 1,6-hexanediol, 1,8-octanediol, neopentyl glycol, 1,4-bis-hydroxymethiylcyclohexane, 2- Methyl-1,3-propanediol, 2,2,4-trimethylpentanediol-1,3-dipropylene glycol, polypropylene glycols, dibutylene glycol, polybutylene glycols, bisphenol A are lactone-modified diols of the abovementioned type.

Instead of or in addition to pure polycarbonate diols, it is also possible to use polyether-polycarbonate diols.

Polyetherester polyols which can be used according to the invention are those compounds which contain ether groups, ester groups and OH groups. Organic dicarboxylic acids having up to 12 carbon atoms are suitable for preparing the polyetherester polyols, preferably aliphatic dicarboxylic acids having ≥ 4 to Kohlenstoffatomen 6 carbon atoms, or aromatic dicarboxylic acids used singly or in admixture. Examples which may be mentioned are suberic acid, azelaic acid, decanedicarboxylic acid, maleic acid, malonic acid, phthalic acid, pimelic acid and sebacic acid, and in particular glutaric acid, fumaric acid, succinic acid, adipic acid, phthalic acid, terephthalic acid and isoterephthalic acid. As derivatives of these acids, for example, their anhydrides and their esters and half esters can be used with low molecular weight, monofunctional alcohols having ≥ 1 to ≤ 4 carbon atoms.

As a further component for the preparation of the polyetherester polyols polyether polyols are used which are obtained by alkoxylating starter molecules such as polyhydric alcohols. The starter molecules are at least difunctional, but may also contain portions of higher functional, especially trifunctional starter molecules.

Starter molecules are, for example, diols with primary OH groups and number-average molecular weights M _n of preferably 18 18 g / mol to ≦ 400 g / mol or of ≥ 62 g / mol to ≦ 200 g / mol such as 1,2-ethanediol, 1, 3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,10-decanediol, 2- Methyl-1,3-propanediol, 2,2-dimethyl-1,3-propanediol, 3-methyl-1,5-pentanediol, 2-butyl-2-ethyl-1,3-propanediol, 2-butene-1,4 -diol and 2-butyne-1,4-diol, ether diols such as diethylene glycol, triethylene glycol, tetraethylene glycol, dibutylene glycol, tributylene glycol, tetrabutylene glycol, dihexylenglycol, trihexylene glycol, tetrahexylenglycol and oligomer mixtures of alkylene glycols, such as diethylene glycol.

In addition to the diols, it is also possible to use polyols having number-average functionalities of 2 2 to ≦ 8, or of 3 3 to ≦ 4, for example 1,1,1-trimethylolpropane, triethanolamine, Glycerol, sorbitol, sorbitan vind pentaerythritol and triols or tetraols started polyethylene oxide polyols having average molecular weights of preferably ≥ 18 g / mol to ≤ 400 g / mol or from ≥ 62 g / mol to ≤ 200 g / mol.

Polyacrylate polyols which can be used according to the invention can be obtained by free-radical polymerization of hydroxyl-containing, olefinically unsaturated monomers or by free-radical copolymerization of hydroxyl-containing, olefinically unsaturated monomers with optionally other olefinically unsaturated monomers. Examples thereof are ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, isobornyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, cyclohexyl methacrylate, isobornyl methacrylate, styrene, acrylic acid, acrylonitrile and / or memacrylonitrile. Suitable hydroxyl-containing, olefinically unsaturated monomers are, in particular, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, the hydroxypropyl acrylate isomer mixture obtainable by addition of propylene oxide onto acrylic acid and the hydroxypropyl methacrylate isomer mixture obtainable by addition of propylene oxide onto methacrylic acid. Terminal hydroxyl groups may also be in protected form. Suitable free radical initiators are those from the group of azo compounds, such as azoisobutyronitrile (AIBN), or from the group of peroxides such as di-tert-butyl peroxide, dicumyl peroxide, dibenzoyl peroxide or tert-butyl peroctoate.

In a further embodiment of the present invention, the reaction is further carried out in the presence of a physical blowing agent and / or a chemical blowing agent. This allows PUR / PIR foams to be obtained. Conceivable are chemical blowing agents such as water, formic acid and physical blowing agents such as hydrocarbon blowing agents (in particular n-pentane, i-pentane and cyclopentane and mixtures thereof).

In a further embodiment of the present invention, the reaction is carried out at an NCO index of ≥200. The NCO index is defined as one hundred times the molar ratio of NCO groups in the polyisocyanate to isocyanate-reactive groups of the polyol component. This characteristic may also be in a range of 250 250 to ≦ 500 or else of 300 300 to ≦ 400.

Another aspect of the present invention is a polyurethane / polyisocyanurate foam made by a process of the invention.

Preferably, the polyurethane / polyisocyanurate foam further has a flammability index BKZ of 5 and a flame height of .ltoreq.135 mm (more preferably .ltoreq.130 mm), each determined in the BVD test according to the Swiss basic test for determining the flammability degree of Construction materials of the Association of Cantonal Fire Insurance in the 1988 edition, with the supplements of 1990, 1994, 1995 and 2005.

Finally, the invention also relates to a thermal insulation element comprising a polyurethane / polyisocyanurate foam according to the invention. It is preferably an insulation panel laminated with cover layers, the cover layers being e.g. made of steel, aluminum, kraft paper, etc. Materials can exist. Methods for producing such thermal insulation elements are known and e.g. in Günter Oertel, Polyurethane Handbook, Carl Hanser Verlag, Munich, 1985, p. 239f.

EXAMPLES The present invention will be explained in more detail with reference to the following figures and examples, without, however, being restricted thereto.

Show it:

FIG. 1 shows a measurement of the foam height from Example 2-1 * (Ac) and 2-2 (3-MP) as a function of time in the Foamat apparatus of the Fa. Format, equipped with the "Advanced Test Cylinder" (ATC). ATC and device bottom were kept at 50 ° C.

2 shows a time-resolved ATR mid-infrared spectrum of the foam systems catalyzed by Ac or 3-MP from FIG. Shown is the time evolution of the carbamate-specific peak area (amide m between 1170 and 1250 cm ^-1 ).

FIG. 3 shows a time-resolved ATR mid-infrared spectrum of the foam systems of FIG. 1 catalyzed by Ac or 3-MP. The development over time of the trimer-specific peak area (isocyanurate ring oscillation between 1380 and 1450 cm ^-1 ) is shown.

methods:

In situ infrared spectroscopy: The composition of the reaction mixture as a function of time was monitored using a Bruker MATRIX-MX spectrometer. The infrared (IR) spectrometer was equipped with a high pressure ATR (attenuated total reflectance) IR glass fiber probe (diameter 3.17 mm). The ATR-IR fiber optic probe (90 ° diamond prism with 1 x 2 mm base and 1 mm height as ATR element, 2 ^χ 45 ° reflection of the IR beam, IR beam-coupled fiber optic) was so in the reaction was inserted so that the diamond at the end of the probe completely immersed in the reaction mixture. The IR spectra (20 scans per measurement) were time resolved at a scan rate of 266.7 scans per minute in the range of 400-4000 cm ^-1 at a resolution of 4 cm ^-1 in Recorded time intervals of 4.5 seconds. At the beginning of each experiment, a background spectrum (100 scans) was taken against argon. The software used to record the spectra was OPUS 7.0.

The quantitative evaluation of the measured IR spectra was carried out using the software PEAXACT 3.5.0 Software for Quantitative Spectroscopy from S ^» PACT GmbH using the Integrated Hard Model (IHM) method. The Hard Model for the product mixture was generated from the characteristic IR absorption bands of the individual components isocyanate, isocyanurate and carbamate. For the quantitative determination of the concentrations of the individual components in the reaction mixture was carried out a calibration with known concentrations of the individual components at the respective reaction temperature.

The time-resolved measurements in the reacting foam system (see Figures 2 and 3) were carried out in a Bruker Tensor 27 spectrometer on a 1x5 cm ² ZnSe ATR crystal embedded in a heated metal plate at a constant temperature of 40, 70 or 120 ° C. The reaction sequences in the approximately 1 μm thick contact zone of the foam material with the ATR crystal are followed at the set temperature (spectral resolution 4 cm ^-1 , averaging over 8 scans).

For the description of the fire behavior, the BVD test according to the Swiss basic test for determining the flammability of building materials of the Association of cantonal fire insurance in the 1988 edition, with the supplements of 1990, 1994,1995 and 2005 (available from Association of cantonal fire insurance, Bundesstr. 20, 3011 Bern, Switzerland). In this small burner test, a flammability index (BKZ) and a flame height (in mm) are determined for the foam.

Used connections:

Unless otherwise stated, the catalysts used were prepared from the corresponding catalyst precursor (thiol-containing carboxylic acid: 3-mercaptopropionic acid, 2-mercaptoacetic acid, 4-mercapto-butyric acid, o-thiosahecylic acid, S-methyl-thiosalicylic acid) according to the following procedure:

Preparation of the catalyst as a solid

Under argon atmosphere, a solution of the catalyst precursor (0.01 mol) in anhydrous methanol (15 mL) and at 25 ° C a 25% solution of potassium in methanol (0.745 g, 2.66 mmol, to form the Disalze and 0.372 g, corresponding to 1.33 mmol, to form the monosalts) was added dropwise. The resulting reaction mixture became 30 Stirred at 25 ° C for minutes followed by the addition of anhydrous diethyl ether (10 mL), whereupon a colorless solid precipitated. The supernatant solution was filtered off through a filter cannula and the solid filtration residue washed three times with 10 mL each of a 1: 5 mixture of anhydrous methanol and anhydrous diethyl ether. The solid thus obtained was dried at 60 ° C. for 16 h in vacuo (2.0 × 10 ^-2 mbar).

Preparation of the catalyst solution in diethylene glycol monomethyl ether (DEME)

An 11.2 percent solution of the solid state catalysts in diethylene glycol monomethyl ether (DEME) was prepared

Examples 1-1 to 1-10: Preparation of isocyanurates from p-Tolvlisocvanat in the presence of Diethvlenglvkol Monoethvlether

All reactions listed in Examples 1-1 to 1-10 were carried out according to the following general procedure:

In a stainless steel autoclave having an internal volume of 160 mL, a mixture of para-toluene isocyanate (11 mL, 11.62 g, 0.087 mol) and propylene carbonate (47.40 mL, 57.05 g, 0.559 mol) was charged A small stream of argon (20 L / min) was passed through the reactor in an autoclave and the reaction mixture was heated to the reaction temperature with stirring. After a constant reaction temperature was observed over a period of 5 minutes, the in situ IR-Mossung was started. Subsequently, the catalyst solution was injected in the stated amounts in the reaction mixture. The reaction mixture thus obtained was stirred at the corresponding reaction temperature at a stirring speed of 500 rpm. When the intensity of the in situ IR signal of the isocyanate group had dropped below the detection limit in a period less than 40 minutes, the reaction was stopped after further 20 minutes by cooling the reactor to 25 ° C and stopping the stirrer. Otherwise, the reaction was terminated in the same manner after one hour. The results are shown in Table 1.

Examples marked with * are comparative examples.

1

The degree of deprotonation is to be understood as meaning the percentage of Zerivitmoff-active protons which has been removed from the acid underlying the catalyst molecule. As Zerivitinoff- active protons are those which react with the Grignard reagent methylmagnesium iodide to form one molecule of methane per active proton. The comparison of Example 1-1 with Examples 1-5 to 1-7 shows that the dipotassium salts of the mercapto acids are superior to the potassium acetate (prior art) in terms of activity, since the time to reach a given conversion is always lower.

Examples 1-2 and 1-8 in comparison with Examples 1-5 to 1-7 show that it is advantageous if the mercapto group and not only the carboxyl group is deprotonated. A comparison of Example 1-2 with Example 1-9 and a comparison of Example 1-5 with Example 1-10 show that the addition of DBTL (prior art), the activity is reduced, so that the sole use of the deprotonated mercapto acids is advantageous over the prior art. The formation of trimers is desirable since they are advantageous for flame retardancy and temperature resistance. Example 1-5 shows that the dipotassium salt of 3-mercaptopropionic acid shows the highest selectivity for trimer formation at all isocyanate conversions tested. The comparisons of Example 1-2 with Example 1-9 and Example 1-5 with Example 1-10 show that the addition of DBTL (dibutyltin dilaurate) adversely affects the selectivity for trimer formation. Examples 1-3 to 1-5 show that even with degrees of deprotonation of the catalyst in the range from ≥ 70% to ≦ 100% (Examples 1-3 to 1-5) or from ≥ 80% to ≦ 100% (Examples 1-1). 4 to 1-5) a high selectivity for trimer formation is obtained at all isocyanate conversions studied.

Example Group 2: Preparation of Polyurethane / Polvicovanate Foams The following compounds were used in the production of rigid foams:

Polyesterpolyol P1 obtained from phthalic anhydride, adipic acid, monoethylene glycol and

Diethylene glycol, OH number 240 mg KOH / g

TCPP Tris (1-chloro-2-propyl) -phosphate from Lanxess GmbH, Germany.

TEP triethyl phosphate from Lanxess GmbH, Germany.

Stabilizer B8443 Polyetherpolysiloxancopolymerisat the company. Evonik.

Desmophen® V 657 Polyether polyol based on trimethylolpropane and ethylene oxide with an OH number of 255 mg KOH / g in accordance with DIN 53240 from Bayer MaterialScience AG, Leverkusen, Germany.

Additive 1132 Polyesterpolyol of phthalic anhydride and diethylene glycol, OH number

795 mg KOH / g from Bayer MaterialScience AG, Leverkusen, Germany.

Desmodur® 44V70L polymeric polyisocyanate based on 4,4-diphenylmethane diisocyanate with an NCO content of about 31.5 wt .-% of Fa. Bayer MaterialScience AG, Leverkusen, Germany.

3-MP solution of 3-mercaptopropionic acid dipotassium salt (3-MP) (17.3 wt%) in DEG

For the production of rigid foams, the raw materials indicated in Table 2 were weighed into a paper cup with the exception of the polyisocyanate component, heated to 23 ° C., mixed by means of a Pendraulik laboratory mixer (eg Type LM-34 from Pendraulik) and volatilized propellant (n -Pentan) if necessary supplemented. Subsequently, with stirring, the polyisocyanate component (also heated to 23 ° C) added to the polyol mixture and the resulting reaction mixture for 8 s at 4200 U / min mixed.

Examples marked with * are comparative examples.

Table 2

Characterization of the reactivity of the catalyst 3-MP

FIG. 1 shows an estimate of the rise in height of the PUR / PIR foam versus time, measured for the foam formulation from Example 2-2, in which potassium acetate as the catalyst was replaced by 3-MP (K / S = 2). The catalyst concentration was in both cases 0.5 mol%, based on the isocyanate groups used.

It was observed that the foam obtained using 3-MP reached a higher rise in less time than the foam obtained using the comparative catalyst potassium acetate (Ac).

Thus, the catalyst according to the invention has a higher activity. When potassium acetate (Example 2-1 *) was used, a slower increase in the height of rise ("PIR kink"), which is usually associated with the onset of the trimerization reaction (isocyanurate formation), was also observed after a time of> 100 s ,

Without adhering to a scientific theory, the failure of the PIR kink when using 3-MP as a catalyst is attributed to the fact that the trimerization reaction in this case begins earlier and runs parallel to the urethane formation. Thus, the catalyst derived from 3-mercaptopropionic acid has increased relative reactivity to the comparative catalyst potassium acetate for the formation of isocyanurate units.

2 shows the increased activity of 3-MP with respect to trimer formation also by IR spectroscopic studies. FIG. 2 shows a corresponding analysis of the reaction processes in the edge zone of the reacting foams in contact with a substrate at constant temperature (40, 70 or 120 ° C.). The experiments reflect the reaction behavior which the foam systems e.g. would show in contact with appropriately tempered cover layers in the production of metal panels. The carbamate formation is activated almost identically by both catalysts (FIG. 2).

3 shows temperature-dependent differences in the formation of trimer: at 40 and 70 ° C 3-MP catalyzes the trimer formation much earlier and stronger than Ac. At 120 ° C, there is still a difference in time, while the final level reached is comparable. Characterization of the fire behavior of foams prepared with the catalyst 3-MP

All foams were adjusted to equal catalyst concentrations of 0.5 mol% based on isocyanate groups used and similar densities. It can be seen that the foams activated with potassium acetate (Examples 2-3 * and 2-5 *) have distinctly longer setting times, thus demonstrating the lower activity towards 3-MP (Examples 2-4 and 2-6). At the same time, although all foams reach the degree of flammability 5, the foams produced with the catalyst 3-MP according to the invention have markedly lower flame heights.

Claims

claims

A process for the preparation of isocyanurates and isocyanurate-containing polyurethanes, comprising the step of reacting an isocyanate in the presence of a catalyst, characterized in that the catalyst is the product of the reaction of a thiol-containing carboxylic acid with an alkali metal, alkaline earth metal, Scandiumgruppen- or Lanthanoid base, wherein the reaction is carried out in the absence of tin or lead-containing compounds, wherein the degree of deprotonation of the catalyst> 50% to ≤ 100% and present in carboxyl groups H atoms and the carboxylate groups and present in thiol groups H atoms and the thiolate groups are taken into account in the calculation of the degree of deprotonation.

2. A process according to claim 1, wherein the thiol group-containing carboxylic acid comprises a thiol group and a carboxyl group. 3. The method according to claim 2, wherein the thiol-containing carboxylic acid 2-mercaptoacetic acid,

3-mercaptopropionic acid, 4-mercaptobutyric acid and / or thiosalicylic acid.

4. The method according to one or more of claims 1 to 3, wherein the Deprotonierungsgrad of the catalyst ≥ 70% to ≤ 100% and present in carboxyl H atoms and the carboxylate groups and present in thiol H atoms and the thiolate groups be taken into account in the calculation of Deprotonierungsgrades.

5. The method according to one or more of claims 1 to 4, wherein the base for deprotonation of the catalyst precursor, an alkali metal, alkaline earth metal, Scandiumgruppen- or lanthanide hydride, an alkali metal, alkaline earth metal, scandium or lanthanide alkoxide is an alkali metal, alkaline earth metal, scandium group or lanthanoid alkyl.

6. The method according to one or more of claims 1 to 5, wherein the catalyst is dissolved or suspended in a solvent before the start of the reaction.

7. The method according to one or more of claims 1 to 6, wherein the temperature at the beginning of the reaction of ≥ 20 ° C to ≤ 90 ° C.

8. The method according to one or more of claims 1 to 7, wherein the isocyanate is a polyisocyanate

The process of claim 8, wherein the reaction is further conducted in the presence of a polyol.

A process according to claim 9, wherein the reaction is further carried out in the presence of a physical blowing agent and / or a chemical blowing agent.

11. The method according to claim 10, wherein the reaction is carried out at an NCO index of ≥200.

12. Polyurethane Z polyisocyanurate foam, prepared by a process according to claim 10 or 11.

13. polyurethane / polyisocyanurate foam according to claim 12, wherein the polyurethane / polyisocyanurate foam further has a flammability index BKZ of 5 and a flame height of ≤ 135 mm, each determined in the BVD test according to the Swiss basic test for determining the degree of flammability of Construction materials of the Association of Cantonal Fire Insurance in the 1988 edition, with the supplements of 1990, 1994, 1995 and 2005.

14. A thermal insulation element comprising a polyurethane / polyisocyanurate foam according to claim 12 or 13.