Production of flame-retardant polyurethane foam

Abstract

The invention relates to a composition for producing PU foam, preferably rigid PU foam, said composition comprising - at least one halogen-free polyester polyol and at least one halogenated polyol, - at least one physical blowing agent, - at least one flame retardant selected from (a) the group of phosphoric acid esters, preferably TCPP, TEP and / or TCEP, in particular TCPP and / or TEP, and / or (b) the group of phosphonates, preferably DMMP and / or DMPP, - red phosphorus, and at least one polyisocyanate component, the composition having an index of at least 200.

Description

[0001] Production of flame-retardant polyurethane foam

[0002] The present invention lies in the field of polyurethanes, preferably polyurethane foams, especially rigid polyurethane foams. In particular, it relates to the production of flame-retardant polyurethane foams, preferably flame-retardant rigid polyurethane foams, using a combination of synergistically acting components, as well as to compositions for producing such foams and, furthermore, to the use of these foams.

[0003] For the purposes of the present invention, polyurethane (PU) is understood in particular to mean a product obtainable by reacting a polyisocyanate component with a polyol component or compounds containing isocyanate-reactive groups. In addition to the polyurethane, other functional groups such as uretdiones, carbodiimides, isocyanurates, allophanates, biurets, ureas and / or uretimines can also be formed. Therefore, PU for the purposes of the present invention is understood to mean polyurethane as well as polyisocyanurate, polyureas and polyisocyanate reaction products containing uretdione, carbodiimide, allophanate, biuret and uretimine groups. For the purposes of the present invention, polyurethane foam (PU foam) is understood to mean foam which is obtained as a reaction product of a polyisocyanate component and a polyol component or compounds containing isocyanate-reactive groups.In addition to the name-giving polyurethane, other functional groups such as allophanates, biurets, ureas, carbodiimides, uretdiones, isocyanurates or uretimines can also be formed.

[0004] PU rigid foam is a well-established technical term. The well-known and fundamental difference between flexible foam and rigid foam is that flexible foam exhibits elastic behavior and, therefore, deformation is reversible. Rigid foam, on the other hand, is permanently deformed. The terms foam and foamed plastic are used synonymously for the purposes of this invention. This also applies to related terms such as PU foam and PU foam, etc.

[0005] In the context of the production of PU foams, especially rigid PU foams, it is particularly important to produce PU foams with good flame-retardant properties. For this reason, flame retardants are used. Flame retardants are well-known substances used to limit, slow, or prevent the spread of fires. The known state of the art, e.g., in the "Plastics Flammability Handbook," Carl Hanser Verlag, 3rd edition 2004, describes corresponding flame retardants that exhibit flame-retardant properties and are suitable for use in PU foam. In recent years, the global requirements for construction materials, particularly for insulation materials, with regard to flame retardancy have increased significantly due to a large number of fire incidents.This means that conventional rigid polyurethane foams can no longer be used in countries with particularly stringent requirements, such as Japan or South Korea, because they do not meet the new applicable standards. For example, in South Korea, the maximum total heat release in the cone calorimeter according to KS F ISO 5660-1:2015-03 is 8 MJ / m. 2 and a heat release rate of no more than 200 kW / m 2 which means that the requirements for rigid polyurethane foam there are among the highest in the world.

[0006] To improve the flame-retardant properties of polyurethane foams, especially rigid polyurethane foams, the amount of flame retardants used is generally increased. However, the achievable effects and the maximum possible amount used are limited by the fact that the flame retardants negatively impact the overall properties of the foam, such as its mechanical strength and / or the processing and production of the polyurethane foam. For example, the use of triethyl phosphate (TEP), tris(2-chloroethyl)phosphate (TCEP), or tris(1-chloro-2-propyl)phosphate (TCPP) usually has a strong plasticizing effect, which reduces mechanical strength and thus limits the amount used.Other flame retardants, especially those used as solids, pose significant problems with dispersion in liquid starting materials and lead to an increase in viscosity, which significantly complicates or even makes processing impossible. Since many flame retardants also have ecological and toxicological disadvantages, efforts are being made to minimize their use while simultaneously meeting all requirements.

[0007] Against this background, the specific object of the present invention was to enable the provision of PU foams, in particular PU rigid foams, which meet increased requirements for flame retardancy, preferably according to KS F ISO 5660-1:2015-03, i.e. preferably a total heat release of at most 8 MJ / m 2 and a heat release rate of no more than 200 kW / m 2 at a heating rate of 50 kW / m 2and a test duration of 600 s, but do not or only slightly influence the processing and foam properties.

[0008] In this context, it was surprisingly found within the scope of the present invention that the use of a specific combination of compounds, as described in claim 1, in compositions for producing PU foam, preferably PU rigid foam, in particular PU rigid foam with an index greater than 200, makes it possible to achieve the above-mentioned object. The processing and foam properties are not affected or are only slightly affected. The above-mentioned object is achieved by the subject matter of the invention. The subject matter of the invention is a composition for producing PU foam, preferably PU rigid foam, comprising

[0009] • at least one halogen-free polyester polyol and at least one halogenated polyol,

[0010] • at least one physical blowing agent,

[0011] • at least one flame retardant selected from

[0012] (a) the group of phosphoric acid esters, preferably tris(1-chloro-2-propyl)phosphate (TCPP), triethyl phosphate (TEP) and / or tris(2-chloroethyl)phosphate (TCEP), in particular TCPP and / or TEP, and / or

[0013] (b) the group of phosphonates, preferably dimethylmethanephosphonate (DMMP) and / or dimethylpropanephosphonate (DMPP),

[0014] • red phosphorus, and at least one polyisocyanate component, wherein the composition has an index of at least 200. An upper limit for the index can preferably be, for example, 1000, preferably 500.

[0015] The subject matter of the invention is associated with numerous advantages. It enables the provision of PU foams, preferably rigid PU foams, that meet particularly stringent flame retardancy requirements, in particular as defined in KS F ISO 5660-1:2015-03. This is advantageously achieved without compromising the other properties of the foam, particularly its mechanical properties. With regard to the provision of PU foams, preferably rigid PU foams, particularly fine-cell, uniform, and low-defect foam structures are also possible. This makes it possible to provide corresponding PU foams with particularly good performance properties. Overall, the invention enables simple processing during foam production.

[0016] If the red phosphorus (CAS No. 7723-14-0) used according to the invention is microencapsulated, then this constitutes a particularly preferred embodiment of the invention. The microencapsulation of red phosphorus is well known in the art. One possible variant is described, for example, in EP 1 262 453 A2.

[0017] If the composition according to the invention additionally contains at least one flue gas reducer, preferably selected from the group consisting of antimony trioxide, zinc stannate, zinc hydroxystannate, zinc borate, calcium borate, zinc pyrophosphate, aluminum orthophosphate and aluminum phosphinate(s), with antimony trioxide and / or zinc borate being most preferred, then a particularly preferred embodiment of the invention is present.

[0018] If a component or at least one component, such as a chemical compound, is selected within the meaning of this invention from a group "consisting of" several components, such as several chemical compounds, this means within the meaning of this invention that each of the named components of this group can be selected, or mixtures of this group can be selected. Using the example of the previously mentioned flue gas reducers, this means that, for example, zinc stannate or, for example, antimony trioxide, etc., can be selected, or, for example, antimony trioxide and zinc hydroxystannate or, for example, other mixtures can be selected.

[0019] The solid flame retardants used, such as red phosphorus or flue gas reducers, can be introduced into the reaction mixture via one of the two reaction components (i.e., via the polyol component or the polyisocyanate component). Introduction via the polyol component is preferred.

[0020] If in a composition according to the invention the at least one halogenated polyol is selected from the group consisting of

[0021] (i) brominated and / or chlorinated aliphatic or aromatic polyetherdiol and / or polyethertriol, preferably brominated, aliphatic or aromatic polyetherdiol and / or polyethertriol and

[0022] (ii) Polyester polyol based on tetrabromophthalate, preferably compound 1 ,

[0023] Compound 1 (CAS 77098-07-8), with compound 1 being most preferred, this corresponds to a particularly preferred embodiment of the invention.

[0024] If the composition according to the invention contains the compound 1 and TCPP and / or TEP and also antimony trioxide and / or zinc borate, then a further particularly preferred embodiment of the invention is present.

[0025] Furthermore, it is preferred that the composition according to the invention contains at least one catalyst, preferably at least one trimerization catalyst, in particular selected from the group consisting of ammonium and metal salts of 2-ethylhexanoic acid, formic acid, acetic acid, propionic acid, neodecanoic acid and pivalic acid.

[0026] This also corresponds to another particularly preferred embodiment of the invention.

[0027] It is also preferred that the at least one physical blowing agent is selected from the group consisting of dimethoxymethane, methyl formate, HFC-245fa, 1233zd, 1336mzz, cyclopentane, isopentane, and n-pentane, particularly preferably selected from the group consisting of HFC-245fa, 1233zd, cyclopentane, isopentane, and n-pentane. This also corresponds to another particularly preferred embodiment of the invention.

[0028] If the composition according to the invention is characterized in that, based on 100 parts by weight of the total halogen-free polyol component,

[0029] • halogenated polyol in a total amount of 1 to 80 parts by weight, preferably 1.5 to 50 parts by weight, particularly preferably 2 to 40 parts by weight,

[0030] • Flame retardants selected from (a) the group of phosphoric acid esters, preferably TCPP, TEP and / or TCEP and / or selected from (b) the group of phosphonates, preferably DMMP and / or DMPP, in a total amount of 2 to 60 parts by weight, preferably 5 to 50 parts by weight, particularly preferably 5 to 40 parts by weight,

[0031] • red phosphorus in a total amount of 1 to 45 parts by weight, preferably 2 to 35 parts by weight, particularly preferably 5 to 30 parts by weight,

[0032] • optionally flue gas reducers, preferably selected from the group consisting of antimony trioxide, zinc stannate, zinc hydroxystannate, zinc borate, calcium borate, zinc pyrophosphate, aluminum orthophosphate and aluminum phosphinate(s) are contained in a total amount of 0 to 40 parts by weight, preferably 1 to 35 parts by weight, particularly preferably 1.5 to 25 parts by weight, this also corresponds to a particularly preferred embodiment of the invention.

[0033] A further particularly preferred embodiment of the invention is when the composition according to the invention is characterized in that, based on 100 parts by weight of the total halogen-free polyol component,

[0034] • Compound 1 in a total amount of 1 to 80 parts by weight, preferably 1.5 to 50 parts by weight, particularly preferably 2 to 40 parts by weight,

[0035] • TCPP and / or TEP in a total amount of 2 to 60 parts by weight, preferably 5 to 50 parts by weight, particularly preferably 5 to 40 parts by weight,

[0036] • Red phosphorus in a total amount of 1 to 45 parts by weight, preferably 2 to 35 parts by weight, particularly preferably 5 to 30 parts by weight,

[0037] • Antimony trioxide and / or zinc borate are present in a total amount of 1 to 40 parts by weight, preferably 1.5 to 35 parts by weight, particularly preferably 1.5 to 25 parts by weight. Furthermore, it is particularly preferred if the composition according to the invention additionally contains at least one foam stabilizer, preferably based on a polyether siloxane, in particular in amounts of 0.1 to 4 parts, based on 100 parts of the total polyol component. This corresponds to a particularly preferred embodiment of the invention. Foam stabilizers used in connection with the production of PU foams, preferably those based on a polyether siloxane, are known per se. Suitable foam stabilizers are also described below.

[0038] If the composition according to the invention contains water and / or formic acid, this is a further particularly preferred embodiment of the invention.

[0039] Of course, the composition according to the invention may, if desired, contain further optional additives as are known from the prior art in connection with the production of polyurethanes, in particular PU foams, and as are commonly used.

[0040] The invention further provides a process for producing PU foams, preferably rigid PU foams, using foamable reaction mixtures containing a composition according to the invention, in particular as defined in any of claims 1 to 10, or as described above, particularly in the preferred embodiments. The foamable reaction mixture can preferably also consist of said composition according to the invention.

[0041] A particularly preferred PU foam formulation, in particular PU rigid foam formulation, within the meaning of this invention has the composition stated in Table 1:

[0042] Table 1 : Composition of a preferred PU rigid foam formulation

[0043] Yet another object of the present invention is a PU foam, preferably PU rigid foam, produced according to the above-mentioned process according to the invention, in particular using a composition according to the invention.

[0044] If the PU foam according to the invention, in particular PU rigid foam, has a density of 5 to 900 kg / m 3 , preferably 5 to 350 kg / m 3 , especially 10 to 200 kg / m 3 This is a preferred embodiment of the invention.

[0045] A further subject matter of the present invention relates to the use of PU foam according to the invention, in particular PU rigid foam, as mentioned above, as an insulating material and / or as a construction material, in particular in construction applications, in particular as spray foam or in the cooling sector or pipe sheathing for pipes.

[0046] The invention has thus already been described in detail, and the production of PU, in particular PU foams, using at least one polyol component and at least one polyisocyanate component is familiar to those skilled in the art. According to a particularly preferred embodiment of the invention, the composition according to the invention contains in particular the following constituents: a) polyol component comprising at least one halogen-free polyester polyol and at least one halogenated polyol, b) polyisocyanate component (at least one polyisocyanate and / or polyisocyanate prepolymer), c) catalyst which catalyzes the reaction of isocyanate groups with OH, NH, or other isocyanate-reactive groups and / or the reaction of isocyanate groups with one another, d) optionally foam stabilizer, e) blowing agent, f) flame retardant, g) optionally further additives.

[0047] As polyol component (a), one or more organic compounds having OH groups, SH groups, NH groups, and / or NH2 groups, with a functionality of 1.8 to 8, can be used. The polyol component comprises at least one organic compound having at least two isocyanate-reactive groups selected from OH groups, SH groups, NH groups, and / or NH2 groups, in particular OH groups.

[0048] A functionality that is not an integer, e.g., 1.8, can result from mixing at least one compound with a higher functionality, e.g., greater than or equal to 2, with at least one compound with a functionality of, e.g., 1. This can occur in particular when a polyisocyanate component (b) with a functionality greater than 2 or additional crosslinkers are used as optional additives (g).

[0049] Corresponding compounds that can typically be used in the production of PU are known to the person skilled in the art and are described, for example, in "Kunststoffhandbuch, Volume 7, Polyurethane," Carl Hanser Verlag, 3rd edition 1993, Chapter 3.1. Compounds with OH numbers in the range of 10 to 1200 mg KOH / g are typically used.

[0050] Particularly preferred compounds are all polyether polyols and polyester polyols commonly used for the production of polyurethane systems, in particular polyurethane foams.

[0051] Polyether polyols can be prepared by known processes, e.g. by polymerization of alkylene oxides, preferably ethylene oxide, 1,3-propylene oxide, 1,2- or 2,3-butylene oxide, and / or tetrahydrofuran.

[0052] Preferred polyester polyols are based on esters of polybasic aliphatic or aromatic carboxylic acids, preferably having 2 to 12 carbon atoms. Examples of aliphatic carboxylic acids are succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, decanedicarboxylic acid, maleic acid, and fumaric acid. Examples of aromatic carboxylic acids are phthalic acid, isophthalic acid, terephthalic acid, and the isomeric naphthalenedicarboxylic acids. Preferred polyester polyols can be obtained in particular by condensing these polybasic carboxylic acids with polyhydric alcohols, preferably diols or triols having 2 to 12, particularly preferably 2 to 6, carbon atoms, preferably trimethylolpropane, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, and / or glycerol.

[0053] In addition, polyether polycarbonate polyols, natural oil-based polyols (NOPs; described in WO 2005 / 033167, US 2006 / 0293400, WO 2006 / 094227, WO 2004 / 096882, US 2002 / 0103091, WO 2006 / 116456, EP 1678232), filler polyols, prepolymer-based polyols and / or recycling polyols can be used.

[0054] Recycling polyols are polyols obtained from the chemical recycling of polyurethanes, for example, by solvolysis, such as glycolysis, hydrolysis, acidolysis, or aminolysis. The use of recycling polyols represents a particularly preferred embodiment of the invention.

[0055] In the context of this invention, the polyol component necessarily comprises at least one halogen-free polyester polyol and at least one halogenated polyol, as already described above.

[0056] As polyisocyanate component (b), one or more polyisocyanates with two or more isocyanate groups can generally be used. Suitable polyisocyanates for the purposes of this invention are all organic isocyanates with two or more isocyanate groups, in particular the known aliphatic, cycloaliphatic, arylaliphatic, and preferably aromatic polyfunctional isocyanates.

[0057] Examples which may be mentioned here are alkylene diisocyanates having 4 to 12 carbon atoms in the alkylene radical, such as 1,12-dodecane diisocyanate, 2-ethyl-tetramethylene-1,4-diisocyanate, 2-methyl-pentamethylene-1,5-diisocyanate, tetramethylene-1,4-diisocyanate, pentamethylene diisocyanate (PDI) and preferably hexamethylene-1,6-diisocyanate (HMDI), cycloaliphatic diisocyanates such as cyclohexane-1,3- and -1,4-diisocyanate and the corresponding isomer mixtures, 4,4'-methylenedicyclohexyl diisocyanate (H12MDI), isophorone diisocyanate (IPDI), 2,4- and 2,6-methylcyclohexyl diisocyanate and the corresponding isomer mixtures and preferably aromatic di- and polyisocyanates such as 2,4- and 2,6-Toluene diisocyanate (TDI) and the corresponding isomer mixtures, naphthylene diisocyanate, diethyltoluene diisocyanate, 4,4'- or 2,2'- or 2,4'-diphenylmethane diisocyanate (MDI) and polymethylene polyphenyl polyisocyanate (PMDI, “polymeric MDI”).The organic polyisocyanates can be used individually or in the form of mixtures. Corresponding "oligomers" of diisocyanates can also be used, such as the IPDI trimer based on isocyanurate, biuret, or urethdione. Furthermore, the use of prepolymers based on the above-mentioned isocyanates is possible. Particularly suitable is the mixture known as "polymeric MDI" (also called "crude MDI"), consisting of MDI and more highly condensed analogues with an average functionality of 2 to 4, as well as the various isomers of TDI in pure form or as a mixture of isomers. It is also possible to use isocyanates modified by the incorporation of urethane, uretdione, isocyanurate, allophanate, and other groups, so-called modified isocyanates. Examples of particularly suitable isocyanates include:in EP 1712578, EP 1161474, WO 00 / 58383, US 2007 / 0072951 , EP 1678232 and WO 2005 / 085310, which are incorporated herein by reference.

[0058] A preferred ratio of total polyisocyanate component and total polyol component, expressed as the formulation index, ie the stoichiometric ratio of isocyanate groups to isocyanate-reactive groups (e.g., OH groups, NH groups) multiplied by 100, is in the range from 200 to 1000, preferably 200 to 500. An index of 100 represents a molar ratio of the reactive groups of 1 to 1. According to the invention, the claimed composition has an index of at least 200.

[0059] Suitable catalysts (c) that can be used for the production of polyurethanes, in particular PU foams, are known to the skilled person from the prior art. For the purposes of the present invention, all compounds capable of catalyzing the reaction of isocyanate groups with OH, NH, or other isocyanate-reactive groups and / or the reaction of isocyanate groups with one another can be used. Compounds that catalyze the reaction of the isocyanate groups with one another, in particular the trimerization reaction, are also known to the skilled person as trimerization catalysts and are described, for example, in EP 1 745 847 A1.

[0060] The usual catalysts known from the prior art can be used, including, for example, amines (cyclic, acyclic; monoamines, diamines, oligomers with one or more amino groups), ammonium compounds, organometallic compounds and / or metal salts, preferably those of tin, iron, bismuth, potassium and / or zinc. In particular, mixtures of several such compounds can be used as catalysts.

[0061] Foam stabilizers (d) and their use in the production of PU foams are known to the person skilled in the art. The use of foam stabilizers is optional; preferably, one or more foam stabilizers are used. Surface-active compounds (surfactants) can be used as foam stabilizers. Foam stabilizers are preferably used in the production of PU foams. They can serve to optimize the desired cell structure and the foaming process. Within the scope of this invention, one or more of the known Si-containing compounds can be used, in particular, which support foam production (stabilization, cell regulation, cell opening, etc.). These compounds are sufficiently known from the prior art. Particular preference is given to using at least one foam stabilizer based on a polyether siloxane. Corresponding siloxane structures that can be used within the meaning of this invention are described, for example, indescribed in the following patent specifications, although their use is only described in classic PU foams (e.g. as molded foam, mattress, insulation material, construction foam, etc.): CN 103665385, CN 103657518, CN 103055759, CN 103044687, US 2008 / 0125503, US 2015 / 0057384, EP 1520870 A1, EP 1211279, EP 0867464, EP 0867465, EP 0275563. In addition to surface-active Si-containing compounds, Si-free surfactants can also be used. For example, EP2295485 A1 describes the use of lecithin, and US Pat. No. 3,746,663 describes the use of vinylpyrrolidone-based structures as foam stabilizers for the production of rigid PU foam. Other Si-free foam stabilizers are described, for example, in EP 2511328 B1, DE 1020011007479 A1, DE 3724716 C1, EP 0734404, EP 1985642, DE 2244350, and US Pat. No. 5,236,961.

[0062] Blowing agents and their use in the production of PU foams are known to those skilled in the art. The use of one or a combination of several blowing agents depends fundamentally on the type of foaming process used, the type of system, and the application of the resulting PU foam. According to the invention, at least one physical blowing agent is used. Chemical blowing agents can also be used in addition. Depending on the amount of blowing agent used, a foam with a high or low density is produced. For example, foams with densities of 5 kg / m 3 up to 900 kg / m 3 , preferably 5 to 350, particularly preferably 8 to 200 kg / m 3 , especially 8 to 150 kg / m 3 be manufactured.

[0063] One or more of the corresponding compounds with suitable boiling points, as well as mixtures thereof, can be used as physical blowing agents. Preferred physical blowing agents have already been mentioned.

[0064] As chemical blowing agents, one or more compounds can be used that react with NCO groups to release gases, such as water or formic acid, or that release gases due to the temperature increase during the reaction, such as sodium bicarbonate. A particularly preferred embodiment of the invention is for the composition according to the invention to contain, in addition to the physical blowing agent, water and / or formic acid as a chemical blowing agent.

[0065] As flame retardants (f), preference is given, as already described, to using at least one compound from the group of phosphoric acid esters, preferably TCPP, TEP and / or TCEP and / or from the group of phosphonates, preferably DMMP and / or DMPP, and additionally red phosphorus, preferably microencapsulated red phosphorus.

[0066] As optional additives (g), one or more of the substances known in the art which are used in the production of polyurethanes, in particular PU foams, such as crosslinkers, chain extenders, stabilizers against oxidative degradation (so-called antioxidants), biocides, cell-refining additives, nucleating agents, cell openers, solid fillers, antistatic additives, thickeners, dyes, pigments, color pastes, fragrances and / or emulsifiers, etc., can be used.

[0067] Furthermore, the composition according to the invention optionally contains so-called smoke reducers. Preferred smoke reducers have already been mentioned. These are advantageously characterized in that, when used alone, they have no direct effect on flame retardancy, but they can significantly enhance the effectiveness of other flame retardants and / or reduce smoke development. Smoke reducers are known to those skilled in the art and include, for example, antimony trioxide, zinc hydroxystannate, zinc stannate, zinc borate, calcium borate, or antimony pentoxide. These are also described, for example, in Weil, Edward D. Levchik, Sergei V. (2016) Flame Retardants for Plastics and Textiles - Practical Applications (2nd edition); Carl Hanser Verlag, Chapter 4 or WO 2009109318 A1 or Su et al., Polymer degradation and stability, 2012;97(11):2128-2135 or Horrocks et al., Journal of Fire Sciences, 2010;28(3):217-248.

[0068] Unless otherwise apparent from this description, any preferred or particularly preferred embodiment of the invention may be combined with one or more of the other preferred or particularly preferred embodiments of the invention.

[0069] The inventive process for producing PU foams can be carried out by all known methods, e.g., by hand mixing or, preferably, using foaming machines. If the process is carried out using foaming machines, high-pressure or low-pressure machines can be used. The inventive process can be carried out both batchwise and continuously, and 1K, 1.5K, or 2K systems, as described in EP3717538 A1, US7776934 B2, EP1400547 B1, or EP2780384 B2, can be used.

[0070] The objects of the invention are described below by way of example, without the invention, the scope of which emerges from the entire description and the claims, being intended to be limited to these exemplary embodiments.

[0071] If ranges, general formulas or classes of compounds are given, these are intended to include not only the corresponding ranges or groups of compounds that are explicitly mentioned, but also all sub-ranges and sub-groups of compounds that can be obtained by removing individual values ​​(ranges) or compounds. If documents are cited within the scope of this description, their content, particularly with regard to the facts in connection with which the document was cited, is intended to be fully part of the disclosure of the present invention. Percentages are, unless otherwise stated, given in percent by weight. Mean values ​​are, unless otherwise stated, numerical averages. If parameters are given that were determined by measurement, the measurements were carried out at a temperature of 23 °C and atmospheric pressure, unless otherwise stated.

[0072] Examples:

[0073] The formulations shown in Tables 2 and 3 were used for the application-related comparison. The comparative foamings were carried out using a hand-mixing method. The polyol component, catalysts, water, foam stabilizer, flame retardant, physical blowing agent, and optionally other additives were weighed into a beaker and mixed with a 6 cm diameter plate stirrer at 1000 rpm for 30 seconds (batch size 500 g). The amount of blowing agent evaporated during the mixing process was determined by reweighing and then replenished. The pMDI ("polymeric MDI") was then added, and the mixture was stirred with the described stirrer for 5 seconds at 3000 rpm. The mixture was immediately transferred to a 25 cm x 50 cm x 7 cm aluminum mold lined with polyethylene film and thermostatted to 60 °C. After 10 minutes, the foams were demolded. The foams were analyzed one day after foaming.The surface of the top and bottom sides as well as the internal disturbances were subjectively assessed using a scale of 1 to 10, where 10 represents an (idealized) undisturbed foam and 1 represents an extremely disturbed foam.

[0074] The fire behavior was determined using a cone calorimeter according to KS F ISO 5660-1:2015-03. Three test specimens, each measuring 10 x 10 x 5 cm, were cut from each foam and the total heat release (THR) in MJ / m 2 ) within 600 s, the maximum heat release rate (“Peak Heat Release Rate” - PHRR in kW / m 2 ) within 600 s, the mass loss during the burning period (in %), and the burning time (in s), more precisely, the time between ignition and extinguishing of the flame, were measured. The heating rate was 50 kW / m 2 The arithmetic mean of the values ​​of the three test specimens was determined. The test is considered passed if the THR is < 8 MJ / m 2and PHRR < 200 kW / m 2 The results are shown in Tables 4 and 5.

[0075] Table 2: PU rigid foam formulations (composition in parts by weight) Table 3: PU rigid foam formulations (composition in parts by weight)

[0076] * Diethylene glycol phthalic anhydride based polyester polyol with hydroxyl number 315 mg KOH / g ** Polyether siloxane based foam stabilizer from Evonik Operations GmbH

[0077] *** Amine catalyst from Evonik Operations GmbH

[0078] **** Trimerization catalyst from Evonik Operations GmbH

[0079] ***** B r O mier t es aliphatic polyether triol with hydroxyl number 330 mg KOH / g and 31.5 wt.% bromine Table 4: Physical properties and fire behavior

[0080] Table 5: Physical properties and fire behavior

[0081] The results show that the foams based on the composition according to the invention, in contrast to the selected non-inventive references, meet the flame retardancy requirements and that the relevant foam properties are not or only slightly affected by the use of the composition according to the invention. The significantly lower mass loss as well as the shorter burning time of the compositions according to the invention is also an indication of a significantly lower

[0082] Smoke gas development occurs because less material enters the gas phase. Samples 20 and 21 produced very coarse, unusable foams, making fire tests impossible.

Claims

Patent claims:

1. Composition for the production of PU foam, preferably rigid PU foam, comprising at least one halogen-free polyester polyol and at least one halogenated polyol, at least one physical blowing agent, at least one flame retardant, selected from (a) of the group of phosphoric acid esters, preferably tris(1-chloro-2-propyl) phosphate, triethyl phosphate and / or tris(2-chloroethyl) phosphate, in particular tris(1-chloro-2-propyl) phosphate and / or triethyl phosphate, and / or (b) of the group of phosphonates, preferably dimethylmethanephosphonate and / or dimethylpropanephosphonate, red phosphorus, and at least one polyisocyanate component, wherein the composition has an index of at least 200.

2. Composition according to claim 1, characterized in that it additionally contains at least one flue gas reducer, preferably selected from the group consisting of antimony trioxide, zinc stannate, zinc hydroxystannate, zinc borate, calcium borate, zinc pyrophosphate, aluminum orthophosphate and aluminum phosphinate(s), wherein antimony trioxide and / or zinc borate are most preferred.

3. Composition according to claim 1 or 2, characterized in that the at least one halogenated polyol is selected from the group consisting of (i) brominated and / or chlorinated aliphatic or aromatic polyether diol and / or polyether triol, preferably brominated, aliphatic or aromatic polyether diol and / or polyether triol and (ii) Polyester polyol based on tetrabromophthalate, preferably compound 1 , Compound 1 (CAS 77098-07-8), where Compound 1 is most preferred.

4. Composition according to one of the preceding claims, characterized in that it contains compound 1 and tris(1-chloro-2-propyl)phosphate and / or triethyl phosphate, as well as antimony trioxide and / or zinc borate.

5. Composition according to one of claims 1 to 4, characterized in that it contains at least one catalyst, preferably at least one trimerization catalyst, in particular selected from the group consisting of ammonium and metal salts of 2-ethylhexanoic acid, formic acid, acetic acid, propionic acid, neodecanoic acid and pivalic acid.

6. Composition according to one of claims 1 to 5, characterized in that the at least one physical blowing agent is selected from the group consisting of dimethoxymethane, methyl formate, HFC-245fa, 1233zd, 1336mzz, cyclopentane, isopentane and n-pentane, and is particularly preferably selected from the group consisting of HFC-245fa, 1233zd, cyclopentane, isopentane and n-pentane.

7. Composition according to any one of claims 1 to 6, characterized in that, based on 100 parts by weight of the total halogen-free polyol component, halogenated polyol in a total amount of 1 to 80 parts by weight, preferably 1.5 to 50 parts by weight, particularly preferably 2 to 40 parts by weight, flame retardant selected from (a) the group of phosphoric acid esters, preferably tris(1-chloro-2-propyl)phosphate, triethyl phosphate and / or tris(2-chloroethyl)phosphate and / or selected from (b) the group of phosphonates, preferably dimethylmethanephosphonate and / or dimethylpropanephosphonate, in a total amount of 2 to 60 parts by weight, preferably 5 to 50 parts by weight, particularly preferably 5 to 40 parts by weight, red phosphorus in a total amount of 1 to 45 parts by weight, preferably 2 to 35 parts by weight, particularly preferably 5 to 30 parts by weight, optionally a flue gas reducer, preferably selected from the group consisting of antimony trioxide, zinc stannate,Zinc hydroxystannate, zinc borate, calcium borate, zinc pyrophosphate, aluminum orthophosphate and aluminum phosphinate(s) are contained in a total amount of 0 to 40 parts by weight, preferably 1 to 35 parts by weight, particularly preferably 1.5 to 25 parts by weight.

8. Composition according to one of the preceding claims, characterized in that, based on 100 parts by weight of the total halogen-free polyol component, Compound 1 in a total amount of 1 to 80 parts by weight, preferably 1.5 to 50 parts by weight, particularly preferably 2 to 40 parts by weight, Tris(1-chloro-2-propyl)phosphate and / or Triethyl phosphate in a total amount of 2 to 60 parts by weight, preferably 5 to 50 parts by weight, particularly preferably 5 to 40 parts by weight, Red phosphorus in a total quantity of 1 to 45 parts by weight, preferably 2 to 35 parts by weight, particularly preferably 5 to 30 parts by weight, Antimony trioxide and / or zinc borate are contained in a total amount of 1 to 40 parts by weight, preferably 1.5 to 35 parts by weight, particularly preferably 1.5 to 25 parts by weight.

9. Composition according to one of claims 1 to 8 characterized in that at least one foam stabilizer, preferably based on a polyether siloxane, is included, in particular in amounts of 0.1 to 4 parts, based on 100 parts of the total polyol component.

10. Composition according to any one of claims 1 to 9, characterized in that it contains water and / or formic acid.

11. Method for the production of PU foams, preferably rigid PU foams, using foamable reaction mixtures comprising a composition as defined in any one of claims 1 to 10.

12. PU foam, preferably rigid PU foam, produced according to the method of claim 11.

13. Use of PU foam, preferably rigid PU foam according to claim 12, as insulation material and / or as construction material, particularly in building applications, especially as spray foam or in the cooling sector or as pipe sheathing for tubes.

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