Polyisocyanurate rigid foam material obtained using polyethylene terephthalate esters

Abstract

The present invention relates to a method for producing a rigid foamed polyisocyanurate material, comprising: (a) an aromatic polyisocyanate; (b) at least one polyether ester polyol (b1) having an average functional value of 1.7 or more and 2.8 or less and an OH value of 170 KOH / g or more and 270 mg KOH / g or less; and a polyether ester polyol (b1) having a functional value of 1.7 or more and 2.7 or less and 170 mg KOH / g or more and 280 mg A reaction mixture is formed by mixing (c) a catalyst, (d) a blowing agent, (e) a flame retardant, and (f) optionally auxiliary agents and additives, comprising (b1) a polyether ester polyol (b1) comprising (b1.1) a dicarboxylic acid composition containing an aromatic dicarboxylic acid, (b1.2) one or more hydrophobic compounds or derivatives having at least one hydroxyl group and / or carboxyl group, (b1.3) one or more diols having 2 to 6 C atoms, and (b1.4) an average functional value of 2 to 4. The present invention relates to a method for producing a polyester polyol (b2) obtained by esterification of a polyether polyol produced by alkoxylation of an initiator or initiator mixture, wherein polyethylene terephthalate is used in the production of polyester polyol (b2) in proportion to more than 25% by weight of the total amount of all components used in the production of polyester polyol (b2), the mass ratio of polyether ester polyol (b1) to polyester polyol (b2) is 0.3 or more and 3.0 or less, the sum of the mass fractions of component (b1) and component (b2) is more than 80% by weight of component (b), the mass fraction of free monoethylene glycol is 1.4% by weight or less of the sum of components B, C, E and F, and the mixing for forming the reaction mixture is carried out at an isocyanate index of at least 180. The present invention further relates to a polyol component for producing a polyisocyanurate rigid foam material according to the present invention and a sandwich element comprising a polyisocyanurate rigid foam material obtained by the method according to the present invention, in particular a polyisocyanurate rigid foam material.

Description

[Technical Field]

[0001] The present invention relates to a method for producing a polyisocyanurate rigid foam material, comprising: (a) an aromatic polyisocyanate; (b) a compound having at least two hydrogen atoms reactive with an isocyanate group, comprising at least one polyether ester polyol (b1) and at least one polyester polyol (b2); (c) a catalyst; (d) a blowing agent; (e) a flame retardant; and (f) optionally auxiliary agents and additives, which are mixed to form a reaction mixture and allowed to react completely to form a polyisocyanurate rigid foam material, wherein the polyether ester polyol (b1) is present in proportion to the total amount of each component (b1.1) to (b1.4). (b1.1) A dicarboxylic acid composition containing an aromatic dicarboxylic acid in an amount of 10-50 mol%, (b1.2) 2-20 mol% of one or more hydrophobic compounds or derivatives thereof having at least one hydroxyl group and / or carboxyl group, (b1.3) 10-70 mol% of one or more diols having 2-6 carbon atoms, (b1.4) 15-50 mol% of an initiator or initiator mixture having an average functional value of 2 or more and an ester polyether ester polyol (b1) obtained by esterification of the alkoxylization of the initiator, the polyether ester polyol (b1) having an average functional value of 1.7 or more and an average functional value of 2.8 and 150 mg The present invention relates to a method wherein the polyester polyol (b2) has an OH value of 1.7 to 2.7, an OH value of 170 mg KOH / g to 280 mg KOH / g, and a free monoethylene glycol content of less than 1.3% by weight, polyethylene terephthalate is used in the production of polyester polyol (b2) in proportion to more than 25% by weight of the total amount of all components used in the production of polyester polyol (b2), the mass ratio of polyether ester polyol (b1) to polyester polyol (b2) is 0.3 to 3.0, the sum of the mass fractions of component (b1) and component (b2) is more than 80% by weight of component (b), the mass fraction of free monoethylene glycol supplied to the reaction mixture is 1.4% by weight or less of the total weight of components (b), (c), (e), and (f), and the mixing to form the reaction reaction is carried out at an isocyanate index of at least 180.The present invention further relates to a polyol component for producing a polyisocyanurate rigid foam material according to the present invention, a polyisocyanurate rigid foam material obtained by the method according to the present invention, in particular a sandwich element comprising a polyisocyanurate rigid foam material.

[0002] The production of polyisocyanurate rigid foam materials by converting polyisocyanates with higher molecular weight compounds having at least two reactive hydrogen atoms, in particular polyether polyols from alkylene oxide polymerization or polyester polyols from polycondensation of alcohols and dicarboxylic acids, in the presence of polyurethane catalysts, chain extenders and / or crosslinking agents, blowing agents and further auxiliaries and additives, is known and described in a large number of patents and literature publications.

[0003] Polyisocyanurate rigid foam materials are often used as insulation materials for insulation. In this case, the foam material is used, for example, in the production of cooling devices, containers or planar composite elements having at least one surface layer. For this purpose, polyisocyanurate rigid foam materials are required which have high mechanical strength, in particular compressive strength, low thermal conductivity, little after-foaming behavior, high fire resistance and a surface which is as free of defects as possible.

[0004] Furthermore, attempts have been made to replace crude oil-based starting materials for producing polyurethanes with recycled raw materials. One approach is to replace conventional polyesters with esters obtained from the recycling of polyethylene terephthalate. This is described, for example, in Damayanti; Wu H.-S., "Strategic Possibillity Routes of Recycled PET", Polymers 2021, 13, 1475.

[0005] A disadvantage of using decomposition products of polyethylene terephthalate, such as polyesters obtained starting from the glycol decomposition (Glykolyse) of polyethylene terephthalate, is that these esters have undesirable properties with respect to the mechanical strength, such as compressive strength, post-foaming behavior, and surface quality of polyisocyanurate rigid foam materials, especially when the foaming of the reaction mixture between the two surface layers is carried out by a continuous double-belt process.

[0006] Therefore, an object of the present invention was to provide a polyisocyanurate rigid foam material in which at least a portion of the isocyanate reactive component used is obtained by transesterification of polyethylene terephthalate and glycol, and the polyisocyanurate rigid foam material has high mechanical strength, particularly high compressive strength, low thermal conductivity, less post-foaming behavior, high fire resistance and a surface that is as defect-free as possible. Furthermore, an object of the present invention was to provide a method for producing such a polyisocyanurate rigid foam material in which the starting components, particularly the polyol component, have low viscosity and can be easily mixed with further components for the production of the polyisocyanurate rigid foam material.

[0007] The problem relates to a method for forming a rigid polyisocyanurate foam material by mixing (a) an aromatic polyisocyanate, (b) a compound having at least two hydrogen atoms reactive with an isocyanate group, comprising at least one polyether ester polyol (b1) and at least one polyester polyol (b2), (c) a catalyst, (d) a blowing agent, (e) a flame retardant, and (f) optionally auxiliary agents and additives to form a reaction mixture, and completely reacting the mixture, wherein the polyether ester polyol (b1) is present in amounts of (b1.1) 10 to 5 of the total amount of components (b1.1) to (b1.4). (b1.2) 0 mol% of a dicarboxylic acid composition containing an aromatic dicarboxylic acid, (b1.3) 2 to 20 mol% of one or more hydrophobic compounds or derivatives thereof having at least one hydroxyl group and / or carboxyl group, (b1.3) 10 to 70 mol% of one or more diols having 2 to 6 carbon atoms, and (b1.4) 15 to 50 mol% of an initiator or initiator mixture having an average functional value of 2 to 4, obtained by esterification of a polyether polyol produced by alkoxylation of the constituent, wherein the polyether ester polyol (b1) has an average functional value of 1.7 to 2.8 and an OH value of 150 mg KOH / g to 300 mg KOH / g, and the polyester polyol (b2) has an average functional value of 1.7 to 2.7 and an OH value of 170 mg KOH / g to 280 mg The solution is provided by a polyisocyanurate rigid foam material obtained by a method having an OH number of KOH / g or less and a free monoethylene glycol content of less than 1.3% by weight, in which polyethylene terephthalate is used in the production of polyester polyol (b2) in proportion to more than 25% by weight of the total amount of all components used in the production of polyester polyol (b2), the mass ratio of polyether ester polyol (b1) to polyester polyol (b2) is 0.3 or more and 3.0 or less, the sum of the mass fractions of component (b1) and component (b2) is more than 80% by weight of component (b), the mass fraction of free monoethylene glycol supplied to the reaction mixture is 1.4% by weight or less of the total weight of components (b), (c), (e), and (f), and the mixing to form the reaction reaction is carried out at an isocyanate index of at least 180.The present invention further relates to a polyol component for producing a polyisocyanurate rigid foam material according to the present invention, and to a sandwich element comprising a polyisocyanurate rigid foam material obtained by the method according to the present invention, particularly a polyisocyanurate rigid foam material.

[0008] In the present invention, the polyisocyanurate rigid foam material is understood to be a foamed polyisocyanurate, preferably a foamed material conforming to DIN 7726, having a compressive strength of 80 kPa or more, preferably 150 kPa or more, and particularly preferably 180 kPa or more, in accordance with DIN 53421 / DIN EN ISO 604. Furthermore, the polyisocyanurate rigid foam material conforming to DIN ISO 4590 has a closed-cell ratio (Geschlossenzelligkeit) of more than 50%, preferably more than 85%, and particularly preferably more than 90%. Here, the polyisocyanurate rigid foam material contains both urethane bonds and isocyanurate bonds.

[0009] Polyisocyanates (a) can be known aliphatic, alicyclic, or aromatic aliphatic, preferably aromatic polyhydric isocyanates. Such polyfunctional isocyanates are either known or can be produced by known methods. Polyfunctional isocyanates can also be used as a mixture, in which case component (a) comprises various polyfunctional isocyanates. Polyfunctional isocyanates considered as polyisocyanates have two (hereinafter referred to as diisocyanates) or three or more isocyanate groups per molecule.

[0010] Specifically, the following: alkylene diisocyanates having 4 to 12 carbon atoms in the alkylene residue, e.g., 1,12-dodecane diisocyanate, 2-ethyltetramethylene-1,4-diisocyanate, 2-methylpentamethylene-1,5-diisocyanate, tetramethylene-1,4-diisocyanate, preferably hexamethylene-1,6-diisocyanate; alicyclic diisocyanates, e.g., cyclohexane-1,3- and 1,4-diisocyanates, and any mixtures thereof, 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane (IPDI), 2,4- and 2,6-hexahydrotoluylene diisocyanates, and corresponding Examples include isomer mixtures, 4,4'-, 2,2'- and 2,4'-dicyclohexylmethane diisocyanate, and corresponding isomer mixtures, preferably aromatic polyisocyanates, such as 2,4- and 2,6-toluylene diisocyanate, and corresponding isomer mixtures (TDI), 4,4'-, 2,4'-, 2,2'-diphenylmethane diisocyanate, and more polycyclic (hoeherkernige) homologs of diphenylmethane diisocyanate, and corresponding mixtures (MDI), mixtures of 4,4'-, 2,4'- and 2,2'-diphenylmethane diisocyanate and polyphenylpolymethylene polyisocyanate (polymer MDI), and mixtures of MDI and TDI.

[0011] Particularly suitable are 2,2'-, 2,4'- and / or 4,4'-diphenylmethane diisocyanate, as well as more polycyclic homologs of diphenylmethane diisocyanate (MDI), 1,5-naphthylene diisocyanate (NDI), 2,4- and / or 2,6-toluylene diisocyanate (TDI), 3,3'-dimethyldiphenyl diisocyanate, 1,2-diphenylethane diisocyanate and / or p-phenylene diisocyanate (PPDI), tri-, tetra-, penta-, hexa-, hepta- and / or octamethylene diisocyanate, and 2-methylpentamethylene-1,5-diiso These include cyanates, 2-ethylbutylene-1,4-diisocyanate, pentamethylene-1,5-diisocyanate, butylene-1,4-diisocyanate, 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethyl-cyclohexane (isophorone diisocyanate, IPDI), 1,4- and / or 1,3-bis(isocyanatomethyl)cyclohexane (HXDI), 1,4-cyclohexane diisocyanate, 1-methyl-2,4- and / or-2,6-cyclohexane diisocyanate, and 4,4'-, 2,4'- and / or 2,2'-dicyclohexylmethane diisocyanate.

[0012] Modified polyisocyanates, i.e., products obtained by the chemical conversion of organic polyisocyanates and having at least two reactive isocyanate groups per molecule, are also frequently used. In particular, polyisocyanates having ester groups, urea groups, biuret groups, allophanate groups, carbodiimide groups, isocyanurate groups, uretdione groups, carbamate groups and / or urethane groups are often mentioned, along with unconverted polyisocyanates.

[0013] Particularly preferably, the polyisocyanate of component (a) includes 2,2'-MDI, 2,4'-MDI, or 4,4'-MDI (also referred to as monomeric diphenylmethane or MMDI), or oligomeric MDI consisting of a more polycyclic congener of MDI having at least three aromatic rings and at least three functional values, or a mixture of at least two of these isomers, optionally further including a mixture of at least one isomer of MDI and at least one more polycyclic congener of MDI, or crude MDI produced during the production of MDI, or preferably a mixture of at least one more polycyclic congener of MDI and at least one of the aforementioned low molecular weight MDI derivatives 2,2'-MDI, 2,4'-MDI, or 4,4'-MDI (also referred to as polymeric MDI). Typically, isomers and congeners of MDI are obtained by distillation of crude MDI.

[0014] Particularly preferably, polymer MDI is used as isocyanate (a). The average functional value of polymer MDI varies in the range of preferably 2.2 to 4, particularly preferably 2.4 to 3.8, and especially 2.6 to 3.0. Polymer MDI is sold, for example, by BASF Polyurethanes GmbH under the names Lupranat® M20 or Lupranat® M50.

[0015] Preferably, component (a) contains at least 70%, particularly preferably at least 90%, and especially 100% by weight of one or more isocyanates selected from the group consisting of 2,2'-MDI, 2,4'-MDI, 4,4'-MDI, and MDI oligomers, relative to the total weight of component (a). Here, the content of oligomer MDI is preferably at least 20% by weight, particularly preferably more than 30% but less than 80% by weight, relative to the total weight of component (a).

[0016] The viscosity of component (a) used can vary over a wide range. Preferably, component (a) has a viscosity of 100 to 3000 mPa·s at 25°C, particularly preferably 100 to 1000 mPa·s, especially preferably 100 to 600 mPa·s, especially 200 to 600 mPa·s, and especially 400 to 600 mPa·s.

[0017] Compound (b) reactive to the isocyanate group comprises at least one polyether ester polyol (b1) and at least one polyester polyol (b2). Here, the weight fractions of component (b1) and component (b2) are each greater than 80% by weight, preferably 85 to 100% by weight, more preferably 90 to 100% by weight, and particularly 95 to 98% by weight, relative to the total weight of component (b), and the mass ratio of polyether ester polyol (b1) to polyester polyol (b2) is 0.3 to 3.0, preferably 0.4 to 2.5, particularly preferably 0.5 to 2.0, and especially 0.7 to 1.5.

[0018] According to the present invention, component (b) comprises at least one aromatic polyether ester polyol (b1), which can be produced by esterification of a polyether polyol produced by alkoxylation of an initiator or initiator mixture having an average functional value of 2 or more or less, in proportion to the total amount of components (b1.1) to (b1.4): (b1.1) 10 to 50 mol% of a dicarboxylic acid composition containing an aromatic dicarboxylic acid, (b1.2) 2 to 20 mol% of one or more hydrophobic compounds or derivatives thereof having at least one hydroxyl group and / or carboxyl group, (b1.3) 10 to 70 mol% of one or more aliphatic or alicyclic diols having 2 to 6 C atoms or an alkoxylate thereof, and (b1.4) 15 to 50 mol% of an initiator or initiator mixture having an average functional value of 2 or more or less. Preferably, the total proportion of components b1.1) to b1.4) is 100 mol%.

[0019] Here, the polyether ester polyol (b1) has an average functional value of 1.7 to 2.8, preferably 1.9 to 2.6, particularly preferably 2.0 to 2.5, especially 2.5, and an OH value of 150 mg KOH / g to 300 mg KOH / g, preferably 170 mg KOH / g to 280 mg KOH / g, particularly preferably 190 mg KOH / g to 260 mg KOH / g.

[0020] The dicarboxylic acid composition (b1.1) typically comprises a dicarboxylic acid and / or its derivatives that can be used for the production of esters. Preferably, the dicarboxylic acid composition (b1.1) comprises at least one compound selected from the group consisting of terephthalic acid, dimethyl terephthalate (DMT), polyethylene terephthalate (PET), phthalic acid, phthalic anhydride (PSA), and isophthalic acid. Particularly preferably, component (b1.1) comprises phthalic anhydride, phthalic acid, terephthalic acid, especially phthalic anhydride or terephthalic acid, and especially terephthalic acid. Generally, component (b1.1) may also contain aliphatic dicarboxylic acids or aliphatic dicarboxylic acid derivatives. When aliphatic dicarboxylic acids are used, they are generally present in amounts of 0.5 to 30 mol%, preferably 0.5 to 10 mol%, relative to component (b1.1). Preferably, adipic acid or a mixture of dicarboxylic acids consisting of succinic acid, glutaric acid, and adipic acid is used as the aliphatic dicarboxylic acid. Preferably, the dicarboxylic acid composition (b1.1) does not contain aliphatic dicarboxylic acids or their derivatives, and therefore consists of one or more aromatic dicarboxylic acids or their derivatives up to 100 mol%. Most preferably, the dicarboxylic acid composition (b1.1) has a terephthalic acid content of more than 80% by weight, more preferably more than 90% by weight, based on the total weight of component (b1.1), and consists particularly of terephthalic acid.

[0021] Generally, component (b1.1) is used in an amount of 10 to 50 mol%, preferably 20 to 45 mol%, relative to components (b1.1), (b1.2), (b1.3), and (b1.4) used in the production of aromatic polyether ester polyol (b1).

[0022] To produce aromatic polyether ester polyols (b1), one or more hydrophobic compounds or derivatives thereof (b1.2) having at least one hydroxyl group and / or carboxyl group are also used. In the present invention, the hydrophobic compounds or derivatives thereof (b1.2) having at least one hydroxyl group and / or carboxyl group are compounds having an aliphatic hydrophobic group. In the present invention, an aliphatic hydrophobic group is understood to be an aliphatic hydrocarbon group having preferably more than 6, particularly preferably more than 8 and less than 100, and especially at least 10 and up to 50 directly adjacent carbon atoms. Here, the adjacent carbon atoms may be connected not only by carbon-carbon single bonds but also by carbon-carbon double bonds. In this case, the C atoms of the hydrophobic group are directly bonded to each other and are not interrupted by heteroatoms, for example. In contrast, the hydrogen atoms of the hydrocarbon may be substituted by halogen atoms, OH groups or carboxylic acid groups, for example.

[0023] Compound (b1.2) is preferably a fluid substance at a temperature of 20°C and an ambient pressure of 1 bar. Examples of compound (b1.2) include carboxylic acid esters, such as lower alkanol esters of carboxylic acids, such as fatty acids or fatty acid derivatives, such as fatty acid ethyl esters, or preferably fatty acid methyl esters.

[0024] Fatty acids and / or fatty acid derivatives can, in this case, have both biological and petrochemical origins. Examples of fatty acids include caproic acid, caprylic acid, capric acid, lauric acid, myristic acid, myristoleic acid, palmitic acid, palmitoleic acid, stearic acid, oleic acid, vaccenic acid, petroseric acid, gadolic acid, erucic acid, nervonic acid, linoleic acid, linolenic acid, stearidonic acid, arachidonic acid, thymnodonic acid, culpanodonic acid, cervonic acid, ricinoleic acid, and mixtures thereof. Examples of fatty acid derivatives include glycerol esters of fatty acids, such as castor oil, grape seed oil, black cumin oil (schwarzes Kuemmeloel), pumpkin seed oil, borage seed oil, soybean oil, wheat germ oil (Weizensamen-oel), rapeseed oil, sunflower seed oil, peanut oil, apricot kernel oil, pistachio oil, almond oil, olive oil, macadamia oil, avocado oil, sea buckthorn oil, sesame oil, hemp oil, hazelnut oil, evening primrose oil, rosehip oil, safflower oil, and walnut oil.

[0025] Further examples of fatty acid derivatives include hydroxyl-modified fats or fatty acids, hydrogenated fats or fatty acids, epoxidized fats or fatty acids, alkyl-branched fats or fatty acids, fatty acid amides, animal fats, such as beef tallow, alkyl esters or especially methyl esters of fatty acids, such as biodiesel.

[0026] Generally, component (b1.2) is used in an amount of 2 to 20 mol%, preferably 5 to 15 mol%, and particularly preferably 7 to 12 mol%, relative to the total components (b1.1) to (b1.4) used in the production of the aromatic polyether ester polyol (b1).

[0027] In particularly preferred embodiments of the present invention, the fatty acid or fatty acid derivative (b1.2) is oleic acid, biodiesel, soybean oil, rapeseed oil, or animal fat, particularly oleic acid or biodiesel, especially oleic acid, and is used in an amount of more than 5 mol%, particularly preferably more than 8 mol%. The fatty acid or fatty acid derivative improves the solubility of the foaming agent, particularly during the production of polyisocyanurate rigid foam materials.

[0028] As component (b1.3), one or more aliphatic or alicyclic diols having preferably 2 to 6 carbon atoms or their alkoxylates are used. Preferably, component (b1.3) contains at least one compound from the group consisting of monoethylene glycol, diethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 2-methyl-1,3-propanediol, 3-methyl-1,5-pentanediol and their alkoxylates. Particularly preferably, the aliphatic diol (b1.3) is monoethylene glycol or diethylene glycol, particularly diethylene glycol. Preferably, component (b1.3) is used in an amount of 10 to 70 mol%, particularly preferably 20 to 65 mol%, especially 30 to 60 mol% based on all components used in the production of aromatic polyether ester polyol (b1).

[0029] The polyether polyol (b1.4) is obtained by alkoxylation of an initiator or initiator mixture having an average functionality of 2 or more and 4 or less, particularly a trifunctional initiator molecule, preferably glycerol. As the alkylene oxide, preferably ethylene oxide and / or propylene oxide can be used. Preferably, at least 80% by weight of ethylene oxide, particularly preferably only ethylene oxide is used as the alkylene oxide. The hydroxyl value of the polyether polyol (b1.4) is preferably more than 300 mg KOH / g, particularly preferably more than 400 mg KOH / g and less than 800 mg KOH / g, especially more than 450 mg KOH / g and less than 600 mg KOH / g.

[0030] In a particularly preferred embodiment, the aromatic polyether ester polyol (b1) has an OH value of 190 to 260 mg KOH / g and a functionality of 1.7 to 2.5.

[0031] To produce the aromatic polyether ester polyol (b1), dicarboxylic acid (b1.1), at least one hydrophobic compound or its derivative (b1.2) having at least one hydroxyl group and / or carboxyl group, an aliphatic or alicyclic diol or its alkoxylate (b1.3) having 2 to 18 C atoms, and a higher functionality polyol (b1.4) are polycondensed without a catalyst or preferably in the presence of an esterification catalyst, appropriately in an atmosphere consisting of an inert gas, such as nitrogen, in a melt at a temperature of 150 to 280 °C, preferably 180 to 260 °C, optionally under reduced pressure, preferably to a desired acid value of less than 10, particularly preferably less than 2. According to a preferred embodiment, the esterification mixture is polycondensed at the above temperature under normal pressure and then to an acid value of 80 to 20, preferably 40 to 20, under a pressure of less than 500 mbar, preferably 40 to 400 mbar. As the esterification catalyst, for example, iron catalysts, cadmium catalysts, cobalt catalysts, lead catalysts, zinc catalysts, antimony catalysts, magnesium catalysts, titanium catalysts and tin catalysts in the form of metals, metal oxides or metal salts can be considered. However, the polycondensation can also be carried out in the liquid phase in the presence of a diluent and / or an azeotropic agent for the azeotropic fractional distillation of condensed water, such as benzene, toluene, xylene or chlorobenzene.

[0032] Polyester polyol (b2) has a functional value of 1.7 to 2.7, preferably 1.9 to 2.6, particularly preferably 2.0 to 2.4, especially 2.0, and an OH value of 170 mg KOH / g to 280 mg KOH / g, preferably 180 mg KOH / g to 260 mg KOH / g, particularly 190 mg KOH / g to 250 mg KOH / g. To produce polyester polyol (b2), polyethylene terephthalate is used in a proportion of more than 25% by weight, preferably 28% by weight or more, particularly preferably 35% by weight or more, and particularly 40% by weight or more, relative to the total amount of all components used in the production of polyester polyol (b2). Here, it is important for the present invention that the content of free monoethylene glycol is less than 1.3% by weight, preferably less than 1.2% by weight, and particularly preferably less than 1.1% by weight, relative to the total weight of polyester polyol (b2).

[0033] A suitable polyester polyol (b2) can be obtained by reacting a polycarboxylic acid, particularly a dicarboxylic acid, and a polyhydric alcohol with the addition of polyethylene terephthalate, in which case the alcohol component is used in excess. As the polycarboxylic acid, in this case, aliphatic polycarboxylic acids, aromatic polycarboxylic acids or mixtures thereof, and derivatives thereof can be used. Here, the functional value of the starting material is selected so that a polyester polyol having the required functional value is obtained. As the carboxylic acid derivative, all carboxylic acid derivatives that are normally used in the production of polyesterols suitable for use in the production of polyurethanes can be used. These include, for example, polycarboxylic acid esters or polycarboxylic acid anhydrides of alcohols having 1 to 4 carbon atoms. Polycarboxylic acids also include functionalized carboxylic acids, such as hydroxycarboxylic acids.

[0034] Preferably, at least one aliphatic dicarboxylic acid is used to produce polyester (b2). For example, adipic acid, glutaric acid, succinic acid, fumaric acid, malonic acid, maleic acid, oxalic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, or derivatives thereof can be used. Furthermore, aliphatic polycarboxylic acids can also be used. Examples of derivatives of aliphatic polycarboxylic acids are dimethyl adipate and diethyl adipate. Dicarboxylic acids having 4 to 6 carbon atoms, such as adipic acid, glutaric acid or succinic acid, or derivatives thereof, particularly adipic acid or derivatives of adipic acid are especially preferred. Preferably, the proportion of aliphatic dicarboxylic acid is 10% by weight or more, preferably 12 to 30% by weight, and particularly 15 to 25% by weight, based on the total components used to produce polyester polyol (b2).

[0035] Preferably, aromatic dicarboxylic acids or aromatic dicarboxylic acid derivatives include phthalic acid, phthalic anhydride, terephthalic acid and / or isophthalic acid, and their derivatives, such as dimethyl terephthalate, diethyl terephthalate, dimethyl phthalate, and diethyl phthalate, used as a mixture or individually, with phthalic acid, phthalic anhydride, and terephthalic acid being preferred. It is particularly preferable to use terephthalic acid or dimethyl terephthalate, especially terephthalic acid.

[0036] In addition to aliphatic and / or aromatic polycarboxylic acids and / or functionalized aliphatic carboxylic acids, monofunctional carboxylic acids or conversion products of monofunctional carboxylic acids may also be used. As monofunctional carboxylic acids, for example, saturated or unsaturated monocarboxylic acids having 1 to 24 carbon atoms can be used. Examples include formic acid, acetic acid, propionic acid, acrylic acid, butyric acid, valeric acid, caproic acid, benzoic acid, heptanoic acid, caprylic acid, nonanoic acid, capric acid, and fatty acids, such as lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, ricinoleic acid, linoleic acid, and linolenic acid.

[0037] As conversion products of monofunctional carboxylic acids, bio-based starting materials and / or derivatives, such as castor oil, polyhydroxy fatty acids, hydroxyl-modified oils, grape seed oil, black cumin oil, pumpkin seed oil, borage seed oil, soybean oil, wheat germ oil, rapeseed oil, sunflower seed oil, peanut oil, apricot kernel oil, pistachio oil, almond oil, olive oil, macadamia oil, avocado oil, sea buckthorn oil, sesame oil, hemp oil, hazelnut oil, evening primrose oil, rosehip oil, safflower oil, walnut oil, as well as fatty acid esters based on myristoleic acid, palmitoleic acid, oleic acid, vaccenic acid, petroseric acid, gadoleic acid, erucic acid, nervonic acid, linoleic acid, α- and γ-linolenic acid, stearidonic acid, arachidonic acid, thymnodonic acid, clupanodonic acid, and cervonic acid, can also be used.

[0038] When a monofunctional carboxylic acid or its derivative is used in the production of a polyester polyol (b2), it is preferable that the polyester polyol (b2) contains 15% by weight or less, particularly 5% by weight or less, of fatty acid residues based on its total weight, and is produced in an amount that does not contain any fatty acid residues.

[0039] Furthermore, polyethylene terephthalate is used for the production of polyester, for example, in the form of granules. A possible explanation for the incorporation of polyethylene terephthalate into polyester(b2) is that under esterification conditions for the production of polyol(b2), a transesterification reaction occurs that results in the incorporation of the decomposition products of polyethylene terephthalate into polyester(b2). Possible decomposition reactions of polyethylene terephthalate (PET) that result in incorporation into polyester polyol(b2) are described, for example, in "Damayanti; Wu H.-S., "Strategic Possibility Routes of Recycled PET, Polymers 2021, 13, 1475, in particular in Kapitel 5" or "Chemistry and Technology of Polyols for Polyurethanes, 2nd Edition, Volume 2, chapter 5.2". Polyester polyol(b2) may also have monoethylene glycol from transesterification with polyethylene terephthalate, for example, in addition to the ester obtained by the conversion of polyethylene terephthalate.

[0040] Examples of polyhydric alcohols include ethanediol, diethylene glycol, 1,2- or 1,3-propanediol, dipropylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,10-decanediol, glycerol, trimethylolpropane, and pentaerythritol, or alkoxylates thereof. Preferably, ethylene glycol, diethylene glycol, propylene glycol, glycerol, trimethylolpropane, or alkoxylates thereof, or a mixture of at least two of the above polyhydric alcohols, particularly diethylene glycol and / or glycerol, is used.

[0041] In a particularly preferred embodiment, in addition to polyethylene terephthalate and adipic acid, diethylene glycol and optionally a fatty acid or fatty acid derivative are also used to produce polyester (b2). In this case, particularly preferably, the hydroxyl value of polyester (b2) is less than 200 mg KOH / g, and the fatty acid content is more than 8% by weight relative to the total weight of polyester (b2).

[0042] If no fatty acids or fatty acid derivatives are present, the hydroxyl value of polyester (b2) is preferably greater than 200 mg KOH / g.

[0043] The production of polyesterol (b2) is carried out in a molten material at a temperature of 150-280°C, preferably 180-260°C, and optionally under reduced pressure, in an atmosphere of an inert gas, such as nitrogen, either without a catalyst or preferably in the presence of an esterification catalyst, and preferably without a catalyst, to a desired acid value of less than 10, and particularly preferably less than 2. According to a preferred embodiment, the esterification mixture is polycondensed at the above temperature under atmospheric pressure, followed by polycondensation at a pressure of less than 500 mbar, preferably 40-400 mbar, to an acid value of 80-20, preferably 40-20. Possible esterification catalysts include, for example, iron catalysts in the form of metals, metal oxides or metal salts, cadmium catalysts, cobalt catalysts, lead catalysts, zinc catalysts, antimony catalysts, magnesium catalysts, titanium catalysts and tin catalysts. However, polycondensation may also be carried out in the presence of a diluent and / or an azeotrope for azeotropic fractional distillation of condensate, such as benzene, toluene, xylene or chlorobenzene.

[0044] Component (b) further comprises a polyether esterol (b1) and a polyester (b2), plus a polyetherol (b3) having a hydroxyl value of 150-300 mg KOH / g, produced by alkoxylation of an initiator or initiator mixture, wherein at least 80% by weight of ethylene oxide is used as the alkylene oxide for producing the polyether polyol (b3), and the polyether polyol (b3) has at least 90%, preferably at least 95%, and particularly preferably at least 99% primary hydroxyl terminal groups, especially only primary hydroxyl terminal groups.

[0045] Polyether polyols (b3) are produced by known methods, for example, by anionic polymerization of one or more alkylene oxides having 2 to 4 carbon atoms, including ethylene oxide, using a common catalyst, such as an alkali hydroxide, such as sodium hydroxide or potassium hydroxide; an alkali alcoholate, such as sodium methylate, sodium ethylate or potassium ethylate, or potassium isopropylate; or an amine-based alkoxylation catalyst, such as dimethylethanolamine (DMEOA), imidazole and / or imidazole derivatives, with at least one initiator molecule or a mixture of initiator molecules containing an average of 2 to 3.0 bonded reactive hydrogen atoms, particularly preferably 2. In addition to anionic polymerization of initiator molecules, production can also be carried out by cationic polymerization, in which case Lewis acids, such as antimony pentachloride, boron trifluoride ether, or bleached earth, are used as catalysts.

[0046] Preferred alkoxylation catalysts are KOH and amine-based alkoxylation catalysts. In some cases, when using KOH as an alkoxylation catalyst, it is necessary to first neutralize the polyether and separate the resulting potassium salt. In such cases, the use of amine-based alkoxylation catalysts is particularly preferred. Preferred amine-based alkoxylation catalysts are selected from the group including dimethylethanolamine (DMEOA), imidazole and imidazole derivatives, and mixtures thereof, with imidazole being particularly preferred.

[0047] Suitable alkylene oxides, in addition to ethylene oxide, include, for example, tetrahydrofuran, 1,3- or 1,2-propylene oxide, 1,2- or 2,3-butylene oxide, styrene oxide, preferably 1,2-propylene oxide. In a particularly preferred embodiment, only ethylene oxide is used as the alkylene oxide. Alkylene oxides can be used alone, alternately, or in mixtures. According to the present invention, at least 80% by weight of ethylene oxide, preferably at least 90% by weight of ethylene oxide, particularly preferably at least 95% by weight, and especially at least 98% by weight of ethylene oxide is used as the alkylene oxide for the production of polyether polyol (b3). In this embodiment, only ethylene oxide is most preferably used as the alkylene oxide for the production of polyether polyol (b3), i.e., the amount of ethylene oxide by weight relative to the total weight of alkylene oxides in component (b3) is 100% by weight. When ethylene oxide is used as a mixture with other alkylene oxides, it is necessary to ensure that the polyether polyol produced therefrom has a content of primary hydroxyl-terminated groups according to the present invention.

[0048] Examples of initiator molecules include water, organic dicarboxylic acids such as succinic acid, adipic acid, phthalic acid, and terephthalic acid, or preferably dihydric or polyhydric alcohols such as ethanediol, 1,2- and 1,3-propanediol, diethylene glycol (DEG), dipropylene glycol, 1,4-butanediol, 1,6-hexanediol, glycerol, trimethylolpropane, bisphenol A, bisphenol F, and pentaerythritol. Diethylene glycol, monoethylene glycol, 1,2-propanediol, and glycerol are particularly preferred as initiator molecules, with diethylene glycol being especially preferred.

[0049] When using polyether polyol (b3), it is preferably used in an amount of 2 to 25% by weight, preferably 4 to 20% by weight, and particularly 6 to 15% by weight, relative to the total weight of component (b).

[0050] It is important for the present invention that the free monoethylene glycol content of the monoethylene glycol (MEG) is less than 1.4% by weight, preferably less than 1.3%, particularly preferably less than 1.1%, and especially less than 1.0% by weight, relative to the sum of components (b), (c), (e), and (f).

[0051] As a catalyst (c) for producing the polyisocyanurate rigid foam material according to the present invention, a compound that significantly accelerates the reaction between the compounds of components (b) to (f) containing reactive hydrogen atoms, particularly hydroxyl groups, and the polyisocyanate (a) is used.

[0052] Suitablely, a basic polyurethane catalyst, such as a tertiary amine, such as triethylamine, tributylamine, dimethylbenzylamine, dicyclohexylmethylamine, dimethylcyclohexylamine, N,N,N',N'-tetramethyldiaminodiethyl ether, bis(dimethylaminopropyl)urea, N-methylmorpholine or N-ethylmorpholine, N-cyclohexylmorpholine, N,N,N',N'-tetramethylethylenediamine, N,N,N,N-tetramethylbutanediamine, N,N,N,N-tetramethylhexanediamine-1,6-pentamethyldiethylenetriamine, bis(2-dimethylaminoethyl) ether, or dimethylpiperazine. N-dimethylaminoethylpiperidine, 1,2-dimethylimidazole, 1-azabicyclo-(2,2,0)-octane, 1,4-diazabicyclo-(2,2,2)-octane (Dabco), and alkanolamine compounds such as triethanolamine, triisopropanolamine, N-methyl- and N-ethyldiethanolamine, dimethylaminoethanol, 2-(N,N-dimethylaminoethoxy)ethanol, N,N',N''-tris-(dialkylaminoalkyl)hexahydrotriazine, such as N,N',N''-tris-(dimethylaminopropyl)-s-hexahydrotriazine and triethylenediamine are used.

[0053] However, metal salts, such as iron(II) chloride, zinc chloride, lead octanoate, and tin salts, such as tin dioctanoate, tin diethylhexanoate, and dibutyltin dilaurate, as well as mixtures of tertiary amines with metal salts, especially organotin salts, are also suitable. Further possible catalysts include amidines, such as 2,3-dimethyl-3,4,5,6-tetrahydropyrimidine, tetraalkylammonium hydroxides, such as tetramethylammonium hydroxide, alkali hydroxides, such as sodium hydroxide, and alkali alcoholates, such as sodium methylate and potassium isopropylate, alkali carboxylates, and alkali salts of long-chain fatty acids having 8 to 20 carbon atoms and optionally side-chain OH groups.

[0054] Furthermore, as catalysts, incorporateable amines, i.e., amines having -OH, -NH, or -NH2 functional groups, such as ethylenediamine, triethanolamine, diethanolamine, ethanolamine, and dimethylethanolamine, are possible. The incorporateable catalyst can be considered as both the compound of component (b) and the compound of component (c).

[0055] It is also possible to allow the reaction to proceed without catalysis. In this case, the catalytic activity of the polyol initiated with an amine is usually utilized.

[0056] Furthermore, catalysts for the trimerization reaction between excess -NCO groups include catalysts that form isocyanurate groups, either alone or in combination with tertiary amines, such as ammonium ion salts or alkali metal salts, particularly ammonium carboxylates or alkali metal carboxylates. The formation of isocyanurates results in flame-retardant PIR foam materials, which are preferably used in industrial rigid foams, for example, as insulation panels or sandwich elements in buildings. Preferred trimerization catalysts are potassium salts of aliphatic carboxylic acids having more than five carbon atoms, selected particularly from the group consisting of potassium 2-ethylhexanoate, potassium octanoate, potassium neodecanoate, potassium hexanoate, and potassium sorbate.

[0057] In preferred embodiments, catalyst (c) comprises an amine catalyst having a tertiary amino group and an ammonium carboxylate catalyst or an alkali metal carboxylate catalyst. In particularly preferred embodiments, catalyst (c) comprises at least one amine catalyst selected from the group consisting of pentamethyldiethylenetriamine and bis(2-dimethylaminoethyl) ether, and at least one alkali metal carboxylate catalyst, such as an alkali metal salt of a carboxylic acid, such as potassium formate or potassium acetate, preferably a potassium salt of an aliphatic carboxylic acid having five or more carbon atoms, selected particularly from the group consisting of potassium 2-ethylhexanoate, potassium octanoate, potassium neodecanoate, potassium pivalate, potassium hexanoate, and potassium sorbate. Surprisingly, when this catalyst is used in the continuous manufacturing of sandwich elements, for example in a double belt, post-foaming behavior after leaving the double belt is particularly reduced, and furthermore, sandwich elements with a particularly small difference between the element center thickness and element end thickness are obtained.

[0058] Preferably, 0.001 to 10 parts by weight of catalyst or combination of catalysts is used per 100 parts by weight of component (b).

[0059] Examples of blowing agents (d) that may be used to produce the polyisocyanurate rigid foam material according to the present invention include water, formic acid, and formic acid-water mixtures. These react with isocyanate groups to form carbon dioxide and carbon monoxide. These blowing agents are referred to as chemical blowing agents because they release gas through a chemical reaction with isocyanate groups. Formic acid with a purity exceeding 98% is considered pure formic acid rather than a formic acid-water mixture in this invention.

[0060] In addition, physical blowing agents such as low-boiling hydrocarbons can be used. In particular, liquids that are inert to polyisocyanate (A) and have a boiling point of less than 100°C, preferably less than 50°C, at atmospheric pressure, and therefore evaporate under the influence of an exothermic polyaddition reaction, are suitable as physical blowing agents.

[0061] Examples of physical blowing agents include industrial mixtures of alkanes, such as heptane, hexane, n-pentane and isopentane, preferably n-pentane and isopentane, n-butane and isobutane, and propane; cycloalkanes, such as cyclopentane and / or cyclohexane; ethers, such as furan, dimethyl ether and diethyl ether; ketones, such as acetone and methyl ethyl ketone; alkyl carboxylates, such as methyl formate, dimethyl oxalate and ethyl acetate; and halogenated saturated and unsaturated hydrocarbons, such as methylene chloride, dichloromonofluoromethane, and difluorometh Trifluoromethane, difluoroethane, tetrafluoroethane, chlorodifluoroethane, 1,1-dichloro-2,2,2-trifluoroethane, 2,2-dichloro-2-fluoroethane, and heptafluoropropane, as well as unsaturated hydrocarbons such as trifluoropropene and tetrafluoropropene, e.g. (HFO-1234), pentafluoropropene, e.g. (HFO-1225), chlorotrifluoropropene, e.g. (HFO-1233), chlorodifluoropropene, chlorotetrafluoropropene, and hexafluorobutene, and mixtures of one or more of these components can be used. Tetrafluoropropene, pentafluoropropene, chlorotrifluoropropene, and hexafluorobutene are preferred, where the unsaturated terminal carbon atom has at least one chlorine or fluorine substituent. Examples include 1,3,3,3-tetrafluoropropene (HFO-1234ze); 1,1,3,3-tetrafluoropropene; 1,2,3,3,3-pentafluoropropene (HFO-1225ye); 1,1,1-trifluoropropene; 1,1,1,3,3-pentafluoropropene (HFO-1225zc); 1,1,2,3,3-pentafluoropropene (HFO-1225yc); 1-chloro-2,3,3,3-tetrafluoropropene (HFO-1224yd); 1,1,1,2,3-pentafluoropropene (HFO-1225yez); 1-chloro-3,3,3-trifluoropropene (HCFO-1233zd); and 1,1,1,4,4,4-hexafluorobuta-2-ene (HFO-1336mzz).Mixtures of these low-boiling point liquids and / or mixtures with other substituted or unsubstituted hydrocarbons can also be used.

[0062] Furthermore, organic carboxylic acids, such as acetic acid, oxalic acid, ricinoleic acid, and carboxyl group-containing compounds, are suitable as foaming agents.

[0063] Preferably, halogenated hydrocarbons are not used as blowing agents. Preferably, water, a formic acid-water mixture, or formic acid is used as a chemical blowing agent, and particularly preferably a formic acid-water mixture or formic acid.

[0064] Preferably, a pentane isomer or a mixture of pentane isomers is used as a physical blowing agent. In this case, a chemical blowing agent is used together with the physical blowing agent, and it is preferable to use a formic acid-water mixture or pure formic acid together with a pentane isomer or a mixture of pentane isomers.

[0065] The amount of foaming agent or foaming agent mixture used is 0.1 to 45% by weight, preferably 1 to 30% by weight, particularly preferably 1 to 20% by weight, and especially 1.5 to 20% by weight, based on the total of components (b) to (f).

[0066] In this case, water, formic acid, or a formic acid-water mixture is used in an amount of preferably 0.2 to 10% by weight, particularly 0.5 to 4% by weight, relative to component (b). When a formic acid-water mixture is used, the proportion of formic acid is preferably more than 40% by weight, particularly preferably 50 to 98% by weight, more preferably 70 to 95% by weight, and especially 80 to 90% by weight, relative to the total weight of formic acid and water. Particularly preferably, formic acid or a formic acid-water mixture is used in combination with pentane as a chemical blowing agent.

[0067] As the flame retardant (e), generally, flame retardants known from the prior art can be used. Suitable flame retardants include, for example, brominated esters, brominated ethers (Ixol), or brominated alcohols, such as dibromoneopentyl alcohol, tribromoneopentyl alcohol, and PHT-4-diol, as well as chlorinated phosphates, such as tris(2-chloroethyl) phosphate, tris(2-chloropropyl) phosphate (TCPP), tris(1,3-dichloropropyl) phosphate, tricresyl phosphate, tris(2,3-dibromopropyl) phosphate, tetrakis(2-chloroethyl)ethylenediphosphate, dimethylmethanephosphonate, diethyl diethanolaminomethylphosphonate, and commercially available halogen-containing flame retardant polyols. As further phosphates or phosphonates, diethylethanephosphonate (DEEP), triethyl phosphate (TEP), dimethylpropylphosphonate (DMPP), and diphenylcresyl phosphate (DPK) can be used as liquid flame retardants. In this case, compounds containing a phosphorus atom, a chlorine atom, or a bromine atom and having a group reactive with isocyanate are not considered in the present invention to be compounds (b) having at least two hydrogen atoms reactive with the isocyanate group, and are not included in the calculation of the quantitative ratio of component (b).

[0068] In addition to the flame retardants already mentioned, inorganic or organic flame retardants, such as red phosphorus, red phosphorus-containing finishing agents, aluminum oxide hydrate, antimony trioxide, arsenic oxide, ammonium polyphosphate and calcium sulfate, expanded graphite or cyanuric acid derivatives, such as melamine, or mixtures of at least two flame retardants, such as ammonium polyphosphate and melamine, as well as optionally corn starch or ammonium polyphosphate, melamine, expanded graphite, and optionally aromatic polyesters can also be used to flame retardate polyisocyanurate rigid foam materials. Preferred flame retardants do not have groups that are reactive with isocyanate groups. Preferably, the flame retardant is liquid at room temperature. TCPP, DEEP, TEP, DMPP and DPK, particularly TCPP and TEP, with TCPP being especially preferred.

[0069] Generally, the proportion of flame retardant (e) is 1 to 20% by weight, preferably 2 to 15% by weight, and particularly preferably 3 to 10% by weight, relative to the total weight of components (b) to (f).

[0070] Preferably, component (e) contains a phosphorus-based flame retardant, and the phosphorus content is preferably less than 0.7% by weight, more preferably less than 0.6% by weight, particularly preferably less than 0.5% by weight, and especially less than 0.4% by weight, relative to the total weight of components (a) to (f).

[0071] To produce the polyisocyanurate rigid foam material according to the present invention, further auxiliary agents and / or additives (f) may be added to the reaction mixture as needed. Examples include surfactants, foam stabilizers, foam regulators, fillers, light stabilizers, dyes, pigments, hydrolysis inhibitors, and fungiostatic and bacteriostatic substances.

[0072] Examples of surfactants include compounds used to help homogenize starting materials and, in some cases, to adjust the foam structure of plastics. Examples include emulsifiers such as castor oil sulfate or sodium salts of fatty acids, and salts of fatty acids with amines, such as diethylamine oleate, diethanolamine stearate, diethanolamine ricinoleate, salts of sulfonic acids such as dodecylbenzenesulfonic acid or dinaphthylmethanedisulfonic acid and alkali or ammonium salts of ricinoleic acid, and foam stabilizers such as siloxane oxyalkylene copolymers and other organopolysiloxanes and dimethylpolysiloxanes. Furthermore, acrylate oligomers having polyoxyalkylene groups and fluoroalkane groups as side groups are suitable for improving emulsification, foam structure, and / or foam stabilization. Surfactants are typically used in amounts of 0.01 to 10 parts by weight per 100 parts by weight of component (b). As foam stabilizers, general foam stabilizers, such as silicone-based ones, such as siloxane oxyalkylene copolymers and other organopolysiloxanes, can be used.

[0073] Fillers, particularly reinforcing fillers, are understood to be known common organic and inorganic fillers, reinforcing agents, bulking agents, agents for improving the wear behavior of paints, coating agents, etc. Specifically, examples include inorganic fillers, such as silicate minerals, such as layered silicates, such as antigorite, serpentine, hornblende, amphibole, chrysotile, and talc; metal oxides, such as kaolin, aluminum oxide, titanium oxide, and iron oxide; metal salts, such as chalk and barite; and inorganic pigments, such as cadmium sulfide and zinc sulfide; and glass. Preferably, kaolin (clay), aluminum silicate, and coprecipitates of barium sulfate and aluminum silicate are used, as well as natural and synthetic fibrous minerals, such as wollastonite; metal fibers, in particular glass fibers of various lengths, which may be sized in some cases. Examples of organic fillers include charcoal, melamine, rosin, cyclopentadienyl resins and graft polymers, as well as cellulose fibers, aromatic and / or aliphatic dicarboxylic acid-based polyamide fibers, polyacrylonitrile fibers, polyurethane fibers, polyester fibers, and especially carbon fibers. Inorganic and organic fillers can be used alone or in mixtures and are advantageously added to the reaction mixture in amounts of 0.5 to 50% by weight, preferably 1 to 40% by weight, relative to the weight of components (a) to (f). However, the content of natural and synthetic fiber mats, nonwovens and wovens may reach up to 80% by weight relative to the weight of components (a) to (f).

[0074] According to the present invention, the production of polyisocyanurate rigid foam material is carried out by mixing components (a) to (e) and (f) if present to form a reaction mixture. To reduce complexity, a premix can also be produced. This premix comprises at least one isocyanate component containing polyisocyanate (a) and a polyol component containing compound (b) having at least two hydrogen atoms reactive with the isocyanate. All or part of the further components (c) to (f) can be added completely or partially to the isocyanate and polyol components, where, often, components (c) to (f) are added to the polyol component to avoid side reactions due to the high reactivity of the isocyanate. However, a physical blowing agent can also be mixed with the isocyanate component (a). Typically, water, a formic acid-water mixture, or formic acid is present completely or partially dissolved in the polyol component, and the remainder of a physical blowing agent (e.g., pentane) and optionally a chemical blowing agent is added directly "online" during production. Preferably, a physical blowing agent is supplied online to a separate stream of the reaction mixture, and particularly preferably, the remaining components (c), (e), and (f) are added to the polyol component. Typically, the catalyst is supplied online by metering, but may already be partially or completely dissolved in the polyol component. Accordingly, the present invention also relates to a polyol component comprising component (b) as defined above, optionally a catalyst (c), a blowing agent (d), a flame retardant (e), and optionally auxiliary agents and additives (f), wherein the mass ratio of polyether ester polyol (b1) to polyester polyol (b2) is 0.3 or more and 3.0 or less, the sum of the mass fractions of components (b1) and (b2) is greater than 80% by weight relative to component (b), and the mass fraction of free monoethylene glycol supplied to the reaction mixture is less than 1.4% by weight relative to the total weight of components (b), (c), (e), and (f).

[0075] Preferably, polyester (b2) is used in such an amount that the polyethylene terephthalate content is at least 2.5% by weight, particularly preferably at least 3% by weight, even more preferably at least 4% by weight, and especially at least 5% by weight, relative to the total weight of each of the components (a) to (f).

[0076] Preferably, the polyol component for producing the polyisocyanate rigid foam material according to the present invention comprises, each based on the total weight of components (b) to (f), 70 to 90% by weight of a compound (b) having at least two hydrogen atoms reactive with an isocyanate group, 0.5 to 10% by weight of a catalyst (c), 2 to 20% by weight of a blowing agent (d), 1 to 20% by weight of a flame retardant (e), and 0 to 20% by weight of further auxiliary agents and additives (f). In a particularly preferred embodiment, the total proportion of components (b) to (f) is 100% by weight.

[0077] Next, the reaction mixture is allowed to react completely to form a polyisocyanate rigid foam material. Here, in the present invention, the reaction mixture refers to a mixture of polyisocyanate (a), a compound (b) having at least two hydrogen atoms reactive to the isocyanate group, and all further components (c), (d), (e), and optionally (f), with a reaction conversion rate to the isocyanate group of less than 90%.

[0078] Here, the mixing of the components to form the reaction mixture is carried out at an isocyanate index of at least 180, preferably 220-400, particularly preferably 260-360, and especially 280-330. In this case, the starting components are mixed at a temperature of 15-90°C, preferably 20-60°C, and particularly 20-45°C. The reaction mixture can be mixed by mixing in a high-pressure or low-pressure measuring machine.

[0079] The reaction mixture can be introduced, for example, into a mold to allow it to react completely. This technique allows for the production of, for example, intermittent sandwich elements. The rigid foam according to the present invention is preferably produced in a continuously operating double-belt apparatus. In this case, the polyol component and the isocyanate component are preferably introduced using a high-pressure machine and mixed in a mixing head. The catalyst and / or blowing agent can be pre-introduced to the polyol mixture using a separate pump. The reaction mixture is applied to a continuously moving lower surface layer, preferably a metal surface layer. The lower surface layer with the reaction mixture and the upper surface layer, preferably a metal surface layer as well, enter the double belt where the reaction mixture foams and hardens. After leaving the double belt, the continuous strand is cut to the desired dimensions. In this way, a sandwich element having a metal surface layer or a flexible surface layer can be produced. The lower and upper surface layers, which may be the same or different, can be flexible or rigid surface layers commonly used in the double-belt method. These include metal surfaces, such as aluminum or steel; bitumen surfaces; paper; nonwoven fabrics; plastic plates, such as polystyrene; plastic films, such as polyethylene films; or wood surfaces. The surfaces may be coated with, for example, conventional varnishes or adhesion promoters. Particularly preferred are surfaces that are impermeable to the bubbly gases of polyisocyanate rigid foam materials.

[0080] Such methods are known and are described, for example, in "Kunststoffhandbuch, Band 7, Polyurethane," Carl Hanser Verlag, 3rd edition 1993, Chapter 6.2.2, or in European Patent No. 2234732. Finally, the subject of the present invention is a polyisocyanate-based rigid foam material obtained by the method according to the present invention, and a polyurethane sandwich element comprising such a polyisocyanate-based rigid foam material according to the present invention.

[0081] The polyisocyanurate rigid foam material according to the present invention is characterized by excellent mechanical properties, particularly excellent compressive strength, low thermal conductivity, minimal post-foaming behavior, high fire resistance, and a surface that is as defect-free as possible, as well as good adhesion to the surface. The method according to the present invention for producing such a polyisocyanurate rigid foam material is characterized by the ease of processing of the raw materials, particularly due to their low viscosity, and the starting components can be easily mixed with further components for the production of the polyisocyanurate rigid foam material. Furthermore, the polyisocyanate-based rigid foam material according to the present invention has excellent flame resistance even when small amounts of ecologically and toxicologically harmful flame retardants are used. In addition, the reaction mixture used in the production of the polyisocyanate-based rigid foam material according to the present invention allows for improved complete curing of the foam and achievement of the required reactivity, even when using smaller amounts of ecologically and toxicologically harmful catalysts.

[0082] The present invention will be described in more detail by the following examples: [Examples]

[0083] The following starting materials were used:

[0084] Polyols: Polyether esterol 1:Hydroxyl functional value of 2.5, hydroxyl value of 240 mg KOH / g, and oleic acid content of 15% by weight, are esterification products from terephthalic acid, oleic acid, diethylene glycol, and ethoxylated glycerol. Polyesterol 2: An esterification product from phthalic anhydride, oleic acid, and diethylene glycol, having a hydroxyl functional value of 1.75, a hydroxyl value of 215 mg KOH / g, and an oleic acid content of 15% by weight. PET polyesterol 1: The esterification product obtained from the conversion of polyethylene terephthalate, adipic acid, and diethylene glycol has a hydroxyl functional value of 2.0, a hydroxyl value of 245 mg KOH / g, and contains 40% by weight polyethylene terephthalate, 22% by weight adipic acid, and 1.09% free MEG. PET polyesterol 2: Esterification product from an ester obtained by the conversion of polyethylene terephthalate, adipic acid, soybean oil, and diethylene glycol, having a hydroxyl functional value of 1.85, a hydroxyl value of 190 mg KOH / g, and containing 40% by weight polyethylene terephthalate, 18% by weight adipic acid, 12% by weight fatty acid, and 0.79% free MEG. PET Polyesterol 3: An esterification product obtained from esters obtained by the conversion of polyethylene terephthalate, adipic acid, and diethylene glycol, having a hydroxyl functional value of 2, a hydroxyl value of 240 mg KOH / g, and containing 30% by weight polyethylene terephthalate and 1.4% free MEG. PET Polyesterol 4: An esterification product obtained from esters obtained by the conversion of polyethylene terephthalate, adipic acid, and diethylene glycol, having a hydroxyl functional value of 2, a hydroxyl value of 290 mg KOH / g, and containing 45% by weight polyethylene terephthalate and 1.05% free MEG. Polyetherol 1: A polyether polyol produced by ethoxylation of ethylene glycol, having a hydroxyl functional value of 2 and a hydroxyl value of 190 mg KOH / g.

[0085] Flame retardant: TCPP: Tris(2-chloroisopropyl) phosphate having a chlorine content of 32.5% by weight and a phosphorus content of 9.5% by weight.

[0086] Foam stabilizer: Stabilizer: Silicone-containing foam stabilizer from Evonik.

[0087] catalyst: Catalyst A: A catalyst consisting of 23.1% by weight of bis(2-dimethylaminoethyl) ether and 76.9% by weight of dipropylene glycol. Catalyst B: A catalyst consisting of 40% by weight potassium formate, 54% by weight monoethylene glycol, and 6% by weight water. Catalyst C: A catalyst consisting of 54 wt% potassium-2-ethylhexanoate, 20.5 wt% diethylene glycol, 22.5 wt% triethyl phosphate, and 3.0 wt% water.

[0088] Chemical foaming agents: Amasil 85%: A foaming agent mixture consisting of 85% by weight of formic acid and 15% by weight of water.

[0089] Physical foaming agents: Pentane S80 / 20: A foaming agent mixture consisting of 80 mol% n-pentane and 20 mol% isopentane.

[0090] Isocyanates: Lupranat® M50: A polymer methylenediphenyl diisocyanate (PMDI) from BASF with a viscosity of approximately 550 mPa·s at 25℃.

[0091] Using the listed starting materials, the polyol components listed in Table 2 were prepared and converted using a high-pressure machine in a continuous double-belt process.

[0092] Continuous manufacturing of sandwich elements using the double-belt method: Composite elements with thicknesses of 50 mm and 120 mm were manufactured using the double-belt process. For manufacturing, the polyol components listed in Table 2, temperature-controlled to 22 ± 1°C, were converted together with Lupranat® M50, also temperature-controlled to 22 ± 1°C.

[0093] The amount of Lupranat® M50 was always selected so that all rigid foam materials processed into 50mm sandwich elements had an isocyanate index of 305±15, and all rigid foam materials processed into 120mm sandwich elements had an isocyanate index of 325±15.

[0094] To manufacture the composite elements, both a 0.05 mm thick aluminum film heated to 35 ± 2°C and a 0.5 mm thick double-sided coated aluminum sheet heated to 40 ± 2°C were used as the bottom surface layer. Both surface layers are industry standards and are also used in conventional continuous manufacturing processes for sandwich elements. The temperature of the double belt was consistently 60 ± 2°C.

[0095] To produce a composite element with a thickness of 50 mm, 100 parts of the polyol component were mixed with the parts of Amasil 85% listed in Table 2. The amounts of catalyst B and catalyst C were selected so that the proportion of potassium ions was 0.11 ± 0.02% by weight relative to the total components for producing the foam. The amounts of catalyst A and the physical blowing agent were selected so that the gelation time of the reaction mixture was exactly 25 seconds, the contact time between the reaction mixture and the upper belt was exactly 20 seconds, and the foam had a total density of 39.5 ± 1.5 g / l.

[0096] To produce a composite element with a thickness of 120 mm, 100 parts of the polyol component were mixed with the parts of Amasil 85% listed in Table 2. The amounts of catalyst B and catalyst C were selected so that the proportion of potassium ions was 0.10 ± 0.02% by weight relative to the total components for producing the foam. The amounts of catalyst A and the physical blowing agent were selected so that the gelation time of the reaction mixture was exactly 32 seconds, the contact time between the reaction mixture and the upper belt was exactly 26 seconds, and the foam had a total density of 39.5 ± 1.5 g / l.

[0097] To determine the compressive strength and foam surface, after successfully adjusting the foaming parameters, a test plate measuring 2.0 m in length and 1.25 m in width was cut out, and then the test specimens required for testing were consistently cut from the same position.

[0098] Determining the central thickness of a sandwich form element: The thickness of the sandwich elements of a test plate manufactured with a 12mm gap between the upper and lower belts was measured at the center of the element width between the groove and the key side immediately after leaving the double belt and 24 hours later (after cooling). These values ​​are shown as "Element Center Thickness (Immediate)" and "Element Center Thickness (24 Hours)". The difference between "Element Thickness (Immediate)" and the set gap size of 120mm is shown as "Element Center Thickness Difference (Immediate)".

[0099] In addition, the warp of the sandwich elements was determined. This is expressed in millimeters as the difference between the element center thickness (24 hours) and the element end thickness (24 hours). The element end thickness (24 hours) is the average of two element thicknesses measured at a distance of 5 cm from the edge of the key and groove.

[0100] Determining the compressive strength of sandwich foam: After storage under standard conditions for 24 hours, additional test specimens with dimensions of 100 mm × 100 mm × sandwich thickness were cut from the test specimen using a band saw. The test specimens were cut at the same position (left, center, right) across the width of the element, and the compressive strength of the foam was determined according to the sandwich standard DIN EN ISO 14509-A.2, which conforms to EN 826.

[0101] Determination of lateral tensile strength: Further test specimens with dimensions of 100 mm × 100 mm × sandwich thickness (50 mm, 100 mm, 170 mm) were cut from the test specimen using a band saw. The test specimens were cut at the same position (left, center, right) across the width of the element, and the lateral tensile strength of the foam, or adhesion to the surface, was determined according to the sandwich standard DIN EN ISO 14509-A.1, which conforms to EN 1607.

[0102] Evaluation of the foam surface after peeling of the lower surface layer: After mechanically removing the aluminum film and the aluminum sheet (lower surface layer) applied using the double-belt method with the liquid reaction mixture, the foam surface was visually evaluated and graded. Here, Grade 1 represents the best foam surface, and Grade 5 represents the worst foam surface.

[0103] [Table 1]

[0104] Small burner testing in accordance with EN-ISO 11925-2: Test specimens for the small burner test were prepared as follows: 300g of the reaction mixture, adjusted to the same reaction time and foam density, was vigorously stirred in a paper cup at 1500 rpm for 10 seconds using a laboratory stirrer, and then transferred to a box mold with inner dimensions of 150mm × 250mm (length × width). After 24 hours, the rigid foam block was removed from the mold and all ends were shortened by 30mm. The test specimens, cut to dimensions of 190 × 90 × 20mm, were then conditioned for one day and tested by applying a flame to the 90mm end in accordance with DIN EN-ISO 11925-2. The values ​​shown in Table 3 are the average values ​​of 5 determinations.

[0105] [Table 2]

[0106] [Table 3]

[0107] [Table 4]

[0108] Tables 3 and 4 show the foam and sandwich element properties of the manufactured 50mm and 120mm thick sandwich elements. The polyol component of Example 1, containing "Polyether Esterol 1" as the sole polyester, when processed into a 50mm thick sandwich element, resulted in a foam surface without voids beneath the aluminum film and sheet, and yielded an acceptable flame height in a small burner test. The manufactured 120mm thick elements, after being separated from the double belt, showed only a very small element-center thickness difference for a set gap size of less than 2.0mm. In addition, the elements had an acceptable compressive strength value.

[0109] As can be seen from Examples 3 and 5, completely replacing "Polyether Esterol 1" with "PET Polyesterol 1" and "PET Polyesterol 2" results in significant drawbacks in both the manufacture of 50 mm thick and 120 mm thick sandwich elements.

[0110] Compared to Example 1, the foams of Examples 3 and 5 show significant deterioration of the foam surface after removal of both surface layers. In addition, the 120mm elements show a clear increase in the thickness difference between the elements' centers after exiting the double belt. Surprisingly, using a combination of "Polyether Ester Polyol 1" and "PET Polyester All 1" or "PET Polyester All 2" yields a foam that meets all the requirements of the double belt process.

[0111] Therefore, it can be seen that Examples 2, 4, and 9 of the present invention, like the foam of Example 1, have the same good foam surface beneath both surface layers. The difference in thickness between the elements is also within an acceptable range. In this case, it can be easily seen from Example 9 that the difference in thickness between the elements is further reduced by the use of catalyst C, and that an even higher proportion of PET polyester polyol can be used.

[0112] Compared to Example 1, the foams of Examples 2, 4, and 9 according to the present invention surprisingly show improved foam compressive strength and improved flame resistance. The use of catalyst C surprisingly results in further improvement of foam compressive strength and acceptable flame resistance.

[0113] The combination of "Polyether Ester All 1" and "PET Polyester" is important to the present invention. Therefore, from Example 6, it can be seen that if "Polyether Ester All 1" is replaced with another ester that does not contain polyether components, a foam that no longer meets all requirements is obtained. For this reason, "Polyester All 2" causes defects on the foam surface beneath both surface layers. Furthermore, the 120 mm elements produced from Example 6 have an increased element thickness difference compared to the 120 mm elements from Example 4.

[0114] The present invention also demonstrates that not all PET polyesterols are suitable. For example, PET polyesters with a high free monoethylene glycol content exhibit significantly strong recompression (Nachdruecken) even when used in combination with "Polyether Ester Polyol 1" (see Examples 7 and 8). PET polyesters with excessively high OH values ​​are also unsuitable. This is because, even when the proportion of free monoethylene glycol is within the range according to the present invention, they similarly result in increased element central thickness and deterioration of the foam surface (see Example 10).

Claims

1. A method for producing a polyisocyanurate rigid foam material, a) Aromatic polyisocyanates, b) A compound comprising at least one polyether ester polyol (b1) and at least one polyester polyol (b2), having at least two hydrogen atoms reactive with an isocyanate group. c) catalyst; d) Foaming agent, e) Flame retardants f) Depending on the circumstances, auxiliary agents and additives The mixture is used to form a reaction mixture, and the mixture is allowed to react completely to form the polyisocyanurate rigid foam material. The polyether ester polyol (b1) is, in proportion to the total amount of each component b1.1) to b1.4), b1.1) A dicarboxylic acid composition containing 10 to 50 mol% aromatic dicarboxylic acid, b1.2) 2 to 20 mol% of one or more hydrophobic compounds or derivatives thereof having at least one hydroxyl group and / or carboxyl group, b1.3) 10 to 70 mol% of one or more diols having 2 to 6 carbon atoms, b1.4) Polyether polyols produced by alkoxylation of 15 to 50 mol% of an initiator or initiator mixture having an average functional value of 2 or more and 4 or less. Obtained by esterification, the polyether ester polyol (b1) has an average functional value of 1.7 or more and 2.8 or less and an OH value of 150 mg KOH / g or more and 300 mg KOH / g or less. The polyester polyol (b2) has a functional value of 1.7 or more and 2.7 or less, an OH value of 170 mg KOH / g or more and 280 mg KOH / g or less, and a free monoethylene glycol content of less than 1.3% by weight, and polyethylene terephthalate is used in the production of the polyester polyol (b2), and its proportion is more than 25% by weight of the total amount of all components used in the production of the polyester polyol (b2). The mass ratio of polyether ester polyol (b1) to polyester polyol (b2) is 0.3 or more and 3.0 or less, and the sum of the mass fractions of component (b1) and component (b2) is greater than 80% by weight relative to component (b). The mass fraction of free monoethylene glycol supplied to the reaction mixture is less than 1.4% by weight relative to the total weight of components (b), (c), (e), and (f). The mixing for forming the reaction mixture is carried out at an isocyanate index of at least 180. method.

2. The method according to claim 1, characterized in that the proportion of polyethylene terephthalate is 28% by weight or more of the total amount of all components used in the production of polyester polyol (b2).

3. A method according to any one or more of claims 1 to 2, characterized in that, for the production of polyester polyol (b2), at least one aliphatic dicarboxylic acid having 4 to 6 carbon atoms is used, and the proportion of the aliphatic dicarboxylic acid is 10% by weight or more of the total components used in the production of polyester polyol (b2).

4. The method according to any one or more of claims 1 to 3, characterized in that the polyester polyol (b2) has a hydroxyl value of less than 200 mg KOH / g and has a fatty acid content of more than 8% by weight relative to the total weight of the polyester polyol (b2).

5. The method according to any one or more of claims 1 to 3, characterized in that the polyester polyol (b2) has a hydroxyl value of more than 200 mg KOH / g and a fatty acid content of 0% by weight relative to the total weight.

6. The method according to any one or more of claims 1 to 5, characterized in that the dicarboxylic acid composition (b1.1) has a terephthalic acid content of more than 80% by weight relative to the total weight of component (b1.1).

7. The method according to one or more of claims 1 to 6, characterized in that oleic acid is used as component (b1.2), and the proportion of oleic acid is 8 mol% or more relative to the total amount of components b1.1) to b1.4).

8. The method according to any one or more of claims 1 to 7, characterized in that the polyether polyol (b1.4) is produced by alkoxylation with ethylene oxide, has a functional value of 3, and the ethylene oxide content is more than 80% by weight relative to the total alkylene oxide used in the production of the polyether polyol (b1.4).

9. The method according to any one or more of claims 1 to 8, characterized in that component (b) is obtained by ethoxylation of the initiator or initiator mixture having an average functional value of 2 or more and 3 or less, and comprises at least one polyether polyol (b3) having an OH value of 150 to 300 mg KOH / g, wherein the proportion of ethylene oxide is more than 80% by weight relative to the total alkylene oxide used in the production of (b3).

10. The method according to any one of claims 1 to 9, characterized in that catalyst (c) contains a potassium salt of an aliphatic carboxylic acid having more than five carbon atoms.

11. The method according to any one or more of claims 1 to 10, characterized in that the blowing agent (d) comprises a chemical and a physical blowing agent, and the chemical blowing agent is selected from the group consisting of water, a formic acid-water mixture, and formic acid.

12. The method according to any one or more of claims 1 to 11, characterized in that the flame retardant (e) includes a phosphorus-based flame retardant, and the phosphorus content is less than 0.7% by weight relative to the total weight of components (a) to (f).

13. The method according to any one or more of claims 1 to 12, characterized in that the polyethylene terephthalate content is more than 2.5% by weight relative to the total weight of components (a) to (f).

14. The method according to any one of claims 1 to 13, characterized in that the reaction mixture is applied to a continuously moving surface in a double-belt apparatus for manufacturing sandwich elements.

15. A polyol component for the manufacture of polyisocyanurate rigid foam material, b) A compound comprising at least one polyether ester polyol (b1) and a polyester polyol (b2), wherein the number average content of isocyanate-reactive hydrogen atoms in components (b1) and (b2) is at least 1.7, and which has at least two isocyanate-reactive hydrogen atoms. c) Depending on the case, a catalyst, d) Foaming agent, e) Flame retardants, and f) Depending on the circumstances, auxiliary agents and additives Includes, The polyether ester polyol (b1) is, in proportion to the total amount of each component b1.1) to b1.4), b1.1) A dicarboxylic acid composition containing 10 to 50 mol% aromatic dicarboxylic acid, b1.2) 2 to 20 mol% of one or more hydrophobic compounds or derivatives thereof having at least one hydroxyl group and / or carboxyl group, b1.3) 10 to 70 mol% of one or more diols having 2 to 6 carbon atoms, b1.4) Polyether polyols produced by alkoxylation of 15 to 50 mol% of an initiator or initiator mixture having an average functional value of 2 or more and 4 or less. Obtained by esterification, the polyether ester polyol (b1) has an average functional value of 1.7 or more and 2.8 or less and an OH value of 170 mg KOH / g or more and 270 mg KOH / g or less. The polyester polyol (b2) has a functional value of 1.7 or more and 2.7 or less, an OH value of 170 mg KOH / g or more and 280 mg KOH / g or less, and a free monoethylene glycol content of less than 1.3% by weight, and polyethylene terephthalate is used in the production of the polyester polyol (b2), and its proportion is more than 25% by weight of the total amount of all components used in the production of the polyester polyol (b2). The mass ratio of polyether ester polyol (b1) to polyester polyol (b2) is 0.3 or more and 3.0 or less, and the sum of the mass fractions of component (b1) and component (b2) is greater than 80% by weight relative to component (b). The mass fraction of free monoethylene glycol supplied to the reaction mixture is less than 1.4% by weight relative to the total weight of components B, C, E, and F. Polyol components.

16. A polyisocyanurate rigid foam material obtained by the method described in one or more of claims 1 to 14.

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