MXPA97005666A - Production of rigi polyurethane foams - Google Patents

Abstract

Rigid polyurethane foams are produced by reacting a) Organic and / or modified organic diisocyanates and / or polyisocyanates with b) Specific polyester polyols and / or polyether ester polyols which can be prepared by polycondensation of dicarboxylic acid with polyfunctional alcohols using polyalkylene terephthalates and , if desired, subsequent reaction with lower alkylene oxides, if desired, additional relatively high molecular weight compounds, containing at least two reactive hydrogen atoms and, if desired, c) low molecular weight chain extenders and / or crosslinkers in the presence of d) blowing agents e) catalysts and, if desired, f) additional auxiliaries and / or additives, wherein the polyester polyols and / or polyether ester polyols are prepared in a stepwise polycondensation, wherein the first step is introduced polyalkylene terephthalate in addition to the starting components in to condensation, as it is started and / or while it is started and in at least one additional stage, catalytically active substances are added. These rigid polyurethane foams can be used as insulation material for the long-distance energy and cooling sectors, as a sandwich material in building and construction, and as a support and training material in the furniture sector.

Description

PRODUCTION OF RIGID POLYURETHANE FOAMS The present invention relates to a process for producing rigid polyurethane foams by reacting a) organic and / or organic modified diisocyanates and / or polyisocyanates with b) specific polyester polyols and / or polyether ester polyols which can be prepared by polycondensation of dicarboxylic acids with polyfunctional alcohols using polyalkylene terephthalates and, if desired, subsequent reaction with lower alkylene oxides, plus, if desired, additional relatively high molecular weight compounds containing at least two atoms of reactive hydrogen, and if desired, c) low molecular weight chain extenders and / or crosslinkers in the presence of d) blowing agents e) catalysts, and if desired, f) additional auxiliaries and / or additives. The production of rigid polyurethane foams makes reacting organic and / or modified organic diisocyanates -and / or polyisocyanates with relatively high molecular weight compounds containing at least two reactive hydrogen atoms, in particular with polyether polyols from polyethylene. The conversion of alkylene oxide or polyester polyols from the polycondensation of alcohols with dicarboxylic acids, with the concomitant use of polyurethane catalysts, chain extenders and / or crosslinkers, blowing and auxiliary agents and additional additives, is known and has been described in numerous patent and literature publications. Mention may be made, by way of example, of Kunststo fhandbuch, Volume VII, Polyurethane, Carl-Hanser-Verla Munich, 1§ Edition 1966, edited by Dr. R. Vieg and Dr. A. Höchtlen, and 1-ed. 1983 and 3 ^ 1993 edition, edited by Dr. G. Oertel. The proper selection of the forming components and their relationships allows rigid polyuronal foams to be produced which have very good mechanical properties. When polyester polyols are used, it is customary to use polycondensates of aromatic and / or aliphatic dicarboxylic acids and alkanediols and / or alkantriols or ether diols. However, it is also possible to process polyester wastes and here in particular polyethylene terephthalate (PET) or polybutylene terephthalate (PBT) wastes. A complete series of processes for this purpose is known and described. The basis of some processes is the conversion of the polyester to a teresphthalic acid diester, e.g., to dimethyl terephthalate. In DE-A-1003714 and US-A-5 051 528, said transesterifications are carried out using methanol and transfection catalysts. All these processes have many disadvantages as a result of complicated technological steps, e.g., the use of methanol vapor, and also secondary reactions that proceed in an uncontrolled manner. Additional processes, e.g., as described in De-C-4227299, add tracy-ester catalysts and dialkyl esters for the purpose of depolymerization. The catalysts used are manganese acetate or zinc compounds. The processes actually differ only in the catalyst used: in DE-A-4220473 PBT is prepared by treating PET waste with a titanium or tin catalyst and 1,4-butanediol. Polym. Mater. Sci. Eng. (1990) 63, p. 1029 - 1033, 5S, 1B, 6T, 19Q - describes the use of zinc acetate for the glycolysis of PET waste. As a result of the addition of catalyst together with alcohol just at the beginning of glycolysis, the dissociation and polycondensation reactions proceed simultaneously in an uncontrolled manner, the degradation of PET is interrupted and insoluble constituents (turbidity) result. These insoluble constituents prevent further processing to provide the polyurethane. In EP-A-134661, these disadvantages are avoided by means of glycolysis of catalyst-free PET using ethylene glycol and subsequent alkoxylation using sodium acetate as a catalyst. The principle of glycolysis proceeds formally, but the reaction remains very incomplete. The process only allows certain types of PET to be worked and the addition of the basic catalyst reinforces a series of undesired hydrolysis reactions and thus greatly widens the molecular weight distribution. US-A-2030997 describes the production of rigid polyurethane foam from polyols derived from recycled p-lyalkylene terephthalate. The glycolysis of alkylene terephthalates is, as is generally known, carried out in a single-step reaction with alkyl glycol ethers or ethers of g 1 i col with the specific addition of bis (2-hydroxyethoxy ethyl) glutarate. . This also leads to inhomogeneities and the pre-excitation of oligomeric dissociation and reaction products immediately after tranesterification of the polyalkylene terephthalates is congested and in particular after storage of the products for 2-3 days. In this way, the use of said polyol products results, similarly to the case of polyols prepared as described in EP-A-0710686, in the form of polyurethane even before the actual polyurethane reaction. The stable precipitates of the polyol components for the p-lurethane formed in rigid polyurethane foams produced therefrom have considerable mechanical deficiencies. Furthermore, the process described in EP-A-0710686 is also extremely uneconomical to carry out, since, among others, they have to feed large amounts of SDR towards and have to be distilled off in a distillation at 10 ° C which is difficult to control industrially. An object of the present invention is to provide a process for producing rigid polyurethane foams by reacting specific aromatic diisocyanates and / or polyisocyanates with specific polyols that have been prepared using all types of industrially available PET / PBT in the presence of auxiliaries and customary additives, whose process avoids r unwanted actions of hydrolysis and displacements of mol- cular weight that damage the quality. We have found that this object is achieved by producing the rigid polyurethane foams using specific polyester polyols and / or polyether ester polyols which can be prepared by polycondensation of dicarboxylic acids with polyfunctional cools using polyalkylene terephthalates and, if desired , Subsequent reaction with lower alkylene oxides, wherein the polyester polyols and / or polyether ester polyols are prepared in stepwise polycondensation wherein, in the first step, polyalkylene terephthalate is introduced further than the starting components towards condensation as it begins and / or while it is on the way and, at least in an additional stage, catalytically active substances are added. The present invention consequently provides a process for producing rigid polyurethane foams by reacting: a) diisocyanates and / or organic polyisocyanates and / or organic modifi ed with b) polyester polyols and / or polyether ester polyols which can be prepared by polycondensation of dicarboxylic acids with polyfunctional alcohols using polyalkylene terephthalates and, if desired, subsequent reaction with alkylene oxides in ferments, plus, if desired, additional compounds of relatively high molecular weight containing at least two atoms of reactive hydrogen and, if desired c) low molecular weight chain extenders and / or withdrawers in the presence of d) blowing agents, e) catalysts, and if desired, f) auxiliary and / or additional additives, in wherein the polyester polyols and / or poly ether ester polyols are prepared in a stepwise polycondensation wherein, in the first step, polyalkylene terephthalate is added further than the starting components towards condensation as it begins, and / or while it is on the way and, at least one additional step, catalytically active substances are added. The present invention also provides the use of such rigid polyurethane foams as insulating material for the long-distance energy cooling sectors, as a sandwich material in the construction and as a support and as a training material in the furniture sector.

It was surprising and in no way expected that this multistage polycondensation sought, the addition coincided in a precise manner with the polyalkylene terephthalate products and the subsequent additional addition of catalysts and, if desired, carboxylic acids and Additional alcohols result in a homogeneous polyol mixture which remains homogeneous, even for weeks, by itself and in a mixture as the polyol component of a polyurethane system. Additionally, it was also surprising that this process allows all the available terephthalate-p-alkylene products to be processed without losses to provide homogeneous polyols. The rigid polyurethane foams produced from these polyol blends are of high quality, the process is smooth, the curing and fluidity are optimal and the mechanical properties fulfill the high demands of the refining, construction and construction industries. and long distance energy. An economical process has been found in this way to produce rigid polyurethane foams that are very suitable as insulating material for the long distance energy and refrigeration sectors, as a sandwich material in construction and as a support and training material in the sector. Of furniture. The specific polyester polyols and / or polyether ester polyols which are used in accordance with the present invention are preferably prepared by polycondensation of dicarboxylic acids with polyfunctional alcohols using polyalkylene reftalates and, if desired, subsequent reaction with lower alkylene oxides. In accordance with the present invention, the polyester polyols and / or polyether ester polyols are prepared in a stepwise polycondensation. In the first stage of the polycondensation, polyalkylene terephthalate is introduced in addition to the starting components, namely, the dicarboxylic acids and polyfunctional alcohols, towards condensation as it begins, and / or while it is on the way. . The precondensation product, in at least one additional step, is mixed with catalytically active sub-tances, if desired in combination with additional quantities of dicarboxylic acids and / or poly-unic alcohols. The product can be modified to form polyether ester polyols by subsequent reaction with lower alkylene oxides. The polyalkylene terephthalate is preferably added at a temperature of the starting components or the condensation mixture of 150 to 25 ° C, in particular of 180 to 240 ° C, at atmospheric pressure or under slightly reduced pressure of 1 to 200 mbar, in particular of 10. at 100 mbar. The polyalkylene terephthalates can be used individually or in admixture with another. Preference is given to using PET and / or PBT.

In particular, use is made of polyalkylene terephthalate waste such as PBT and PET granules from the recirculation of PBT or PET articles, films, fibers and sheets or liquid pastes or PBT and liquid PET. of production. In the preparation of the polyester polyols and / or polyether ester polyols to be used according to the present invention, the acid components used are the dicarboxylic acids used in a customary manner for this purpose, preference adipic acid, glutaric acid, succinic acid and / or phthalic acid and / or its anhydrides, in particular phthalic anhydride. The dicarboxylic acids are reacted with polyfunctional alcohols, preferably alkanediols and / or alkanols having 2 to 20 carbon atoms and / or ether diols having 4 to 20 carbon atoms. In particular, monoglycols and / or monotrichols such as 1,3- and 1,4-butanediol, -hexandiols, neopentyl glycol, ethylene and / or propylene glycol, glycerol and / or trimethylolpropane and their diols are used. of ether, preferably -diethylene, triethylene and / or propoeti-lecrylics and / or dipropylene, tripropylene and / or polypropylene glycols having an average molecular weight of up to 1000. Preference is given to using ethylene and / or propylene glycol as diols and glycerol and / or trimetiolpropanol as triols. As catalytically active substances in the condensation reaction, preference is given to using tita-nio and / or tin compounds and / or Lewis acids in amounts of up to 1000 ppm, for example, tetrabutyl orthotitanate, tin octoact (II) , tin (II) chloride or iron (II) chloride. The polyols prepared in accordance with the present invention can be subjected to a distillation extraction or preference treatment. The further preferred distillation is carried out using a short residence time ad 100 to 280 ° C, particularly preferably at 250 to 270 ° C, under a reduced pressure similar to that in the post-condensation and / or with gas feed inert. The inert gas used herein is particularly preferably nitrogen. The extraction treatment is carried out using an extractive agent on a wide temperature scale, preferably 20 to 250 ° C. The extractants used are preferably inert solvents, in particular aliphatic hydrocarbons or aliphatic cyclones such as hexane, heptane, cyclohexane and ethylcyclohexane or mixtures thereof. The removal of the low molecular weight components can be carried out batchwise in a commercial apparatus for liquid-liquid extraction, e.g., in a rotary perforator, or continuously in countercurrent in a tube. The remaining solvent residues from the extraction can be easily removed by subsequent treatment under reduced pressure, preferably at elevated temperature. Polyester polyols and / or polyether ester polyols prepared in this manner, if desired, are in admixture with additional compounds of relatively high molecular weight - which contain at least two reactive hydrogen atoms, as described below, reacted with the other components to provide the rigid polyurethane foams of the present invention. These foams have a uniformly high level of mechanical properties as well as a high hardness and a low thermal conductivity and are particularly suitable for use in the insulation sector and for producing intermeshed elements. The process of the present invention has the advantage that the mild polycondensation in the first stage results in a homogeneous polycondensation / tranesterification reaction which, by means of the modification in the second stage, leads to homogenous polyols that can be processed towards rigid polyurethane foams that have excellent properties. The otherwise usual secondary reactions, product dissociations and considerable displacements of molecular weight, in particular widening of the molecular weight distributions leading to considerable amounts of precipitate and loss of quality, are completely or largely avoided. . It is surprising that the object of the invention can be achieved by the use of the polyether polyols and / or polyether ester polyols specifically prepared in the present invention. Rather, it would have been expected that the polycondensation / transesterification by stages would have resulted, in a manner similar to the prior processes of the prior art, in inhomogeneous, cloudy polyols, whose turbidity occurs immediately or is thus left to stand for a short time. or long or in a mixture of the polyol component of the polyurethane. In order to produce the rigid polyurethane foams mediated by the process of the present invention, use is made, apart from the polyester polyols and / or polyether ester polyols specified above, of the forming components known per se. which the following details can be provided. a) The appropriate modified organic and / or organic polyisocyanates (a) are polyfunctional isocyanates, cycloaliphatics, araliphatics and preferably armatics, known per se. Specific examples of alkylene diisocyanates having from 4 to 12 carbon atoms in the alkylene radical, for example, 1,12-docecan diisocyanate, 1,4-di-isocyanate of 2-ethyltetramethylene, 1,5-diisocyanate of 2-methylpentamethyl, 1,4-diisocyanate of tetramethyl, and preferably 1,6-diisocyanate of hexamethyl; cycloaliphatic diisocyanates such as 1,3- and 1,4-cyclohexane diisocyanate and also mixtures of these isomers, 1-isocyanate-3, 3, trimethyl-1-5-isocyanatomethylcyclohexane (IPDI), 2,4- and 2, 6-hexahydrotol diisocyanate and also the corresponding isomeric substances, 4,4'-, 2,2'- and 2,4'-diisocyanate of dicyclohexylmethane and also the corresponding isomeric mixtures, and preference is given to aromatic diisocyanates and polyisocyanates such as tolylene 2,4- and 2,6-diisocyanate, and the corresponding isomeric mixtures, 4,4'-, 2,4'- and 2, 2'-diphenylmethane diisocyanate and the corresponding isomeric mixtures, mixtures of 4,4'- and 2, 2'-diphenyl diisocyanates , polyphenylene polyisocyanates, polypropylene, a mixture of 2,4'-, 2,4'- and 2,2'-diisocyanates of diphenylmethane polyisocyanates of polyfluoroethanol (crude MDl) and mixtures of crude MDl and tolylene diisocyanates. Organic diisocyanates and polyisocyanates can be used individually or in the form of their mixtures. Also frequently used are modified polyfunctional isocyanates, that is, products obtained by chemical reaction of diisocyanates and / or organic polyisocyanates. The examples that can They are diisocyanates and / or polyisocyanates which contain ester, urea, biuret, allophanate, carbodiimide, isocyanurate, uretdione and / or urethane groups. The specific examples are: organic polyisocyanates, preferably aromatic containing urethane groups and Having NCO contents of from 33.6 to 15% by weight, preferably from 31 to 21% by weight, based on the total weight, for example, of 4,4 '-di-diisocyanate modified diphenylmethane with low weight diols molecular, triols, dialkylene glycols, trialkylene glycols or polyoxyalkylene glycols having molecular weights of up to 6000, in particular having molecular weights of up to 1500, 4,4'- and 2, 4'-di and diphenylmethane soci mixtures thereof, modified crude MDl or tolylene 2,4- or 2,6-diisocyanate, with examples of dialkylene or -10-polyoxyalkylene glycols, which may be used individually or as mixtures being: diethylene and dipropyl glycol, polyoxyethylene, pol ioxipropi len and pol ioxipropi le pol ixoeti lengl icoles, triols and / or tetroles. Also suitable are prepolymers containing NCO groups, Having contents of from 25 to 3.5% by weight, preferably from 21 to 14% by weight, based on the total weight, and prides from the polyester polyols and / or preferably polyether polyols described below and 4,4'-diphenylmethanediisocyanate, mixtures of 2,4'- 4,4'-diisocyanate of diphenylmethane, 2,4- and / or 2,6-diis cyanates of tolylene or crude MDl. Other polyisocyanates which have been found to be useful are liquid-based polyisocyanates containing carbodiimide groups and / or isocyanurate rings having NCO contents. 33.6 to 155 by weight, preferably 31 to 21% by weight based on the total weight, e.g., those based on 4,4'-, 2,4'- and / or 2,2'-di diphenylmethane isocyanate and / 2,4- and / or 2,6-di-tolylene isocyanate. If desired, the modified polyisocyanates can be mixed with each other or with unmodified organic polyisocyanates such as 2,4'- and / or 2,4 '-di-di-isocyanate of difimethylmethane, crude MDl, 2,4- and / or 2, 6-di isocyanate of wood. The organic polyisocyanates that have been found to are particularly useful and, therefore, are preferably used are: mixtures of tolyl non-diisocyanates and crude MDl or mixtures of modified organic polyisocyanates containing urethane groups and having an NCO content of 33.6 to 15% by weight, in particular Those based on tolylene diisocyanates, 4,4'-diphenylmethane diisocyanate, isomeric mixtures of diphenylmethane diisocyanate or crude MDl and in particular crude MDl having an isomer content of diphenylmethane diisocyanate of 30 to 80% in weight, of Preferably from 30 to 60% by weight, in particular from 30 to 55% by weight. b) The specific polyester ester polyols and / or ester polyols used are those prepared in accordance with the present invention, as described above. In addition to these, it is possible to use relatively high molecular weight compounds containing at least two reactive hydrogen atoms in an amount of 10 to 90% by weight, preferably 20 to 60% by weight, based on the weight of component (b). Additional compounds of relatively high molecular weight which contain at least two reactive hydrogen atoms which are used are advantageously those having a functionality of 2 to 8, preferably 2 to 6, and a molecular weight of 300 to 8000, from Preference from 300 to 3000. The compounds used depend on the desired properties of the rigid polyurethane foam that is to be produced. Examples of additional compounds of relatively high molecular weight which have been found useful are poly etherpoly amines and / or preferably polyols selected from the group consisting of polyester polyols, polyester polyols, polythioether polyols, polyeste ramides, hydroxyl-containing polyactals and hydrocarbyl-containing aliphatic polycarbonate butes or mixtures thereof.

At least two of the mentioned polyols. Preference is given to using polyester polyols and / or polyester polyols. The hydroxyl humerus of the polyhydroxyl compounds herein is generally 150 850 mg KOH / g and preferably 200 to 60 mg KOH / g. Suitable additional polyester polyols can be prepared, for example, from organic dicarboxylic acids having from 2 to 12 carbon atoms, preferably aliphatic dicarboxylic acids having from 4 to 6 carbon atoms, and alcohols. polyhydrides, preferably diols, having from 2 to 12 carbon atoms, preferably from 2 to 6 carbon atoms. Examples of suitable dicarboxylic acids are: succinic acid, glutaric acid, adipic acid, suberic acid, acelaic acid, sebacic acid, decand acid carboxylic acid, maleic acid, fumaric acid, phthalic acid, isophthalic acid and terephthalic acid. The dicarboxylic acids can be used either individually or in admixture with each other. Instead of free dicarboxylic acids, it is also possible to use d corresponding dicarboxylic acid derivatives such as dicarboxylic esters of alcohols having from 1 to 4 carbon atoms or dicarboxylic anhydrics Preference is given to using dicarboxylic acid mixture of succinic, glutaric and adipic acids in in weight from 20-35: 35-50: 20-32, and in particular adipic acid. Examples of dihydric and polyhydric alcohols, in particular diols, are: ethanediol, diethylene glycol, 1,2- or 1,3-propanediol, dipropylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,10j;; candiol, glycerol and trimethylolpropane. Preference is given to using ethanediol, diethylene glycol, 1,4-butanediol 1,5-pentanediol, 1,6-hexanediol or mixtures of at least two of the aforementioned diols, in particular 1,4-butanediol mixtures, 1, 5 -pentanediol and 1, 6-hexanediol. It is also possible to use polyester polyols derived from lactone, e.g., -caprolacone or hydrocarbyl acids, v, g, hydroxycaproic acid. To prepare the polyester polyols, the aromatic and preferably aliphatic polycarboxylic acids, Organic compounds and / or derivatives and polyhydric alcohols can be polycondensed in the absence of catalysts or preferably in the presence of esterification catalysts advantageously in an atmosphere of inert gas such as nitrogen, carbon monoxide, helium, argon, etc., in the melting at 150 to 250SC, preferably 180 to 2209C, at atmospheric pressure or under reduced pressure to the desired acid number which is advantageously less than 1, preferably less than 2. According to a preferred embodiment, the mixture of etherification is poricon dense at the temperatures mentioned above to an acid number of 80 to 30, preferably from 40 to 30, under atmospheric pressure and subsequently under a pressure of less than 500 mbar, preferably from 50 to 150 mbar. The appropriate esterification catalysts are, for For example, iron, cadmium, cobalt, lead, zinc, antimony, magnesium, titanium and tin catalysts in the form of metals, metal oxides or metal salts. However, the polycondensation can also be carried out in the liquid phase in the presence of diluents and / or trappers such as benzene, toluene, xylene or chlorobenzene to azeotropically distill the condensation water. To prepare the polyester polyols, organic polycarboxylic acids and / or derivatives and alcohols pol Water is advantageously polycondensed in a molar ratio of 1: 1-1.8, preferably 1: 1.05-1.2. The polyester polyols obtained preferably have a functionality from 2 to 4, in particular from 2 to 3 and a molecular weight from 480 to 3000, preferably from -15,600 to 2,000 and in particular from 600 to 1,500. It is also possible making concomitant use of polyether polyols which are prepared by known methods for example of one or more alkylene oxides having from 2 to 4 carbon atoms in the alkylene radical i by anionic polymerization using alkali metal hydroxides such as sodium or potassium hydroxide or talc-metal metal alkoxides such as sodium methoxide, sodium or potassium ethoxide or potassium sipropoxide as catalysts with addition of at least one Initiator molecule containing from 2 to 8, preferably from 2 to 6, reactive hydrogen atoms in gada form, or by cationic polymerization using Lewis acids such as antimony pentachloride, boron fluoride etherate, etc., or bleached earth as catalysts. Suitable alkylene oxides are, for example, tetrahydrofuran, 1,3-propylene oxide, 1,2 or 2,30-butyl oxide, styrene oxide and preferably ethylene oxide and 1,2-oxide. propi leño. The alkylene oxides can be used individually, alternatively in succession or as mixtures. Suitable initiator molecules are, for example: water, organic dicarboxylic acids such as succinic acid, adipic acid, phthalic acid and tereft acid Lyric, aliphatic and aromatic diamines, not alkylated, N-monoalkyl, N, N- and N, N'-dyalkyl having 1 to 4 carbon atoms in the alkyl radical, for example, ethylenediamine not alkylated , monoalkylated and alkylated, diethylenetriamine, triethylenetetramine, 1,3-20 propy lenediamine, 1,3- or 1,4-butylenediamine, 1,2-, 1,3- 1,4-, 1,5-, and 1 , 6-hexamethylenediamine, phenylenediamines, 2, 3-, 2, 4- and 2,6-tolylenediamine and 4,4'-, 2,4'- and 2,2'-diaminodiphenyl ethane. Other appropriate starter molecules are: alcanolap such as ethanolamine, N-methylethanolamine and N-ethanolamine, dialkanolamines such as diethanolamine, N-methyldiethanolamine and N-ethyldiethanolamine, and trialca nola such as triethanolamine and ammonia. Preference is given to using polyhydric alcohols, in particular dihydric and / or trihydric alcohols, such as ethanediol, 1,2- and 1,3-propanediol, diethylene glycol, dipropylene glycol 1,4-butanediol, 1,6-hexanediol, glycerol, trimethiol lolprop no, pentaerythritol, sorbitol and sucrose. Polyether polyols, preferably polyoxypropyl and polyoxypropylene polyoxyethylene glycols have a functionality of preferably from 2 to 6 and in particular from 2 to 4 and molecular weights from 300 to 3000, preferably from 300 to 2000 and in particular from 400 to 2000, and polite oxytetramethyl glycols have a high molecular weight Polymer-modified polyether polyols, preferably polyether graft polyols, in particular those based on styrene and / or acrylonitrile which are preferably polyether polyols. prepare, by in situ polymerization, acrylonitrile, styrene or preferably mixtures of styrene and acrylonitrile, eg, in a weight ratio of 90: 10 to 10: 90, preferably 70: 30 to 30: 70, are seen in the polyether polyols mentioned above two using a method similar to that provided in German Patents 11 11 394, 12 22 669 (US 3 304 273, 3 383 351, 3 523 093), 11 52 536 (GB 10 40 452) and 11 52 537 (GB 987 618), and also polyether polyol dispersions containing as dispersed phase usually in an amount of 1 to 50% by weight, preferably from 2 to 25% by weight: e.g., polyureas, polyhydrides , polyurethanes containing bound tertiary amino groups, and / or melamine and which are described, for example in EP-B-011 752 (US 4 304 708), US-A-4 374 209 and US Pat.

DE-A-32 31 497. Like polyester polyols, polyether polyols can be used individually or in the form of mixtures. In addition, they can be mixed with the graft polyether polyols or polyester polyols or the poly steramides containing hydroxyl, polyacetals, polycarbonates and / or polyetherpolyamines. Suitable hydroxyl-containing polyacetals are, for example, compounds which can be prepared from glycols such as diethylene glycol, triethyl col, 4,4'-dihydroxyethoxy-difeni ldimeti l methane, or hexan diol and formaldehyde. Suitable polyacetals can also be prepared by polymerization of cyclic acetyls. The appropriate hydroxyl-containing polycarbonates are those of the type known per se which can be prepared, for example, by reacting diols such co-1,3-propanediol, 1,4-butanediol and / or 1,6-hexanediol, di-ti-glycol, trieti-lingolol tetraet i lengl icol with diaryl carbonates, e.g., diphenyl carbonate or phosgene. Polyester amides include, for example, those with predominantly linear densities obtained from polybasic, saturated and / or unsaturated carboxylic acids or their anhydrides and polyfunctional amino alcohols saturated and / or unsaturated or mixtures of polyfunctional alcohols and aminoalcohols and / or polyamines. Suitable polyether polyamines can be prepared from the polyether polyols mentioned above by known methods. Examples which may be mentioned are the cyanoalkislation of 1-oxyalkylene polyols and subsequent hydrogenation of the formed nitrile (EUA 3 267 050) or the partial or complete amination of polyoxyalkylene polyols with amines or ammonia in the presence of hydrogen. and catalysts (DE 12 15 373). O Rigid polyurethane foams can be produced - with or without the concomitant use of chain extenders and / or crosslinkers (C). However, the addition of former chain tensioners, crosslinkers or, if desired, of them can prove to be advantageous for modifying the mechanical properties, e.g., the hardness. The chain extenders and / or crosslinkers used are diols and / or triols having molecular weights of less than 400, preferably from 60 to 300. Examples of suitable chain / crosslinker extenders are aliphatic, cycloaliphatic and / or araliphatic diols they have from 2 to 14, preferably from 4 to 10 carbon atoms, eg, ethylene glycol, 1,3-propanediol, 1,10-of candiol, o-, m- or p-dihydroxycyclohexane, diethyl col, dipropylene glycol and preferably 1,4-butanediol, 1,6-hexanediol and bis (2-hydroxyeti 1) hydroquinone, triole such as 1,2,4- and 1,3,5-trihydroxycyclohexane, glyce trimethylolpropane and polyalkylene oxides containing low molecular weight hydroxyl, based on Ethylene and / or 1,2-propylene oxide and the aforementioned diols and / or triols as initiator molecules. If chain extenders, crosslinkers or mixtures thereof are used to produce the rigid polyurethane foams, they are advantageously used in a quantity from 0 to 20% by weight, preferably from 2 to 8% by weight, based on the weight of component (b). d) The blowing agents which are used to produce rigid polyurethane foams preferably include water which reacts with isocyanate groups to form the sea carbon dioxide, and / or blowing agents that physically act. Physically suitable blowing agents are liquids which are inert to the unmodified or modified organic polyisocyanates and which have boiling points below 100 C, preferably below 50 QC, in particular from -50 Qc to 30 ° C, under pressure atmospheric so that vapor curl under the action of thermal exo polyaddition reaction. Examples of said preferred liquids are alkanes such as heptane, hexane, n- and iso-penta , preferably industrial mixtures of n-and iso-petan and propane, cycloalkanes such as cyclopentane and / cyclohexane, ethers such as furan, dimethyl ether and diethyl ether, ketones such as acetone and methyl ethyl ketone, alkyl carboxylates. such as format methyl, dimethyl oxalate and ethyl acetate, and halogenated hydrocarbons such as methylene chloride, dichloromonof luoromethane, difluoromethane, trifluoromethane, difluoroethane, tetraf luoretane, chlorodifluoroethane, 1,1- dichloro-2, 2,2- trifluoroethane, 2, 2-dichloro-2-f luoretane heptafluoropropane. Mixtures of these boiling liquids with each other and / or with other substituted or unsubstituted hydrocarbons can also be used. Also suitable are organic carboxylic acids such as formic acid, acetic acid, oxalic acid, ricinoleic acid and compounds containing ca boxi lo groups. Preferred silk to use water, chlorodifluoromethane, chlorodifluorethanes, dichlorofluorethanes, mixtures of pentane, cyclohexane and mixtures of at least two of these copying agents, eg, mixtures of water and cyclohexane, mixtures of chlorodifluoromethane and 1-chloro-2,2-difluoroethane and, if desired, agaa. These blowing agents are usually added to component (b). However, they can be added to the component of isocyanate (a) or as a combination of both the component (b) and the isocyanate component (a) or premeasures of these components with the other components of formation. The amount of blowing agent or agent mixture The blowing used is from 1 to 25% by weight, preferably from 5 to 15% by weight, in each case based on the polymer component (b). If water is used as the blowing agent, the formation component (b) is preferably added in one to 0.5 to 5% by weight, based on component (b) d formation. The addition of water can be carried out in combination with the addition of the other blowing agents described. e) The catalysts (e) used to produce the More than rigid polyurethanes are, in particular, compounds that strongly accelerate the reaction of the compounds containing the reactive hydrogen atoms, in particular hydroxyl groups, of component 9b) and, if used, (c) with polyisocyanates organic, unmodified or modified (a). Advantageously use is made of basic polyurethane catalysts, for example tertiary amines such as triethylamine, tributylamin, dimethylbenzylamine, d i c i clohexi lmeti sheet, dimethylcyclohexylamina, bis (N, N-di meti laminoeti 1) ether, bis (dimeti laminopropy 1) urea, N methymmorphol ina or N-eti lmorfol ina, N-cyclohexylmorphine in N, N, N ', N' -tetramethylethylenediamine, N, N, N ' , N '-tetramet butandimine, N, N, N', N '-tetrameth 1-hexane-1,6-diamine, peme tanmeti ldieti lentria ina, dimeti lpiperazine, N-dimethyl aminoethylpiperidine, 1,2-dimethyl imidazole, 1-azabicyclo / 2.0.2.0) -7-octane, 1,4-diazabicyl-1-2,2.2-octane (Dabc and alkanolamine compounds such as triethanolamine tri isopropanolamine, N -metildietanolamine and N-ethyldiet nola ina, dimet i laminoethanol, 2- (N, N-dimethylaminoethoxy) Ethanol, N, N ', N "-tris (dialkylaminoalkyl) hexahydrotria zines, e.g., N, N' N" -tr is (dimet i 1 aminopropi 1) -s-hexahi drotriazine, and triethi lendiamine. However, metal salts such as iron (II) chloride, zinc chloride, lead octoate and preferably tin salts such as tin dioctoate, tin diethylhexanoate and dibutyltin dilaurate and also, in particular, mixtures of tertiary amines and organic tin salts are also useful. Other suitable catalysts are: amidines such as 2, 3-dimeti-1,3,4,5,6-tetrahydropyrimidine, tetraalkylammonium hydroxides, such as tetramethylammonium hydroxide, alkali metal hydroxides, such as sodium hydroxide and alkali metal alkoxides such as sodium methoxide and potassium isoproposium, and Also, alkali metal salts of long chain fatty acids having from 10 to 20 carbon atoms and possibly side OH groups. Preference is given to using 0.001 to 5% by weight, in particular 0.05 to 2% by weight, of catalyst or catalyst combination, based on the weight of component (b). f) If desired, additional auxiliaries and / additives (f) can also be incorporated into the reaction mixture to produce the rigid polyurethane foams. The examples that can be mentioned are surfactant substances Active agents, foam stabilizers, cell regulators, fillers, dyes, pigments, flame retardants, hydrolysis inhibitors, fungistatic and bacteriostatic substances. The appropriate surface-active substances are, for example compounds, which serve to assist in the homogenization of the starting materials and may also be suitable for regulating the cell structure of plastics. Examples which may be mentioned are emulsifiers such as sodium salt of castor oil or fatty acid sulfates and also fatty acid amine salts, e.g., diethylamine oleate, diethanolamine stearate, diethanolamine ricinoleate , salts of sulphonic acids, e.g., alkali metal or ammonium salts of dodecylben- or dinafti lmetan disulphonic and ricinoleic acid; butadiene stabilizers such as copolymers of loxano-oxyalkylene lobules and other organopolysiloxanes, ethoxylated alkylfhenols, ethoxylated fatty cools, paraffin oils, reicino oil or ricinoleic esters. Red pavement oil and peanut oil, and cell regulators such as paraffins, fatty alcohols, and dimethylpolysi loxanes. Also suitable for improving the emulsifying action, the cell structure and / or stabilizing the spum are the oligomeric acrylates described above which have polyoxyalkylene radicals and fluoralkane as side groups. The surfactants are usually used in amounts of 0.01 to 5% by weight, based on 100% by weight of component (b). The fillings, in particular reinforcement fillings, are The customary organic and inorganic fillers, reinforcers, weight agents, agents for improving abrasion performance in paints, coating compositions, etc., known per se. Specific examples are: inorganic fillers such as siliceous materials, for example sheet silicates such as antigorite, serpentine, hornablendas, anfibolas and talc, metal oxides such as kaolin, aluminum oxides, titanium oxides and iron oxides, metal salts such as limestone, barite and inorganic pigments such as cadmium sulfide and zinc sulfide, and also glass, among others. Preference is given to using kaolin (China clay), aluminum silicate and co-precipitates of barium sulfate and aluminum silicate and also natural and synthetic fibrous minerals such as wollastonite, metal and in particular glass fibers of various lengths which They can also be dimensioned. Suitable organic fillers are, for example: carbon, melamine, tremen-tub resin, cyclopentadienyl resins and graft polymers and also cellulose fibers, polyamide, polyacryl nitrile, polyurethane and polyester fibers based on aromatic dicarboxylic esters and / or aliphatics and, in particular, carbon fibers. The inorganic and organic fillers can be used individually or as mixtures and are preferably incorporated into the reaction mixture in amounts of 0.5 to 50% by weight, preferably 1 to 40% by weight, based on the weight of the components (a) to (c), even though the content of mats, non-woven fabrics and knits of natural and synthetic fibers may be up to 80% by weight. Suitable flame retardants are, for example, tricresyl phosphate, tris (2-chloroethyl) phosphate, tris (2-chloropropyl) phosphate), tris (1,3- 10 dichloropropyl) phosphate, tris (2,3-dibromopropyl) phosphate, tetrakis-2-chloroeti-1-dihydrogen phosphate, dimethyl methane phosphate, diethyl diethanolaminomethyl phosphonate and also polyol retarders. It is also possible to use inorganic or organic flame retardants such as red phosphorus, hydrous aluminum oxide, antimony trioxide, arsenic oxide, ammonium polyphosphate and other commercially available flame retardants. sulfate Calcium, expanded graphite or cyanuric acid derivatives, e.g., melamine, or mixtures of at least two flame retardants such as ammonium polyphosphates melamine and also, if desired, corn starch or ammonium phosphate. , melamine and expanded graphite and / or po aromatic or aliphatic liesters to make polyisocyanate polyaddition products resistant to flames. In general, it has been found to be advantageous to use from 5 to 50% by weight, preferably from 5 to 25% by weight, of the flame retardants specified in component (b). Further details regarding the auxiliaries and additives mentioned above and other customary ones can be found in the specialist literature, for example, in the monograph by J. H. Saunders and K.C. Frisch "High Polymers" Volume XVI, Polyurethanes, Parts 1 and 2, Interscience Publishers 1962 and 1964, or the Kunststof Handbuch, Polyurethane, Voluemn VII, Hanser-Verlag, Munich, Vienna 1st and 2nd editions, 1966 and 1983. To produce the rigid polyurethane foams of the present invention, organic and / or modified organic polyisocyanates (a), relatively high molecular weight compounds containing at least two reactive hydrogen atoms (b) and, if desired, chain extenders and / or crosslinkers (c) are reacted in amounts such that the ratio of the NCO group equivalence of the polyisocyanates (a) to the sum of the reactive hydrogen atoms of components 9b) and, if u ^ (c) is 0.85 - 1.25: 1, preferably 0.95 - 1.15: 1 and in particular 1 - 1.05: 1. If the rigid polyurethane foams contain at least some bound isocyanurate groups, a ratio of NCO groups of the polyisocyanates (a) to the sum of the hydrogen atoms of component (b) and, if used, (c) of 1.5 - 60: 1, preferably 1.5 - 8: 1, is usually employed. Rigid polyurethane foams are advantageously produced by the single operation method, for example by means of the high pressure or low pressure technique in open or closed molds, for example metal molds. It is also customary to continuously apply the reaction mixture to appropriate panels to produce panels. It has been found to be particularly advantageous to produce the polyurethane foams by the two-component method and combine the forming components (b), (d), (e) and, if used, (c) and (f) to form the component (A) and use the modified organic and / or organic polyisocyanates (a) or mixture of said polyisocyanates and, if desired, blowing agents (d) as component (B). The starting components are mixed at from 15 to 90 ° C, preferably from 20 to 60 ° C and in particular from 20 to 35 ° C, and are introduced into the open mold or, if desired under incriminated pressure, into the closed mold or, in the case of a continuous work station, it is applied to a band that accommodates the reaction mixture. The mixing, as already indicated, can be carried out mechanically by means of an agitator or an agitation screw. The mold temperature is advantageously from 20 to 110 ° C, preferably from 30 to 60 ° C and in particular from 45 to 50 ° C. The rigid polyurethane foams produced by the process of the present invention have a density of 0.02. 3 3 0.3 g / cm, preferably from 0.025 to 0.24 g / cm and in particular 3 from 0.03 to 0.1 g / cm. They are particularly suitable as insulation material in the construction and refrigeration apparatus sectors, eg, as an intermediate layer for operating elements or for filling refrigerators and freezer boxes with foam, and in the sector of long-distance energy, but also as support material and training in the furniture sector. The invention is illustrated by the following examples.

Example 1 (Comparative) 720 g. of diethylene glycol together with 225 g of adipic acid were placed in a 2 1 reaction flask equipped with agitator., thermometer and distillation facility and melted fully at 1309C. 555 g of PET granules were added thereto a little at a time and 10 ppm of titanium tetrabutoxide was introduced as a catalyst. The polycon reaction mixture was denuded at 220 ° C while the reaction water formed at a customary acid number is removed for polyesters of less than 1 mg KOH / g. The resultant green, cloudy reaction product had the following properties: Hydroxyl number = 347 mg KOH / g in accordance with DIN 53240 Acid number = 0.65 mg KOH / g in accordance with DIN 53402 Viscosity at 259C = 120 mPa.s in accordance with DIN 53015 Example 2 (Comparative) In a 1.5 1 reaction flask equipped with stirred thermometer and distillation fixation, 360 g of diethylene glycol and 113 g of adipic acid were completely liquefied at 135 QC and subsequently metered with 278 g of recycled PET added One po at a time while stirring. In order to carry out the densation polycor, the reaction temperature was increased to 220 ° C. and the reaction water formed was removed under atmospheric pressure. After an acid number of less than 5 mg KOH / g was reached, the remaining water was removed under reduced pressure at an acid number customary for polyesterols of less than 1 mg KOH / g. The reaction product prepared in this way had the following properties: Hydroxyl number: 351 mg KOH / g Acid number = 0.47 mg KOH / g Viscosity at 259C = 1041 Mpa.s Turbid reaction product had a green color OSCJ ro .

Example 3 (in accordance with the present invention) In a 2 1 flask equipped with stirrer, distillation fixation thermometer, 40 g of a PET waste solution, in a first stage, were transferred to a metal diethyl ether. hydroxyl number of 623 mg KOH / g and 184 g of phthalic anhydride were mixed. At a reaction temperature of 230 C, the water of the reaction formed was removed by distillation under reduced pressure. After a reaction time of 5 hours, the reaction product was cooled to 140 ° C, admixed with 168 adipic acid and 10 ppm titanium tetrabutoxide and, in an additional step, polycondensed at 210 SC under reduced pressure. It is to provide a transparent, slightly yellow, low viscosity reaction product that has the following properties Hydroxyl number: 299 mg KOH / g Acid number = 1.04 mg KOH / g Viscosity at 259C = 2755 mPa.s Example 4 (in accordance with the present invention) In a stirred reactor of 25 1 to prepare polyester, 2.2 kg of adipic acid, in a first reaction step, were melted in 6.8 kg of diethylene glycol at 130 ° C. and mixed while stirring. shake with 13.54 kg of PBT. At a reaction temperature of 220 ° C, the mixture was polycondensed at an acid number d less than 8 mg KOH / g. The reaction product was subsequently mixed with 10 ppm of tin (II) isooctoate and, in a second step, drained by application of a vacuum. The resulting pale yellow product was transparent and had the following properties: Hydroxyl number = 253 mg KOH / g Acid number = 0.74 mg KOH / g Water content: 0.06% Viscosity at 759C = 467 mPa.s Example 5 (in accordance with the present invention) In a 25 1 reactor for preparing polyesterols, 12.8 kg of diethylene glycol and 4.0 kg of phthalic anhydride, in a first stage, it was liquefied at 130 ° C. After the addition of 9.9 kg of recycled PET while stirring, the reaction temperature was increased to 210 ° C and the reaction water formed was removed under atmospheric pressure and the remaining reaction water was removed under reduced pressure. 15.0 kg of the resultant polycondensate having a hydroxyl number of 380 mg kOH / g, an acid number of 0.77 mg kOH / g and a viscosity at 759C to 1787 mPa.s, in a subsequent reaction step, was mixed with 0.3% aqueous KOH as a catalyst and it was alkylated with 4.5 kg of ethylene oxide under pressure in an autoclave, then neutralized with phosphoric acid and freed from the salts formed by filtration. The slightly turbid reaction product had the following -properties : Hydroxyl number = 301 mg kOH / g Acid number = 0.42 mg KOH / g Viscosity at 259C = 1014 Mpa.s Example 6 (Comparative) The polyol component comprising 50 parts by mass (pbm) of a polysterol based on adipic acid diethylene glycol and PET (of Example 1), Number OH 347 mg KOH / g, 31 pbm of a polyetherol based on sucrose, glycerol and propylene oxide, OH number 400 mg KOH / g, 1 pbm of silicone stabilizer B 8409 (Goldschmidt), 1 pbm of dimethylcyclohexylamina, 2 pbm of water and 15 pbm of R 141 b, were intensively mixed with 110 pbm of crude MDl, 31.5% NCO content by mass (index 110). The resulting foam foamed freely in a 3 foaming cup and had a density of 31.0 kg / m. The resulting foams were examined for curing by means of the indentation test and for flowability by means of the hose test. Indentation test Using a standard indenter having a diameter of 20 mm, the penetration force towards the foam was measured at certain time intervals after production. In this test, the indenter penetrates 10 mm towards the foam.

Hose test Immediately after mixing the components, 100 g of reaction mixture is poured into a continuous hose - made of plastic film and having a diameter of 4.5 cm. The hose is then released and the length of foam obtained was taken as a measure of the flow capacity. The results obtained are shown in Table 1.

Example 7 (Comparative) A polyol component as described in Example 6, but comprising 50 pbm of a polysterol based on adipic acid, diethylene glycol and PET (of Example 2), OH number 351 mg KOH / g, was mixed intensively with 100.5 pbm of crude MDl (index 110). The resulting foam had a density of 31.5 kg / m.

Example 8 (in accordance with the present invention) A polyol component as described in the Example 6, but comprising 50 pbm of a polyesterol based on adipic acid, anhydride, phthalic acid, diethylene glycol and PET (of Example 3), OH number 299 mg KOH / g, was mixed indefinitely with 105 pbm of crude MDl (Index 110). ).

The resulting foam had a density of 29 kg / m3.

Example 9 (in accordance with the present invention) A polyol component as described in the Example 6, but comprising 50 pbm of a polyesterol based on adipic acid, diethylene glycol and PET (from Example 4), number OH 253 mg KOH / g, was mixed intensively with 98 pbm of crude MDl (index 110). o The resulting foam had a density of 29.5 kg / m.

Example 10 (in accordance with the present invention) A polyol component as described in the Example 6, but comprising 50 pbm of a polyether sterol based on phthalic anhydride, diethylene glycol, PET and ethylene oxide (from Example 5) number OH 301 mg KOH / g, was intensively mixed with 105 pbm of crude MDl (index 110) . 3 The resulting foam had a density of 30 kg / m.

Table 1: Results of indentation tests and hose Ej 8 10 Penetration force (N) after 3 min. 8 12 25 21 20 after 5 min. 12 21 55 50 48 Foam length (cm) 13 300 134 150 148 145 The polyols prepared according to the present invention were homogeneous immediately after preparation and after storage for 4 weeks. The processing of the polyols both immediately after their preparation and also after storage for 4 weeks to provide homogeneous polyurethane systems for various applications, ie with different system constituents, was possible in all cases. The rigid polyurethane foams based on the polyols of the present invention had significantly better cure and better flow behavior than those based on the comparative polyols.

Claims (4)

CLAIMS:

1. - A process for producing rigid polyurethane foams by reacting a) organic and / or organic modified diisocyanates and / or polyisocyanates with b) specific polyester polyols and / or polyether polyols thereof which can be prepared by polycarboxylation of dicarboxylic acids 1 ions with polyfunctional alcohols using polyalkylene terephthalates and, if desired, subsequent reaction with lower alkylene oxides, plus, if desired, additional compounds of relatively high molecular weight containing at least two reactive hydrogen atoms, and , if desired c) chain extenders and / or crosslinkers in the presence of d) blowing agents, e) catalysts and, if desired, f) auxiliaries and / or additional additives, wherein the polyester polyols and / or polyols of ether ester are prepared in a stepwise polycondensation where, in the first stage, polyalkylene terephthalate is added in addition to the components d Starting to condensation as it begins and / or while it is on the way, and at least one additional stage, catalytically active substances are added.

2. A process as described in claim 1, wherein the polyalkylene terephthalate is added at a temperature of the starting components or the condensation mixture of 150 to 250 ° C.

3. A process as described in claim 1, wherein the polyalkylene terephthalate is added under pressure to mospheric or under a slightly reduced pressure of 1 to 200 mbar

4. - A process as described in claim 1, wherein mixtures of various alkali metal terephthalates are used. 3. A process as described in claim 1, wherein polyalkyl non-terftalate waste is used. 6. A process as described in claim 1, wherein the polyalkylene terephthalate is polyethylene terephthalate or polybutylene terephthalate. 7. A process as described in claim 1, wherein the dicarboxylic acids used are adipic acid, glutaric acid, succinic acid and / or phthalic acid and / or their a hydrides. 8. A process as described in claim 1, wherein the polyfunctional alcohols used are alkanediols and / or alkantriols and / or ether diols. 9. A process as described in the claim, wherein the catalytically active substances used n titanium and / or tin compounds and / or Lewis acids. SUMMARY OF THE INVENTION Rigid polyurethane foams are produced by reacting a) organic and / or modified organic diisocyanates and / or polyisocyanates with b) polyester polyols and / or specific polyether ester polyols which can be prepared by polycarboxylation of dicarboxylic acids with polyfunctional alcohols using polyalkylene terephthalates and, if desired, subsequent reaction with lower alkylene oxides, plus, if desired, additional relatively high molecular weight compounds containing at least two reactive hydrogen atoms, and if desired , c) low molecular weight chain extenders and / or crosslinkers in the presence of d) blowing agents, e) catalysts and, if desired, f) auxiliary and / or additional additives, wherein the polyester polyols and / or or poly ether ester polyols are prepared in a stepwise polycondensation wherein, in the first step, polyalkylene terephthalate is introduced in addition to the starters towards the condensation when it starts or while it is on the way, and, at least one additional stage, catalytically active substances are added. These rigid polyurethane foams can be used as insulation material for the refrigeration and long-distance energy sectors, as sandwich material in construction and building and as support and training material in the furniture sector.