DE19708570A1 - Polyurethane foam production for use as e.g. thermal insulating material - Google Patents

Abstract

The production of foam containing polyisocyanate poly-addition products comprises reacting: (a) polyisocyanates; (b) isocyanate-reactive compounds with a molecular weight of 500-8000; and optionally (c) chain extenders and/or crosslinkers with a molecular weight of less than 500, in the presence of: (d) blowing agents; (e) catalysts; and optionally (f) other additives. The blowing agents contain hydrocarbons with 3- or 4-carbon rings, with a b. pt. of 0-75 deg C at 1013 mbar. Also claimed are: (i) isocyanate-reactive components for foam production, containing 5-25 wt.% cyclic hydrocarbons and optionally homogeneously miscible compounds with a b.pt. of between -40 and +100 deg C at 1013 mbar, 0.5-3 wt.% water and 82-94.5 wt.% components (b) and optionally (c); and (ii) foam obtained by the above process.

Description

The invention relates to a process for the production of foams containing polyisocyanate polyadducts by reacting (a) polyisocyanates, (b) compounds reactive towards isocyanates with a molecular weight of 500 to 8000 g / mol and optionally (c) chain extension and / or crosslinking agents with a molecular weight of less than 500 g / mol in the presence of blowing agents (d) and catalysts (e) and optionally (f) auxiliaries and additives and on the foams produced by this process. Furthermore, the invention relates to blowing agent-containing components that are reactive towards isocyanates and the use of mixtures containing hydrocarbons with C ₃ or C ₄ rings, which have a boiling point between 0 ° C. and 75 ° C. at a pressure of 1013 mbar, as Blowing agent in the production of foams containing polyisocyanate polyadducts.

The production of foams, for example soft, half rigid or rigid foams based on isocyanate by reaction of (a) polyisocyanates, (b) reactive towards isocyanates Compounds with a molecular weight of 500 to 8000 g / mol and optionally (c) chain extension and / or crosslinking average with a molecular weight less than 500 g / mol in the presence of blowing agents (d) and catalysts (e) and optionally (f) Auxiliaries and additives are generally known and examples wise in the "Kunstoff-Handbuch", Volume 7, Polyurethane, 3rd edition, 1993, published by G. Oertel, Carl-Hanser-Verlag, Munich and 1st edition, 1966, edited by R. Vieweg and A. Höchtlen, Carl-Hanser-Verlag, Munich.

The most important chemical raw materials are multifunctional iso cyanate. As chemical structures made from these isocyanates can arise, polyurethanes, polyureas, polyisocyanurates as well as further isocyanate adducts such as, for example, allophanates, Biurets, carbidiimides and their isocyanate adducts, oxazolidones, Polyimides, polyamides are present, the type of structures of the reactants of the isocyanates, the catalysis and the Reaction conditions depends. The Polyisocya is generally understood nat polyadducts together under the term polyurethane men because the polyurethanes gave way to the polyisocyanate adducts  Most common and most common group of substances for foams based on isocyanate are based.

As a blowing agent in the production of polyurethane foam substances used essentially two types of blowing agents:

Low-boiling, inert liquids that are under the influence of Vaporize exothermic polyaddition reaction, preferably halogen hydrocarbons such as methylene chloride, trichlorofluorine than u. a., and chemical compounds created by a chemical Reaction or thermal decomposition form propellants. Example The reaction of water with isocyanates may be mentioned below Formation of amines and carbon dioxide, which are in sync with the polyure thanbildung expires, and the cleavage of thermally labile Ver ties such as B. azoisobutyronitrile, which in addition to nitrogen as a cleavage product he toxic tetraethylsuccinonitrile there, or azodicarbonamide, the use of which as an ingredient propellant combination in EP-A-0 092 740 (CA 1 208 912) is described. While the latter method, where thermally labile compounds, such as. B. Azo compounds, Hydrazi de, semicarbazides, N-nitroso compounds, benzoxazines u. a. (Kunststoffe 66 (1976), 10, pages 698 to 701), usually in a pre-made polymer can be incorporated, technically by remained subordinate meaning, find the physical effect low-boiling liquids, on a large scale worldwide as a blowing agent for the production of polyurethane or polyisocya nurat foams use.

According to EP-A-351 614 can be used as a blowing agent for Her position of polyurethane foams fluorinated hydrocarbon substances, perfluorinated hydrocarbons, sulfur hexafluoride or mixtures of at least two of these compounds will. Because these fluorinated or perfluorinated blowing agents in the structural components for the production of the polyisocyanate polyaddi tion products are difficult or insoluble, they will at least least an organic and / or modified organic poly isocyanate, at least one higher molecular compound with min at least two reactive hydrogen atoms or a mixture of at least one higher molecular compound with at least two reactive hydrogen atoms and a low molecular weight chain extenders and / or crosslinking agents emulsified. After this Method can use cellular plastics with more even and fine Cell structure can be made. The main disadvantage here is the high price of these propellants. To cell-containing plastics to get with a particularly advantageous cell structure is on  a narrow selection of blends of perfluoropentane and Perfluorohexane instructed.

Furthermore, alkanes such as butane, pentane and. a. be used. DE-A-3 933 335 the use of Cy clopentan suggested.

EP-A-0 405 439 describes the combination of perfluoroalkanes with Cycloalkanes mentioned, but the cycloalkane content is smaller O is said to be the proportion of the perfluoroalkane compound. The minor The blowing effect of this blowing agent mixture requires a high amount content of the polyol component, which is above 3%. So here made polyurethane foams have a lower heat insulation and poorer mechanical properties, in particular higher brittleness and poorer adhesion than with conventional ones Foams made from blowing agents.

Cyclopentane, also in mixtures with e.g. B. high and / or per fluorinated organic compounds or (cyclo-) aliphatic Compounds is also described in DE-A-4 200 558 as a blowing agent described for the production of rigid polyurethane foams.

Disadvantages had an effect with rigid foams that described the NEN blowing agents that were compared to for example, trichlorofluoromethane foamed rigid foams poorer dimensional stability under almost due to ausdif sound propellant and increased thermal conductivity out.

The present invention was therefore based on the object Process for the production of polyurethane foams, ins to develop special rigid polyurethane foams in which Blowing agents are used that lead to foams with a lower thermal conductivity and an improved dimension stability, d. H. e.g. B. a lower shrinkage due to diffusion lead blowing agent.

The object was achieved in that blowing agents containing hydrocarbons with C ₃ - or C ₄ rings, which have a boiling point between 0 ° C and 75 ° C, preferably 10 ° C to 70 ° C, particularly preferably 20 ° C to 50 ° C, in particular 25 ° C to 46 ° C at a pressure of 1013 mbar.

The invention furthermore relates to blowing agent-containing components which are reactive toward isocyanates and contain 5 to 25% by weight of hydrocarbons with C ₃ or C ₄ rings and a boiling point between 0 ° C. and 75 ° C., preferably 10 ° C. to 70 ° C. ° C, FITS preferably 20 ° C to 50 ° C, especially 25 ° C to 46 ° C at a pressure of 1013 mbar, and optionally homogeneously miscible with these compounds with a boiling point between -40 ° C and + 100 ° C. at a pressure of 1013 mbar, 0.5 to 3 wt .-% water and 82 to 94.5 wt .-% of components (b) and optionally (c) for the production of polyurethane foams.

The blowing agent (d) used is preferably alicyclic compounds with C ₃ or C ₄ rings and a total of 4 to 7 carbon atoms, preferably 5 or 6 carbon atoms, particularly preferably: bicyclo [1.1.1] pentane, spiropentane, trans-1, 2-dimethyl cyclopropane, cis-1,2-dimethylcyclopropane, 1-methylbi cyclo [1.1.0] butane, ethylcyclopropane, methylcyclobutane and / or bicyclo [2.1.0] pentane.

The blowing agents according to the invention are used in the manufacture of the Rigid polyurethane foams usually in an amount of 0.5 to 25 wt .-%, preferably from 5 to 15 wt .-%, based on the used in the production of rigid polyurethane foams Component (b), d. H. the higher molecular compound with mind at least two reactive hydrogen atoms.

To expand the processing area in relation to the reak tion parameters and foaming devices and an increase processing security, combined with a reduction in Formation of technically unusable foam board, it has proved to be advantageous, the propellant according to the invention tel (d) in conjunction with water as an additional blowing agent use. Depending on the desired foam density and the amount of blowing agent mixture used are the water contents, based on component (b), expediently above 0.1% by weight, preferably in the range from 0.5 to 3% by weight.

The compounds of the invention can be used as blowing agents teren in mixtures with with these completely or partially homogeneous miscible compounds that have a boiling point between -40 ° C and + 100 ° C at a pressure of 1013 mbar can be used. For example, they can be mixed completely or partially homogeneously Compounds cyclic, linear and / or branched hydrocarbons substances, for example cycloalkanes, preferably cyclopentane and / or highly and / or perfluorinated hydrocarbons in Mixtures with the blowing agents according to the invention who used the, for example, come as fluorinated or perfluorinated Consider connections:  

E.g. can be fluorinated or perfluorinated, linear or cy clische Ether with 4 to 12 carbon atoms, preferably 4 to 6 carbon atoms, e.g. B. perfluorodiethyl, perfluorodipropyl and perfluoroethyl propyl ether, oligomers of perfluoroethylene oxide, of perfluoropropylene oxide or mixed perfluoroethylene-perflu orpropylene oxides and cyclic perfluoroethers such. B. Perfluor tetrahydrofuran or perfluoroalkyltetrahydrofurans, and highly fluo rated or perfluorinated tertiary alkylamines with 1 to 5 carbons atoms, preferably 2 to 4 carbon atoms in the alkyl radical, such as B. Perfluorotriethyl-, Perfluortripropyl- or Perfluortri butylamine, as well as aliphatic or gaseous at room temperature cycloaliphatic perfualkanes, e.g. B. Perfluoropropane, Per fluorobutane or perfluorocyclobutane, which is under pressure, e.g. B. at egg pressure up to about 25 bar, liquefied, mixed and emul be greeded.

As (per) -fluorinated and highly fluorinated hydrocarbons Examples include: Perfluorpentane, Perfluorhexane, Perfluorheptane, perfluorooctane, perfluorocyclopentane, perfluor cyclohexane as well as hexafluoropropane and heptafluoropropane. use preferably find perfluoropentane and in particular perfluorine orhexane and mixtures thereof. As a fluorinated organic compound expedients can expediently be used such predominantly, for example at least 85% fluorinated, however at least one, preferably only one hydrogen atom have bound.

This if necessary in the starting components for the polyure than rigid foam production difficult or insoluble, (per) fluorinated, organic compounds that are convenient a maximum boiling point of 150 ° C, preferably from -40 to 100 ° C, particularly preferably 0 ° C to 90 ° C, in particular 10 ° C to 60 ° C at a pressure of 1013 mbar, individually or can be used in the form of a mixture with one another.

As hydrocarbons with the propellant according to the invention are completely homogeneously miscible, for example Cyclo alkanes with more than 4 carbons in the ring such as B. Cyclohexane and preferably cyclopentane can be used. Furthermore come for example the linear and / or branched alkanes with 4 to 8 carbon atoms, such as butane, pentane, hexane, heptane or octane, into consideration. The li near and / or branched alkanes with 5 or 6 carbon atoms proven, in particular n-pentane, isopentane, isomeric pentane mixtures cal or iso-hexane.  

The production of the polyurethane foams, in particular rigid polyurethane foams, is carried out by implementation in a manner known per se

• a) organic and / or modified organic polyisocyanate ten with
• b) at least one compound with at least two reactive Hydrogen atoms and a usual molecular weight of 500 up to 8000 g / mol and optionally
• c) chain extenders and / or crosslinking agents with a molecular weight less than 500 g / mol
  in the presence of
• d) the blowing agents according to the invention and
• e) catalysts and optionally
• f) usual other auxiliaries and / or additives.

For the production of rigid polyurethane foams according to the inventions find processes according to the invention, with the exception of the blowing agents (d), the known structural components use, to which in the following is to be carried out individually.

a) The known organic polyisocyanates aliphatic, cycloaliphatic, araliphatic and before preferably aromatic polyvalent isocyanates in question.

Examples include: alkylene diisocyanates with 4 to 12 carbon atoms in the alkylene radical, such as 1,12-dode can-diisocyanate, 2-ethyl-tetramethylene-diisocyanate-1,4, 2-Me thyl-pentamethylene-diisocyanate-1,5, tetramethylene-diisocya nat-1,4 and preferably hexamethylene-diisocyanate-1,6; cy cloaliphatic diisocyanates, such as cyclohexane-1,3- and 1,4-diisocyanate and any mixtures of these isomers, 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethyl-cyclohexane (Isophorone diisocyanate), 2,4- and 2,6-hexahydrotoluylene diisocyanate and the corresponding isomer mixtures, 4,4'-, 2,2'- and 2,4'-dicyclohexylmethane diisocyanate and the ent speaking isomer mixtures, and preferably aromatic Di- and polyisocyanates, such as. B. 2,4- and 2,6-tolylene diiso cyanate and the corresponding isomer mixtures, 4,4'-, 2,4'- and 2,2'-diphenylmethane diisocyanate and the corresponding Mixtures of isomers, mixtures of 4,4'- and 2,4'-diphenylme  than diisocyanates, polyphenyl polymethylene polyisocyanates, Mixtures of 4,4'-, 2,4'- and 2,2'-diphenylmethane diisocya naten and polyphenylpolymethylene polyisocyanates (raw MDI) and mixtures of crude MDI and tolylene diisocyanates. The organic di- and polyisocyanates can be used individually or in Form of their mixtures are used.

So-called modified polyvalent iso are also common cyanate, d. H. Products that are organi shear di- and / or polyisocyanates are used. Examples include ester, urea, biuret and allo phanate, carbodiimide, isocyanurate, uretdione and / or ure Di- and / or polyisocyanates containing thane groups. In one for example, the following may be considered: urethane groups holding organic, preferably aromatic polyisocyanates with NCO contents of 33.6 to 15% by weight, preferably 31 to 21 wt .-%, based on the total weight, for example with low molecular weight diols, triplets, dialkylene glycols, Trialkylene glycols or molecular polyoxyalkylene glycols weights up to 6000, in particular with molecular weights up to 1500, modified 4,4'-diphenylmethane diisocyanate, modified decorated 4,4'- and 2,4'-diphenylmethane diisocyanate mixtures, or modified crude MDI or 2,4- or 2,6-tolylene diiso cyanate, being as di- or polyoxyalkylene glycols, individually or can be used as mixtures, for example May be mentioned: diethylene, dipropylene glycol, polyoxyethylene, Polyoxypropylene and polyoxypropylene-polyoxyethylene glycols, -triols and / or -tetrols. NCO groups are also suitable containing prepolymers with NCO contents of 25 to 3.5 % By weight, preferably from 21 to 14% by weight, based on the Ge velvet weight, made from those described below Polyester and / or preferably polyether polyols and 4,4'-diphenylmethane diisocyanate, mixtures of 2,4'- and 4,4'-diphenylmethane diisocyanate, 2,4- and / or 2,6-tolylene diisocyanates or raw MDI. Have also proven to be liquid containing carbodiimide groups and / or isocyanurate rings Polyisocyanates with NCO contents of 33.6 to 15, preferably 31 to 21 wt .-%, based on the total weight, for. B. on Ba sis of 4,4'-, 2,4'- and / or 2,2'-diphenylmethane diisocyanate and / or 2,4- and / or 2,6-tolylene diisocyanate.

The modified polyisocyanates can be used together or with unmodified organic polyisocyanates such as B. 2,4'-, 4,4 'diphenylmethane diisocyanate, crude MDI, 2,4- and / or 2,6-tolylene diisocyanate may be mixed.  

Organic polyisocyanates have proven particularly useful and are therefore preferably used: mixtures of Toluene diisocyanates and crude MDI or mixtures of modes organic polyisocya containing urethane groups naten with an NCO content of 33.6 to 15 wt .-%, in particular those based on tolylene diisocyanates, 4,4'-diphe nylmethane diisocyanate, diphenylmethane diisocyanate isomer mix or raw MDI and especially raw MDI with a Di phenylmethane diisocyanate isomer content of 30 to 80% by weight, preferably from 30 to 55% by weight.

b) As higher molecular weight compounds b) with at least two reak tive hydrogen atoms are expediently those with a functionality of 2 to 8, preferably 2 to 6, and a molecular weight of usually 500 to 8000 preferably used from 1200 to 6000. Have proven themselves e.g. B. polyether polyamines and / or preferably polyols chooses from the group of polyether polyols, polyester polyo le, polythioether polyols, polyester amides, hydroxyl groups containing polyacetals and hydroxyl-containing aliphati rule polycarbonates or mixtures of at least two of the mentioned polyols. Polyester is preferably used polyols and / or polyether polyols. The hydroxyl number of the Po lyhydroxyl compounds is usually 150 to 850 and preferably 200 to 600.

Suitable polyester polyols can, for example, from organic Dicarboxylic acids with 2 to 12 carbon atoms, preferred wise aliphatic dicarboxylic acids with 4 to 6 carbon a toms, and polyhydric alcohols, preferably diols, with 2 up to 12 carbon atoms, preferably 2 to 6 carbon atoms toms are produced. As dicarboxylic acids come in Examples include: succinic acid, glutaric acid, adipine acid, suberic acid, azelaic acid, sebacic acid, decanedicarbonate acid, maleic acid, fumaric acid, phthalic acid, isophthalic acid and terephthalic acid. The dicarboxylic acids can both used individually as well as in a mixture with each other. Instead of the free dicarboxylic acids, the corre sponding Chenden dicarboxylic acid derivatives, such as. B. dicarboxylic acid esters of alcohols with 1 to 4 carbon atoms or dicarbon acid anhydrides are used. Preferably used who the dicarboxylic acid mixtures of amber, glutaric and adipine acid in proportions of, for example, 20 to 35:35 to 50: 20 to 32 parts by weight, and in particular Adipin acid. Examples of dihydric and polyhydric alcohols, in particular their diols are: ethanediol, diethylene glycol, 1,2- or 1,3-propanediol, dipropylene glycol, 1,4-butanediol, 1,5-pentane  diol, 1,6-hexanediol, 1,10-decanediol, glycerin and trimethy lolpropane. Ethanediol, Diethy are preferably used lenglycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol or Mixtures of at least two of the diols mentioned, in particular mixtures of 1,4-butanediol, 1,5-pentanediol and 1,6-He xandiol. Polyester polyols can also be used from lactones, e.g. B. ε-caprolactone or hydroxycarboxylic acids, e.g. B. ω-hydroxycaproic acid.

To produce the polyester polyols, the organic, e.g. B. aromatic and preferably aliphatic, polycarbonate acids and / or derivatives and polyhydric alcohols peat-free or preferably in the presence of esterification catalysts analyzers, suitably in an atmosphere of inert gas such as B. nitrogen, carbon monoxide, helium, argon and. a., in the melt at temperatures of 150 to 250 ° C, preferably as 180 to 220 ° C, optionally under reduced pressure up to the desired acid number, which is advantageous is less than 10, preferably less than 2, polycondenses be settled. According to a preferred embodiment, the Esterification mixture at the above temperatures up to an acid number of 80 to 30, preferably 40 to 30, under Normal pressure and then under a pressure of less than 500 mbar, preferably 50 to 150 mbar, polycondensed. For example, iron, Cadmium, cobalt, lead, zinc, antimony, magnesium, titanium and tin catalysts in the form of metals, metal oxides or Metal salts into consideration. However, the polycondensation can also in the liquid phase in the presence of dilution and / or the entrainer such. As benzene, toluene, xylene or Chlorobenzene, for azeotropic distillation of the condensation water.

The organic polyols are used to produce the polyester polyols Polycarboxylic acids and / or derivatives and polyhydric alcohols advantageously in a molar ratio of 1: 1 to 1.8, preferably wise 1: 1.05 to 1.2 polycondensed.

The polyester polyols obtained preferably have one Functionality from 2 to 4, especially 2 to 3, and a mo molecular weight of usually 500 to 3000, preferably 1200 to 3000 and especially 1800 to 2500.

However, polyethers are used in particular as polyols polyols by known methods, for example by anionic polymerization with alkali hydroxides, such as. B. Well trium or potassium hydroxide or alkali alcoholates, such as. B.  Sodium methylate, sodium or potassium ethylate or potassium iso propylate, as catalysts and with the addition of at least one Starter molecule, the 2 to 8, preferably 2 to 6, reactive Contains hydrogen atoms bound, or by cationic Po lymerization with Lewis acids, such as antimony pentachloride, boron fluoride etherate u. a. or bleaching earth, as catalysts one or more alkylene oxides with 2 to 4 carbon atoms Men are produced in the alkylene radical.

Suitable alkylene oxides are, for example, tetrahydrofuran, 1,3-propylene oxide, 1,2- or 2,3-butylene oxide, styrene oxide and preferably ethylene oxide and 1,2-propylene oxide. The alkyleno xids can be used individually, alternately one after the other or as Mi be used. Come as starter molecules Examples include: water, organic dicarboxylic acids, such as succinic acid, adipic acid, phthalic acid and terephthalate acid, aliphatic and aromatic, optionally N-mono-, N, N- and N, N'-dialkyl substituted diamines with 1 to 4 Koh lenstoffatomen in the alkyl radical, such as mono- and dialkyl-substituted ethylenediamine, diethylenetriamine, trie ethylene tetramine, 1,3-propylene diamine, 1,3- or 1,4-butylene dia min, 1,2-, 1,3-, 1,4-, 1,5- and 1,6-hexamethylene diamine, Phe nylenediamines, 2,3-, 2,4- and 2,6-toluenediamine and 4,4'-, 2,4'- and 2,2'-diamino-diphenylmethane.

Other suitable starter molecules are: alkanolamines, such as B. ethanolamine, N-methyl and N-ethylethanolamine, Dialkanolamines such as e.g. B. diethanolamine, N-methyl and N- Ethyl diethanolamine, and trialkanolamines, such as. B. Triethano lamin, and ammonia. Mehrwerti are preferably used ge, especially di- and / or trihydric alcohols, such as Ethanediol, 1,2-propanediol and 1,3, diethylene glycol, dipropy lenglycol, 1,4-butanediol, 1,6-hexanediol, glycerin, trimethy lolpropane, pentaerythritol, sorbitol and sucrose.

The polyether polyols, preferably polyoxypropylene and Po lyoxypropylene-polyoxyethylene-polyols, have a function nality of preferably 2 to 6 and in particular 2 to 4 and usually molecular weights from 500 to 8000, preferably two se 1200 to 6000 and in particular 1800 to 4000 and suitable Polyoxytetramethylene glycols have a molecular weight of up to about 3500.

Polymer-modified polyols are also suitable as polyether polyols Polyether polyols, preferably graft polyether polyols, especially those based on styrene and / or acrylonitrile, by in situ polymerization of acrylonitrile, styrene or  preferably mixtures of styrene and acrylonitrile, e.g. B. in Weight ratio 90:10 to 10:90, preferably 70:30 to 30:70, advantageously in the aforementioned polyether polyols analogous to the information in German patent specifications 11 11,394, 12,22,669 (U.S. 3,304,273, 3,383,351, 3,523,093), 11 52 536 (GB 10 40 452) and 11 52 537 (GB 987 618) be, as well as polyether polyol dispersions, which are disperse Phase, usually in an amount of 1 to 50% by weight preferably 2 to 25 wt .-%, contain: z. B. polyureas, Po lyhydrazide, tertiary amino groups containing bound polyure thane and / or melamine and the z. B. are described in the EP-B-011 752 (US 4 304 708), US-A-4 374 209 and DE-A-32 31 497.

The polyether polyols can just like the polyester polyols used individually or in the form of mixtures. Further you can use the graft polyether polyols or polyester polyols and the hydroxyl-containing polyester amides, Polyacetals, polycarbonates and / or polyether polyamines be mixed.

As polyacetals containing hydroxyl groups such. B. from Glycols, such as diethylene glycol, triethylene glycol, 4,4'-dihy droxyethoxy-diphenyl-dimethylmethane, hexanediol and formaldehyde hyd producible compounds in question. Also through polymer suitable polyacetals produce.

Such polycarbonates come as hydroxyl groups of the type known per se, for example by reacting diols, such as propanediol (1,3), butane diol- (1,4) and / or hexanediol- (1,6), diethylene glycol, trie ethylene glycol or tetraethylene glycol with diaryl carbonates, e.g. B. diphenyl carbonate, or phosgene can be produced nen.

The polyester amides include e.g. B. from polyvalent, ge saturated and / or unsaturated carboxylic acids or their An hydride and polyvalent saturated and / or unsaturated Amino alcohols or mixtures of polyhydric alcohols and Amino alcohols and / or polyamines obtained, mainly li near condensates.

Suitable polyether polyamines can be obtained from the above Polyether polyols are produced by known processes the. The cyanoalkylation of Po may be mentioned by way of example lyoxyalkylene polyols and subsequent hydrogenation of the gebil  Detected nitrile (US 3,267,050) or the partially or fully permanent amination of polyoxyalkylene polyols with amines or ammonia in the presence of hydrogen and catalysts (DE 12 15 373).

Mixtures which expediently contain have proven particularly useful as polyol compounds and are therefore preferably used:

• bi) 0 to 95 parts by weight, preferably 20 to 80 parts by weight a sucrose-started polyether polyol with a Hydroxyl number from 300 to 500, preferably 350 to 450 based on 1,2-propylene oxide or 1,2-propyls oxide and ethylene oxide,
• bii) 0 to 95 parts by weight, preferably 20 to 80 parts by weight a polyether polyol started with sorbitol with a Hydroxyl number from 400 to 600, preferably from 450 to 550 based on 1,2-propylene oxide or 1,2-Pro pylene oxide and ethylene oxide,
• biii) 0 to 20 parts by weight, preferably 5 to 15 parts by weight of egg nes started with ethylenediamine polyether polyols a hydroxyl number of 700 to 850, preferably 750 to 800 based on 1,2-propylene oxide
• biv) 0 to 60 parts by weight, preferably 5 to 40 parts by weight of egg nes polyether polyol with a hydroxyl number of 400 to 600, preferably from 450 to 550 based on 1,2-Pro pylene oxide or 1,2-propylene oxide and ethylene oxide represents using a mixture of sucrose and Triethanolamine in a weight ratio of 1: 2 to 2: 1 as Starter molecules and
• bv) 0 to 40 parts by weight, preferably 10 to 30 parts by weight of a TDA-started polyether polyol with a hydroxyl number of 300 to 500, preferably 350 to 450, based on 1,2-propylene oxide and ethylene oxide,
  with the proviso that the sum of the parts by weight of the component bi-v) is not more than 100.

The rigid polyurethane foams can be with or without use of chain extension and / or crosslinking agents be manufactured. To modify the mechanical  Properties, e.g. B. the hardness, however, the addition of chain extenders, crosslinking agents or counter Mixtures of these may also prove to be advantageous.

Used as a chain extender and / or crosslinking agent diols and / or triols with molecular weights become smaller than 500, preferably from 60 to 300 for example aliphatic, cycloaliphatic and / or arali phatic diols with 2 to 14, preferably 4 to 10 carbons atoms of matter, such as B. ethylene glycol, 1,3-propanediol, decane diol-1,10, o-, m-, p-dihydroxycyclohexane, diethylene glycol, Dipropylene glycol and preferably 1,4-butanediol, hexane diol-1,6 and bis (2-hydroxy-ethyl) hydroquinone, triols, such as 1,2,4-, 1,3,5-trihydroxycyclohexane, glycerin and trimethy lolpropane and low molecular weight hydroxyl-containing polyal kylene oxides based on ethylene and / or 1,2-propylene oxide and the aforementioned diols and / or triols as starter molecules.

Provided that for the production of rigid polyurethane foams Ket ten extenders, crosslinking agents or mixtures there of application, they are conveniently in one Amount from 0 to 20% by weight, preferably from 2 to 8% by weight, based on the weight of the polyol compound (b).

The blowing agent mixtures according to the invention from the previous described blowing agents according to the invention and against if necessary with these homogeneously miscible compounds a boiling point between -40 ° C and + 150 ° C, preferably -40 ° C up to 100 ° C, particularly preferably 10 ° C to 60 ° C, at one pressure of 1013 mbar, for example aliphatic and / or cycloa lipatic hydrocarbon and / or high and / or per fluorinated compounds are used for processing in the Processes according to the invention preferably in the structural components ten (a), (b) or in mixtures of (b) and (c) or in (a) and (b) dissolved or emulsified. To achieve such blowing agent-containing emulsions are suitable from the poly emulsifiers known in urethane chemistry. In particular as emulsifiers Special use is made of oligomeric acrylates as sides groups bound polyoxyalkylene and fluoroalkane and a fluorine content of approximately 5 to 30% by weight point. Oligomeric acrylates of this type are from art chemistry well known (see, among others, EP A-351 614).

The z as an emulsifier. B. suitable oligomeric acrylates with Po lyoxyalkylene and fluoroalkane residues as side groups expediently in an amount of 0.01 to 6 parts by weight, preferably 0.2 to 3.5 parts by weight and in particular 0.5 to  2.0 parts by weight, based on 100 parts by weight of the composition nenten (a), (b) or the mixture of (b) and (c) used.

Suitable for emulsifying the blowing agent mixture (d) are has already been run, the organic and / or modifi graced organic polyisocyanates (a) and the higher molecular weight ren compounds with at least two reactive hydrogen tomen (b). Mixtures of (b) and never are also suitable the molecular chain extension and / or crosslinking agent teln (c).

When using organic and / or modified organi find polyisocyanates (a) as another emulsion phase preferably aromatic polyisocyanates selected from the Group 2,4-, 2,6-tolylene diisocyanate or mixtures of the mentioned isomers, 4,4'-, 2,4'- and 2,2'-diphenylmethane diisocyanate or mixtures of at least two of the above Isomers and mixtures of diphenylmethane diisocyanates and Polyphenyl-polymethylene-polyisocyanate application. If the organic polyisocyanates crystalline at room temperature they are made by mixing with liquid polyisocyanates and / or by suitable partial modification, such as. B. Carbodiimidization and / or urethanization, liquefied.

However, the other emulsion phase is preferably the high hermolecular compounds with at least two reactive Hydrogen atoms (b) use. Are particularly suitable Polyester polyols or their mixtures with a functional act from 2 to 3 and a molecular weight from 480 to 3000 and polyether polyols or their mixtures with a function nality from 2 to 6 and a molecular weight of 400 to 8000, these being expediently selected from the Group of polyoxyethylene, polyoxypropylene, polyoxypropy len-polyoxyethylene polyols and polyoxytetramethylene glycols or mixtures thereof.

Solutions which contain blowing agents or emulsions have proven particularly useful
5-25% by weight of a blowing agent mixture according to the invention described above, containing hydrocarbons with C ₃ or C ₄ rings, which have a boiling point between 0 ° C. and 75 ° C. at a pressure of 1013 mbar and, if appropriate, homogeneous with them miscible compounds with a boiling point between -40 ° C and 150 ° C, preferably -40 ° C to 100 ° C, particularly preferably 0 ° C to 90 ° C, especially 10 ° C to 60 ° C at one. Pressure of 1013 mbar,
0-5% by weight, preferably 0.5 to 3% by weight of water and 82 to 94.5% by weight of at least one compound having at least two reactive hydrogen atoms (b) or mixtures of (b) and chain extender and / or crosslinking agents (c) and optionally the emulsifier.

For the production of blowing agent solutions or Emulsions are the structural components (a) or (b) or Mi combinations of (b) and (c) and the blowing agent mixture (d) expediently in the presence of an emulsifier, preferably an oligomeric acrylate, at temperatures from 0 to 70 ° C, preferably from 20 to 40 ° C, mixed intensively. As suitable Nete mixing units for this are mentioned as an example: sta table mixers, such as B. SMX from Sulzer (Switzerland) or dynamic mixers, e.g. B. propeller stirrer or ultra-door rax® from Hanke and Kunkel (FRG).

e) As catalysts (e) for the production of the polyurethane hard Foams are used in particular compounds that the reaction of reactive hydrogen atoms, especially Hy Compounds of component (b) containing droxyl groups and optionally (c) with the organic, optionally accelerate modified polyisocyanates (a) strongly. In Be traditional metal organic compounds, preferably or ganic tin compounds such as tin (II) salts from organi 's carboxylic acids, e.g. B. tin (II) acetate, tin (II) octoate, Tin (II) ethylhexoate and tin (II) laurate and the dialkyl Tin (IV) salts of organic carboxylic acids, e.g. B. Dibutyl tin diacetate, dibutyltin dilaurate, dibutyltin maleate and Dioctyltin diacetate. The organic metal compounds who the alone or preferably in combination with strong basi used amines. Examples include Amidi ne, such as 2,3-dimethyl-3,4,5,6-tetrahydropyrimidine, tertiary Amines, such as triethylamine, tributylamine, dimethylbenzylamine, N- Methyl, N-ethyl, N-cyclohexylmorpholine, N, N, N ', N'-tetrame ethylethylenediamine, N, N, N ', N'-tetramethylbutanediamine, N, N, N ', N' tetramethyl-hexanediamine-1,6, pentamethyl-diethylene triamine, tetramethyl-diaminoethyl ether, bis (dimethylamino propyl) urea, dimethylpiperazine, 1,2-dimethylimidazole, 1-aza-bicyclo- (3,3,0) -octane and preferably 1,4-diaza-bi cyclo (2,2,2) octane, and alkanolamine compounds such as Trie thanolamine, triisopropanolamine, N-methyl and N-ethyl dietha nolamine and dimethylethanolamine.  

Other possible catalysts are: tris (dialkyla minoalkyl) -s-hexahydrotriazines, especially tris- (N, N-dime thylaminopropyl) -s-hexahydrotriazine, tetraalkylammonium hydro xides, such as tetraethylammonium hydroxide, alkali metal hydroxides, such as Sodium hydroxide and alkali alcoholates such as sodium methylate and Potassium isopropylate, as well as alkali salts of long chain fat acids with 10 to 20 carbon atoms and optionally sideways only OH groups. 0.001 to 5 are preferably used % By weight, in particular 0.05 to 2% by weight, of catalyst or Ka Talysator combination, based on the weight of the component (b).

The reaction mixture to make the polyurethane hard foams can optionally also contain auxiliaries and / or additives (f) are incorporated. May be mentioned at for example surface-active substances, foam stabilizer Ren, cell regulator, fillers, dyes, pigments, flame Protective, hydrolysis, fungistatic and bak teriostatic substances.

As surface-active substances such. B. Connections in Consider which to support the homogenization of the Serve as starting materials and are also suitable if necessary, regulate the cell structure of plastics. Be mentioned for example emulsifiers, such as the sodium salts of Ricinus oil sulfates, or of fatty acids and salts of fatty acids with amines, e.g. B. oleic acid diethylamine, stearic acid dietha nolamine, ricinoleic acid diethanolamine, salts of sulfonic acids, e.g. B. alkali or ammonium salts of dodecylbenzene or di naphthylmethane disulfonic acid and ricinoleic acid; Foam stabilizer catalysts, such as siloxane-oxalkylene copolymers and others Organopolysiloxanes, ethoxylated alkylphenols, ethoxylated Fatty alcohols, paraffin oils, castor oil or ricinoleic acid esters, Turkish red oil and peanut oil and cell regulators such as paraffins, Fatty alcohols and dimethylpolysiloxanes. To improve the Emulsifying effect, the cell structure and / or stabilization of the The oligomers described above are also suitable for foam Acrylates with polyoxyalkylene and fluoroalkane residues as sides groups. The surface-active substances are becoming more common wise in amounts of 0.01 to 5 parts by weight, based on 100 Parts by weight of component (b) applied.

As fillers, in particular reinforcing fillers, are the usual organic and anorga known per se African fillers, reinforcing agents, weighting agents, Means to improve the abrasion behavior in paint ben to understand coating agents, etc. In particular  Examples include: inorganic fillers such as silica minerals, for example layered silicates such as antigo rit, serpentine, hornblende, amphibole, chrisotile, talc; Metal oxides such as kaolin, aluminum oxides, titanium oxides and egg senoxides, metal salts such as chalk, heavy spar and inorganic Pigments such as cadmium sulfide, zinc sulfide and glass u. a. Before Kaolin (China Clay), aluminum Si are preferably used Likate and coprecipitates made from barium sulfate and aluminum silicate as well as natural and synthetic fibrous minerals like Wollastonite, various metal and especially glass fibers ner length, which can be arbitrated if necessary. As Organic fillers can be considered, for example: Koh le, melamine, rosin, cyclopentadienyl resins and graft polymers and cellulose fibers, polyamide, polyacrylic tril, polyurethane, polyester fibers based on aromatic and / or aliphatic dicarboxylic acid esters and especially carbon fibers.

The inorganic and organic fillers can be used individually or used as mixtures and are the reaction mixture advantageously in amounts of 0.5 to 50% by weight, preferably 1 to 40 wt .-%, based on the weight of the com components (a) to (c), but the content of Mats, fleeces and fabrics made of natural and synthetic Fibers can reach values up to 80.

Suitable flame retardants are, for example, tricresyl phosphate, tris (2-chloroethyl) phosphate, tris (2-chloroprop pyl) phosphate, tris (1,3-dichloropropyl) phosphate, tris (2,3-di bromopropyl) phosphate, tetrakis (2-chloroethyl) ethylene diphosp has, dimethylmethanephosphonate, diethanolaminomethylphosphon acid diethyl ester and commercially available halogen-containing flame protective polyols.

In addition to the halogen-substituted phosphates already mentioned inorganic or organic flame retardants, such as red phosphorus, aluminum oxide hydrate, antimony trioxide, Ar senoxide, ammonium polyphosphate and calcium sulfate, expandable graphite or cyanuric acid derivatives, such as. B. melamine, or mixtures from at least two flame retardants, such as. B. ammonium po lyphosphates and melamine and optionally corn starch or Ammonium polyphosphate, melamine and expandable graphite and / or also aromatic polyester to flame retard the bottom lyisocyanate polyaddition products are used. Generally mine has proven to be useful, 5 to 50 Parts by weight, preferably 5 to 25 parts by weight, of the aforementioned  Flame retardant for 100 parts by weight of the component (b) to use.

Details of the other usual above mentioned Auxiliaries and additives are in the specialist literature, for example se of the monograph by J.H. Saunders and K.C. Fresh "high Polymers "Volume XVI, Polyurethanes, Parts 1 and 2, Publisher In terscience Publishers 1962 or 1964, or the plastic Manual, Polyurethane, Volume VII, Hanser-Verlag, Munich, Vienna, 1st and 2nd editions, 1966 and 1983.

To manufacture rigid polyurethane foams, the orga African polyisocyanates (a), higher molecular weight compounds with at least two reactive hydrogen atoms (b) and given if chain extender and / or crosslinking agent (c) in sol Chen amounts implemented that the equivalence ratio of NCO groups of the polyisocyanates (a) to the sum of the reactive Hydrogen atoms of components (b) and optionally (c) 0.85 to 1.25: 1, preferably 0.95 to 1.15: 1 and in particular 1 to 1.05: 1. If the rigid polyurethane foams at least partially contain bound isocyanurate groups, is more common have a ratio of NCO groups of the polyisocyanates (a) to Sum of the reactive hydrogen atoms of component (b) and counter optionally (c) from 1.5 to 60: 1, preferably 1.5 to 8: 1 turns.

The rigid polyurethane foams are advantageously after the one shot process, for example with the help of high pressure or low pressure technology in open or closed molds witness, for example, metallic molds.

It has proven to be particularly advantageous after the two-com component process and the structural components (b), (d), (e) and optionally (c) and (f) in component (A) combine and as component (B) the organic polyisocyanates, modified polyisocyanates (a) or mixtures of the genann ten polyisocyanates and optionally blowing agent (d) to use the.

The starting components are at a temperature of 15 to 90 ° C, preferably from 20 to 60 ° C and in particular from 20 to 35 ° C, mixed and raised in the open or, if necessary, under pressure into the closed mold. The Ver Mixing can, as already explained, mechanically by means of an egg a stirrer or a stirring screw. The Mold temperature is advantageously 20 to 110 ° C, preferably 30 to 60 ° C and in particular 45 to 50 ° C.  

The polyurethane rigid foams or rigid molded foams produced by the process according to the invention generally have a density of 0.02 to 0.75 g / cm ³ , preferably 0.025 to 0.24 g / cm ³ and in particular 0.03 to 0.1 g / cm ³ . They are particularly suitable as insulation material in the construction and cooling furniture sector, e.g. B. for thermal insulation in cooling and / or heating devices, sand winding elements or pipes.

The improved dimensional stability of the invention Foams with low thermal conductivity should be based on the following examples are shown.

Example 1 (comparison)

Mixture of

Component A
60.3 parts polyol made from 25.2 parts sorbitol and
74.8 parts of propylene oxide with KOH as catalyst and
0.5 parts water as a costarter. The hydroxyl number (OH number or OHZ) is 495 mg KOH / g, the viscosity at 25 ° C 17900 mPas.
24.1 parts polyol, made from 22.7% mixture of 2,3- and 3,4-toluenediamine, 28% ethylene oxide and 72% propylene oxide with KOH as catalyst. The OHZ is 406 mg KOH / g, the viscosity at 25 ° C 8500 mPas.
2.3 parts of water
1.5 parts of stabilizer B 8423 from Goldschmidt
0.8 parts of dimethylcyclohexylamine
11.0 parts cyclopentane
and

Component B
144 parts of B component, a mixture of diphenylmethane diisocyanate and polyphenylpolymethylene polyisocyanates (M 20 A from BASF Schwarzheide GmbH) with an NCO content of 31.5% by mass.

Component A was obtained by mixing the substances mentioned made into a homogeneous mixture.  

46.0 g of the polyisocyanate (B component) were mixed with 32.0 g of A component with a laboratory stirrer that with a stirrer Vollrath was equipped in a polystyrene cup (through knife 115 mm) mixed with 1750 revolutions per minute.

After foaming, specimens with a diameter were used of 80 mm and a thickness of 20 mm measured the thermal conductivity sen.

Measurements were taken on further test specimens 5 cm × 5 cm × 5 cm and weighing the core bulk density.

The resistance against was then at the aforementioned cubes Shrinkage assessed as follows:

The test specimens were stored at room temperature for 14 days and then subjected to a uniaxial compressive stress of 0.05 N / mm ² for 50,000 minutes. The deformation is a measure of the mechanical stability z. B. against negative pressure, which is generated by diffusion of CO ₂ out of the foam. The shrinkage behavior is improved if the deformation is less at the same density or the deformation is not greater at lower density.

Example 2

As example 1, instead of 11.0 parts of cyclopentane 11.0 parts Spiropentane.

Example 3

As example 1, instead of 11.0 parts of cyclopentane 11.0 parts Ethylcyclopropane.

Example 4

As example 1, instead of 11.0 parts of cyclopentane 11.0 parts Trans-1,2-dimethyl-cyclopropane.

Example 5

As example 1, instead of 11.0 parts of cyclopentane 11.0 parts Cis-1,2-dimethyl-cyclopropane.  

Example 6 (comparison)

Mixture of

Component A
63.2 parts of polyol, made from 25.2 parts of sorbitol and 74.8 parts of propylene oxide with KOH as catalyst and 0.5 parts of water as costarter. The hydroxyl number (OH number or OHZ) is 495 mg KOH / g, the viscosity at 25 ° C 17900 mPas.
25 parts of polyol, made from 22.7% mixture of 2,3- and 3,4-toluenediamine, 28% ethylene oxide and 72% propylene oxide with KOH as catalyst. The OHZ is 406 mg KOH / g, the viscosity at 25 ° C 8500 mPas.
3.5 parts water
1.5 parts of stabilizer B 8423 from Goldschmidt
0.8 parts of dimethylcyclohexylamine
6.0 parts cyclopentane
and
160 parts of B component, a mixture of diphenylmethane diisocyanate and polyphenylpolymethylene polyisocyanates (M 20 A from BASF Schwarzheide GmbH) with an NCO content of 31.5% by mass.

Component A was obtained by mixing the substances mentioned made into a homogeneous mixture.

48.0 g of the polyisocyanate (B component) were mixed with 30.0 g of the A component with a laboratory stirrer that with a stirrer Vollrath was equipped in a PS cup (diameter 115 mm) mixed with 1750 revolutions per minute.

After foaming, test specimens with a diameter were made of 80 mm and a thickness of 20 mm measured the thermal conductivity sen.

Measurements were taken on further test specimens 5 cm × 5 cm × 5 cm and weighing the core bulk density.

The resistance to shrinkage was then assessed on the aforementioned cubes as follows: The test specimens were stored at room temperature for 14 days and then subjected to a uniaxial compressive stress of 0.05 N / mm ² for 50,000 minutes. The deformation is a measure of the mechanical stability z. B. against negative pressure, which is generated by diffusion of CO ₂ from the foam.

The shrinkage behavior is improved if the density is the same the deformation low or at lower density the deformation mung is not stronger.

Example 7

As example 6, instead of 6.0 parts of cyclopentane 6.0 parts of Spi ropentan.

Example 8

As example 6, instead of 6.0 parts of cyclopentane 6.0 parts Ethylcyclopropane.

Example 9

As example 6, instead of 6.0 parts of cyclopentane 6.0 parts Trans-1,2-dimethyl-cyclopropane.

Example 10

As example 6, instead of 6.0 parts of cyclopentane 6.0 parts Cyclopentane 6.0 parts cis-1,2-dimethyl-cyclopropane.

Table 1

In comparison to the known samples foamed with cyclopentane show the foams according to the invention with also low heat conductivity a significantly reduced deformation, e.g. B. by diffusing blowing agent.

Claims (10)

1. A process for the preparation of foams containing poly isocyanate polyadducts by reacting (a) poly isocyanates, (b) isocyanate-reactive compounds having a molecular weight of 500 to 8000 g / mol and, if appropriate, (c) chain extenders and / or crosslinking agents with a molecular weight of less than 500 g / mol in the presence of blowing agents (d) and catalysts (e) and optionally (f) auxiliaries and additives, characterized in that blowing agents containing hydrocarbons with C ₃ - or C ₄ rings, the one Have boiling point between 0 ° C and 75 ° C at a pressure of 1013 mbar. 2. The method according to claim 1, characterized in that one uses alicyclic compounds with C ₃ - or C ₄ rings and a total of 4 to 7 carbon atoms. 3. The method according to claim 2, characterized in that one Blowing agent containing bicyclo [1.1.1] pentane, spiropentane, Trans-1,2-dimethylcyclopropane, cis-1,2-dimethylcyclopropane, 1-methylbicyclo [1.1.0] butane, ethylcyclopropane, methylcyclobu uses tan and / or bicyclo [2.1.0] pentane. 4. The method according to any one of claims 1 to 3, characterized in that blowing agents containing mixtures of Koh lenwasserstoffe with C ₃ - or C ₄ rings and with these completely or partially homogeneously miscible compounds that you a point between -40 ° C and 100 ° C at a pressure of 1013 mbar. 5. The method according to claim 4, characterized in that one Mixtures containing cyclopentane and / or high and / or perfluorinated hydrocarbons are used. 6. The method according to any one of claims 1 to 5, characterized records that the blowing agent in an amount of 0.5 to 25% by weight, based on the weight of component (b) puts.   7. blowing agent-containing isocyanate-reactive components for the production of foams according to claim 1 containing 5 to 25 wt .-% hydrocarbons with C ₃ - or C ₄ rings, which have a boiling point between 0 ° C and 75 ° C at a Have pressure of 1013 mbar and, if appropriate, homogeneously miscible compounds with a boiling point between -40 ° C. and + 100 ° C. at a pressure of 1013 mbar, 0.5 to 3% by weight of water and 82 to 94.5% by weight. -% of components (b) and optionally (c). 8. Foams containing polyisocyanate polyaddition products obtainable by a method according to one of claims 1 until 6. 9. Use of foams according to claim 8 as a material for thermal insulation in cooling and / or heating devices, sandwich elements or pipes. 10. Use of mixtures containing hydrocarbons with C ₃ - or C ₄ rings, which have a boiling point between 0 ° C and 75 ° C at a pressure of 1013 mbar, for the production of foams containing polyisocyanate polyaddition products.