DE4321204C2 - Process for the production of rigid polyurethane foams - Google Patents

Description

The invention relates to a method for producing Rigid polyurethane foams using polyether poly oils based on sucrose.

The production of rigid polyurethane foams by implementation of organic polyisocyanates and / or modified organi cal polyisocyanates with higher functional compounds at least two reactive hydrogen atoms, for example poly oxyalkylene polyamines and / or preferably organic polyhydro xyl compounds with molecular weights of z. B. 300 to 2,000, and optionally chain extension and / or crosslinking agent with molecular weights up to about 400 in the presence of Ka analyzers, blowing agents, auxiliaries and / or additives is known and has been described many times. A summary Overview of the production of rigid polyurethane foams z. B. in the plastic manual, volume VII, "Polyurethane", 1st edition 1966, published by Dr. R. Vieweg and Dr. A. Höchtlen and 2nd edition, 1983, published by Dr. G. Oertel (Carl. Hanser Verlag, Munich).

As polyol components for rigid polyurethane foam systems mostly highly functional short-chain polyether alcohols with one high hydroxyl number used. The production of such pro products are usually made by lower anionic polymerization Alkylene oxides, usually 1,2-propylene oxide, optionally in a mixture with ethylene oxide, on highly, mostly at least 4-functional Compounds with active hydrogen atoms. Common start In addition to amines, substances are highly functional hydroxyl groups containing compounds, such as pentaerythritol, sorbitol, Mannitol, xylitol, glucose or sucrose.

The sucrose obtained from renewable raw materials is based on their high functionality of 8 very often as a starting substance used for rigid foam polyether alcohols. In addition to their high Functionality, which is the production of highly cross-linked poly Sucrose is characterized by high availability availability and a low price. Since it is a solid only is difficult to implement with alkylene oxides, it is usually common sam with other NH and / or liquid at the alkoxylation temperature especially OH-functional compounds, so-called Co-starters implemented.  

There are a large number of publications in the booth the technology, e.g. B. in the plastic manual, Volume VII, "Polyure thane ", 1st edition 1966, published by Dr. R. Vieweg Dr. A. Höchtlen and 2nd edition, 1983, published by Dr. G. Oertel (Carl-Hanser Verlag, Munich), but also in the Patent literature, examples include DE-B 14 93 395, DE-B 11 76 358, DE-C 11 96 870, DE-B 12 10 554, DE-A 25 49 449, DD-WP 1 36 833 and DD-A 3 01 355.

A commonly used co-starter in the alkoxylation of Sac charose is the glycerin. The use of such sucrose glyces However, rin polyetherols in rigid foam polyurethane systems result mostly foams with insufficient level of properties in the Flow, hardening and mechanical strength parameters and brittleness.

In particular, it was previously not possible to use rigid polyurethane foams using sucrose-started polyetherols, that satisfy in all quality-determining parameters. So far improvements of individual parameters were mostly by Ver bought deteriorations of other parameters.

It has now been shown that the quality defects of these foams also with the presence of short-chain diols in the sucrose bottom caused by lyetherol. These diols arise from the um settlement of water present in the starting substance mixture the alkylene oxides.

The water is partially targeted as the starting substance mixture Solubilizers added, some of it gets to us formation of aqueous basic, especially alkaline Catalysts as a solvent or as a reaction product in the Alcoholate formation in the starting substance mixture.

Removal of the diols from the finished polyetherol is very difficult and in many cases practically impossible.

The object of the invention was therefore to rigid polyurethane foams Base of polyetherols with sucrose and glycerin as the starting sub to develop the known disadvantages of the stand of technology.

The task could surprisingly be solved by a Process for the production of rigid polyurethane foams Implementation of

• a) organic and / or modified organic polyiso cyanates with
• b) at least one higher molecular compound with at least two reactive hydrogen atoms and optionally
• c) low molecular chain extension and / or crosslinking average

in the presence of

• d) blowing agents,
• e) catalysts and optionally
• f) auxiliaries and / or additives,

being as higher molecular weight compounds with at least two reactive hydrogen atoms (b) polyoxypropylene polyols and / or Polyoxyethylene-polyoxypropylene-polyols with up to 30% by weight, based on the weight of the alkylene oxide units, medium bonded oxyethylene units, with secondary hydroxyl groups, a functionality of 4.5 to 4.8, a hydroxyl number of 430 up to 470 mg KOH / g, producible by anionic polymerization of 1,2-propylene oxide and possibly ethylene oxide to an anhydrous binary Starter molecule mixture consisting of sucrose and glycerin be set.  

The starting substance mixture is advantageously composed from 17 to 21% by weight sucrose and 8 to 12% by weight glycerin, each Weil based on the total weight of the polyether alcohol.

To do this, glycerine and aqueous potassium hydroxide solution are used first the alcoholate with complete removal of the water of reaction formed, then added the sucrose with exclusion of water until intensively mixed for complete homogenization of the sucrose and only then with alkylene oxide around the starter mixture thus obtained set.

That solved the goal of the invention by this simple measure was surprising. The using the Polyurethane hard produced according to the invention foams are characterized by good flowability and hardening in their manufacture as well as good mechanical strength and ge wring out brittleness.

In another embodiment, glycerol and alkali especially potassium hydroxide with complete removal of the Water of reaction formed the alcoholate, this with a part amount, up to 20 wt .-%, based on the total amount of alkylene oxide, implemented on alkylene oxide and the sucrose to this prepolymer given, preventing the ingress of water must, and this mixture with the remaining amount of alkylene oxide vice is set.

To remove the water of reaction, the formation of alcoholate reduced pressure, approx. 25 mbar, and elevated temperature, approx. 80 up to 100 ° C.  

To prevent moisture from entering the start The sucrose is mixed by storage during storage conduct dry inert gas kept water-free and when entering bring the sucrose into the starter mixture dry inert gas, in particular nitrogen, passed through the reaction vessel.  

The preparation of the polyethers used according to the invention alcohols take place according to the generally known mechanism of ba catalyzed alkylene oxide addition to OH-functional Starting substances, described for. B. in Robert Becker, "Polyure thane ", specialist book publisher Leipzig, 1973.

Here the starting substance mixture with the basic Kataly sator, for this purpose amines, but preferably alkali and / or earth alkali metal hydroxides and / or their basic salts, in particular Potassium hydroxide, are used, added and the usual temperatures, usually in the range of about 80 to 150 ° C, the Alkylene oxides, especially propylene oxide, optionally together with up to 20% by weight of the amount of alkylene oxide in ethylene oxide, added.

To prevent side reactions and for safety reasons the reactor should be flushed with nitrogen before adding alkylene oxide be rinsed.

It is advantageous to add the alkylene oxide only after complete homogenization of the starting substance mixture to begin nen. To do this, the starter mixture should be added after sucrose addition intensive for at least 1 hour at room temperature, up to a maximum of 70 ° C be stirred. Following the alkylene oxide metering complete conversion of the alkylene oxide to a post-reaction phase closed.

The basic catalyst is then neutralized as usual and away. This can be done by neutralization with acids or acid Salting takes place, it is also possible to add adsorbent teln, z. B. aluminosilicates. The solids are usually removed by pressure filtration or centrifugation.

This is usually followed by vacuum distillation at approx. 1 mbar and about 100 ° C to remove residual monomers and others easily volatile components.

Ready to stabilize against thermo-oxidative degradation polyether alcohol with stabilizers, e.g. B. sterically hindered Phenols.

The rigid polyurethane foams are manufactured by Implementation in a manner known per se from

• a) organic and / or modified organic polyisocyanate ten with  
• b) the polyether alcohols according to the invention, optionally ge together with other higher molecular compounds with mind at least two reactive hydrogen atoms
• c) low molecular chain extension and / or crosslinking average

in the presence of

• d) propellants and
• e) catalysts and optionally
• f) usual other auxiliaries and / or additives.

For the production of rigid polyurethane foams according to the inventions The method according to the invention finds the known construction compo nent use, to which the following must be carried out in detail is.

• 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 up to 21% by weight, 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 graced 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, e.g. 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) In addition to the polyetherols used according to the invention further higher molecular compounds with at least two reactive hydrogen atoms can be used. In doing so expediently those with a functionality of 2 to 8, preferably 2 to 6, and a molecular weight of 300 to 8000, preferably from 300 to 3000 used. Proven have z. B. polyether polyamines and / or preferably Po lyols selected from the group of polyether polyols, poly ester polyols, polythioether polyols, polyester amides, hydro xyl group-containing polyacetals and hydroxyl group-containing aliphatic polycarbonates or mixtures of at least two of the polyols mentioned. Po is preferably used polyester polyols and / or polyether polyols. The hydroxyl number the polyhydroxyl compounds are 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 entraining agents, such as. 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 from 480 to 3000, preferably 600 to 2000 and especially 600 to 1500.

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 Molecular weights of 300 to 3000, preferably 300 to 2000 and in particular 400 to 2000 and suitable polyoxytetrams ethylene glycols have a molecular weight of up to approximately 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 (US 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 contain 2 to 25 wt .-%: 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).

• c) 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 400, 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).

• d) As a blowing agent, those from polyurethane chemistry my well-known chlorofluorocarbons as well as high and / or perfluorinated hydrocarbons can be used. Of the However, these substances are used for ecological reasons severely restricted or completely discontinued.

As an alternative, there are e.g. B. aliphatic and / or cyclo aliphatic hydrocarbons, especially cyclopentane on.

These hydrocarbons are usually, if necessary in connection with highly and / or perfluorinated hydrocarbon substances, in the form of an emulsion of the structural component (b) admitted. Usually used as emulsifiers oligomeric acrylates, which are polyoxyalkylene and Contained fluoroalkane residues and a fluorine content of about 5 to 30% by weight. Such products are well known from plastics chemistry, e.g. B. EP-A 351 614.  

The amount of blowing agent or blowing agents used The mixture is 2 to 25% by weight, preferably 5 to 15 wt .-%, that of the emulsifier at 0.01 to 6 wt .-%, respectively based on the structural component (b).

It is also possible to use the structure as a blowing agent component (b) water in an amount of 0.5 to 5% by weight, based on the structural component (b). The water addition can also be combined with the use of the others described blowing agents take place.

• 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'-tetrams ethylethylenediamine, N, N, N ′, N′-tetramethylbutanediamine, N, N, N ', N'-tetramethyl-1,6-hexanediamine, 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 ominoalkyl) -s-hexahydrotriazines, especially tris- (N, N-dime thylaminopropyl) -s-hexahydrotriazine, tetraalkylammonium hydro xides, such as tetramethylammonium 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 component (b).

• f) The reaction mixture for the production of 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 castor 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 aminonium 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% by weight, 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 if necessary aromatic polyesters for flame retarding the polyisocyanate polyadducts be 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 polyures produced by the process according to the invention than rigid foams or rigid molded foams have a seal te from 0.02 to 0.75 g / cm³, preferably from 0.025 to 0.24 g / cm³ and in particular from 0.03 to 0.1 g / cm³. They are particularly suitable itself as insulation material in the construction and refrigeration sector, e.g. B. as Intermediate layer for sandwich elements or for foaming Fridge and freezer cases.  

Examples Production of polyoxyalkylene polyols example 1

In a 10 liter stirred autoclave, 617 g of glycerol and 38.8 g aqueous potassium hydroxide solution (47%) submitted and at 90 ° C and re reduced pressure (25 mbar) the alcoholate formed for 1 hour det. After pressure equalization with nitrogen and lowering the Temperature to 60 ° C became slow under constant nitrogen flow 1129 g of sucrose added and stirred for 1 hour. Then was the reactor temperature increased to 110 ° C and with constant Ge speed 4076 g of propylene oxide metered in over 6 hours. After a reaction period of 3 hours, all residual mono mere removed under reduced pressure (1 mbar, 30 minutes, 110 ° C) and 50 g of water and 200 g of adsorb to remove the catalyst added agent. After a stirring time of 2 hours the solids removed by pressure filtration and at reduced Pressure drained (1 mbar, 2 hours, 100 ° C). For stabilization 7.5 g of di-tert-butyl-p-cresol were then prepared provided polyetherol dissolved and the product homogenized. That so The product obtained had a hydroxyl number of 443 mg KOH / g, a Viscosity 8280 mPas at 25 ° C, a residual water content of 0.015 wt .-%, based on the weight of polyether and one Functionality of 4.6.

Example 2

In a 10 liter stirred autoclave, 617 g of glycerol and 38.8 g aqueous potassium hydroxide solution (47%) submitted and at 90 ° C and re reduced pressure (25 mbar) the alcoholate formed for 1 hour det. After pressure equalization with nitrogen, a Prepolymer then within 2 hours at 110 ° C 506 g propylene oxide added. After an initial reaction phase of one hour and lowering the temperature to 60 ° C was under constant Nitrogen stream slowly added 1129 g of sucrose and ge for 1 hour stirs. The reactor temperature was then raised again to 110 ° C increased and at constant speed for 5 hours 3570 g of propylene oxide are metered in. After a reaction phase of All residual monomers were removed under reduced pressure for 3 hours distant (1 mbar, 30 minutes, 110 ° C) and to remove the Kataly sator 50 g of water and 200 g of adsorbent added. After the solids were stirred for two hours Pressure filtration removed and dewatered at reduced pressure (1 mbar, 2 hours, 100 ° C). Subsequently, for stabilization 7.5 g of di-tert-butyl-p-cresol in the finished polyetherol  dissolves and homogenizes the product. The product thus obtained be had a hydroxyl number of 440 mg KOH / g, a viscosity 8170 mPas at 25 ° C, a residual water content of 0.02 wt .-%, based on the polyether weight and a functionality of 4.6.

Example 3 (comparison)

1166 g sucrose, 332 g polypropylene glycol (OHZ250), 50.4 g water and 24 g aqueous potassium hydroxide solution (47%) were in the 10 liter car mixed in a nitrogen atmosphere. Then were 3736 g of propylene oxide were metered in at 110 ° C. for 6 hours. After In a reaction phase of 3 hours, all residual monomers removed under reduced pressure (1 mbar, 30 minutes, 110 ° C) and 50 g of water and 200 g of adsorpti to remove the catalyst onsmittel added. After a stirring time of two hours the solids removed by pressure filtration and at reduced Pressure drained (1 mbar, 2 hours, 100 ° C). For stabilization 7.5 g of di-tert-butyl-p-cresol were then prepared provided polyetherol dissolved and the product homogenized. Man received a product with a hydroxyl number of 367 mg KOH / g, one Viscosity 9990 mPas at 25 ° C, a residual water content of 0.02 % By weight, based on the weight of polyether and one Functionality of 4.7.

Example 4 (comparison)

1266 g sucrose, 332 g polypropylene glycol (OHZ250), 63.4 g water, 24.5 g aqueous potassium hydroxide solution (47%) and 3818 g propylene oxide was obtained by the method described in Example 3 Polyether polyol with hydroxyl number 357 mg KOH / g, a viscosity 7852 mPas at 25 ° C, a residual water content of 0.02% by weight, based on the weight of polyether and a functionality of 4.4.

Example 5 (comparison)

1026 g sucrose, 636 g diethylene glycol and 34 g aqueous potassium hydroxide solution (47%) were mixed in a 10 l autoclave and at 90 ° C and reduced pressure (25 mbar) for 1 hour Alcoholate formed. After pressure equalization with nitrogen 110 ° C metered in 3390 g of propylene oxide for 6 hours. After a Abreaktionphase of 3 hours, all residual monomers under re reduced pressure removed (1 mbar, 30 minutes, 110 ° C) and Ent removal of the catalyst 50 g of water and 200 g of adsorbent admitted. After a stirring time of two hours, the feasts became substances removed by pressure filtration and at reduced pressure dewatered (1 mbar, 2 hours, 100 ° C). For stabilization  then 7.5 g of di-tert-butyl-p-cresol in the finished Dissolved polyetherol and homogenized the product. You got one Product with a hydroxyl number of 432 mg KOH / g, a viscosity 2250 mPas at 25 ° C, a residual water content of 0.02 wt .-%, bezo on the polyether weight and a functionality of 4.0.

Example 6 (comparison)

From 1368 g sucrose, 636 g diethylene glycol, 41.1 g aqueous Potassium hydroxide solution (47%) and 4166 g of propylene oxide were added the process described in Example 3 is a polyether polyol keep with hydroxyl number 453 mg KOH / g, a viscosity 4390 mPas at 25 ° C, a residual water content of 0.01 wt .-%, based on the Polyether weight and a functionality of 4.4.

Example 7 (comparison)

From 2100 g sucrose, 750 g glycerin, 48.2 g aqueous potassium hydroxide solution (47%) and 8000 g of propylene oxide were after the in Process described in Example 3 obtained a polyether polyol with a hydroxyl number of 365 mg KOH / g, a viscosity of 6100 mPas 25 ° C, a residual water content of 0.025 wt .-%, based on the Polyether weight and functionality of 5.1.

Example 8 (comparison)

From 2100 g sucrose, 1125 g glycerin, 42.8 g aqueous potassium hydroxide solution (47%) and 7970 g of propylene oxide were after the in Process described in Example 3 obtained a polyether polyol with hydroxyl number 410 mg KOH / g, a viscosity of 6740 mPas 25 ° C, a residual water content of 0.045 wt .-%, based on the Polyether weight and functionality of 4.7.

Example 9 (comparison)

From 573 g sucrose, 463 g glycerin, 17.8 g aqueous potassium hydroxide solution (47%) and 2960 g of propylene oxide were after the in Process described in Example 3 obtained a polyether polyol with hydroxyl number 394 mg KOH / g, a viscosity of 2440 mPas 25 ° C, a residual water content of 0.01 wt .-%, based on the Polyether weight and functionality of 4.3.  

Example 10 (comparison)

From 50 g sucrose, 126 g glycerin, 9 g aqueous potassium hydroxide solution (47%), 23.3 g water and 1909 g propylene oxide were added 5 the process described in Example 3, a polyether polyol keep with hydroxyl number 400 mg KOH / g, a viscosity 5500 mPas at 25 ° C, a residual water content of 0.01 wt .-%, based on the Polyether weight and functionality of 4.3.

Example 11 (comparison)

From 516 g sucrose, 322 g glycerin, 11.4 g aqueous potassium hydroxide solution (47%) and 1789 g of propylene oxide were after the in Process described in Example 3 obtained a polyether polyol with hydroxyl number 500 mg KOH / g, a viscosity of 8400 mPas 25 ° C, a residual water content of 0.01 wt .-%, based on the Po lyetherol weight and a functionality of 4.3.

Example 12 (comparison)

From 536 g glycerin, 10.4 g aqueous potassium hydroxide solution (47%) and 1919 g of propylene oxide were described in Example 3 NEN process a polyether polyol with a hydroxyl number of 400 mg KOH / g, a viscosity of 365 mPas at 25 ° C, a residual water content of 0.01 wt .-%, based on the weight of polyether and a functionality of 3.0.

The hydroxyl number is determined in accordance with DIN 53 240, which the Viscosity according to DIN 51 550, that according to the water content DIN 51 777.

Examples 13 to 24 Production of rigid foams containing urethane groups

A component:
Mix that consisted of
100 parts by weight of one of the polyols according to Examples 1 to 12
1.0 part by weight of a silicone as foam stabilizer (Polyurax SR 321 from BP Chemicals)
1.4 parts by weight of N, N, N ', N'-tetramethylhexamethylene diamine
4.5 parts by weight of water

B component:
Mixture of diphenylmethane diisocyanates and polyphenyl-polyme thylene polyisocyanates with an NCO content of 31% by weight and a viscosity of approx. 200 mPas at 23 ° C. The quantity used is included in the index 110.

The A and B components, which were heated to 23 ° C., were at 23 ° C. Intensively ge for 10 seconds using a stirrer at 1200 rpm mixes the reaction mixture in a polystyrene beaker with a Filled volume of 1.1 l and let it foam there.

On the rigid foam containing urethane groups thus produced were determined:

• - the start and setting times,
• - the total density according to DIN 53 420,
• - the setting height, d. H. the relative height at the time of Ab bind with a LAM 80 airborne distance measuring device Krautkrämer, Großburgwedel,
• - The increase in compressive strength as a function of time a tensile / compression tester T 2001 from Lloyd Instruments, Offenbach am Main.

In a second series of experiments, four times the amounts of Components A and B mixed intensively in the same way and the reaction mixture in a carton with dimensions Let 20 × 20 × 20 cm foam freely.

On the rigid polyurethane foam produced in this way were determined after storage for 24 hours at room temperature Compressive strength according to DIN 53 421 and the abrasion (brittleness) after ASTM C 421.

The fluidity was used in a commonly used Flow form determined (tube diameter 42-45 mm, sample weight A + B = 100 g).

The polyols used and the foam made The above-mentioned properties are measured in the table summarized.

The table clearly shows that the inventive Polyetherols in an ideal way with the decisive quality Features such as flowability, hardening of the PUR systems or also compressive hardness the brittleness (abrasion) a high level pass. The use of the comparative polyetherols leads to Foaming, which is unsatisfactory in individual parameters have shafts.

Claims (7)

1. Process for the production of rigid polyurethane foams by reacting

• a) organic and / or modified organic polyiso cyanates with
• b) at least one higher molecular weight compound with at least two reactive hydrogen atoms and optionally
• c) low molecular chain extenders and / or crosslinking agents

in the presence of

• d) blowing agents,
• e) catalysts and optionally
• f) auxiliaries and / or additives,

being as higher molecular weight compounds with at least two reactive hydrogen atoms (b) polyoxypropylene polyols and / or polyoxyethylene-polyoxypropylene-polyols with up to 30% by weight, based on the weight of the alkylene oxide units, middle bound oxyethylene units, with secondary Hydroxyl groups, a functionality of 4.5 to 4.8, one Hydroxyl number from 430 to 470 mg KOH / g, producible by anionic polymerization of 1,2-propylene oxide and possibly Ethylene oxide to an anhydrous binary starter molecule Mixture consisting of sucrose and one during processing temperature liquid trifunctional polyol, who used the. 2. The method according to claim 1, characterized in that from the trifunctional polyol and the alkaline catalyst with complete removal of the water of reaction initially the alcoholate formed, the sucrose added, completely homogenized and only then the resulting starter mixture is reacted with alkylene oxide.   3. The method according to claim 1, characterized in that the trifunctional polyol reacted with alkylene oxide, the The resulting prepolymer drains, then the sucrose added and this mixture is reacted with alkylene oxide. 4. The method according to any one of claims 1 to 3, characterized records that used as a trifunctional polyol glycerol becomes. 5. The method according to claim 4, characterized in that the mixture of starter molecules, based on the total weight of the polyoxyalkylene polyol, 17 to 21% by weight of sucrose and 8 to 12 wt .-% glycerin composed.