DE10357531A1 - Production of polyether alcohols, used for producing polyurethanes, e.g. rigid foam, involves adding all or part of polyethylene imine starter to reaction mixture during reaction with alkylene oxide - Google Patents

Abstract

In the production of polyether alcohols (I) by reacting polyethylene imines (II) with alkylene oxides (III), part or all of (II) is dosed into the reaction mixture during reaction with (III).

Description

object The invention relates to a process for the preparation of polyether alcohols by addition of alkylene oxides to polyethyleneimines prepared in this way Polyether alcohols, their use for the production of polyurethanes and the polyurethanes thus prepared.

Polyurethane have long been known and widely described in the literature. Their production usually takes place by reacting polyisocyanates with compounds having at least two hydrogen atoms reactive with isocyanate groups. As connections with at least two isocyanate-reactive hydrogen atoms are preferably polyalcohols, often referred to as polyols, in particular polyether alcohols and / or polyester alcohols used.

By the targeted selection of starting materials, and especially the Polyols, can the properties of the polyurethanes are specifically influenced.

Polyeteralkohole become common by addition of alkylene oxides to H-functional starter substances produced. One often used class of starter substances are aliphatic and / or aromatic amines. Such polyols are usually characterized by a high reactivity out. A disadvantage can be the use of such compounds, that not all amino groups are reacted with alkylene oxides. The can be an undesirable high reactivity lead the polyols. By extension the reaction time or the addition of more alkylene oxide This deficiency can be partially corrected. The options mentioned are but also associated with disadvantages. Especially when using larger quantities Of alkylene oxides occur frequently to products with undesirable high viscosities.

Especially in the implementation of high molecular weight compounds with amino or imino groups, such as polyethyleneimines, these disadvantages are clearly noticeable. The use of polyethylene mines and their reaction products with alkylene oxides for the production of polyurethanes is known. So describes EP 858 005 the use of ethoxylated polyethylenimines and polyurethanes for use as surface coating in offset printing. In DE 100 03 156 For example, functionalized polyurethane foams are described for use as filter media in which polyethyleneimines are joined to the foam by reaction with the isocyanate groups.

In JP 5 9173 378 describes the reaction of polyethyleneimines with alkylene oxides and the subsequent use of the products thus obtained as feedstocks in the production of polyurethanes for textile applications.

In DE 100 03 156 describes a process for the production of polyurethane foams which can be used for the adsorption of heavy metal ions. The foams are contacted during or after their preparation with polyethyleneimines which serve as adsorbents.

polyethyleneimines would be up Reason for their high functionality and the big one Number of amino groups is an advantageous starting substance for the preparation of polyether alcohols for the use in polyurethane foams. Such polyether alcohols would have autocatalytic properties and high crosslinking the foams contribute.

In The practice encounters the manufacture However, such polyether alcohols to considerable difficulties. So has been shown that the implementation of the Polyethyleniminine with the alkylene oxides run very unevenly. This may be due, for example, to the lack of homogenization of the polyethyleneimines in the reaction mixture during the implementation lie. A possibility to the solution this problem could for example, the use of co-starters. The disadvantage is Here, however, that the properties of the resulting polyether then often determined by the co-starters and the desired effects the use of polyethyleneimines as starters for polyether alcohols not zum Wear come.

task The invention was a process for the preparation of polyether alcohols to develop, used in the polyethyleneimines as starter substances become and that to polyether alcohols with a uniform structure and good processing properties.

The Task could surprisingly solved by it that at least some of the polyethyleneimines are not as usual, before, but during the reaction with the alkylene oxides added to the reaction mixture.

object The invention accordingly provides a process for the preparation of polyether alcohols by reaction of polyethylene mines with alkylene oxides, thereby characterized in that a part or the entire amount of the polyethyleneimines while the reaction with the alkylene oxides is added to the reaction mixture.

Polyethyleneimines in the context of the present invention are high molecular weight nitrogen-hydrocarbon compounds having internal nitrogen atoms and amino groups and having terminal amino groups, in particular primary amino groups. Particularly suitable for the process according to the invention are liquid polyethyleneimines having an average molecular weight M _w of 200-800 g / mol and a viscosity of 3000-5000 mPas at 20 ° C. according to DIN EN ISO 2555 Brookfield RTV 20 ° C. A manufacturer of polyethyleneimines is BASF AG Ludwigshafen, which sells such products under the product name Lupasol ^® . A preferred process of the invention is the product of Lupasol ^® R.

The Formula (I) exemplifies a polyethyleneimine having a molecular weight of 449 g / mol.

The Reaction of the polyethyleneimines with the alkylene oxides alone or in the presence of other compounds having active hydrogen atoms, hereinafter also referred to as co-starter, are performed. The co-starters are mostly connections with at least two active hydrogen atoms, preferably at Room temperature liquid are. In particular, compounds having at least two hydroxyl groups, at least one primary Amino group or at least one secondary amino group and another Group having at least one active hydrogen atom or at least one Hydroxyl group and at least one amino group used.

Examples for co-starters are ethylenediamine, diethylenetriamine, triethylenetetramine, as well as their derivatives, aniline, toluenediamine (TDA), diphenylmethanediamine (MDA), ethylene glycol and its higher homologues, propylene glycol and its higher Homologs, glycerol, trimethylolpropane, sugar alcohols such as sucrose or Sorbitol, their reaction products with alkylene oxides and mixtures from at least two of said compounds. As mentioned above, should the co-starters for better handling at room temperature liquid be. This can be done with solid co-starters, such as the sugars be achieved by mixing them with liquid compounds. When co-starters are used, they are used in one Weight ratio, based on the weight of the polyethyleneimines, from 1:10 to 10: 1.

The inventive method can according to different embodiments carried out become. In one embodiment of the process, the total amount of polyethyleneimines during the Reaction with the alkylene oxides added to the reaction mixture. To start the reaction, first the co-starter with alkylene oxides reacted and in this reaction mixture the whole Amount of polyethyleneimine and further alkylene oxide added.

In another embodiment of the process according to the invention, only part of the amount of polyethyleneimine used is added to the reaction mixture during the reaction with the alkylene oxides puts. In this case, initially a part of the polyethyleneimine, if appropriate in the presence of at least one co-initiator, is initially charged and reacted with the alkylene oxides. To this reacting mixture, the residual amount of the polyethyleneimine and further alkylene oxide is added.

The Dosage of the polyethyleneimine to the reaction mixture can be continuous or in portions. In the continuous addition is over the total time of the dosage polyethyleneimine added. This addition can over the entire time of metering of the alkylene oxides or at least a part the time of dosing the alkylene oxides take place. At the gradual Dosage of the polyethyleneimine is one or more times a certain Amount of the polyethyleneimine added to the reaction mixture. there the addition can be made continuously or in portions. in principle it is also possible Polyethyleneimine after completion of the metered addition of the alkylene oxides during the Time in which free alkylene oxide is still present in the reactor, too dosing. However, this variant is not preferred because not here It is certain that the entire amount of polyethyleneimine will react can.

The inventive method becomes common carried out in the presence of alkoxylation catalysts. in this connection preferably basic catalysts, such as amines, basic Salts and in particular hydroxides of alkali metals and / or alkaline earth metals, particularly preferably potassium hydroxide used. The catalyst becomes common added to the starting mixture at the beginning of the reaction. If necessary, can be added during the process further catalyst.

If a part of the polyethyleneimine is presented, it is advantageous at least 10% by weight and at most 60 wt .-% of the total amount of polyethyleneimines and continuously or gradually add as much polyethyleneimine as reacting respectively can. The weight percent refers to the total amount of polyethyleneimine and co-starters.

In a preferred embodiment the method according to the invention be in the dosage of polyethyleneimines during the Alkylenoxiddosierung 40 to 60 wt .-% of the polyethyleneimines used in a first Stage and the rest Quantity added in a second stage.

in principle Is it possible, also the co-starter in whole or in part to the reaction mixture to dose. This variant is not preferred.

When Alkylene oxides are in particular lower alkylene oxides, preferably Ethylene oxide, propylene oxide and / or butylene oxide, particularly preferred Ethylene oxide and / or propylene oxide are used.

The Implementation of the starting substance with the alkylene oxides is the usual for this To press in the range between 0.1 and 1.0 MPa and the usual temperatures in the range between 80 and 140 ° C carried out. The dosing of the alkylene oxides is usually followed by a post-reaction phase to completely react the alkylene oxides.

To the addition of the alkylene oxides and the post-reaction phase the polyether, if necessary, freed from the catalyst.

The according to the inventive method Polyether alcohols prepared preferably have a functionality in the range of> 3 and a hydroxyl number of> 200 mg KOH / g.

The according to the inventive method Polyether alcohols prepared alone, but preferably in combination with other compounds with at least two with Isocyanate-reactive hydrogen atoms converted to polyurethanes become.

When Compound having at least two active hydrogen atoms together with the polyether alcohols according to the invention can be used in particular polyester alcohols and preferably polyether alcohols with a functionality from 2 to 8, in particular from 2 to 6, preferably from 2 to 4 and an average molecular weight in the range of 400 to 10,000 g / mol, preferably from 1000 to 8000 g / mol, into consideration. The salary the polyether alcohols of the invention in the compounds having at least two isocyanate-reactive Hydrogen atoms are preferably in the range between 0.1 and 20 wt .-%, more preferably between 0.5 and 10 wt .-% based on the weight of all compounds containing at least two isocyanate groups reactive hydrogen atoms.

The polyether alcohols used in combination with the polyether alcohols according to the invention can be prepared by known methods, usually by catalytic addition of alkylene oxides, in particular ethylene oxide and / or propylene oxide, to H-functional starter substances, or by condensation of tetrahydrofuran. In particular, polyhydric alcohols and / or amines are used as H-functional starter substances. Preference is given to using water, dihydric alcohols, for example ethylene glycol, propylene glycol or butanediols, trihydric alcohols, for example glycerol or trimethylolpropane, and also higher-value alcohols, such as pentaerythritol, sugar alcohols, for example sucrose, glucose or sorbitol. Preferably used amines are aliphatic amines having up to 10 carbon atoms, for example, ethylenediamine, diethylenetriamine, propylenediamine, and amino alcohols, such as ethanolamine or diethanolamine. As alkylene oxides, preference is given to using ethylene oxide and / or propylene oxide, with polyether alcohols which are used for the production of flexible polyurethane foams frequently being attached to the chain end by an ethylene oxide block. As catalysts in the addition of the alkylene oxides in particular basic compounds are used, in which case the potassium hydroxide has the greatest technical importance. If the content of unsaturated constituents in the polyether alcohols should be low, multimetal cyanide compounds, so-called DMC catalysts, can also be used as catalysts.

For certain Fields of application, in particular for increasing the hardness in polyurethane flexible foams, can also so-called polymer-modified polyols can be used. such For example, polyols can be used by in situ polymerization of ethylenically unsaturated Monomers, preferably styrene and / or acrylonitrile, in polyether alcohols getting produced. The polymer-modified polyether alcohols also include Polyurea dispersions containing polyether alcohols, preferably by reaction of amines with isocyanates in polyols become.

to Production of flexible foams and integral foams in particular, difunctional and / or trifunctional polyether alcohols used. For the production of rigid foams in particular polyether alcohols used by addition of alkylene oxides to four or higher functionality Starters, such as sugar alcohols or aromatic amines are produced.

To The compounds having at least two active hydrogen atoms also belong the chain extension and crosslinking agents which may optionally be included. When chain extenders and crosslinking agents will preferably be 2- and 3-functional Alcohols with molecular weights below 400 g / mol, in particular in Range of 60 to 150 g / mol, used. Examples are ethylene glycol, Propylene glycol, diethylene glycol, 1,4-butanediol, glycerol or trimethylolpropane. As crosslinking agents can also diamines are used. If chain extenders and crosslinkers be used is their amount preferably up to 5 wt .-%, based on the weight the compounds having at least two active hydrogen atoms.

When Polyisocyanates can the usual and known aromatic di- and polyisocyanates individually or in any mixtures are used with each other. Examples for aromatic Di- or polyisocyanates are 2,4-tolylene diisocyanate (2,4-TDI), 2,6-tolylene diisocyanate (2,6-TDI), 2,4'-diphenylmethane diisocyanate (2,4'-MDI), 4,4'-diphenylmethane diisocyanate (4,4'-MDI), polyphenyl polymethylene polyisocyanates, as obtained by condensation of aniline and formaldehyde and subsequent Phosgenation (polymer-MDI), p-phenylene diisocyanate, Toluidine diisocyanate, xylylene diisocyanate or 1,5-naphthylene diisocyanate (NDI).

Preferably together with or in place of these monomeric isocyanates or mixtures of these prepared oligo- or polyisocyanates, so-called prepolymers, in particular based on TDI and MDI, used. These oligo- or polyisocyanates can be from the mentioned di- or polyisocyanates or mixtures thereof and optionally Mono- or polyalcohols by linking by means of urethane, allophanate, Urea, biuret, uretdione, amide, isocyanurate, carbodiimide, Uretonimine, oxadiazinetrione or iminooxadiazinedione structures produce. Preferably urethane, allophanate, carbodiimide, Uretonimine, biuret or isocyanurate group-containing polymers from TDI or MDI and optionally mono- or polyalcohols used.

For the preparation of the polyurethanes, further starting materials, in particular catalysts, blowing agents and auxiliaries and / or additives may be used, to which the following is to be said in detail:
As catalysts for the preparation of the polyurethane foams according to the invention, the customary and known polyurethane-forming catalysts can be used, for example organic tin compounds such as tin diacetate, tin dioctoate, dialkyltin dilaurate, and / or strongly basic amines such as triethylamine, pentamethyldiethylenetriamine, tetramethyldiaminoethyl ether, imidazoles or preferably triethylenediamine. The catalysts are preferably used in an amount of 0.01 to 5 wt .-%, preferably 0.05 to 2 wt .-%.

When Propellant for the production of polyurethane foams is preferred Water is used, with release of the isocyanate groups reacted by carbon dioxide. Together with or in place of water can also physically acting blowing agents, for example carbon dioxide, Hydrocarbons, such as n-, iso- or cyclopentane, cyclohexane or halogenated hydrocarbons, such as tetrafluoroethane, pentafluoropropane, Heptafluoropropane, pentafluorobutane, hexafluorobutane or dichloromonofluoroethane become. The amount of the physical blowing agent is preferably in the range between 1 and 15% by weight, in particular 1 and 10% by weight, the amount of water preferably in the range between 0.5 and 10 Wt .-%, in particular 1 and 5 wt .-%.

When Auxiliaries and / or additives are, for example, surface-active Substances, foam stabilizers, cell regulators, external and internal release agents, fillers, Flame retardants, pigments, hydrolysis and fungistatic and bactericidal substances used.

at In the technical production of polyurethane foams it is customary to Compounds having at least two active hydrogen atoms and the other starting materials and auxiliaries and / or additives before Implementation to combine a so-called polyol component.

Further Information about the starting materials used are found, for example, in the Kunststoffhandbuch, Volume 7, Polyurethane, edited by Günter Oertel, Carl-Hanser-Verlag, Munich, 3. Edition 1993.

to Preparation of the polyurethanes of the invention are the organic polyisocyanates with the compounds with at least two active hydrogen atoms and the aforementioned blowing agents, Catalysts and auxiliaries and / or additives (polyol component) reacted.

at The preparation of the polyurethanes are isocyanate and polyol component brought together in such an amount that the equivalence ratio of Isocyanate groups to the sum of the active hydrogen atoms 0.6: 1 to 1: 1.4, preferably 0.7: 1 to 1: 1.20.

The according to the inventive method produced polyether alcohols have good compatibility with the rest for the production of polyurethanes used starting materials. Because of their high functionality to lead they lead to an optimal crosslinking of the polyurethanes.

The Invention will be explained in more detail in the following examples.

example 1

In a 1.5 l steel autoclave with attached thermostat for heating and cooling, an agitator with an agitator and a dosing pump connected to the metering of the alkylene 193 g polyethyleneimine Lupasol ^® R, 57 g of glycerol and 27 g of solid potassium hydroxide were charged, rendered inert with nitrogen and Stirring heated to 125 ° C. When these temperatures were reached, 200 g of ethylene oxide were metered in successively with stirring of the reaction mixture and then 300 g of propylene oxide were added without reaction interruption within 2.5 hours. After a short reaction phase and cooling to 60 ° C for an additional 83g of Lupasol ^® R were introduced into the reaction mixture. After a nitrogen purge and heating to 130 ° C., 333 g of propylene oxide were metered in succession over a period of 3 hours up to a pressure of 3 bar at this temperature. After a 1.5 continuous reaction time at 120 ° C, the crude polyether was filled and neutralized at 80 ° C after addition of water and phosphoric acid. Thereafter, water and other volatile compounds were removed by distillation at 110 ° C. and a vacuum of 15 mbar and the salts were separated off via a cellulose filter. The finished polyether had a hydroxyl number of 420 mg KOH / g, a viscosity at 25 ° C of 6700 mPas, a water content of 0.08%, an acid value of 0.03 mg KOH / g and a pH of 8.3 and could be used for the production of highly crosslinked, thermostable rigid polyurethane foams.

Claims (11)

A process for the preparation of polyether alcohols by reacting polyethyleneimines with alkylene oxides, characterized in that a portion or the entire amount of the polyethyleneimines during the reaction with the alkylene oxides is added to the reaction mixture. A method according to claim 1, characterized in that the polyethyleneimines have an average molecular weight M _w of 200-800 g / mol. Method according to claim 1, characterized in that that the reaction of the polyethyleneimines with the alkylene oxides alone or in the presence of other compounds with active hydrogen atoms he follows. Method according to claim 1, characterized in that that the other compounds having active hydrogen atoms are selected from the group comprising ethylenediamine, diethylenetriamine, triethylenetetramine, and their derivatives, aniline, toluenediamine, diphenylmethanediamine, Ethylene glycol and its higher homologues, Propylene glycol and its higher Homologs, glycerol, trimethylolpropane, sugar alcohols such as sucrose or sorbitol, their reaction products with alkylene oxides and mixtures from at least two of said compounds. Method according to claim 1, characterized in that that the other compounds with active hydrogen atoms in one weight ratio from 1:10 to 10: 1 based on the weight of the polyethyleneimines become. Method according to claim 3, characterized that first the other compound with active hydrogen atoms with alkylene oxides implemented and the total amount of polyethyleneimines during the reaction is added to the reaction mixture with the alkylene oxides. Method according to claim 3, characterized that first the other compound with active hydrogen atoms and a subset of the polyethyleneimine reacted with alkylene oxides and then the residual amount the polyethyleneimines during the reaction with the alkylene oxides added to the reaction mixture becomes. Polyether alcohols, preparable according to one of claims 1 to 7th Use of polyether alcohols according to Claim 8 for the production of polyurethanes. Process for the preparation of polyurethanes by Reaction of polyisocyanates with compounds having at least two isocyanate-reactive hydrogen atoms, characterized that as compounds having at least two isocyanate-reactive Hydrogen atoms polyether alcohols are used according to claim 8. Polyurethanes, preparable according to claim 10.