DE10003156A1 - Polyurethane foam for adsorbing chemicals or gases or for purifying waste water contains immobilized ethyleneimine, polyethyleneimines and/or alkali(ne earth) hydroxides - Google Patents

Abstract

Polyurethane foams contains (i) ethyleneimine, polyvinyl amines or their copolymers or optionally carboxymethylated-, phosphonomethylated-, quaternized- and/or dithiocarbamatized-polyethyleneimine and/or (ii) alkali(ne earth) hydroxides. An independent claim is also included for the preparation of the foam.

Description

The invention relates to polyurethane foams, for example Soft, semi-rigid or rigid foams, preferably open-celled Foams, preferably hydrophilic foams, containing (i) Ethyleneimine, polyethyleneimine, polyvinylamine, carboxymethylated Polyethyleneimines, phosphonomethylated polyethyleneimines, quarter nized polyethyleneimines and / or dithiocarbamitized poly ethylenimines, their use and processes for their manufacture position.

The production of polyurethane foams, below also known as PUR foams, by implementing Polyisocyanates with compounds with at least two reactive Hydrogen atoms have been known for a long time and have become numerous described.

Because of the advantageous properties of PUR foam fabrics, for example, with regard to their low abrasion and their chemical resistance make these foams suitable in principle, excellent materials as carrier materials for Active ingredients. The support on polymers offers both for physical as well as chemical processes compared to un methods supported the advantages of heterogeneous reactions. These include, for example, easy removal and return obtaining connections, e.g. B. by simple filtration or Regeneration, recycling and the possibility of using it in continuous flow processes as well as the high effectiveness, due to the large surface area of the carrier material. Frequently complexing agents are used as supported active ingredients.

For example, WO 95/18159 describes the production of an ion exchanger materials based on a polyurethane foam, the Ion exchange material either already the starting substances for the production of the foam is added or after is polymerized sluggishly on the foam. As ions A variety of polymers are added to the exchange material leads, among other things polystyrene-polyethyleneimine. The usage A polystyrene-polyethyleneimine is disadvantageous for two reasons. On the one hand, the polyethyleneimine has to be added first Work step to be bound to the polystyrene. On the other hand is the effective amount of active ingredient introduced by the not as Active ingredient suitable polystyrene less than a direct one Use of polyethyleneimine.

The object of the present invention was to provide polymers with excellent adsorption capabilities for different compounds, to develop especially for heavy metal ions.

The object of the present invention was achieved by the described polyurethane foams are solved before pulls (i) covalently bound to the polymer of the foam contain.

As a complexing agent, i. H. Compounds (i) are according to the invention Ethyleneimine, polyethyleneimine, polyvinylamine, carboxymethylated Polyethyleneimines, phosphonomethylated polyethyleneimines, quarter nized polyethyleneimines and / or dithiocarbamitized poly ethyleneimine used.

Examples include: ethyleneimine, polyethyleneimines with a molecular weight range of 500 to 30000 g / mol, carboxymethylated polyethyleneimines with a molecular weight range from 1000 to 50000 g / mol, phosphonomethylated poly ethyleneimines with a molecular weight range of 1000 to 50000 g / mol, quaternized polyethyleneimines with one mole molecular weight range from 1000 to 50000 g / mol, dithiocarba mitized polyethyleneimines with a molecular weight range from 1000 to 50000 g / mol, polyvinylamines.

Preferred as (i) polyethyleneimine, carboxymethylated poly ethyleneimine and / or polyvinylamine.

The adsorption capacity for individual substances is determined by the supported complexing agent (i) controlled. As carrier materials polyurethane foams have been particularly suitable proven.

In addition to the adsorption of heavy metal ions, the produced Foams also for the adsorption of anionic heavy metal complexes or anions. In addition, the foams can Adsorption of organic molecules (e.g. aldehydes) or acidic Gases are used.

The complexing agents (i) can be prepared by two different methods be supported on the polyurethane foam.

On the one hand, the production of the polyurethane foam can be carried out by Reaction of polyisocyanates with compounds with at least two hydrogen atoms reactive with isocyanates in the presence of (i) be carried out. From the complexing agents (i) can can also be prepared by reaction with isocyanate prepolymers,  this means the reaction products of the complexing agents and Polyisocyanates that have free isocyanate groups at the chain end point. The prepolymers and quasi-prepolymers and their manufacturers position are well known and widely described.

On the other hand, you can make the polyurethane foam according to its manufacture soak the position with (i). By soaking the foam with the liquid complexing agent (i) or a solution of solid or liquid complexing agent in a suitable solution medium is (i) impregnated on the foam. As a solvent Protic solvents are suitable, for example water, acetone, i-propanol, methyl ethyl ketone or haloalkanes such as 1,2-dichloro- methane. From the foams soaked with complexing agents the solvent can then be removed. This can ge done by simply applying a vacuum or by drying at temperatures up to max. 50 ° C. By temperature treatment at Temperatures between 50 and 150 ° C over a period of 4 to The complexing agent (i) can be applied to the foam for 72 hours react and thus be covalently connected.

For better fixation of the complexing agent (i), the Foam can be made with an excess of isocyanates - in In this case, the complexing agent can have residual isocyanate groups are fixed to the foam structure.

The foam can also be pre-diluted with a diluted isocyanate solution can be soaked. The foam thus prepared is then then soaked with the complexing agent solution. Here too can the complexing agent on the isocyanate groups on the foam be bound.

With a subsequent impregnation of the foams with complex solution containing the image is the absorption capacity of the foam also depends on the type and polarity of the solvent, in which the active ingredient was dissolved. Especially the use of Acetone as the preferred solvent for the compound (i) increases the capacity of the foam for (i).

The complex applied to the foam by soaking If necessary, formers (i) can be added in a further step crosslink the foam. As crosslinkers are for example as non-volatile PEG bisglycidyl ether or comparable Functionalities, or suitable polycarboxylic acids. The ver The temperatures required for the ether are 80 ° C for the polycarboxylic acids at 120 to 130 ° C.  

The polyurethane foams according to the invention preferably have a content of (i) of 0.1 to 50 wt .-%, based on the Weight of the foam.

The polyurethane foams according to the invention are preferred Application in the. Adsorption of heavy metal ions from liquid keiten. However, the foams can also be used for adsorption of anionic heavy metal complexes, anions, acidic ver bonds and organic substances such as formaldehyde be set. The foams can also be used for gas scrubbing For example, can be used as an ozone filter in cars.

The metal ions, especially heavy metal ions, by the Polyurethane foams according to the invention preferably adsorbed can result from the choice of the supported complex educator. Some heavy metals (especially mercury and lead) are also adsorbed by the polyurethane foam, thereby there is an additional increase in depletion. By the supported complexing agents are especially copper, Nickel, cobalt, cadmium, mercury, lead, chrome, manganese, Iron, rhenium, silver, zinc adsorbed.

As liquids from which the heavy metal ions are adsorbed in principle, all liquids are suitable in which the ions are soluble in, and which the polyurethane foam matrix do not destroy. Water is particularly suitable if polar, water-miscible organic solvents and any mixtures of the compounds mentioned. With watery Solutions should be ahead of the percentage of organic solvents does not exceed 30% by weight, based on the weight of the Solution, because otherwise a partial adsorption Separation can occur, which leads to disturbances in the adsorption leads.

The liquid containing heavy metal ions is preferred with the polyurethane foam according to the invention containing (i) brought into contact. The polyurethane foam can be used as geometric shape, e.g. B. as cubes or balls, or introduced into the liquid in a flocked form, in this ge stirred and removed after adsorption, for example by filtration. In a further embodiment of the Invention, the polyurethane foam, for example in fixed a tube or a cartridge and the liquid passed through this fixed foam. The fixation of the Foam can be used, for example, as a fixed bed in an exchanger column. It has proven to be cheap, the shredded one  Attach foam as a filter bed and the replacement solution to pass through this filter.

Flocculated are very suitable for the process according to the invention Foams because the accessible surface is particularly high is.

Adsorption should preferably be at a pH in the range take place between 2 to 12, preferably from 4 to 10. The The pH value can be adjusted using buffer solutions be taken. In the event of a failure of the metal hydroxides these are also physisorbed onto the foam and thus be separated. Known buffer solutions for this pH range can be selected, e.g. B. a citrate buffer or a phosphate buffer.

After the exchange capacity of the invention set polyurethane foams may have given if extraction by acids or complexing agents concentrated metal ions can be achieved. The functionalized Foam can be used again after regeneration.

It is difficult or difficult to regenerate the foam possible, this can be used thermally at low cost. The corresponding metals can optionally be used as alloys component can be contained in blast furnace metals.

By adsorbing radioactive compounds, atoms or The radiating components can be collected by ions. The resulting volume concentration is high economic advantage. The PUR foams so loaded can then, if necessary, concreted in or permanently sealed become. Final storage is then possible.

The adsorbent foams used according to the invention are preferred can be used in a temperature range from <0 ° C to 110 ° C, with a limited service life at temperatures <90 ° C is expected.

Accordingly, the use of the invention is preferred Polyurethane foams for the adsorption of heavy metal ions Liquids.  

The polyurethane foams according to the invention are preferred open-celled to have the largest possible surface for contact between the complexing agent (i) and the liquid which which contains the metal ions to be adsorbed.

It is also advantageous to use the polyurethane foams Adjust hydrophilic, this ensures optimal wetting the foam with a liquid to be adsorbed Contains metal ions. The hydrophilicity of the polyurethane Foams can, for example, by using poly etherols with a high content of ethylene oxide in the chain increase.

The polyurethane foams produced by the process according to the invention preferably have a density of 10 to 800 kg / m ³ , particularly preferably 20 to 700 kg / m ³ and in particular 40 to 60 kg / m ³ .

The production of polyurethane foams by implementing Isocyanates, for example polyisocyanates, with compounds with is at least two hydrogen atoms reactive with isocyanates well known.

To produce the polyurethanes according to the invention, the Isocyanates with the compounds with at least two active Hydrogen atoms in the presence of the blowing agent and, if appropriate Catalysts and / or auxiliaries and / or additives for Brought reaction. Here, the connections with at least two hydrogen atoms reactive with isocyanate groups and the named blowing agents, catalysts and auxiliary and / or additive substances often before the conversion to a so-called polyol component combined and this with the isocyanate component brought together.

For the implementation of the method according to the invention possible input products, d. H. the isocyanates, the compound with at least two active hydrogen atoms, the blowing agents and optionally the catalysts and / or the auxiliary and / or additives, the following can be said in detail:

As isocyanates, preferably polyisocyanates, particularly preferred Diisocyanates, preferably organic diisocyanates, can usual and known (cyclo) aliphatic and aromatic Polyisocyanates are used. Examples of aromatic poly isocyanates are 2,4- and 2,6-tolylene diisocyanate (TDI), 4,4'-, 2,4'- and 2,2'-diphenylmethane diisocyanate (MDI), polyphenylene polymethylene polyisocyanates (raw MDI), 1,5-naphthylene diisocyanate.  

Examples of (cyclo) aliphatic di- or tri-isocyanates are 1,4-tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate, iso phorone diisocyanate, 2-methyl-pentamethylene diisocyanate, 2,2,4- or 2,4,4-trimethyl-1,6-hexamethylene diisocyanate, 2-butyl-2-ethyl pentamethylene diisocyanate, 1,4-diisocyanatocyclohexane, 3-iso cyanatomethyl-1-methyl-1-isocyanatocyclohexane, isocyanatopropyl- cyclohexyl isocyanate, xylylene diisocyanate, tetramethylxylylene di isocyanate, bis (4-isocyanatocyclohexyl) methane, lysine ester iso cyanates, 1,3- or 1,4-bis (isocyanatomethyl) cyclohexane, 4-iso cyanatomethyl-1,8-octamethylene diisocyanate and mixtures thereof or the oligo- or polyisocyanates prepared therefrom.

The oligo- or polyisocyanates can be produced from the mentioned di- or triisocyanates or mixtures thereof Linkage using urethane, allophanate, urea, biuret, Uretdione, amide, isocyanurate, carbodiimide, uretonimine, oxa diazintrione or iminooxadiazinedione structures.

The isocyanates mentioned can also be modified, for example wise by incorporating carbodiimide groups. Often they are Polyisocyanates also used in the form of prepolymers. there are reaction products of the named Polyiso cyanates with polyol components. Mostly so-called iso cyanate prepolymers used, that is, such reaction products of polyols and polyisocyanates, the free iso at the chain end have cyanate groups. The prepolymers and quasi-prepolymers and their manufacture are well known and in many cases wrote. In particular, for the method according to the invention Prepolymers with an NCO content in the range from 25 to 3.5% by weight used.

In a preferred embodiment of the Ver are as isocyanate component, MDI and / or raw MDI as well as biurets, isocyanurates, and allophanates based on ali phatic isocyanates can be used.

As a compound with at least two active hydrogen atoms are preferably polyester alcohols and particularly preferred Polyetherols with a functionality of 2 to 8, in particular from 2 to 4, preferably 2 to 3 and a molecular weight in the range of 1000 to 8500 g / mol, preferably 1000 to 6000 used. Connections with at least two active Hydrogen atoms also include the chain extension and ver wetting agents that can be used if necessary. Preferred as chain extenders and crosslinking agents as 2- and 3-functional alcohols with molecular weights less than 1000 g / mol, in particular in the range from 60 to 150.  

Examples are ethylene glycol, propylene glycol, diethylene glycol, Dipropylene glycol, polyethylene glycol with a molecular weight less than 1000, polypropylene glycol with a molecular weight less than 1000 and / or 1,4-butanediol. Can be used as a crosslinking agent diamines can also be used. If chain extension and Crosslinking agents are used, the amount is preferred up to 5 wt .-%, based on the weight of the isocyanates.

As catalysts for the preparation of the invention Polyurethane foams can be the usual and known Polyurethane formation catalysts used, for example organic tin compounds, such as tin diacetate, tin dioctoate, Dialkyltin dilaurate, and / or strongly basic amines such as triethyl amine, pentamethyldiethylenetriamine, tetramethyldiaminoethyl ether, 1,2-dimethylimidazole, dimethylcyclohexylamine, dimethylbenzylamine or preferably triethylenediamine. The catalysts are before preferably in an amount of 0.01 to 5% by weight, preferably 0.05 up to 2% by weight, based on the weight of the isocyanates.

As a blowing agent for the production of polyurethane foams preferably water used with the isocyanate groups under Release of carbon dioxide reacts. Together with or at Instead of water, physically active blowing agents, for example hydrocarbons, such as n-, iso- or cyclopentane, or halogenated hydrocarbons, such as tetrafluoroethane, penta fluoropropane, heptafluoropropane, pentafluorobutane, hexafluorobutane, Dichloro-monofluoroethane or acetals such. B. methylal used become. The amount of physical blowing agent lies there preferably in the range between 1 to 15% by weight, in particular 1 to 10 wt .-%, the amount of water preferably in the range between 0.5 to 10% by weight, in particular 1 to 5% by weight on the weight of connections with at least two active Hydrogen atoms.

As auxiliaries and / or additives, for example surface-active substances, foam stabilizers, cell regulators, external and internal release agents, fillers, pigments, hydrolysis protective agents as well as fungistatic and bacteriostatic Substances are used.

In the production of the polyurethane foams according to the invention the polyisocyanates and the compounds with at least two preferred hydrogen atoms reactive with isocyanate groups reacted in such an amount that the Equivalence ratio of isocyanate groups to the sum of the active ones Hydrogen atoms 0.7 to 1.8: 1, preferably 0.7 to 1.20: 1 is.  

The production of polyurethane foams is preferred wise according to the one-shot process, for example with the help of High pressure or low pressure technology. The foams can be in open or closed metallic molds or through continuous application of the reaction mixture to tape roads for the production of foam blocks.

It is particularly advantageous after the so-called two component process, in which, as explained above, a polyol and an isocyanate component produced and with be foamed on each other. The components are preferred at a temperature in the range between 15 to 90 ° C, preferably 20 to 60 ° C and particularly preferably 20 to 35 ° C mixed and in the mold, or brought to the belt line. The temperature in the mold is usually in the range between 20 and 110 ° C, preferably 30 to 60 ° C and particularly preferred 35 to 55 ° C.

When the complexing agent (i) is added directly to the Component (i) can be produced from the polyurethane foams. both the polyol component and the isocyanate component be added. Preference is given to (i) the polyol component admitted.

Claims (7)

1. Polyurethane foams containing (i) ethylene imine, poly ethyleneimine, polyvinylamine, carboxymethylated polyethylene imines, phosphonomethylated polyethyleneimines, quaternized Polyethyleneimines and / or dithiocarbamitized polyethylene imine. 2. Polyurethane foams according to claim 1 containing (i) covalently bound to the polymer of the foam. 3. Polyurethane foams according to claim 1, characterized records that the polyurethane foams are hydrophilic. 4. Polyurethane foams according to claim 2, characterized records that it has a (i) content of 0.1 to 50% by weight, based on the weight of the foam. 5. Use of polyurethane foams according to claim 1 for adsorption of compounds. 6. Process for the production of polyurethane foams by reacting polyisocyanates with compounds at least two hydrogen atoms reactive with isocyanates, characterized in that the implementation in the presence of (i) ethyleneimine, polyethyleneimine, polyvinylamine, carboxy methylated polyethyleneimines, phosphonomethylated poly ethyleneimines, quaternized polyethyleneimines and / or dithiocarbamitized polyethyleneimines. 7. Process for the production of polyurethane foams by reacting polyisocyanates with compounds at least two hydrogen atoms reactive with isocyanates, characterized in that the polyurethane foam after its production with (i) ethyleneimine, polyethylene imine, polyvinylamine, carboxymethylated polyethyleneimines, phosphonomethylated polyethyleneimines, quaternized poly ethyleneimine and / or dithiocarbamitized polyethyleneimine soaks.