DE10208276A1 - Composite membrane, process for its production and the use of the membrane - Google Patents

Abstract

A composite membrane is described that combines the advantages of inorganic membranes, such as solvent resistance and stability, with the advantages of organic membrane materials. DOLLAR A The composite membrane described consists of a ceramic carrier layer which is applied to a carrier comprising polymer fibers and a ceramic selectively separating layer. The pore sizes of the membrane can be adjusted by the manufacturing conditions of the ceramic selective separation layer.

Description

The invention relates to a composite membrane with a polymer ceramic composite and a ceramic selective separating layer.

Ceramic membranes have been known for more than 10 years and are nevertheless due to their quite high price wherever there is either good temperature resistance (> 80 ° C) or good chemical resistance must be guaranteed. Commercially these membranes are available for microfiltration and for ultrafiltration applications. Recently, various applications in pervaporation and in the Nanofiltration reports (K.-V. Peinemann and S. P. Nunes, Membrane Technology; 2001, VCH-Verlag).

Various applications are known in which composite materials are the ceramics have used.

The advantage of composite materials with ceramics is that they are ceramic Coatings against most chemical substances, such as. B. organic Substances that are chemically inert and also predominantly against acids or alkalis are stable. For this reason, metals are often coated with ceramics in order to Protect metal from chemical influences. Due to the porous surface one with a Ceramic-coated composite material also increases the abrasion resistance of subsequently applied paints or protective coatings. Ceramics themselves are suitable due to their porous surface also very good for use as membranes or Filter.

The disadvantage of the ceramics or the composite materials having ceramics is Brittleness of ceramics. Metals coated with ceramic are therefore very sensitive to impact and the ceramic coating can hardly withstand mechanical stress without the Surface of the ceramic is damaged. Since the bending of such a ceramic Composite material leads to damage to the ceramic layer are the areas of application such ceramic composites are currently limited.

Despite the disadvantages, ceramic composites are often also used in the Filtration technology or membrane technology used.

In EP 0358 338 a method is described with which by applying a Aqueous solution containing metal oxide sol and solidifying this solution on a Surface, preferably a smooth metal surface, this surface by a Ceramic layer can be protected. The aqueous solution can improve the Adhesion of the ceramic layer to the surface to be protected is a metal oxide powder and / or an adhesion promoter can be added. The process does not describe that Application of layers on permeable substrates.

WO 96/00198 teaches the production of ceramic layers on surfaces of diverse Materials. These coated materials can be used as membranes. at In this process, titanium dioxide sol is dispersed with aluminum oxide powder, using hydrochloric acid is used for peptization. However, it is not possible using this procedure Layers with pore sizes of less than 50 nm on porous support materials Pore sizes from 2 µm down to 100 nm to coat, because the particles and brine none Would form a layer on the porous support but instead fill the pores of the support would.

US 4934139 teaches a process for making ceramic membranes for the Ultrafiltration and microfiltration. A is used to manufacture such ceramic membranes Sol or a particle suspension are placed on a porous metal support and sintered. The porous carrier can be stainless steel sintered metal or stainless steel mesh, in the Gaps between metal particles were sintered. Metal mesh with gaps across 100 µm cannot be sintered in without metal particles using this method to process. The process prevents the suspension or sol from entering the Penetrate gaps in the carrier material.

In US 5376442 and US 5605628 is used to bridge gaps in the Carrier material an organic binder incorporated into the coating solution. This Binder must be removed again after solidification, which leads to irregularities in the Ceramic surface and / or structure can lead.

Likewise in DE 42 10 413 the inorganic powder is made with the aid of a polymeric resin fixed. This resin must also be removed after solidification, which leads to Irregularities in the ceramic surface and / or structure can result.

WO 99/15262 describes the production of a flexible, permeable composite material describe on the basis of an openwork carrier material. This is where the wearer can go different materials. Among others also from polymeric perforated foils, fabrics made of polymer, natural fiber, glass and steel or metal fleece. The coating is done with a sol, which is very strong to a large extent from water or from aqueous solutions Acids exist in the particles of the oxides of aluminum, titanium, zirconium or silicon were stirred. The sol can also include organosilyl compounds such as Contain methyltriethoxysilane. These permeable composite materials can u. a. use as membranes in filtration.

All of the membranes described so far have very little flexibility. Also are the ceramic coatings become brittle and, provided the ceramic adheres to the substrate is too small, it can easily be detached from the wearer. Such membranes are then unusable.

It was therefore an object of the present invention to provide a flexible membrane, which has a ceramic selective separation layer and which is more durable than previously known Membranes and which can be manufactured inexpensively.

Surprisingly, it was found that very flexible membranes with porous ceramic separating layers, the pores in ultrafiltration (UF) - or nanofiltration (NF) - own the area, have it manufactured if as a carrier for the release-active layer Composite materials are used which are polymeric fibers or natural fibers as a substrate and have a ceramic component located in and on the substrate.

For the production of ultrafiltration or nanofiltration membranes with ceramic Separating layers based on composite materials supported by polymer fibers have to be used entirely break new ground as the methods of manufacturing known UF and NF membranes cannot be applied. The known processes all work with particulate Systems that have to be sintered at approx. 450 to 1200 ° C or with sol-gel Coatings that contain polymeric binders and therefore also with similarly high ones Temperatures are burned to burn out the binder. These high However, temperatures cannot be used in the composite membranes according to the invention as this inevitably leads to the complete destruction of the substrate polymeric fibers would result, and thereby the membranes the mechanical strength would be lost.

The present invention therefore relates to composite membranes, preferably flexible composite membranes, comprising a composite material that has a flat, with a plurality of openings provided, flexible substrate with one on and in this Coating located substrate, wherein the material of the substrate is selected from woven and / or non-woven fibers of polymers and coating a porous, has ceramic coating, which are characterized in that the Composite material at least one other coating than selective ceramic Has separation layer.

The present invention also relates to a method for producing a composite membrane according to the invention with at least one selective ceramic Separating layer comprising a composite material, which is a flat, with a variety of Opened, flexible substrate with one on and in this substrate Coating, the material of the substrate being selected from woven and / or non-woven fibers of polymers and the coating a porous, ceramic Has coating, which is characterized in that the selective separation layer by applying and solidifying a sol or a suspension of an inorganic Component and a sol is obtained.

The present invention also relates to the use of a device according to the invention Composite membrane as a membrane in pressure-driven membrane processes in which Gas separation, pervaporation, vapor permeation, nanofiltration, ultrafiltration or Microfiltration, or in a membrane reactor.

The composite membranes according to the invention have the advantage that they are essential are more stable in temperature and shape than pure organic polymer membranes, Polymer membranes on polymer supports or as polymer membranes, which inorganic Substances were mixed. The composite membrane according to the invention also has one Composite based on ceramic-coated polymer fibers that are thin and are very flexible, so that the composite membrane is also extremely flexible. The Composite membranes therefore almost imply when choosing the modules and housings no limits compared to pure polymer membranes. Through the pronounced The flexibility of the composite membrane according to the invention keeps it much better mechanical loads stood as ceramic membranes for nano- and ultrafiltration based on pure inorganic carriers.

The composite membranes according to the invention also have the advantage that they are extremely inexpensive to manufacture because polymer fabrics or nonwovens are significantly cheaper are as metal or glass fleeces or fabrics of these materials. In contrast to glass fibers the polymer fibers are also significantly less brittle, which is why the handling of the Starting material is also significantly simplified and therefore cheaper.

The composite membrane according to the invention is described below by way of example, without the invention being restricted to these embodiments.

The flexible composite membrane according to the invention, comprising a composite material which a flat, with a multiplicity of openings provided flexible substrate with a and coating located in this substrate, the material of the substrate is selected from nonwovens of polymer or natural fibers and the coating is a porous, Ceramic coating, is characterized in that the composite material has further coating as a selective ceramic separating layer. This selective Interface determines the suitability of the composite membrane z. B. as a nano or Ultrafiltration membrane.

The special flexibility of the composite membrane is demonstrated by the use of Composites achieved based on ceramic-coated substrates, the polymer and / or have natural fibers.

The ceramic separating layer is preferably a porous separating layer with defined ones Pores that preferably have an average pore size of less than 50 nm. For the The use of the composite membrane as a nanofiltration membrane (NF membrane) shows ceramic separation layer, preferably an average pore size of less than 10 nm, preferably from 0.5 nm to 5 nm nm. For using the composite membrane as The ceramic separating layer preferably has an ultrafiltration membrane (UF membrane) average pore size of less than 50 nm, preferably from 5 nm to 25 nm. The ceramic Separating layer preferably has oxides, the elements Ti, Si, Zr, Sn and / or Al, very particularly preferably oxides of the elements Ti, Si, Zr and / or Al. The preferred particles for this Coatings have a particle size of less than 25 nm, preferably less than 15 nm for UF membranes and for NF membranes, these are preferably smaller than 10 nm and particularly preferably less than 5 nm.

It may be advantageous if the selective separation layer has an average thickness of less than 10 µm, preferably a thickness of 0.005 to 5 µm and very particularly preferred has a thickness of 0.005 to 3 µm. This is particularly advantageous because such a small thickness and a sufficiently high transmembrane flow can be guaranteed can.

The composite membrane according to the invention preferably comprises a composite of based on a flat, flexible substrate provided with a large number of openings with an inorganic component located on and in this substrate, the Material of the substrate is selected from nonwovens, knitted fabrics, felts or fabrics Polymer and / or natural fibers, preferably from nonwovens of polymer and / or natural fibers and the inorganic component is a porous ceramic. By using a Fleece, preferably a very thin and homogeneous fleece material, is a uniform transmembrane flow achieved. Nonwovens also have the advantage of being one have significantly higher porosity than comparable fabrics.

The substrate of the composite material used particularly preferably has a thickness of less than 200 µm. It can be particularly advantageous if the invention Composite membrane has a composite material with a substrate, which has a thickness from 25 to 100 µm and particularly preferably from 30 to 70 µm.

The polymer fibers are preferably selected from polyacrylonitrile, polyamides, polyimides, Polyacrylates, polytetrafluoroethylene, polyesters such as B. polyethylene terephthalate and / or Polyolefins, e.g. B. polypropylene, polyethylene or mixtures of these polymers. But also all other known polymer fibers and many natural fibers, such as. B. flax fibers, Cotton or hemp fibers are conceivable. The membrane according to the invention preferably has Polymer fibers that have a softening temperature of greater than 100 ° C and a Have a melting temperature of greater than 110 ° C. For polymer fibers with lower Temperature limits also reduce the areas of application. Preferred membranes are up to a temperature of up to 150 ° C, preferably up to a temperature of 120 to 150 ° C and very particularly preferably up to a temperature of 121 ° C. It can be advantageous if the polymer fibers of the substrate of the composite material have a diameter of 1 to 25 µm, preferably 2 to 15 µm. Are the Polymer fibers significantly thicker than the areas mentioned, the flexibility of the substrate suffers and thus also that of the membrane.

For the purposes of the present invention, polymer fibers also include fibers of polymers understood partially by a thermal treatment chemically or structurally were changed, such as B. partially carbonized polymer fibers.

The ceramic coating located on and in the substrate preferably has at least an oxide containing the metals Al, Zr, Si, Sn, Ti and / or Y. It particularly preferably has and in the substrate coating an oxide of the metals Al, Zr, Ti and / or Si, as inorganic component.

The coating preferably contains at least one inorganic component in one Grain size fraction with a grain size of 1 to 250 nm or with a grain size of 251 up to 10,000 nm. It can be advantageous if the membrane according to the invention has a Coating having at least two grain size fractions at least one has inorganic component. It can also be advantageous if the coating at least two grain size fractions of at least two inorganic components having. The grain size ratio can be from 1: 1 to 1: 10,000, preferably from 1: 1 to 1: 100. The quantitative ratio of the grain size fractions in the composite material can preferably from 0.01: 1 to 1: 0.01.

It can be advantageous if the ceramic coating or the inorganic components that make up the coating of the composite material are bonded to the substrate, in particular the polymer fibers, via adhesion promoters. Typical adhesion promoters are organofunctional silanes, such as those offered by Degussa under the trade name "Dynasilan", but also pure oxides such as ZrO ₂ , TiO ₂ , SiO ₂ or Al ₂ O ₃ can be suitable adhesion promoters for some fiber materials. Depending on the production conditions and the adhesion promoter used, the adhesion promoters can still be detectably present in the membrane according to the invention.

It may be advantageous if the fleece or fabric is first coated with an adhesion promoter was pre-coated. Accordingly, such a membrane then has a fleece inside, preferably a polymer fleece, the fibers of which are covered with a thin layer of a Adhesion promoter (such as a metal oxide or an organosilane compound) equipped are. The porous is in and on the polymeric, pre-coated carrier Ceramic material.

The composite membrane according to the invention preferably has a porosity of 10% to 70%, preferably from 20% to 60% and particularly preferably from 30% to 50%.

The membranes according to the invention are characterized in that they have a tensile strength of at least 1 N / cm, preferably of 3 N / cm and very particularly preferably of larger 6 N / cm. The membranes according to the invention are preferably flexible and flexible preferably without damage down to every radius down to 100 m, preferably Bend down to 50 mm and most preferably down to 2 mm. The good Bendability of the membrane according to the invention has the advantage that when used in the Filtration or gas separation sudden pressure fluctuations through the membrane without any problems can be tolerated without damaging the membrane. Furthermore, the Membranes can be brought into almost any shape that is required by the application (Winding modules, pocket modules etc.).

The composite membranes according to the invention are preferably by Method according to the invention for producing a composite membrane with a selective Ceramic separating layer, comprising a composite material that has a flat, with a A plurality of openings provided, flexible substrate with one on and in this substrate located coating, wherein the material of the substrate is selected from woven and / or non-woven polymer and / or natural fibers and the coating a porous, has ceramic coating, which is characterized in that the selective Separating layer by applying and solidifying a sol or a suspension from a inorganic component and a sol is obtained.

The separating layer is preferably produced in that the composite material Sol or a suspension containing at least one oxide, the metals Al, Zr, Si, Sn, Ti and / or Y has as an inorganic component and a sol, applied to the composite material and by at least one heating step in which the sol or the suspension is solidified on the composite material, a separating layer is applied.

It can be advantageous if at least one inorganic component, which is a average particle size from 1 to 100 nm, preferably from 2 to 40 nm, particularly preferred from 2 nm to 25 nm, is suspended in at least one sol.

The suspension or the sol can be printed, pressed, pressed in, rolled up, Knife, spread, dip, spray or pour onto the substrate.

The suspension used is preferably at least one of the abovementioned inorganic components and at least one sol, preferably at least one Metal oxide sol, at least one semi-metal oxide sol or at least one mixed metal oxide sol or has a mixture of this brine, by suspending at least one inorganic Component made in at least one of these brine. As an inorganic component very particularly preferably at least one oxide selected from the oxides of the elements Zr, Al, Ti and Si, suspended. The mass fraction of the suspended component can be 0.1 to Correspond to 500 times the sol used.

The brines are hydrolyzed by at least one compound, preferably at least a metal compound, at least one semi-metal compound or at least one Mixed metal compound obtained. The preferred compound to be hydrolyzed is at least one metal nitrate, one metal chloride, one metal carbonate, one Metal alcoholate compound or at least one semi-metal alcoholate compound, particularly preferred hydrolyzed at least one metal alcoholate compound. As a metal alcoholate compound or Semi-metal alcoholate compound preferably becomes an alcoholate compound of the elements Zr, Al, Si, Ti, Sn, and Y or at least one metal nitrate, metal carbonate or Metal halide selected from the metal salts of the elements Zr, Al, Ti, Si, Sn, and Y as Metal compound hydrolyzed. The hydrolysis is preferably carried out in the presence of water, Water vapor, ice, or an acid, or a combination of these compounds.

In one embodiment variant of the process according to the invention, hydrolysis of the to produce hydrolyzing compounds particulate brine. This particular brine are characterized by the fact that they are formed in the sol by hydrolysis Compounds are present particulate with particle sizes of less than 15 nm and for which Production of ultrafiltration membranes are very suitable. The particulate brine can as above or as described in WO 99/15262. These brine show usually has a very high water content, which is preferably greater than 50% by weight. It can be advantageous to hydrolyze the compound before the hydrolysis in alcohol or to give an acid or a combination of these liquids. The hydrolyzed Compound can be used for peptizing with at least one organic or inorganic acid, preferably with a 10 to 60% organic or inorganic acid, especially preferably with a mineral acid selected from sulfuric acid, hydrochloric acid, perchloric acid, Phosphoric acid and nitric acid or a mixture of these acids are treated.

In a further embodiment variant of the method according to the invention, through Hydrolysis of the compounds to be hydrolyzed produced polymeric brine. These polymers Brines are characterized by the fact that those formed in the sol by hydrolysis Compounds are polymeric (i.e. networked in a chain over a larger space) and ideally used for the production of nanofiltration membranes. The polymeric sols usually have less than 50% by weight, preferably much less than 20% by weight of water and / or aqueous acid. To get to the preferred portion of To get water and / or aqueous acid, the hydrolysis is preferably so performed that the compound to be hydrolyzed at 0.5 to 10 times Molar ratio and preferably with half the molar ratio of water, steam or ice, based on the hydrolyzable group, the hydrolyzable compound, is hydrolyzed. Up to 10 times the amount of water can be used with very slow hydrolyzing compounds such as B. be used in tetraethoxysilane. Very fast hydrolyzing Compounds such as zirconium tetraethylate can already do so under these conditions form particulate sols, which is why preferably 0.5 times for the hydrolysis of such compounds Amount of water is used. Hydrolysis with less than the preferred amount Water, steam, or ice also lead to good results. Where a Falling below the preferred amount of half a molar ratio by more than 50% possible but not very sensible, since the hydrolysis does not fall below this value is more complete and coatings based on such brine are not very stable.

To produce this polymeric brine with the desired very low proportion of water and / or acid in the sol it can be advantageous if the compound to be hydrolyzed in an organic solvent, in particular ethanol, isopropanol, butanol, amyl alcohol, Hexane, cyclohexane, ethyl acetate and or mixtures of these compounds is dissolved before the actual hydrolysis is carried out.

The solidification of the suspension or the applied to the composite material applied sols are preferably carried out by heating to 50 to 350 ° C., preferably to 50 to 220 ° C and particularly preferably to 50 to 120 ° C. Very particularly preferably solidification by heating for 10 minutes to 5 hours at a temperature of 50 to 100 ° C or for 0.5 to 5 minutes at a temperature of 101 to 250 ° C, preferably 101 to 200 ° C and very particularly preferably from 105 to 150 ° C.

The solidification temperatures depend on the polymer fibers that are in the Composite are present. Most polymer fibers tolerate Solidification temperatures of 120 ° C, such as. B. polypropylene fibers, some even Temperatures up to 150 ° C, such as B. Polyamides. At higher hardening temperatures composite materials are preferably used that have fibers made of polymers that Carbonize and not melt. Examples of such polymers are e.g. B. polyacrylonitrile or the aromatic polyimides.

It can be advantageous if the suspension to be solidified or the sol to be solidified Viscosity regulators are added, the viscosity regulators being thermal should be as unstable as possible. Possible viscosity regulators are e.g. B. Hydroxyethyl cellulose or polyethylene glycol which is preferred in the presence of a catalyst (such as nitric acid or sulfuric acid), which prevents the decomposition of the polymer Viscosity regulators catalyzed, are used. Polyacrylic acids can also be used or polyacrylamides can be used as viscosity regulators. The viscosity regulators together with a suitable catalyst, the suspension to be applied or be added to the sol to be applied. It can be advantageous if the suspension or the sol from 0.01 to 10 wt .-%, preferably from 0.05 to 1 wt .-% and very particularly preferably has less than 1% by weight of organic viscosity regulator. During the The organic viscosity regulator can solidify by heating decompose and escape from the coating. The porous ceramic layer remains.

However, it is also possible to use inorganic systems instead of the polymeric binders, which can then remain in the material. Inorganic systems are primarily viscosity regulators as they are also used in the paint and food industry, such as. B. pyrogenic silicon dioxide, titanium dioxide, zirconium oxide or aluminum oxide. The specific surface area of these materials should preferably be significantly larger than 50 m ² / g. These viscosity regulators work by the largely aggregated particles building up large structures via hydrogen bonds. As a result, these materials increase the viscosity of ketchup or water, for example. The increase in viscosity even goes so far as to make it possible to coat aqueous systems on porous porous substrates. In addition, these materials are inert to many media to be filtered, so that they can remain in the material. The proportion of the inorganic viscosity regulators in the suspensions used is preferably from 0.1 to 50% by weight, preferably from 0.2 to 30% by weight, based on the other ceramic components in the suspension.

Membranes, in particular micro and Ultrafiltration membranes used, for. B. by the method described below are available, which is characterized in that a flat, with a variety of Opened, flexible substrate in and on this substrate with a coating is provided, the material of the substrate being selected from nonwovens of polymer or natural fibers, the nonwovens preferably having a porosity of greater than 50% and the coating is a porous, ceramic coating that adheres to the substrate Application of a suspension, the at least one oxide, of the metals Al, Zr, Si, Sn, Ti and / or Y and a sol, on the substrate and by at least one heating, at which the suspension is solidified on and in the substrate is applied. The Suspension can have other inorganic components, especially those such as have already been described above as inorganic components.

The suspension can e.g. B. by printing, pressing, pressing, rolling, doctoring, Spreading, dipping, spraying or pouring onto and into the substrate.

The material of the substrate is preferably selected from nonwovens of polymer fibers a thickness of 10 to 200 microns. It can be particularly advantageous if the membrane according to the invention has a substrate which has a thickness of 30 to 100 microns, preferably has from 25 to 50 microns.

The polymer fibers are preferably selected from polyacrylonitrile, polyamides, polyimides, Polyacrylates, polytetrafluoroethylene, polyesters such as B. polyethylene terephthalate and / or Polyolefins. But also all other known polymer fibers and many natural fibers are used. The membrane preferably has polymer fibers which have a softening temperature of greater than 100 ° C and a melting temperature of greater than 110 ° C. at Polymer fibers with lower temperature limits also decrease the Application areas. These membranes are up to a temperature of up to 150 ° C, preferably up to a temperature of 120 to 150 ° C and very particularly preferably up to Can be used at a temperature of 121 ° C. It can be advantageous if the polymer fibers have a diameter of 1 to 25 µm, preferably 2 to 15 µm. Are the Polymer fibers significantly thicker than the areas mentioned, the flexibility of the substrate suffers and thus also that of the membrane.

The suspension used to produce the coating, the at least one has inorganic component, preferably has at least one inorganic oxide of aluminum, titanium, silicon and / or zirconium and at least one sol, at least a semimetal oxide sol or at least a mixed metal oxide sol or a mixture of these sols on, and is achieved by suspending at least one inorganic component in at least one of these brine.

The brines are hydrolyzed by at least one compound, preferably at least a metal compound, at least one semi-metal compound or at least one Mixed metal compound obtained. The preferred compound to be hydrolyzed is at least one metal nitrate, one metal chloride, one metal carbonate, one Metal alcoholate compound or at least one semi-metal alcoholate compound, especially preferably hydrolyzed at least one metal alcoholate compound. As Metal alcoholate compound or semi-metal alcoholate compound is preferably one Alcoholate compound of the elements Zr, Al, Si, Ti, Sn, and Y or at least one metal nitrate, Metal carbonate or metal halide selected from the metal salts of the elements Zr, Al, Ti, Si, Sn, and Y hydrolyzed as a metal compound. The hydrolysis is preferably carried out in Presence of water, water vapor, ice, or an acid, or a combination of these Links.

In one embodiment variant of the process according to the invention, hydrolysis of the to produce hydrolyzing compounds particulate brine. This particular brine are characterized by the fact that they are formed in the sol by hydrolysis Connections are particulate. The particulate sols can be as above or as in WO 99/15262 can be produced. These brines usually have a very high high water content, which is preferably greater than 50 wt .-%. It may be beneficial to compound to be hydrolyzed before hydrolysis in alcohol or an acid or a Combination of these liquids. The hydrolyzed compound can be used for Peptize with at least one organic or inorganic acid, preferably with a 10 to 60% organic or inorganic acid, particularly preferably one Mineral acid selected from sulfuric acid, hydrochloric acid, perchloric acid, phosphoric acid and Nitric acid or a mixture of these acids are treated. The so produced particulate sols can then be used to prepare suspensions, the production of suspensions for application to natural fiber fleeces or with polymeric sol pretreated polymer fiber nonwovens is preferred.

In a further embodiment variant of the method according to the invention, through Hydrolysis of the compounds to be hydrolyzed produced polymeric brine. These polymers Brines are characterized by the fact that those formed in the sol by hydrolysis Compounds are polymeric (i.e. networked in a chain over a larger space). The polymeric sols usually have less than 50% by weight, preferably much less than 20% by weight of water and / or aqueous acid. To get to the preferred portion of To get water and / or aqueous acid, the hydrolysis is preferably so performed that the compound to be hydrolyzed at 0.5 to 10 times Molar ratio and preferably with half the molar ratio of water, steam or ice, based on the hydrolyzable group, the hydrolyzable compound, is hydrolyzed. Up to 10 times the amount of water can be used with very slow hydrolyzing compounds such as B. be used in tetraethoxysilane. Very fast hydrolyzing Compounds such as zirconium tetraethylate can already do so under these conditions form particulate sols, which is why preferably 0.5 times for the hydrolysis of such compounds Amount of water is used. Hydrolysis with less than the preferred amount Water, steam, or ice also lead to good results. Where a Falling below the preferred amount of half a molar ratio by more than 50% possible but not very sensible, since the hydrolysis does not fall below this value is more complete and coatings based on such brine are not very stable.

To produce this polymeric brine with the desired very low proportion of water and / or acid in the sol it can be advantageous if the compound to be hydrolyzed in an organic solvent, in particular ethanol, isopropanol, butanol, amyl alcohol, Hexane, cyclohexane, ethyl acetate and or mixtures of these compounds is dissolved before the actual hydrolysis is carried out. A sol produced in this way can be used Production of the suspension according to the invention or as an adhesion promoter in one Pretreatment step can be used.

Both the particulate brine and the polymer brine can be used as sol in the Processes according to the invention can be used to produce the suspension. In addition to the In principle, brines that are available as just described can also be commercially available Brine, such as B. zirconium nitrate sol or silica sol can be used. The procedure of Production of membranes by applying and solidifying a suspension on a Carrier in and of itself is known from WO 99/15262, but not all parameters can be or feedstocks, transferred to the production of the membrane according to the invention. The The process described in WO 99/15262 is particularly not without in this form Smears can be transferred to polymeric nonwoven materials, since the very described water-containing sol systems, often no continuous wetting of the usual enable hydrophobic polymer fleeces in depth because of the very water-containing sol systems most polymer nonwovens do not or only poorly wet. It was found that even the smallest unwetted spots in the nonwoven material can cause membranes to get that have errors and are therefore unusable.

It has now surprisingly been found that a sol system or a suspension, which or which was adapted in the wetting behavior to the polymers, the Nonwoven materials are completely saturated and thus flawless coatings are available. The method according to the invention is therefore preferably adapted to the Wetting behavior of the sol or suspension. This adjustment is preferably done by the production of polymeric sols or suspensions from polymeric sols this brine one or more alcohols, such as. B. methanol, ethanol or propanol or Mixtures containing one or more alcohols, preferably aliphatic Have hydrocarbons include. But there are also other solvent mixtures conceivable, which can be added to the sol or the suspension to this in Adapt networking behavior to the substance used.

It was found that the fundamental change in the sol system and the resulting resulting suspension to a significant improvement in the adhesive properties of the ceramic components on and in a polymeric nonwoven material. Such good adhesive strengths are usually not available with particulate sol systems. Substrates which have polymer fibers are therefore preferred by means of suspensions coated, which are based on polymeric sols or in an upstream step Treatment with a polymeric sol were equipped with an adhesion promoter.

It can be advantageous if, for the preparation of the suspension as an inorganic component, at least one oxide selected from the oxides of the elements Y, Zr, Al, Si, Sn, and Ti, in a sol is suspended. Preferably, an inorganic component is the at least one compound selected from aluminum oxide, titanium dioxide, zirconium oxide and / or silicon dioxide. The mass fraction is preferably suspended component 0.1 to 500 times, particularly preferably 1 to 50 times and very particularly preferably 5 to 25 times the sol used.

It can be advantageous if at least one inorganic component, which is a average grain size from 1 to 10000 nm, preferably from 1 to 10 nm, 10 to 100 nm, 100 up to 1000 nm or 1000 to 10000 nm, particularly preferably from 250 to 1750 nm and entirely particularly preferably from 300 to 1250 nm, is suspended in at least one sol. Through the use of inorganic components that have an average grain size of 250 to 1250 nm have a particularly suitable flexibility and porosity of the Membrane reached.

To improve the adhesion of the inorganic components to polymer fibers as a substrate, it may be advantageous to add adhesion promoters, such as e.g. B. organofunctional silanes or pure oxides such as ZrO ₂ , TiO ₂ , SiO ₂ or Al ₂ O ₃ . The addition of the adhesion promoters, in particular to suspensions based on polymeric sols, is preferred. In particular, compounds selected from the octylsilanes, the fluorinated octylsilanes, the vinylsilanes, the amine-functionalized silanes and / or the glycidyl-functionalized silanes, such as, for. B. the Dynasilane from Degussa can be used. Particularly preferred adhesion promoters for polytetrafluoroethylene (PTFE) are e.g. B. fluorinated octylsilanes, for polyethylene (PE) and polypropylene (PP) it is vinyl, methyl and octylsilanes, whereby the exclusive use of methylsilanes is not optimal, for polyamides and polyamines it is amine-functional silanes, for polyacrylates and polyesters Glycidyl-functionalized silanes and for polyacrylonitrile it is also possible to use glycidyl-functionalized silanes. Other adhesion promoters can also be used, but these have to be matched to the respective polymers. The addition of methyltriethoxysilane described in WO 99/15262 to the sol system in the coating of polymeric carrier materials is a comparatively poor solution to the problem of the adhesive strength of ceramics on polymer fibers. In addition, the drying time of 30 to 120 minutes at 60 to 100 ° C. is not sufficient for the sol systems described in order to obtain hydrolysis-resistant ceramic materials. This means that these materials will dissolve or be damaged if they are stored in water-containing media for a long time. On the other hand, the temperature treatment of over 350 ° C. described in WO 99/15262 would burn the polymer fleece used here and thus destroy the membrane. The adhesion promoters must therefore be selected so that the solidification temperature is below the melting or softening point of the polymer and below its decomposition temperature. Suspensions according to the invention preferably have significantly less than 25% by weight, preferably less than 10% by weight, of compounds which can act as adhesion promoters. An optimal proportion of adhesion promoter results from the coating of the fibers and / or particles with a monomolecular layer of the adhesion promoter. The required amount of adhesion promoter in grams can be obtained by multiplying the amount of oxides or fibers used (in g) by the specific surface area of the materials (in m ² g ^-1 ) and then dividing by the specific space requirement of the adhesion promoter (in m ² g ^-1 ) are obtained, the specific space requirement often being in the order of 300 to 400 m ² g ^-1 .

The following table contains an exemplary overview of usable adhesion promoters based on organofunctional Si compounds for typical polymers used as nonwoven material.

The coatings according to the invention are made by solidifying the suspension in and on the substrate applied to the substrate. According to the invention on and in the substrate existing suspension can be solidified by heating to 50 to 350 ° C. Since at the Using polymeric substrate materials the maximum temperature through the substrate is specified, it must be adjusted accordingly. Depending on the version of the inventive method through the suspension present on and in the substrate Heating to 100 to 350 ° C and most preferably by heating to 110 to 280 ° C solidified. It can be beneficial if heating for 1 second to 60 minutes at a temperature of 100 to 350 ° C. Heating is particularly preferred the suspension for solidification to a temperature of 110 to 300 ° C, very special preferably at a temperature of 110 to 280 ° C and preferably for 0.5 to 10 min.

When solidifying the membrane, some may, depending on the temperature level selected Polymer materials under the influence of temperature cause changes in chemical Structure come, so that subsequently the polymers are no longer in their initial state modification. This can lead to partial carbonization of polyimides or to form so-called conductor polymers in polyacrylonitrile with the following partial Carbonization is coming. These effects always lead to a change in the Properties of the carrier materials. Depending on the application, this can also be specifically intended because, for example, this increases the resistance to solvents, acids and alkalis can be. The degree of conversion can be influenced by temperature and time become.

The heating of the composite according to the invention can be done by means of heated air, hot air, Infrared radiation or by other heating methods according to the prior art respectively.

In a particular embodiment of the method according to the invention, the abovementioned adhesion promoters are applied to the substrate, in particular the polymer fleece, in an upstream step. For this, the in a suitable solvent, such as. B. dissolved ethanol. This solution can also contain a small amount of water, preferably 0.5 to 10 times the amount based on the molar amount of the hydrolyzable group, and small amounts of an acid, such as. B. HCl or HNO ₃ , as a catalyst for the hydrolysis and condensation of the Si-OR groups. By the known techniques such. B. spraying, printing, pressing, pressing, rolling, knife coating, spreading, dipping, spraying or pouring, this solution is applied to the substrate and the adhesion promoter is fixed by a temperature treatment at 50 to a maximum of 350 ° C. on the substrate. In this embodiment of the method according to the invention, the suspension is applied and solidified only after the adhesion promoter has been applied.

In another embodiment variant of the method according to the invention adhesion-promoting layers in a pretreatment step in which a polymeric sol, applied and solidified, applied. The application and solidification of the polymer This is preferably done in the same way as the application and solidification of the Suspensions. By applying this polymeric brine, the substrates, in particular the polymer fleece with an oxide of Al, Ti, Zr or Si as an adhesion promoter equipped, whereby the substrate is made hydrophilic. So equipped substrates can then according to the prior art described in WO 99/15262 or as above described can be equipped with a porous coating, whereby by the Pretreatment a significantly better adhesion of the coating, especially on Polymer fleeces can be observed.

A typical polymeric sol for pretreatment is about 2 to 10% by weight alcoholic solution of a metal alcoholate (such as titanium ethylate or zirconium propylate) represents the additional 0.5 to 10 mol parts of water as well as small amounts of an acid May contain catalyst. After applying such a sol to the substrate, the Treated substrates, preferably polymer nonwovens at a temperature of maximum 350 ° C. This creates a dense film of a metal oxide around the substrate fibers, causing an infiltration of the substrate with a suspension or a slip based on a commercial zirconium nitrate sol or silica sol is possible without wetting difficulties.

Because polymer sols tend to form dense films than particulate sols, and particulate sols it is always larger quantities of water in the pore structure of the intermediate grain volumes easier to dry polymeric brine than particulate brine. Nevertheless, the membranes be dried at temperatures above 150 ° C, so that the ceramic material receives sufficient good adhesive strength on the carrier. Leave particularly good adhesive strengths at a temperature of at least 200 ° C and very good strength achieve a temperature of at least 250 ° C. However, this is then appropriate temperature-stable polymers are mandatory, such as polyethylene terephthalate (PET), Polyacrylonitrile (PAN), polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF) or Polyamide (PA). If the carrier is not sufficiently temperature-stable, a Predrying at a lower temperature (up to 100 ° C) first pre-consolidation of the Membrane. In the case of post-consolidation at an elevated temperature, the Ceramic layer as support for the support so that it no longer melts away Substrate can come. These process parameters apply not only to the application and Solidifying a polymeric sol z. B. as an adhesion promoter but also for application and solidifying suspensions based on polymeric sols.

By both types of application of an adhesion promoter before the actual one Applying the suspension can particularly adversely affect the adhesive behavior of the substrates aqueous, particulate sols can be improved, which is why pretreated in particular Substrates with suspensions based on commercially available sols, such as. B. Zirconium nitrate sol or silica sol can be coated according to the invention. This approach of Applying an adhesion promoter also means that the manufacturing process of membrane according to the invention extended by an intermediate or pretreatment step must become. This is feasible, however, more expensive than using adapted sols to which adhesion promoters have been added also has the advantage that better results even when using suspensions based on commercially available brines be achieved.

The inventive method can, for. B. be carried out so that the substrate of a roll is unrolled, at a speed of 1 m / h to 2 m / s, preferably with a speed of 0.5 m / min. up to 20 in / min and very particularly preferably with one Velocity from 1 m / min to 5 m / min by at least one apparatus which the Suspension on and in the support, such as B. a roller and at least one other Apparatus which solidifies the suspension on and in the support by heating enables such. B. passes through an electrically heated oven and the so produced Membrane is rolled up on a second roll. In this way it is possible to Manufacture membrane according to the invention in a continuous process. Also the Pretreatment steps can be carried out in a continuous process while maintaining the parameters mentioned be performed.

The suitable composite materials are preferably such that they have a pore size from 1 to 1000 nm, preferably from 2 to 500 nm and very particularly preferably from 3 to 100 nm. The composite material is particularly preferably flexible and has one correspondingly good tensile strength, preferably a tensile strength of at least 1 N / cm, particularly preferably from at least 3 N / cm. Most preferably, the Composite material in the machine direction has a tensile strength of at least 6 N / cm, especially when using polymeric nonwovens.

By using composite materials with high tensile strength, that the composite membrane also has a similar high tensile strength as the composite material having. It can be advantageous if a composite material according to the invention manufactured composite membrane is used. This can be particularly advantageous if if membranes with pore sizes smaller than 15 nm are to be produced. In this case it may be advantageous to first use a method according to the invention from a Microfiltration membrane is an ultrafiltration membrane with an average pore size of to produce less than 25 nm, which then as a composite material for the production of a Membrane with an average pore size of less than 15 nm is used. Depending on desired average pore size of the composite membrane and the pore size of the as The starting composite used membrane can have several such coating steps according to the invention are carried out or may be necessary.

The limitation to the smallest possible pore size in the used Composites is advantageous because the pores are too large to produce the suspension Separating layer, would suck too far into the membrane, resulting in an unnecessarily large one Flow resistance in the composite membrane leads. Pores that are too small can also have one have an adverse effect, since in some cases this increases the adhesion of the separating layer becomes low and there is delamination during use and thus complete destruction of the membrane comes. For this reason, they preferably used composite materials a minimum pore size of 3 nm, preferably of 12 nm and very particularly preferably from 25 nm.

The method for producing the composite membrane according to the invention can also be used in this way be carried out by unrolling the composite material from a roll with a Speed from 1 m / h to 2 m / s, preferably at a speed of 0.5 m / min. up to 20 m / min and very particularly preferably at a speed of 1 m / min to 5 m / min by at least one apparatus which is used to manufacture the selective, ceramic separation layer brings suitable suspension on the composite material and at least one other apparatus, which solidifies the suspension on the Composite material made possible by heating, passes through and the so produced Composite membrane is rolled up on a second roll. In this way it is possible to manufacture the composite membrane continuously in a continuous process.

The composite membranes according to the invention are used in ultrafiltration and Nanofiltration. NF membranes according to the invention, as according to the prior art Technology is known in gas separation, pervaporation and vapor permeation be used.

The advantages of the composite membranes according to the invention are above all the larger ones Resistance of the membranes at high pressures, at high temperatures or at Use in solvents, acids and / or bases.

The following examples are intended to illustrate the composite membranes according to the invention and the Explain the process for producing such composite membranes in more detail without the Invention to be limited to these embodiments.

Example 1a Production of an S450PET MF membrane

15 g of a 5% strength by weight aqueous HCl solution, 10 g, are first added to 160 g of ethanol Tetraethoxysilane, 2.5 g methyltriethoxysilane and 7.5 g Dynasilan GLYMO (Degussa AG) given. In this sol, which was initially stirred for a few hours, are then each 125 g of the aluminum oxides Martoxid MZS-1 and Martoxid MZS-3 (manufacturer: Martinswerke) suspended. This suspension (slip) is treated with a for at least another 24 h Homogenized magnetic stirrer, the mixing vessel must be covered so that it does not close there is a loss of solvent.

A PET fleece with a thickness of approx. 30 µm and a basis weight of approx. 20 g / m2 is thus in a continuous rolling process (belt speed approx. 8 m / h, T = 200 ° C) coated with this slip. In this rolling process, the slip becomes with a roller that runs counter to the belt direction (direction of movement of the fleece) moved, rolled onto the fleece. The fleece then runs through an oven, which the specified temperature. In the subsequent experiments, the same method is used or arrangement used. It becomes a microfiltration membrane with a medium one Pore size of 450 nm obtained.

Example 1b Production of a S240PAN MF membrane

15 g of a 5% strength by weight aqueous HCl solution, 10 g, are first added to 160 g of ethanol Tetraethoxysilane, 2.5 g of methyltriethoxysilane and 7.5 g of Dynasilane GLYMO. In this sol, which was initially stirred for a few hours, is then 280 g of Aluminum oxide AlCoA CT1200 SG suspended. This slurry (suspension) is used for Homogenized for at least another 24 h with a magnetic stirrer, with the stirring vessel must be covered so that there is no loss of solvent.

A PAN fleece (Viledon 1773, Freudenberg) with a thickness of about 100 µm and a basis weight of 22 g / m ² is thus in a continuous rolling process (belt speed about 8 m / h, T = 250 ° C) with the above Slurry coated. A microfiltration membrane with an average pore size of 240 nm was obtained.

Example 1c Production of an S100PET MF membrane

15 g of a 5% strength by weight aqueous HCl solution, 10 g, are first added to 160 g of ethanol Tetraethoxysilane, 2.5 g of methyltriethoxysilane and 7.5 g of Dynasilane GLYMO. In this sol, which was initially stirred for a few hours, is then 280 g of Aluminum oxide AlCoA CT3000 suspended. This suspension will last for at least another Homogenized for 24 h with a magnetic stirrer, whereby the stirring vessel must be covered, so that there is no loss of solvent.

A PET fleece with a thickness of approx. 30 µm and a basis weight of approx. 20 g / m2 is thus in a continuous rolling process (belt speed approx. 8 m / h, T = 200 ° C) coated with the above suspension. A microfiltration membrane with a obtained average pore size of 100 nm.

Example 1d Production of an S100PAN MF membrane

15 g of a 5% strength by weight aqueous HCl solution, 10 g, are first added to 160 g of ethanol Tetraethoxysilane, 2.5 g of methyltriethoxysilane and 7.5 g of Dynasilane GLYMO. In This sol, which was initially stirred for a few hours, is then 300 g of Aluminum oxide AlCoA CT3000 suspended. This slip is used for at least more Homogenized for 24 h with a magnetic stirrer, whereby the stirring vessel must be covered, so that there is no loss of solvent.

A PAN fleece (Viledon 1773, Freudenberg) with a thickness of about 100 µm and a basis weight of 22 g / m ² is thus in a continuous rolling process (belt speed about 8 m / h, T = 250 ° C) with the above Slurry coated. A microfiltration membrane with an average pore size of 100 nm was obtained.

Example 2a Production of a Z025PAN

A suspension consisting of 3.0% nanoparticulate zirconium oxide (VP 25, Degussa), 1% zirconium oxide sol (MEL) and 1.0% Aerosil 300 (Degussa) as a viscosity regulator in deionized water was applied to a composite material from Example 1b with a Pore size of approximately 240 nm in a continuous rolling process (Belt speed approx. 8 m / h, T = 250 ° C) applied and solidified.

There was an ultrafiltration membrane with an average pore size of 25 nm, the one has very good adhesive strength and is very resistant even in very alkaline media (pH> 10) obtained.

Example 2b Manufacture of a T010PAN

A mixture of 180 g of demineralized water and 0.69 g of a 65% nitric acid was added slowly added a mixture of 14.21 g titanium tetraisopropoxide (Fluka) in 27.1 g i-propanol. The resulting titanium dioxide is peptized over a period of 17 days with occasional stirring. The sol produced in this way then becomes one Coating suspension processed further. For this, a suspension consisting of 0.3 vol% TiO2 (from the sol described above) mixed with 0.2 vol% Carbopol 980 and applied to the composite membrane from Example 2a as a composite. (Belt speed approx. 8 m / h, T = 250 ° C).

An ultrafiltration membrane with an average pore size of 12 nm was obtained has a very good adhesive strength of the coating.

Example 2c Manufacture of a T002PAN

To a mixture of 10.51 g diethanolamine (Fluka) and 11.41 g tetraethyl orthotitanate (Fluka) slowly became a mixture of 1.8 g water and 330 g i-propanol (Aldrich) given. The resulting polymeric sol was after a 1 hour stirring on a Composite material applied and solidified as described in Example 2b (Belt speed approx. 0.5 m / min, T = 230 ° C).

A nanofiltration membrane with an average pore size of approximately 1 to 2 nm obtained.

Example 2d Production of a Z025PET

A suspension consisting of 3.0% nanoparticulate zirconium oxide (VP 25, Degussa), 1% zirconium oxide sol (MEL) and 1.0% Aerosil 300 (Degussa) as a viscosity regulator in deionized water was applied to a composite material from Example 1c with a Pore size of approximately 100 nm in a continuous rolling process (Belt speed approx. 8 m / h, T = 250 ° C) applied and solidified.

An ultrafiltration membrane with an average pore size of 25 nm was obtained has a very good adhesive strength of the release-active coating.

Example 2e Production of a Z025PAN

A suspension consisting of 3.0% nanoparticulate zirconium oxide (VP 25, Degussa), 1% zirconium oxide sol (MEL) and 1.0% Aerosil 300 (Degussa) as a viscosity regulator in deionized water was applied to a composite material from Example 1d with a Pore size of approximately 100 nm in a continuous rolling process (Belt speed approx. 8 m / h, T = 250 ° C) applied and solidified.

An ultrafiltration membrane with an average pore size of 25 nm was obtained has a very good adhesive strength of the release-active layer.

Claims (30)

1. Composite membrane comprising a composite material which has a flat, with a plurality of openings provided, flexible substrate with a coating on and in this substrate, wherein the material of the substrate is selected from woven and / or non-woven polymer or natural fibers and the Coating has a porous, ceramic coating, characterized in that the composite material has at least one further coating as a selective ceramic separating layer. 2. composite membrane according to claim 1, characterized, that the substrate comprising polymer or natural fibers is a woven, knitted and / or Has nonwoven. 3. composite membrane according to claim 2, characterized, that the polymer or natural fiber substrate is a nonwoven 4. composite membrane according to at least one of claims 1 to 3, characterized, that the polymer fibers are polymers selected from polyacrylonitrile, polyamides, Polyimides, polyacrylates, polytetrafluoroethylene, polyester, and / or polyolefins exhibit. 5. composite membrane according to at least one of claims 1 to 4, characterized, that the selective separation layer is a porous separation layer with defined pores. 6. composite membrane according to claim 5, characterized, that the ceramic separating layer has an average pore size of less than 50 nm. 7. composite membrane according to one of claims 5 or 6, characterized, that the ceramic separating layer has an average pore size of less than 10 nm. 8. composite membrane according to at least one of claims 1 to 7, characterized, that the ceramic separating layer has oxides of the elements Ti, Si, Zr, Sn, Y or Al. 9. composite membrane according to at least one of claims 1 to 8, characterized, that the composite has a ceramic coating in and on the substrate has at least one oxide of the metals Ti, Si, Zr or Al. 10. Composite membrane according to claim 9, characterized in that the composite material has oxides selected from Al ₂ O ₃ , TiO ₂ , ZrO ₂ or SiO ₂ . 11. composite membrane according to at least one of claims 1 to 10, characterized, that the composite on a permeable substrate, the polymer or Has natural fibers, is based on and in which at least one inorganic Components is present by solidifying a suspension from a inorganic component and a sol was obtained. 12. composite membrane according to at least one of claims 1 to 11, characterized, that the composite membrane is flexible. 13. composite membrane according to at least one of claims 1 to 9, characterized, that the composite membrane without damage down to a radius down to 100 m is bendable. 14. A method for producing a composite membrane according to any one of claims 1 to 13 with at least one selective, ceramic separating layer, comprising one Composite material, which has a flat, provided with a plurality of openings, flexible substrate with a coating on and in this substrate, wherein the material of the substrate is selected from woven and / or non-woven polymer or natural fibers and the coating has a porous, ceramic coating, characterized, that the selective separation layer by applying and solidifying a sol or a Suspension is obtained from an inorganic component and a sol. 15. The method according to claim 14, characterized, that on the composite by applying a sol or a suspension that at least, has an oxide of the metals Al, Zr, Si, Sn, Ti and / or Y and a sol the composite material and by at least one heating step in which the sol or the suspension is solidified on the composite material, a separating layer is applied. 16. The method according to claim 14 or 15, characterized, that the sol or the suspension by printing, pressing, pressing, rolling, Knife, spread, dip, spray or pour onto the substrate becomes. 17. The method according to at least one of claims 14 to 16, characterized, that the suspension that has at least one inorganic component and at least one Sol, at least one semi-metal oxide sol or at least one mixed metal oxide sol or one Mixture of this brine has, by suspending at least one inorganic Component is produced in at least one of these brine. 18. The method according to at least one of claims 14 to 17, characterized, that the brine by hydrolyzing at least one metal compound, at least one Semimetal compound or at least one mixed metal compound with water, Water vapor, ice, alcohol or an acid or a combination of these compounds be preserved. 19. The method according to claim 18, characterized, that at least one metal alcoholate compound or at least one Semi-metal alcoholate compound selected from the alcoholate compounds of the elements Zr, Al, Si, Sn, Ti and Y or at least one metal nitrate, metal carbonate or metal halide selected from the metal salts of the elements Zr, Al, Si, Sn, Ti and Y as Metal compound is hydrolyzed. 20. The method according to at least one of claims 14 to 19, characterized, that as an inorganic component, at least one oxide selected from the oxides of Elements Zr, Al, Ti and Si, is suspended. 21. The method according to at least one of claims 17 to 20, characterized, that the mass fraction of the suspended component 0.1 to 500 times the used sols corresponds. 22. The method according to at least one of claims 14 to 21, characterized, that the suspension or sol applied to the composite material is solidified by heating to 50 to 350 ° C. 23. The method according to claim 22, characterized, that heating for 10 min. up to 5 hours at a temperature of 50 to 100 ° C he follows. 24. The method according to claim 22, characterized, that heating for 0.5 to 5 minutes at a temperature of 101 to 250 ° C he follows. 25. The method according to any one of claims 14 to 24, characterized, that the suspension or sol is organic and / or inorganic Has viscosity regulators. 26. Use of a composite membrane according to one of claims 1 to 13 as a membrane in pressure-driven membrane processes. 27. Use of a composite membrane according to one of claims 1 to 13 as a membrane in nanofiltration, reverse osmosis, ultrafiltration or microfiltration. 28. Use of a composite membrane according to one of claims 1 to 13 as a membrane in pervaporation or vapor permeation. 29. Use of a composite membrane according to one of claims 1 to 13 as a membrane in a membrane reactor. 30. Use of a composite membrane according to one of claims 1 to 13 as a membrane in gas separation.