DE10111666B4 - Polyimide shaped bodies, in particular polyimide membranes, processes for the preparation thereof and the use of the polyimide membrane - Google Patents

Abstract

Porous polyimide molding, in particular a porous polyimide membrane functionalized with a chemical group, obtainable by using as starting material a previously completed porous polyimide molding or a previously prepared porous polyimide membrane having an aqueous modifier solution is brought into contact for a period of 1 second to 1 hour,
the modifier solution contains at least one modifier substance at least partially dissolved therein, which has one primary or secondary amino group or one such amino group and additionally at least one further functional group per molecule and that of the following general formula R ₁ -NH-X- (Y ₂ ) _m , wherein R _{1 represents} a hydrogen atom or an aliphatic or aromatic hydrocarbon radical having up to 6 C atoms,
Y _{2 is} an NH ₂ , NHR ₁ or N (R ₂ ) ₂ group, where R _{2 is} an aliphatic or aromatic hydrocarbon radical of any type and is in particular R ₁ ,
X is a straight-chain or branched aliphatic or aromatic hydrocarbon radical which is the R ₁ NH group with the or the (Y ₂ ) group (s), which are attached to a chain terminally or laterally ...

Description

The Invention relates to a porous Polyimide mold, in particular a porous one Polyimide membrane functionalized with a chemical group is a process for its production and use such a polyimide membrane for the separation of pyrogens.

polyimides with different chemical composition have been around for a long time known and commercially available. From such polyimides can made by melt deformation a variety of moldings become. An essential field of application of polyimides concerns the production of injection moldings and membranes.

polyimides Different construction can be easily via a phase inversion process deform into membranes with different release properties. A known process for preparing integrally symmetric polyetherimide membranes is described for example in DE-A-34 20 373. These known Membranes can For example, after coating with polydimethylsiloxane used for gas separation become.

A another polyimide membrane and a process for their preparation is described in DE-A-37 16 916. This known membrane is used preferably for the ultrafiltration and as a coatable carrier membrane for the production of composite membranes.

Out DE-T-690 15 445 are also a polymide membrane and a method known for their preparation. This is a modification with Amines described. The membrane is a gas separation membrane.

polyimides are generally relatively hydrophobic, poorly water wettable Polymers. Therefore, wetting problems occur in the filtration of aqueous solutions and in particular for non-specific adsorption of solution ingredients (fouling), resulting in a significant decrease in the performance of the membrane is caused. From US-A-4 798 847 a method is now for the production of polyimide membranes, in which the hydrophobic Base polymer a hydrophilic, at least partially in the finished membrane remaining substance, in particular polyvinylpyrrolidone added which is networked to increase performance of the membrane and on this Way is fixed in the membrane. Such hydrophilic modified Polyimide membranes are for Ultra and / or microfiltration suitable.

Polyimide membranes usually contain however, no active functional groups, such as Amine, hydroxyl, carboxyl, aldehyde and other reactive groups. Therefore, these known polyimide membranes are not for the production of affinity membranes suitable.

polyimides Although usually contain Functionalizable building blocks. The introduction of functional groups However, the required chemical reactions are either time-consuming, difficult or impossible to carry out continuously, hazardous to health or damaging the membrane to be functionalized.

Out DE-A 41 17 501 is a modified using amine Polyimide membrane known for the gas separation and ultrafiltration can be used. to Production of this membrane is first prepared a homogeneous polyimide solution, in which an organic, multifunctional compound with at least two primary Amine groups per molecule is introduced and dissolved in a concentration of 0.05 to 5%. This mixture of substances is then allowed React 1 h to 10 days, taking virtually complete consumption the amino groups of the organic, polyfunctional compound the Polyimide macromolecules branched / crosslinked, as a result, the viscosity of the polyamide solution is increased. It has been shown that the Amount of modifying amine compound in the homogeneous solution very must be precisely dosed and depending on the amine compound used must be relatively low to soluble, to membrane processable, modified polymer solutions too receive. In case of overdose Gels the homogeneous solution an insoluble one Gel. This membrane-forming polymer solution is suitable for membrane formation also from dilute ones Polymer solutions, without them solution then penetrated by a textile support. As the amine containing Modifiers react under consumption of all amine functions is the proportion of free amine groups on the surfaces of the formed membrane low, practically zero, so that this Membrane in this form or using the possibly existing Restamin groups not suitable is.

One important task for Membranes in the medical field consists in the blood detoxification for the preparation of dialysate and infusate as well as in the field of pharmacy for the production of pyrogen-free infusates.

endotoxins (ET), which are also called pyrogens, are components of the cell wall of gram-negative bacteria that grow or die off be released and for are toxic to humans. These endotoxins are - depending on Environmental conditions - in aqueous solution in monomeric, aggregated or micellar form. In the presence of Proteins and other constituents of human plasma become endotoxins often adsorbed on plasma components and so masked.

When other toxins that are present in the infusate and in the dialysate, the called CIS substances (cytokine induced substances) called whose chemical structure has not yet been clarified. Especially in monomeric Shape and as fragments can Endotoxins and CIS substances are convective and / or diffusive due to their size, for example during the blood purification itself through the membrane of low-flux dialysis membranes, permeate, thus contaminating blood and activating cascades Initiate defense of this contamination. All these substances are toxic and should therefore not be included in media containing come into contact with biological media. The totality of this Toxins are referred to as pyrogens in this documentation.

• – Adsorption an hydrophoben Stoffen wie Aktivkohle, Ionenaustauschharzen und ähnlichem
• – Abbau mittels Säuren oder Alkalilösungen
• – Abbau mittels oxidierender Substanzen wie Kaliumpermanganat, H₂O₂ und Natriumhypochlorit und
• – Filtration der zu dekontaminierenden Lösungen mittels Ultrafiltration (man vergleiche beispielsweise US-A 4 261 834, 5 605 627 und EP-A 189 561 sowie WO-A 96/31273).

These pyrogens can be removed in a variety of ways from the mentioned media. These include, for example:

• - Adsorption on hydrophobic substances such as activated carbon, ion exchange resins and the like
• - Degradation by means of acids or alkali solutions
• - Degradation by means of oxidizing substances such as potassium permanganate, H ₂ O ₂ and sodium hypochlorite and
• Filtration of the solutions to be decontaminated by ultrafiltration (see, for example, US-A 4,261,834, 5,605,627 and EP-A 189,561 and WO-A 96/31273).

From In these techniques ultrafiltration is the process of decontamination solutions to regard as the means of choice today. Such membrane cleaning systems are based on membranes made of polyamides, polysulfones and also polyimides. Nevertheless, even with these methods, pyrogens do not succeed reasonable effort completely to remove, especially in the currently used in particular filtration technology a minimum flow rate of the membrane and thus a minimum pore size required is to increase the amount of dialysate / infusate needed for blood purification in the user enterprise on-line during to provide the treatment. They are in particular the monomers Endotoxins and the CIS, which is the dialysate / infusate cleansing membrane happen.

It There are already numerous adsorber materials for pyrogens known so that the for one Adsorption principle usable ligands known in the art are. To bind such ligands to membranes, however, is so far not possible with reasonable effort.

moreover Pyrogen-sorptive membranes are already known. So be For example, in DE-A 4209988 Endotoxinadsorber from porous support materials described, which may also be in the form of flat membranes. These have known membranes only over a small number of binding sites for covalent coupling of the Ligands to the membrane and have none sufficient effect against Pyrogen-containing solutions.

In DE-A 19609479 discloses a polyamide membrane having microfiltration properties described, which is a functionalized microfiltration membrane which deals with the removal of pyrogen from water, protein solutions and Parenterals can be used. Also this known membrane is disadvantageous in many ways.

Out US-A-4702840 is modified with cationic charges Membrane with pyrogen-binding function known in which the pyrogen-sorbing Component already during the membrane preparation of the spinning solution added and in the membrane is fixed. However, the fixation is incomplete. It There is therefore a risk that at Use of this membrane for decontamination of dialysate / infusate Components of the membrane during the dialysate / infusate cleaning inadvertently into the to be cleaned Medium eluted.

task The present invention is a functionalized polyimide molding and in particular to provide a functionalized polyimide membrane, which can be functionalized adjustable and in particular via a high degree of functionalization. This functionalized Polyimide membrane is intended in particular for the decontamination of pyrogens contaminated liquids can be used. The object of the invention is also a process for the preparation this polyimide molding or provide this polyimide membrane, with this functionalization in a simpler and more economical way Way in an aqueous medium can be done.

Is solved this task by the independent Claims.

The inventive molding or Membranes can in the functionalized form directly for a variety of tasks in the technical, biotechnological and medical field as well as in the form of a functionalized membrane as the starting membrane for the production of affinity membranes be used. The membrane obtainable according to the invention can in particular for the decontamination of pyrogen-contaminated liquids and thus especially for the blood detoxification for treatment of dialysate / infusate as well as in the field of pharmacy for the production Pyrogen-free infusates are used.

The The invention is hereinafter based on a polyimide membrane, which are the invention before zugten Subject is, closer explains however, this term "polyimide membrane" also a polyimide molding with includes, unless otherwise stated or otherwise stated in the Overall context results.

The Polyimide membrane according to the invention is available from a previously completed polyimide membrane known per se can be. The polyimide membrane is treated with an aqueous modifier solution Contact in which at least one modifier substance is dissolved. The modifier substance has at least one amino group per molecule of the modifier substance as well as additional at least one further functional group per molecule of the modifier substance on. In other words, every modifier substance contains one hand a primary one or secondary Amino group and on the other hand optionally a further functional Group.

Especially this further function is also an amino group.

The Polyimide membrane is during contacting or after contact with the Modifier solution on an increased Temperature brought and then cleaned and dried.

The Modifier solution is for a period of from 0.01 second to 1 hour, preferably from 1 second to 1 h, more preferably from 5 sec. To 10 min. contacted with the modifier solution and at the same time and / or subsequently for a period of preferably 1 second to 1 hour, more preferably 5 seconds to 10 minutes. one Temperature of preferably 50-100 ° C and in particular special preferred from 70-90 ° C exposed and thereby treated.

The Purification of the functionalized polyimide membrane of non-body forming or non-membrane-forming substances with the exception of water and excipients from the contacting modifier solution and / or other treatment solutions is preferably done by washing, extracting and the like from the membrane.

The cleaned membrane is then dried. She can, however, advance to be impregnated with the drying known per se pore-containing substances.

The Concentration of modifier substance or modifier substances in the modifier solution is preferably 0.1-20 wt .-% and further preferably 1-10 wt .-%. The on This functionalized polyimide membrane obtained may, if necessary in addition After treatment treated with other treatment solutions known per se be, for example, a salted function to transform the modifier substance into the acid form or to a neutral one Function, for example, by quaternization into an ionic form to convict.

Depending on the nature of the modifier substance or modifier substances used, the polyimide membrane obtainable according to the invention is correspondingly functionalized and in general forms a porous one Membrane with a high content of functional groups. The polyimide membrane according to the invention can already be used in this form as an adsorbent membrane. In addition, the selectively adjustable, depending on the reaction usually in large numbers freely available functional groups, which are located on the membrane and pore surfaces, can be used for subsequent reactions for the coupling of other, selectively or specifically adsorbing functions. In the case of polyimide moldings, these functional groups are primarily on the mold surface. In porous membranes, the functional groups - depending on the process - evenly or asymmetrically distributed over the membrane cross-section, which will be discussed in more detail below. With the choice of the pore size of the polyimide membrane used as the starting membrane and thus the polyimide membrane to be modified and the size of the molecule of the modifier substance in the modifier solution, it is possible to use a dry polyimide membrane and preferably short treatment times to selectively control the penetration of the modifier substance into the substructure of the membrane so as to realize an asymmetric distribution of the functional groups across the membrane cross section. Therefore, an asymmetric polyimide membrane is preferably used as the starting membrane or as a membrane to be modified. The pore size of the asymmetric polyimide membrane used as starting membrane is preferably smaller in the separation-active layer than the size of the molecule of the modifier substance. That is, in other words, it is preferable to use a membrane as a starting material having a remarkable retention against the molecules of the modifier substance, which membrane is preferably contacted with the modifier solution from the support side.

at Use of an asymmetric membrane by the substructure is treated as described above, is therefore a decreasing Pore size too associated with a decreasing number of freely available functions. The highest Number of freely available Functions is therefore on during the modification in the immediate contact with the modifier solution-standing membrane surface.

To a preferred embodiment has used as the starting membrane polyimide membrane a mean pore diameter smaller than 10 nm. This is especially true for the Case that the present invention available Membrane for the separation of pyrogen is used.

at the inventively available Membrane is thus in particular an amine-functionalized Polyimide membrane with pyrogen-sorptive properties. The freely selectable, covalently bonded to the membrane groups, in particular aminischer and / or hydrophobic nature where the desired adsorptive groups are bound to the polyimide membrane with or without spacer, are specifically adjustable and depending on the reaction in general in high Number available. These functional groups are - as already explained above - either distributed over the entire membrane cross-section or in a preferred embodiment targeted asymmetrically over the cross section of the membrane. Depending on the application, the own available according to the invention Membranes separation effect the pyrogens to be removed, but not to the desired Ingredients of dialysate / infusate. The at the functionalization covalently bound modifier substances can not extra hiert by aqueous solutions become. However, you can if they are not on the carrier are bound, light and complete by rinsing processes be removed from the membrane before use. It is thus a for decontamination processes adsorptive-acting membrane provided, which is practical contains no eluatable ingredients. By the only to the surface ongoing functionalization of a superheated steam or hot water Sterilizable starting membrane material is ensured that too the specifically functionalized membrane material meets the requirements suffices for this type of sterilization. The present invention available Membrane also meets the requirements of a Disposable items are provided.

The Process for the preparation of the membrane obtainable according to the invention can be described with reference to Functionalization step are carried out continuously. In this way is an economic Preparation of the invention available Membrane ensured as for single use items Limiting the cost is to demand. For this purpose are preferably simple and therefore inexpensive and yet very effective adsorbing Modifier substances used.

By the choice of effective modifier substances with hydrophilic head groups especially of an aminic nature, which are freely available in large numbers, can be a change the surface properties the polyimide membrane can be achieved in such a way that the wetting of this membrane with aqueous media is advantageously improved and thus the full performance already at the beginning of contacting with the medium to be detoxified guaranteed is.

• – Hochmolekulare Pyrogene (Aggregate, Mizellen usw.) werden vorzugsweise durch Größenausschluß aus den zu behandelnden Lösungen entfernt, da dieselben nicht durch die trennaktive Schicht der Membran permeieren können.
• – Monomere Pyrogene oder Bruchstücke derselben, die durch Größenausschluß mit der verwendeten Membran nicht zurückgehalten werden können und daher durch die Membran permeieren, werden adsorptiv an der Membranoberfläche bzw. insbesondere an der funktionalisierten Porenoberfläche im Membranquerschnitt bei der Permeation durch die Membran gebunden.

According to the described characteristics of the polyimide membrane obtainable according to the invention, the pyrogens are removed from the solutions to be treated by the simultaneous action of two decontamination possibilities:

• - High molecular weight pyrogens (aggregates, micelles, etc.) are preferably removed by size exclusion from the solutions to be treated, since they can not permeate through the separation-active layer of the membrane.
• Monomeric pyrogens or fragments thereof, which can not be retained by size exclusion with the membrane used and therefore permeate through the membrane, are bound adsorptively to the membrane surface or, in particular, to the functionalized pore surface in the membrane cross-section during permeation through the membrane.

in the The result of this decontamination process is the formation of ultrapure dialysate / infusate solutions. simultaneously guaranteed this kind of decontamination is the on-line provision of this solutions in sufficient quantity during the dialysis treatment with small membrane areas.

All in all Thus, a membrane cleaning system is available, the best conditions for the Use as disposables with high functionality offers.

at a further preferred embodiment is an asymmetric distribution of functional groups over the Diaphragm cross-section available, that - in contrast to the variant described above, in which generally a dry polyimide membrane is used - the pore system of dry Polyimide membrane is filled with a well-wetting, preferably aqueous solution, before the polyimide membrane is contacted with the modifier solution. In conjunction with short contact times of the polyimide membrane in the Modifier solution in this case, without one support the polyimide membrane opposite the molecules the modifier substance can be detected and independent of the structure of the polyimide membrane preferably contacted membrane surface and the adjoining part of the membrane cross section modified. In this way also becomes an asymmetric modification reaches the polyimide membrane.

If in the context of these documents of a polyimide or a polyimide molding or from a polyimide membrane the speech is so embraced the term "polyimide" in addition to the pure Polyimides also have such substance classes, in addition to the imide groups also contain other groups. These include, for example, poly (amide-imide), Poly (ester-imides), poly (ether-imides) and mixed products (polymer blends). It is according to the invention only required that at least a proportion of the body forming body or membrane-forming polymer (s) in the polymer chain imide groups exhibit. Thus, any membrane having this imide function can be used by means of the modification according to the invention be functionalized. Preferably, however, moldings or Membranes made of pure polyimides used. When molding is its form arbitrary. It is only necessary that at all a contact with the treatment solution is possible. As starting membranes can Any membranes are used. It can be hollow or tubular membranes or even flat membranes with or without carrier fleece act.

The used according to the invention brought modifier substances contain at least one primary or secondary Amino group. If the modifier substance has only one amino group otherwise it consists of one of no functional groups Having hydrocarbon residue, then you can this hydrocarbon radical more or less as another functional group. You put such a monoamine for modification, one can the hydrophobic Improve properties of such modified membranes.

The modifier substances used according to the invention preferably have the following general formulas R ₁ -NH-Y ₁ NH- (Y ₁ ) ₂ R ₁ -NH-X- (Y ₂ ) _m , in which R _{1 is} a hydrogen atom or an aliphatic or aromatic hydrocarbon radical having up to 6 C atoms, Y _{1 is} a hydrocarbon radical having 6 or more C atoms, Y _{2 is} a -NH ₂ -, -NNR ₁ - or -NH ( R ₂ ) ₂ group or fluorinated group, wherein R _{2 is} an aliphatic or aromatic Koh lenwasserstoffrest any type means and stands in particular for R _1, X a straight-chain or branched aliphatic or aromatic hydrocarbon radical containing the R ₁ -N, N-group with the or Y ₂ group (s), which can be terminally or laterally attached to a chain can connect, and in a side chain and the main chain by one or more O- or N-heteroatom (s) may be interrupted and / or one or more -C (OH) -, -CO (OH) - and - PO ₃ (OH) function (s), and m is 1, 2 or 3.

The divalent group X, which connects the amine group with at least one further functional group Y ₂ linearly and / or via ring systems, can thus be of any desired nature. This is preferably an aliphatic and / or aromatic hydrocarbon radical which may have the heteroatoms mentioned and may additionally have CO, C (OH), CO (OH) and PO ₃ (OH) groups. In particular, X groups with amine or ether groups in the vicinity of short-chain, aliphatic hydrocarbon chains having a high proportion of heteroatoms from the class of polyamines, for example polyethyleneimine, polyamidines or ethoxylated amines / polyamines are used.

According to a preferred embodiment, the modifier substances used according to the invention have the following general formula: R ₁ -HN-XNR ₂ , R ₃

The radicals R ₁ and X have the meanings given above. The radicals R ₂ and R ₃ independently of one another each represent a hydrogen atom or an aliphatic or an aromatic hydrocarbon radical. In this case, the radical X may be in particular polyamines and polyamidines.

The modifier substances used for modification must be in the solvent used to prepare the modifier solution at least partially soluble be. Preferably, the modifier substances are in the solvent or the solvent mixture the modifier solution completely soluble and form homogeneous and generally low-viscosity solutions, their pH ≥ 7 is. As a solvent Normally water is used. With regard a uniform, short-term Treatment, it is advantageous aqueous solvents with proportions of water-immiscible, short-chain use mono- or polyfunctional alcohols. The proportion of this Alcohols is preferably 10 to 90% by weight, more preferably 20-50% by weight in the solvent mixture for the or the modifier substance (s).

object The invention is also a method for producing the modified invention Polyimide mold and especially the modified polyimide membranes. In this Procedures are the above closer described method steps performed.

As already stated above, the membrane after contacting with the modifier solution at the same time and / or subsequently temperature treated. Preferably, this is done Temperature treatment continuously on a continuous, moving Membrane by contacting the contacted with the modifier solution membrane of Contacting with a short-term temperature pulse is treated. In particular, this temperature pulse at the running membrane produced by means of a continuous microwave.

Functionalized membranes can thus be obtained by the process according to the invention whose ligands are distributed on the one hand practically symmetrically over the entire membrane cross-section, if the modifier substance and the modifier substances can penetrate into the entire pore system of the membrane, as already described above. On the other hand, asymmetric polyimide membranes can be obtained, which are contacted by the coarse-pored membrane surface (support surface) with the modifier solution, wherein the modifier substances can not permeate freely in the entire pore system of the cross section of the membrane due to their size. Functionalized polyimide membranes which, in addition to the structure gradient, simultaneously have a rectified gradient in the degree of functionalization, are produced under these production conditions, in such a way that a small average pore diameter is associated with a low degree of functionalization and vice versa. Advantageously, the degree of functionalization in the active layer and in the underlying region of the membrane cross-section can be greatly reduced or functionalization can be prevented by such a specific choice of the production conditions, which is particularly true for membranes with ultrafiltration properties with respect to the consistency of the release properties and, as in a combination of Filtration adsorption desired, may be associated with a loss of adsorption capacity of the separation-active layer advantageous. The latter prevents or restricts the adsorption of the already realized via the size exclusion separations larger pyrogen aggregates, thus reducing a possible concentration polarization and thus guarantees constant permeate flows during the decontamination process.

The Invention will be described below with reference to the listed examples for the preparation modified polyimide membranes, starting from polyetherimide membranes, explained in more detail. Here come di- and. polyamines or polyethyleneamine as modifier substances for use. These However, modifying amines are merely exemplary and serve primary In order to explain the basic principle for obtaining the inventively modified polyimide molding or Polyimide membranes. In the applied polyetherimide it is Ultem 1000 (General Electric), from the well-known Following the phase inversion method planar membranes on Histar support material or hollow membranes were formed.

to Characterization of the starting membranes and the invention modified Membranes were their water permeability, pore characteristics and Separation characteristic with water or using a mixture from dextrans measured by known methods and selected examples the content of functional groups by titrimetric determination or by determining the dye adsorption with Acid Orange II determined. To evaluate the asymmetry of the functionalization was a qualitative staining test using Orange II (Uchida et al., Langmuir 9 (1993) 1121-1124). The adsorption capacity of the invention modified Membranes for Pyrogens were used under static conditions using Flat membranes tested using endotoxin type E. coli serotype 0111: B4 contaminated isotonic saline solution to be decontaminated solution was used. The endotoxin content of the treated solutions was Quantified by LAL test.

Example 1 (comparative example)

Commercially available flat membranes (manufacturer: GKSS Forschungszentrum Geesthacht GmbH) made of polyetherimide (Ultem 1000, General Electric) on Histar 80 were used as the starting membrane for the modification. Membranes of different production with different separation properties had the following characteristics in this unmodified form: Flat membrane 1: Water permeability: 0.75 l / m ² hkPa Average pore size: 2.64 nm cut-off: 23.2 kg / mol Amount of polymer / cm ² membrane area: 4.178 x 10 ^-3 g / cm ² Contact angle: Advancing angle: 82 ° -86 ° Receding angle: 52 ° -57 ° Flat membrane 2: Water permeability: 2.43 l / m ² hkPa Average pore size: 2.58 nm cut-off: 70.4 kg / mol Amount of polymer / cm ² membrane area: 4.578 x 10 ^-3 g / cm ² Contact angle: Advancing angle: 82 ° -86 ° Receding angle: 52 ° -57 ° Flat membrane 3: Water permeability: 2.15 l / m ² hkPa Average pore size: 3.53 nm cut-off: 15.9 kg · mol ^-1 Contact angle: Advancing angle: 82 ° -86 ° Receding angle: 52 ° -57 °

Furthermore, a hollow membrane was used for the investigations. This hollow membrane was prepared as follows: From a polyetherimide spinning solution, using water (room temperature) as a lumen filler and a mixture of 45 parts of dimethylformamide (DMF), 25 parts of N-methyl pyrrolidone (NMP), 25 parts of gamma-butyrolactone (GBL) and 5 parts of water as a precipitation bath spun a hollow membrane by means of a wet spinning process. The outer surface pore system of this initial gel membrane was opened by gel / sol / gel treatment (1st bath: N-methylpyrrolidone, 30 ° C; 2nd bath: water, 80 ° C); The result is a highly asymmetric hollow membrane with inner separating active layer. After washing out the non-membrane-forming constituents with water, the hollow membrane was dried at room temperature. The hollow hollow membrane thus prepared (hollow membrane 1) had the following characteristic data in the unmodified state: Water permeability: 2.37 l / m ² hkPa Average pore size: 3.23 nm cut-off: 20.3 kg / mol Contact angle: Advancing angle: 82 ° -86 ° Receding angle: 52 ° -57 °

These Characteristics of the output membranes were used to estimate the change of membrane properties as a result of the modification.

Example 2

The investigated in Comparative Example 1 flat membrane 1 was in the dry state, mounted on a metal drum, from the active layer side with a modifi kator solution consisting of 2 parts of 1,6-diaminohexane, 49 parts of water and 49 parts of 1-propanol at 75 ° C, contacted for 30 sec. The unmodified membrane has no support against the 1,6-diaminohexane used as the modifier substance. After the modification reaction, intensive rinsing with water at room temperature to remove non-covalently bound modifier substance at the membrane. This modified membrane was examined wet for separation properties and after drying for the content of free amino groups. The membrane modified in this way had the following characteristics: Water permeability: 1.43 l / m ² hkPa Average pore size: 3.5 nm cut-off: 156 kg / mol Amine content: 0.0391 mmol / g polymer Contact angle: Advancing angle: 82 ° Receding angle: 45 °

The Distribution of the modifier substance over the membrane cross-section was according to the qualitative assessment by means of dyeing test symmetrical.

Example 3

• – die Modifikator-Lösung bestand aus 2 Teilen Polyethylenimin (Molekulargewicht: 700g/mol), 49 Teilen Wasser und 49 Teilen 1-Propanol und
• – die Behandlung wurde 60 sec. durchgeführt.

The starting membrane (flat membrane 1) described in Example 1 was modified according to Example 2 with the following differences:

• - The modifier solution consisted of 2 parts of polyethyleneimine (molecular weight: 700g / mol), 49 parts of water and 49 parts of 1-propanol and
• The treatment was carried out for 60 sec.

The unmodified membrane has over the modifier substance only a small (virtually no) retention (<5%).

The following characteristics of the modified membrane were determined: Water permeability: 1.37 l / m ² hkPa Average pore size: 2.85 nm cut-off: 21.9 kg / mol Amine content: 0.0273 mmol / g polymer

The Distribution of the modifier substance across the membrane cross-section was according to the qualitative assessment by means of dyeing test symmetrical.

Examples 4-7

• 1. Die Modifikator-Lösung bestand aus 4 Teilen einer 50%-igen Polyethylenimin-Lösung in Wasser (Molekulargewicht: 750 000 g/mol), 47 Teilen Wasser und 49 Teilen 1-Propanol. Die unmodifizierte Membran besitzt praktisch einen vollständigen Rückhalt gegenüber der Modifikator-Substanz (> 95 %).
• 2. Die Membran wurde von der Supportseite her mit der Modifikator-Lösung unterschiedliche Zeiten bei 70°C kontaktiert.

The membrane described in Example 1 (flat membrane 1) was modified according to these examples with the following differences:

• 1. The modifier solution consisted of 4 parts of a 50% polyethyleneimine solution in water (molecular weight: 750,000 g / mol), 47 parts of water and 49 parts of 1-propanol. The unmodified membrane has virtually complete retention with respect to the modifier substance (> 95%).
• 2. The membrane was contacted from the support side with the modifier solution for different times at 70 ° C.

The membranes thus modified had the characteristics summarized in Table 1: TABLE 1 Characteristics of the membranes modified according to Examples 4-7

At the staining test showed that the Active layer of the membrane stained significantly less and therefore functionalized was called the support page. The contact angles, measured on the active layer, were virtually identical to the corresponding unmodified data Membrane.

Examples 8 to 10

• – die Ausgangsmembran vor der Kontaktierung mit der Modifikator-Lösung mit dem Lösemittel der Modifizierung, bestehend aus 54 Teilen Wasser und 50 Teilen 1-Propanol, vollständig benetzt und in diesem Zustand zur Modifizierung eingesetzt wurde und
• – die Membran von der Supportseite her mit der Modifikator-Lösung unterschiedliche Zeiten bei 70°C kontaktiert wurde.

The starting membrane used in Example 3 was modified according to Example 2 with a modifier solution consisting of 2 parts of 1,6-diaminohexane, 49 parts of water and 49 parts of 1-propanol with the following differences, that

• - The starting membrane before contacting with the modifier solution with the solvent of the modification, consisting of 54 parts of water and 50 parts of 1-propanol, completely wetted and used in this state for modification, and
• - The membrane was contacted from the support side with the modifier solution different times at 70 ° C.

The membranes thus modified had the characteristics summarized in Table 2: TABLE 2 Characteristics of the membranes modified according to Examples 8 to 10:

Examples 11 to 15

• – 2 Gew.-%ige Lösung des Polyamins in einem Lösemittelgemisch, bestehend aus 50 Teilen Wasser und 50 Teilen n-Propanol.
• – Die Funktionalisierung wurde bei 70°C unter Drehen des Metallzylinders (ca. 40 U/min.) durchgeführt.
• – Es wurde die Aktivschichtseite der asymmetrischen Membran behandelt.

The asymmetrically structured flat membrane 3 described in Example 1 (Comparative Example) was used and, attached to a metal cylinder, functionalized with polyethyleneimine (MW = 700 g / mol) as a function of the treatment time under the following conditions:

• - 2 wt .-% solution of the polyamine in a solvent mixture consisting of 50 parts of water and 50 parts of n-propanol.
• - The functionalization was carried out at 70 ° C while rotating the metal cylinder (about 40 U / min.).
• - The active layer side of the asymmetric membrane was treated.

Around To ensure that the Membrane after treatment to determine the characteristic Data completely wettable, the treated membranes were treated at treatment times of ≤ 60 Sec. contacted with the modifier solution were after treatment for 30 min. at room temperature in the solvent mixture rewetted the functionalization. Finally, the membranes became intense rinsed with water with repeated changes of the same and in subjected to this state of property testing.

The Separation properties of the membranes and on selected samples determined contents of amine groups are summarized in Table 3.

These Dye adsorption data confirm the high degree of functionalization the membranes of the invention, the content of amine groups increasing with the functionalization time elevated; the Separation properties are slightly changed by the functionalization, so that this Findings taken into account in the choice of separation properties of the output membrane must become.

Table 3:

Table 4 contains data on the behavior of these example membranes in pyrogen adsorption for different starting endotoxin levels of the contacting medium. The adsorption capacity was determined under static conditions (duplicate determination) using 100 μl of a 2 to 20 ng / ml endotoxin-containing isotonic saline solution with gentle shaking with a membrane area of 1 cm ² for 1 h at 37 ° C with either the treated one or the untreated membrane surface were contacted.

These Data prove the adsorption capacity of this inventively available Polyimide membranes even under those unfavorable for adsorption static conditions of the experiments. The adsorption capacity is practical independently of whether the treated or the untreated membrane surface with the ET-containing solution due to a symmetric distribution of the amine functions over the Diaphragm cross section indicates. This symmetric distribution could qualitatively with the dyeing test approved become. Nevertheless, a slightly improved adsorption capacity When contacting the support side of the membrane to determine what obviously with the better accessibility of the pore surface than additional adsorption is related.

Table 4:

Examples 16 to 20

• – als Modifikator ein Polyethylenimin der Molmasse 750 kg/Mol verwendet und
• – die Supportseite der asymmetrischen Membran behandelt wurde.

The asymmetrically structured flat membrane 3 described in Example 1 (Comparative Example) was functionalized under the conditions of Examples 11 to 15 according to the inventive method with the differences that

• Used as a modifier a polyethyleneimine of molecular weight 750 kg / mol and
• - the support side of the asymmetric membrane has been treated.

in the Contrary to Examples 11 to 15, the modifier becomes equivalent the separation properties of the membrane practically completely retained by the same.

The Separation properties of the membranes and the determined contents of Amine groups are listed in Table 5.

These Dye adsorption data confirm the high degree of functionalization the inventively available Membranes, with a practically constant amine content already after a functionalization time of 60 sec. is achieved. The pore characteristic the membrane is only slightly changed by the functionalization, however changed the permeability the membrane as a result of increased transport resistance the functionalized support layer.

Table 5:

table 6 contains Files on the behavior of these example membranes in pyrogen adsorption for different Starting endotoxin levels according to the examples of the modification with the low molecular weight polyethyleneimine.

These Data show an adsorption capacity of this inventively available Polyimide membranes among the for an adsorption process unfavorable static conditions of the Adsorptionsversuche. The adsorption capacity is clear less than in the examples described above and surprisingly practically independent of whether the treated or the untreated membrane surface with the ET-containing solution will be contacted. The dyeing test However, it proves clearly that the Amin functions asymmetrically over are distributed over the cross-section and a higher amine activity is present. The speaks for a dependency the adsorption capacity the invention modified Membranes of the ligand used.

Table 6:

Claims (12)

Porous polyimide molding, in particular a porous polyimide membrane functionalized with a chemical group, obtainable by using as starting material a previously completed porous polyimide molding or a previously prepared porous polyimide membrane having an aqueous modifier solution is contacted for a period of 1 second to 1 hour, the modifier solution contains at least one at least partially dissolved modifier substance which has a primary or secondary amino group or such an amino group and additionally at least one further functional group per molecule, and that of the following general formula R ₁ -NH-X- (Y ₂ ) _m , wherein R _{1 represents} a hydrogen atom or an aliphatic or aromatic hydrocarbon radical having up to 6 C atoms, Y _{2 represents} an NH ₂ , NHR ₁ or N (R ₂ ) ₂ group, wherein R _{2 represents} an aliphatic or aromatic hydrocarbon radical of any kind and in particular for R ₁ , X represents a straight-chain or branched aliphatic or aromatic hydrocarbon radical which connects the R ₁ NH group with the or the (Y ₂ ) group (s), which may be terminally or laterally attached to a chain and in a side chain and / or the main chain may be interrupted by one or more O or N heteroatoms and / or may have one or more C (OH), CO (OH) and PO ₃ (OH) functions, and m 1, 2 or 3, the polyimide molding or the polyimide membrane is brought to an elevated temperature during or after being brought into contact with the modifier solution and then cleaned and dried. Polyimide molding according to claim 1, obtainable by carrying out one or more of the following measures: The polyimide molding or the polyimide membrane is brought into contact with the modifier solution for 5 seconds to 10 minutes, the polyimide molding or molding The polyimide membrane is 0.01 sec to 1 h and especially 5 sec to 10 min heated to a temperature of 50 to 100 ° C and in particular from 70 to 90 ° C and the polyimide molding or the polyimide membrane is washed for cleaning in a conventional manner by washing, extraction, etc. with water. Polyimide mold according to claim 1 or 2, obtainable by the fact that the concentration the modifier substance (s) in the modifier solution 0.1 to 20 wt .-% and in particular 1 to 10 wt .-% is. Polyimide mold according to one of the preceding claims in the form of a polyimide membrane, available through that an asymmetric polyimide membrane is used as the starting material becomes. Polyimide mold according to claim 4 in the form of a polyimide membrane, obtainable thereby, that the pore size of the asymmetric Polyimide membrane in the separating active layer is smaller than that Size of the modifier substance. Polyimide mold according to claim 4 or 5 in the form of a polyimide membrane, obtainable thereby, that the polyimide membrane from the support side with the modifier solution is brought into contact. Polyimide mold according to one of the preceding claims in the form of a polyimide membrane, available through that a dry polyimide membrane used as starting material becomes. Polyimide mold according to one of the preceding claims in the form of a polyimide membrane, available through That is, a polyimide membrane having an average pore diameter less than or equal to 10 nm is used as the starting material. Polyimide mold according to one of the preceding claims in the form of a polyimide membrane, available through that a polyimide membrane is used as the starting material, their pore system with a well-wetting and especially aqueous solution filled is. Use of a polyimide membrane according to one of previous claims for the decontamination of pyrogen-contaminated liquids and body fluids. Use according to claim 10 in blood detoxification for the preparation of dialysate and infusate and for the production pyrogen-free pharmaceutical infusate. A process for producing a porous polyimide molding including a porous Polyimide membrane, characterized in that the in claim 1 measures described and optionally at least one of the in claims 2 to 10 described measures carried out become.