DE10111666A1 - Polyimide moldings, in particular polyimide membranes, processes for the production thereof or their production and the use of the polyimide membrane - Google Patents

Abstract

A polyimide moulded body, in particular a polyimide membrane is disclosed, functionalised with a chemical group and a method for the production thereof. Said moulded body or membrane can be obtained whereby a starting material of a pre-prepared polyimide moulded body is brought into contact with an aqueous modifier solution for a period of 1 sec to 1 h, said modifier solution comprising at least one modifier substance at least partly dissolved therein, with a primary or secondary amino group or a similar amino group and at least one additional functional group per molecule, whereby the polyimide moulded body is brought to an elevated temperature either during or after being brought into contact with the modifier solution and then purified and dried. The membrane produced according to the invention can have a freely adjustable functionalisation and can have a high degree of functionalisation. Said functionalisation can be achieved in a simple and economical manner in an aqueous medium. The membranes produced according to the invention find application in technical, biotechnological and medical fields and as starting membranes for the production of affinity membranes. The membranes produced according to the invention can be used in particular for the separation of pyrogens from liquids containing said pyrogens and in particular for blood detoxification.

Description

The invention relates to a polyimide molded body, in particular a polyimide membrane, the or the a chemical group is functionalized, a ver drive to its manufacture and use such a polyimide membrane for the separation of Fumed.

Polyimides with different chemical compositions tongues have long been known and are commercially available. Such polyimides can be formed by melt deformation a wide variety of moldings are produced. An essential area of application of polyimides hits the manufacture of injection molded bodies as well of membranes.  

Polyimides of different structures can be used a phase inversion process easily using membranes deform different separation properties. On Known process for producing integral symmetry trical polyetherimide membranes is for example in DE-A 34 20 373 described. This well-known mem Branches can be coated with, for example Polydimethylsiloxane used for gas separation the.

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

Polyimides are generally relatively hydrophobic, with Water poorly wettable polymers. Hence it comes from the filtration of aqueous solutions to wetting problems and especially for the unspecific adsorption of Solvent constituents (fouling), whereby one pays attention Liche performance decrease of the membrane is caused. From US-A-4 798 847 is now a method for the manufacture position known from polyimide membranes, in which the hydrophobic base polymer a hydrophilic, at least for Part of the fabric remaining in the finished membrane, especially polyvinylpyrrolidone, is added to the cross-linked and on to increase the performance of the membrane is fixed in this way in the membrane. Such hydro phil modified polyimide membranes are used for the ultra and / or microfiltration.

However, polyimide membranes usually do not contain any active, functional groups, such as Amine, hydroxyl, carboxyl, aldehyde and other reactive  Groups. Therefore, these known polyimide Membranes also do not generate affinity suitable for industries.

Polyimides usually contain functionalizers bare building blocks. The introduction of functional Groups are required chemical reactions however, either time consuming, difficult or not to be carried out continuously, hazardous to health or damaging the membrane to be functionalized.

From DE-A 41 17 501 is one using Amine modified polyimide membrane known for the Gas separation and ultrafiltration can be used. To produce this membrane, a ho is first mogene polyimide solution, in which an orga niche, multi-functional connection with at least two primary amine groups per molecule at a concentration from 0.05 to 5% is introduced and dissolved. This The mixture of substances is then allowed to react for 1 h to 10 days, being under virtually complete consumption of Amino groups of the organic, multifunctional compound the branched / cross-linked polyimide macromolecules as a result of which the viscosity of the polyamide solution solution is increased. It has been shown that the amount of modifying amine compound in the homogeneous solution must be dosed very precisely and depending on the used Amine compound must be relatively low to be soluble, too Membrane processable, modified polymer solutions receive. In the event of an overdose, the homogeneous gel Solution to an insoluble gel. This membrane-forming Polymer solution is also suitable for membrane formation more dilute polymer solutions without this solution then penetrated by a textile support. Because the amine-containing  Modifiers using all amine radio react ions is the proportion of free amine groups low on the surfaces of the formed membrane, practically zero, so that this membrane in this form or using the possibly existing residual amine Groups are not suitable.

An important area of responsibility for membranes in medicine African area consists in blood detoxification Preparation of dialysate and infusate as well as in the area the pharmaceutical industry for the production of pyrogen-free infusates.

Endotoxins (ET), which are also called pyrogens, are Components of the cell wall of gram-negative bacteria, which are released when they grow or die and are toxic to humans. These endotoxins are - depending on the ambient conditions - in water Solution in monomeric, aggregated or micellar form in front. In the presence of proteins and other stocks share human plasma, endotoxins are often on plasma components adsorbed and thus masked.

As further toxins that are in the infusate and in the dialysate the so-called CIS substances can be present (cytokine induced substances) whose che mixer structure has not yet been clarified. Especially in monomeric form and as fragments can endotoxins and CIS substances due to their size convective and / or diffusive, for example during blood purification even through the membrane of low-flux dialysis membranes, permeate, thus contaminating blood and activation Initiate cascades to ward off this contamination. All of these substances are toxic and should therefore not be included in media related to biological  Media come into contact. The entirety of these toxins is referred to as pyrogen in the context of these documents net.

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

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

Of these techniques, the ultrafiltration is too decontaminating solutions today as the means of Watch choice. Such membrane cleaning systems are based on membranes made of polyamides, polysulfones and also polyimides. Nevertheless, it also works with these Process not, pyrogens with reasonable effort to be removed completely, especially with the currently special applied filtration technology a minimum flow rate of the membrane and thus a minimum pore size is required to control the amount of dialysate / infu sat, which is needed for blood purification, in the user to provide operation online during treatment len. It is especially the monomeric endotoxins and  the CIS, which is the dialysate / infusate cleaning membrane happen.

There are also numerous adsorber materials for Pyrogens known so that the prin for adsorption ligands which can be used are known to the skilled worker. It has so far been possible to bind such ligands to membranes however not possible with reasonable effort.

In addition, pyrogen-sorbing membranes are already used known. For example, in DE-A 42 09 988 Endotoxin adsorbers from porous carrier materials wrote, which are also in the form of flat membranes can. These known membranes have only one small number of binding sites for a covalent Coupling of the ligand to the membrane and have not sufficient effect against pyrogen-containing Solutions.

DE-A 196 09 479 uses a polyamide membrane Microfiltration properties described in it is a functionalized microfiltration membrane acts to remove pyrogen from water, Protein solutions and parenterals are used can. This known membrane is also in many ways Disadvantageous.

From US-A 4702840 is one with cationic charges modified membrane with pyrogen-binding function known in which the pyrogen-sorbing component already during the membrane production of the spinning solution is added and fixed in the membrane. Indeed the fixation is incomplete. There is therefore the Danger of using this membrane for decontamination nation of dialysate / infusate components of the membrane  inadvertently during dialysate / infusate cleaning the medium to be cleaned is eluted.

The object of the present invention is to provide a radio tionalized polyimide moldings and in particular one to provide functionalized polyimide membrane that can be selectively functionalized and especially with a high degree of functionalization features. This functionalized polyimide membrane is said to especially for the decontamination of with pyrogens contaminated liquids can be used. The object of the invention is also a method for Production of this polyimide molded body or this To provide polyimide membrane with which this radio tionalization in a simple and economical way can take place in an aqueous medium.

This task is solved by the independent contractors claims.

The moldings or membranes according to the invention can in the functionalized form directly for diverse Tasks in technical, biotechnological and medical area as well as in the form of a functionalized Membrane as the starting membrane for the production of Affinity membranes are used. The fiction Available membrane can be used especially for decontamination nation of liquids contaminated with pyrogens and thus especially in blood detoxification Processing of dialysate / infusate and in the area of Pharmaceuticals for the manufacture of pyrogen-free infusates be used.

The invention is described below using a polyimide Membrane, which is the preferred according to the invention  Acting subject, explained in more detail, this The term "polyimide membrane" also means a poly imid molded articles with, unless otherwise is specified or nothing else from the total connection results.

The polyimide membrane according to the invention is obtainable from a previously completed polyimide membrane, which by se can be known. The polyimide membrane comes with brought into contact with an aqueous modifier solution, 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 additionally at least one further functional group per same molecule of the modifier substance. With in other words, each modifier substance contains on the one hand a primary or secondary amino group and on the other hand, possibly another functional one Group.

In particular, this is another radio tion also around an amino group.

The polyimide membrane is in contact during the brin gens or after contacting with the Modifika Tor solution brought to an elevated temperature as well then cleaned and dried.

The modifier solution is for a period of 0.01 sec. to 1 h, preferably from 1 sec to 1 h, further preferably from 5 seconds to 10 minutes. with the Modifika contacted tor solution and at the same time and / or subsequently for a period of preferably 1 sec. to 1 h, particularly preferably from 5 sec to 10 min. a temperature of preferably 50-100 ° C and in particular  preferably exposed from 70-90 ° C and thereby treated.

The cleaning of the functionalized in this way Polyimide membrane of non-molded or non-membrane-forming substances with the exception of water as well as auxiliaries from the contacting modifika tor solution and / or other treatment solutions preferably by washing, extracting and the like from the membrane.

The cleaned membrane is then dried. she can however, before drying with known per se pore-preserving substances are impregnated.

The concentration of the modifier substance or Modifier substances in the modifier solution is preferably 0.1-20% by weight and further preferably 1- 10% by weight. The functional obtained in this way Based polyimide membrane can, if necessary an additional post-treatment level with other known treatment solutions to be treated for example, a function of the salt form To convert the modifier substance into the acid form or a neutral function, for example through Quarter conversion into an ionic form.

The polyimide membrane available according to the invention is depending on the type of modifier substance used or Modifier substances functionalized accordingly and generally represents a porous membrane with a high content of functional groups. The inventions Polyimide membrane according to the invention can already in this form can be used as an adsorbent membrane. You can also  the specifically adjustable, depending on the reaction usually in a large number of freely available functions len groups that focus on the membrane and pore surface surfaces for subsequent reactions for coupling further, selectively or specifically adsorbing Functions are used. In the case of polyimide form these functional groups are primarily located in the body on the molded body surface. With porous membranes the functional groups - depending on the procedure - even or asymmetrical across the membrane cross cut distributed, which is discussed in more detail below will go. With the choice of the pore size as the off gangsmembran used polyimide membrane and thus the to be modified polyimide membrane and the size of the Molecule of the modifier substance in the modifier sol solution you have the option of using a dry polyimide membrane and preferably short Treatment times the penetration of the modifier sub punch this way into the substructure of the membrane control that an asymmetrical distribution of the radio tional groups realized over the membrane cross section becomes. Therefore, an asymmetrical poly is preferred imid membrane as the starting membrane or as too modifi decorative membrane used. The pore size of the as Starting membrane serving asymmetric polyimide mem bran is preferred in the separating layer smaller than the size of the modifier sub molecule substance. In other words, this means that preferably two se a membrane as the starting membrane or material can be used that a remarkable Backing against the molecules of the modifier sub has punch, this membrane preferably from the Contacted support side with the modifier solution becomes.  

When using an asymmetrical membrane that is different from the Substructure is treated as described above, is consequently a decreasing pore size with one decreasing number of freely available functions the. The highest number of freely available functions is therefore on the during the modification in direct contact with the modifier solution membrane surface.

According to a preferred embodiment, the as Starting membrane used polyimide membrane average pore diameter less than 10 nm. This applies especially in the event that the invention Available membrane for the separation of pyrogen is used.

The membrane obtainable according to the invention is thus in particular an amine-functionalized Polyimide membrane with pyrogen sorptive properties. The freely selectable, covalently bound to the membrane Groups, especially amine and / or hydrophobic Nature in which the desired adsorptive groups with or bound to the polyimide membrane without a spacer are specifically adjustable and depending on the reaction tour generally available in large numbers. This functional groups are distributed - as already above outlined - either over the entire membrane cross cut or in a preferred version aims asymmetrically across the cross-section of the membrane. ever according to the field of application they have according to the invention available membranes separating effect compared to removing pyrogens, but not against the desired ingredients of dialysate / infusate. The at the functionalization of covalently bound modifiers Substances cannot be extracted by aqueous solutions  become. However, if they are not on Carriers are bound easily and completely through Flushing processes removed from the membrane before use become. It becomes one for decontamination processes adsorptive membrane provided that contains practically no elutable components. By the functional that only runs on the surface sation of one with superheated steam or hot water Sterilizable starting membrane material is guaranteed Continues that the specifically functionalized membrane ma material the requirements for this type of sterilization enough. The membrane obtainable according to the invention becomes also meet the requirements of a Disposable items are provided.

The process for producing the invention available membrane can in terms of functionality tion step are carried out continuously. On this is an economical production of the inventions according to the available membrane ensures how for disposable items to limit costs demand is. For this purpose, preferably a fold and therefore inexpensive and yet very effective adsorbing modifier substances used.

By choosing effective modifier substances with hydrophilic head groups, in particular aminic in nature, which are freely available in large numbers can change change in the surface properties of the polyimide membrane can be achieved such that the wetting of this membrane is advantageously improved with aqueous media and thus full performance right from the start Ensure contact with the medium to be detoxified is steady.  

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 options:

• - High molecular pyrogens (aggregates, micelles etc.) are preferably by size exclusion removed from the solutions to be treated because the same does not occur through the active separation layer can permeate the membrane.
• Monomeric pyrogens or fragments thereof, which by size exclusion with the used Membrane can not be retained and therefore permeate through the membrane adsorptive on the membrane surface or in particular especially on the functionalized pore surface area in the membrane cross-section during permeation bound by the membrane.

As a result of this decontamination process arise high purity dialysate / infusate solutions. simultaneously this type of decontamination ensures the on-line Provision of these solutions in sufficient quantities during dialysis treatment with small membrane areas chen.

Overall, a membrane cleaning system is available Available, the best conditions for use as Disposable consumer goods with high functionality.

In a further preferred embodiment, a asymmetric distribution of the functional groups over the membrane cross section available in that - in  Contrary to the variant described above, in which generally used a dry polyimide membrane becomes - the pore system of the dry polyimide membrane with a well wetting, preferably aqueous solution is filled before the polyimide membrane with the Modifi kator solution is brought into contact. Combined with short contact times of the polyimide membrane in the Modifi In this case, kator solution will be used without a Retention of the polyimide membrane against the molecules the modifier substance can be detected and regardless of the structure of the polyimide membrane preferably the contacted membrane surface and the adjacent part of the membrane cross-section modifi ed. This will also make an asymmetric Modification of the polyimide membrane achieved.

If a polyimide or a molded polyimide or a polyimide Membrane, the term "polyimide" includes in addition to pure polyimides, such classes of substances, which contain other groups besides the imide groups These include, for example, poly (amide imides), Poly (ester-imide), poly (ether-imide) and mixed products (Polymer blends). According to the invention, it is only required that at least a portion of the form / performing or membrane-forming polymer (s) in the Polymer chain have imide groups. Consequently, everyone can this membrane having imid function by means of modification according to the invention can be functionalized. However, molded articles or membranes are preferably made of pure polyimides used. This is the case with the molded body Any shape. It is only necessary that contact with the treatment solution at all is possible. Any of the starting membranes can be used Membranes are used. It can be about  Hollow or tubular membranes or also around flat membranes trade with or without carrier fleece.

The modifier used according to the invention Substances contain at least one primary or secondary amino group. Assigns the modifier substance only one amino group and otherwise it consists of a cabbage with no functional groups residue, then you can get this hydrocarbon residue can also be considered as another functional group. If you use such a monoamine for modification, you can see the hydrophobic properties of such improve 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 ,

where 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 -, -NHR ₁ - or -NH ( R ₂ ) ₂ group or fluorinated group, where R _{2 is} an aliphatic or aromatic hydrocarbon radical of any kind and in particular represents R ₁ , X is a straight-chain or branched aliphatic or aromatic hydrocarbon radical which the R ₁ -NH group with the or the Y ₂ group (s), which can be terminally or laterally bound to a chain, and can be interrupted in one side chain and the main chain by one or more O or N heteroatoms (s) and / or one or more -C (OH) -, -CO (OH) - and -PO ₃ (OH) -function (s) may have, and m represents 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 nature. It is preferably an aliphatic and / or aromatic hydrocarbon radical which can have the heteroatoms mentioned and can also 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 with a high proportion of heteroatoms from the polyamine substance class, 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 each independently represent a hydrogen atom or an aliphatic or an aromatic hydrocarbon radical. In this case, the radical X can in particular represent polyamines and polyamidines.

The modifier substance used for the modification Zen must be used to manufacture the modifier solution  used solvents are at least partially soluble. The modifier substances are preferably in the Solvent or the solvent mixture of the modifier Solution completely soluble and form homogeneous and im general low-viscosity solutions whose pH is ≧ 7. Water is normally used as the solvent brought. With a view to an even, short-term Treatment is advantageous with aqueous solvents Percentage of completely miscible with water chain mono- or polyfunctional alcohols put. The proportion of these alcohols is preferably 10 to 90 wt .-%, further preferably 20-50 wt .-% in Solvent mixture for the or the modifier sub substance (s).

The invention also relates to a method for Production of the modified poly according to the invention imide molded body and in particular the modified Polyimide membranes. With this procedure, the above Process steps described in more detail.

As already stated above, the membrane is after the Contact with the modifier solution at the same time and / or subsequently heat treated. Preferably this temperature treatment takes place continuously a continuous, moving membrane, by the with the Modifier solution contacted the membrane of the contact with a short-term temperature pulse is treated. In particular, this temperature is pulse on the running membrane by means of a pass microwave generated.

According to the inventive method can functionalized membranes are obtained, the Ligands on the one hand practically symmetrical over the  entire membrane cross-section are distributed when the Modifier substance and the modifier substances in the entire pore system of the membrane can penetrate like this is already described above. On the other hand, you can asymmetric polyimide membranes are obtained that from the coarser-pored membrane surface (Support-Ober surface) are contacted with the modifier solution, taking the modifier substances because of their size not in the entire pore system of the cross section of the Can permeate membrane freely. Among these manufacturers functionalized polyimide Membranes that coexist alongside the structural gradient a rectified gradient in functionalism tion degree, in such a way that a small medium pore diameter with a low function degree of degree and vice versa. benefit In such a targeted choice, the Manufacturing conditions the degree of functionalization in the active layer and in which lie below it greatly reduced the area of the membrane cross-section or functionalization can be prevented what especially for membranes with ultrafiltration properties with regard to the constancy of the separation properties and, like a combination of filtration us Desired adsorption with loss of adsorption ability of the separation-active layer advantageously connected can be. The latter prevents or limits the Adsorption of the reali anyway over the size exclusion separations of larger pyrogen aggregates, min changes a possible concentration polarization and thus guarantees constant permeate flows during the Decontamination process.

The invention is shown below with reference to the Examples for the production of modified polyimide  Membranes, based on polyetherimide membranes, closer explained. Di and. Polyamines or Polyethylene amine as modifier substances for use dung. However, these modifying amines are single Lich exemplary and serve primarily to explain the Basic principle for obtaining the modifi according to the invention graced polyimide moldings or polyimide membranes. at the applied polyetherimide Ultem 1000 (General Electric), from which in known manner according to the phase inversion process flat membranes on Histar carrier material or Hollow membranes were formed.

To characterize the starting membranes and the Membranes modified according to the invention were Water permeability, pore characteristics and separation cha characteristic with water or using a Mixture of dextrans measured by known methods as well as selected examples of the content of functio groups by titrimetric determination or by determining the dye adsorption with Acid Orange II determined. To evaluate the asymmetry of the function a qualitative staining test Use of Orange II (Uchida et al. Langmuir 9 (1993) 1121-1124). The adsorbability the membranes modified according to the invention for pyrogens was carried out under static conditions using Flat membranes tested, with endotoxin type E. coli serotype 0111: B4 contaminated isotonic saline solution was used as the solution to be decontaminated. The endotoxin content of the treated solutions was quantified using the 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 considered Output membrane used for the modification. Membranes of different manufacture with under Different separation properties showed in this unmodi the following characteristics:

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: 4,178.10 ^-3

g / cm ²

Contact angle: Advance angle: 82 ° -86 °
Retraction 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: 4,578.10 ^-3

g / cm ²

Contact angle: Advance angle: 82 ° -86 °
Retraction 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: Advance angle: 82 ° -86 °
Retraction angle: 52 ° -57 °

Furthermore, a hollow membrane was used for the investigations. This hollow membrane was produced as follows: A polyetherimide spinning solution was used using water (room temperature) as a lumen filler and a mixture of 45 parts of dimethylformamide (DMF), 25 parts of N-methylpyrrolidone (NMP) and 25 parts of gamma-butyrolactone (GBL ) and 5 parts of water as a coagulation bath spun a hollow membrane by means of a wet spinning process. The pore system of the outer surface of this initially gel-moist hollow membrane was opened by gel / sol / gel treatment (1st bath: N-methylpyrrolidone, 30 ° C .; 2nd bath: water, 80 ° C); it creates a highly asymmetrical hollow membrane with an inner separating layer. After washing out the non-membrane-forming constituents with water, the hollow membrane was dried at room temperature. The starting hollow membrane produced in this way (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: Advance angle: 82 ° -86 °
Retraction angle: 52 ° -57 °

These characteristics of the starting membranes became one Estimation of the change in membrane properties as Consequence of the modification.

Example 2

The flat membrane 1 examined in Comparative Example 1 was in the dry state, mounted on a metal drum, from the active layer side with a modifier 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 retention against the 1,6-diaminohexane used as a modifier substance. After the modification reaction, intensive rinsing was carried out with water at room temperature in order to remove modifier substance which was not covalently bound to the membrane. This modified membrane was examined in the moist state with regard to separating properties and after drying with regard to 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: Advance angle: 82 °
Retraction angle: 45 °

The distribution of the modifier substance over the mem branch cross-section was according to the qualitative Assessment symmetrical using the dye test.

Example 3

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

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

The unmodified membrane has compared to the Modifi kator substance only a small (practically none) Backing (<5%).

The following characteristics of the modified membrane were averaged:
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 over the mem branch cross-section was according to the qualitative Assessment symmetrical using the dye test.

Examples 4-7

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

• 1. The modifier solution consisted of 4 parts a 50% polyethyleneimine solution in water (Molecular weight: 750,000 g / mol), 47 parts Water and 49 parts 1-propanol. The unmodifi decorated membrane practically has a full constant backing against the modifier Substance (<95%).
• 2. The membrane was from the support side different with the modifier solution Times contacted at 70 ° C.

The membranes modified in this way had those in Table 1 compiled characteristics on:

Table 1

Characteristic data of the membranes modified according to Examples 4-7

The dye test showed that the active layer of Membrane stained much less and therefore functional was identified as the support site. The contact angles, measured on the active layer, were practically identical with the corresponding data of the unmodified mem bran.  

Examples 8-10

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:

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

The membranes modified in this way had those in Table 2 compiled characteristics on:

Table 2

Characteristic data of the membranes modified according to Examples 8 to 10

Examples 11 to 15

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) depending on the treatment time under the following conditions:

• - 2 wt .-% solution of the polyamine in one Solvent mixture consisting of 50 parts Water and 50 parts n-propanol.
• - The functionalization was below at 70 ° C Turning the metal cylinder (approx. 40 rpm) carried out.  
• - It became the active layer side of the asymme treated membrane.

To ensure that the membrane after treatment to determine the characteristic data completely is wettable, the treated membranes were used Treatment times of ≦ 60 sec. With the modifier Solution were contacted, 30 minutes after treatment. the radio at room temperature in the solvent mixture nationalization. Finally, the mem branches intensely with water with repeated changes the same rinsed and in this state of its own subjected to an audit.

The separation properties of the membranes and the out selected samples are determined contents of amine groups compiled in Table 3.

These data of dye adsorption prove the high Degree of functionalization of the membranes according to the invention, where the content of amine groups increases with the increase in Functionalization time increased; the separation properties are slightly changed by the functionalization changes, so that this finding in the choice of separation properties of the starting membrane are taken into account got to.  

Table 3

Table 4 contains data on the behavior of these example membranes during pyrogen adsorption for different starting endotoxin contents of the contacting medium. The adsorbability was determined under static conditions (double determination), 100 µl of a 2 to 20 ng / ml endotoxin-containing isotonic saline solution with slight shaking with a membrane area of 1 cm ² for 1 h at 37 ° C either with the treated or the untreated membrane surface have been contacted.

These data demonstrate the adsorption capacity of these Polyimide membranes themselves obtainable according to the invention among the static ones that are unfavorable for adsorption Conditions of the trials. The adsorption capacity is practically regardless of whether the treated or the untreated membrane surface with the ET-containing Solution was contacted, resulting in a symmetrical Distribution of the amine functions across the membrane cross cut notes. This symmetrical distribution could be qualitatively confirmed with the dye test. Yet is a slightly improved adsorption capacity Contacting the support side of the membrane len, which is obviously more accessible the pore surface as an additional adsorption surface related.  

Table 4

Examples 16 to 20

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

• - As a modifier, a polyethyleneimine Molar mass 750 kg / mol used and
• - the support side of the asymmetrical membrane was treated.

In contrast to Examples 11 to 15, the Modifier according to the separation properties of the Membrane practically completely returned from the same hold.

The separation properties of the membranes and the ermit The contents of the amine groups are shown in Table 5 compiled.

These data of dye adsorption prove the high Degree of functionalization of those obtainable according to the invention Membranes, with a practically constant amine content after a functionalization time of 60 sec. is achieved. The pore characteristic of the membrane is only slightly changed by the functionalization, however, the permeability of the membrane changes as Result of an increased transport resistance of the functionalized support layer.  

Table 5

Table 6 contains files on the behavior of these cases play membranes in pyrogen adsorption for under different endotoxin levels corresponding to the Examples of modification with the low molecular weight Polyethyleneimine.

These data demonstrate an adsorption capacity of these Polyimide membranes obtainable according to the invention among the for an adsorption process unfavorable static Conditions of the adsorption experiments. The Adsorptionska capacity is significantly lower than in the previous ones described examples and surprisingly practical table regardless of whether the treated or the untreated membrane surface with the ET-containing  Solution is contacted. The dye test, however, shows clearly that the amine functions are asymmetric over the Cross-section are distributed and a higher amine activity is present. That speaks for a dependence of the adsorp tion capacity of the modified Mem Branches of the ligand used.

Table 6

Claims (13)

1. molded polyimide body, in particular polyimide membrane, the or the functional with a chemical group Siert is available in that as a starting material a previously finished polyimide molded body or Polyimide membrane with an aqueous modifier solution contacted for a period of 1 sec to 1 h the modifier solution has at least one in it contains at least partially dissolved modifier substance, which is a primary or secondary amino group or one such amino group and additionally at least one has another functional group per molecule, and the polyimide molded body or the polyimide membrane during or after contacting the Modifi kator solution is brought to an elevated temperature  and then cleaned and dried. 2. Polyimide molded body according to claim 1, thereby receives Lich that one or more of the following is carried out: the polyimide molded body or Polyimide membrane is 5 to 10 minutes with the Modifika Tor solution is brought into contact, the polyimide form body or the polyimide membrane is 0.01 sec to 1 h and in particular 5 seconds to 10 minutes to a temperature from 50 to 100 ° C and in particular from 70 to 90 ° C heated and the polyimide molded body or the polyimide Membrane is used for cleaning in a manner known per se washed with water by washing, extracting, etc. 3. Polyimide molded article according to one of the preceding Claims, obtainable in that the concentration of Modifier substance (s) in the modifier solution 0.1 is up to 20 wt .-% and in particular 1 to 10 wt .-%. 4. Polyimide molded article according to one of the preceding claims, obtainable in that the modifier substances have the following general formulas
R ₁ -NH-Y ₁
NH- (Y ₁ ) ₂
R ₁ -NH-X- (Y ₂ ) _m ,
wherein R _{1 represents} a hydrogen atom or an aliphatic or aromatic hydrocarbon radical with up to 6 C atoms, Y _{1 represents} a hydrocarbon radical with 6 or more C atoms, Y _{2 represents} a -NH ₂ -, -NHR ₁ -, or -NH (R ₂ ) ₂ -, -OH-, -CH ₂ OH-, -CO (OH) -, -SO ₂ (OH) -, or -PO ₃ (OH) group or fluorinated group, wherein R _{2 is} an aliphatic or aromatic hydrocarbon radical of any kind and in particular represents R ₁ , X is a straight-chain or branched aliphatic or aromatic hydrocarbon radical which contains the R ₁ --NH group with the (Y ₂ ) group (s) which are terminally or laterally attached a chain can be bound, connects and in a side chain and / or the main chain can be interrupted by one or more O or N heteroatoms and / or one or more -C (OH) -, -CO (OH) - and - PO May have ₃ (OH) functions, and m represents 1, 2 or 3, correspond. 5. Polyimide molded article according to one of the preceding Claims in the form of a polyimide membrane, thereby available as an asymmetric polyimide membrane Starting material is used. 6. Polyimide molded body according to claim 5 in the form of a Polyimide membrane, available in that the pore size the asymmetrical polyimide membrane in the separation active Layer is smaller than the size of the modifier Substance. 7. polyimide molded body according to claim 5 or 6 in the form a polyimide membrane, obtainable in that the Polyimide membrane from the support side with the Modifier solution is contacted. 8. Polyimide molded article according to one of the preceding Claims in the form of a polyimide membrane, thereby available as a dry polyimide membrane Starting material is used. 9. Polyimide molded article according to one of the preceding Claims in the form of a polyimide membrane, thereby  available that a polyimide membrane with a mitt pore diameter less than or equal to 10 nm than Starting material is used. 10. Polyimide molded article according to one of the preceding Claims in the form of a polyimide membrane, thereby available that a polyimide membrane as a starting material rial is used, whose pore system with a good wetting and especially aqueous solution filled is. 11. Use of a polyimide membrane according to one of the previous claims for the decontamination of with Pyrogenic contaminated fluids and body fluids fluids. 12. Use according to claim 11 in the blood detoxifica tion for the preparation of dialysate and infusate as well as Production of pyrogen-free pharmaceutical infusates. 13. A process for producing a polyimide molded body including a polyimide membrane, characterized thereby records that the measures described in claim 1 and optionally at least one of the claims Chen 2 to 10 measures carried out become.