Filter cartridge, filter module and method for producing a gas filter membrane

Abstract

The present invention relates to a filter cartridge, having an elongated extension along a longitudinal axis (L), comprising a fibre group composed of individual fibres as the gas separation membrane, wherein the fibre group has a respective potting section at both ends in which the fibre ends are moulded in an open-flow manner, wherein the potting section is formed from a potting mixture which comprises at least the following (material) components: a resin component A, a hardener B, wherein the proportion of the resin component A is in the range from 65 to 85 wt. % and the proportion of the hardener B is in the range from 15 to 35 wt. %, wherein the potting mixture comprises, as a further component, at least one inert filler C which has an average particle diameter of less than 100 nm and a weight proportion of 10 to 30 wt. %, ideally 15 to 25 wt. %. The invention further relates to a production method for a filter cartridge.

Description

[0001] Filter cartridge, filter module and method for manufacturing a gas filter membrane

[0002] The invention relates to a filter cartridge with a potting compound, a filter module with such a filter cartridge and a manufacturing method for the filter cartridge, in particular for the use of O2 depletion in aviation, such as in particular the so-called OBIGGS (On-Board Inert Gas Generating Systems).

[0003] Two main techniques are known in the field for gas separation and liquid filtration using hollow fiber membranes. On the one hand, there are membrane modules containing hollow fiber membranes, in which the filter cartridge tube, into which the fibers are potted, also serves as the pressure-bearing shell. On the other hand, there are systems in which filter cartridges are installed in a pressure-bearing housing, and in which the filter cartridge tube itself does not constitute the pressure-bearing shell.

[0004] In the aerospace sector, for example in OBIGGS applications, membrane modules are typically preferred in which the fibers are directly potted into a pressure-bearing tube, as this results in weight savings compared to a cartridge solution in a separate pressure tube. These filter cartridge tubes, which also function as pressure vessels, are also called "shells" in the OBIGGS field.

[0005] The filter modules or filter cartridges can be used for various applications, especially in gas separation, such as biogas processing, helium or H2 production / processing, for the production of N2 from air, for the production of O2 from air, for gas drying, etc.

[0006] The separation membranes and associated cartridges or modules for fluid separation have a limited lifespan and are typically replaced several times during the lifetime of a membrane system. Examples of membrane modules can be found in US 2012 / 0304856 A1, US 2010 / 0072124 A1, US 2003 / 0102264 A1, and WO 2002 / 04100 A1. In so-called cartridge systems, the separation membrane surface consists of a bundle of several hundred to several hundred thousand individual hollow fibers arranged in a cartridge tube, usually a metallic cartridge tube made of stainless steel or aluminum, although plastic tubes can also be used. This filter cartridge with the bundle of separation-active hollow fiber membrane can be found, for example, in US 2012 / 0304856 A1, EP 1005896 A1, JP 1 1028341 A, US 4480683, US 5470469 A, US 2011 / 036764 A1, WO 01 / 66231 A1, WO 2011 / 022380 A1 and WO 2012 / 170956 A1.

[0007] It is known that the bundle of hollow fibers typically needs to be encased at both ends of the cartridge tube with a resin to separate the feed / retentate space from the permeate space. These resin-encased sections, such as those made of epoxy resins, must withstand the process conditions necessary for gas separation throughout the product's lifespan, particularly temperature, pressure, and the effects of chemically aggressive feed components like oxygen, water, or VOCs. Especially in OBIGGS applications, the filter cartridges must withstand numerous temperature and pressure changes due to the many take-off and landing cycles. Particularly under frequent load changes, cracks can form in the encased sections (tube heads), potentially leading to gas leakage or even rupture of the encased section.

[0008] This problem is described, for example, in WO 2014 / 143336 A1 for the assembly and curing or cooling step of the potting section, also referred to there as the tube sheet. EP 2 762 222 A1 addresses the problem of cracking, particularly for so-called OBIGGS (On-Board Inert Gas Generating Systems), and proposes using suitable O-ring arrangements to dampen differing material expansion processes between the filter cartridge and the actual pressure housing. To improve this solution using O-rings, WO 2014 / 143336 A1 proposes using end caps made of a polymer material for the potting compound supply line, which adhere to the cartridge element. Finally, to avoid stress cracks in the potting section, EP 3 007 807 B1 proposes to provide a multi-layered connection structure between the potting section and the cartridge tube and / or the pressure housing.

[0009] Finally, WO 96 / 08306 A1 already proposes that the potting sections be made of an organic material with inorganic filler particles of glass, ceramic, cement, or metal, although the purpose or advantage of this is not described in detail in this document. EP 2 112 195 A2 proposes in this regard to provide an epoxy resin with metallic flakes, such as aluminum flakes, for the potting mixture in order to reduce cracking in the potting section, especially under high temperature-induced stress cycles, with the metallic flakes having a particle size of 10 pm to 20 pm.

[0010] This solution of EP 2 112 195 A2 (D1. A1-A3) is already taken up in the aforementioned EP 2 762 222 A1 and combined with the core idea of ​​this publication.

[0011] In OBIGGS applications in aviation, the aircraft and all relevant components are exposed to temperature fluctuations ranging from +50°C (desert climate, summer) to below -50°C at high altitudes, in addition to sometimes very rapid thermal changes due to aircraft operation processes. Given the extreme load changes present in OBIGGS applications, it has been observed that damage still occurs to the membrane fibers, the potting sections, and / or the transitions between the filter cartridge, the filter module (housing), or the filter cartridge (also called the "shell"), which is typically designed as a module housing in OBIGGS applications. Therefore, the object of the present invention is to provide a filter cartridge that does not exhibit the aforementioned defects or exhibits them to a significantly reduced degree.

[0012] The present invention solves the problem by a filter cartridge, hereinafter also referred to as a "cartridge", having an elongated extension along a longitudinal axis (L), comprising a cartridge tube, a fiber group of hollow individual fibers as a gas separation membrane, wherein the fiber group has a potting section at each end in which the fiber ends are embedded in the cartridge tube in a flow-open manner, wherein the potting section is formed from a potting mixture comprising at least the following (material) components

[0013] - a resin component A, in particular an epoxy resin,

[0014] - a hardener B, wherein the potting compound comprises as a further component at least an inert filler e, which has a mean particle diameter of less than 100 nm.

[0015] The potting section functions similarly to a tube sheet, as is often referred to in the prior art. In this context, the term "flow-open potting" refers to a connection of adjacent hollow individual fibers (hollow fibers), which can be arranged essentially parallel to each other, whereby the flow surfaces at the fiber end faces are not covered by the potting compound, and thus the inner cavity is open for fluid inlet and / or outlet. Here, the term "potting" is also sometimes used synonymously with the term "potting," as in "potting compound material, section" and "potting mixture, material, section."

[0016] The cartridge tube can, in principle, be made of any suitable material; however, it is advantageously a metal tube, in particular a stainless steel tube, preferably an aluminum tube. Plastic tubes are possible in principle, but are uncommon for use in the OBIGGS sector due to their generally unsuitable mechanical properties, such as lower temperature resistance, insufficient mechanical strength, tendency to creep and cold deformation, as well as regulatory requirements. For many reasons, especially manufacturing considerations, the cross-section of the cartridge tube perpendicular to the longitudinal axis is advantageously round, although the cross-section is not limited to this and can have any suitable oval or polygonal geometry.

[0017] For the passage of fluids, especially the drainage of permeate from the cartridge tube of the filter cartridge, the cartridge has one or more openings around its circumference. The filter cartridge forms the separation element and marketable product, which can be inserted into and operated within a pressure vessel, the filter module. For this purpose, a filter module has and / or can be connected to corresponding fluid inlets, outlets, connection elements, closure elements, fastening elements, sealing elements, etc. To reduce weight, it is also known that the filter module has a central filter cartridge, which simultaneously forms the outer shell and pressure vessel. This outer shell has at least one permeate outlet and corresponding permeate connection. For the introduction of raw gas (feed) and the drainage of retentate, end caps are provided at both ends.The end caps are arranged, each having at least one gas connection. The end caps can be clamped or flanged onto the cartridge tube (shell), for example.

[0018] In the present context, "filter cartridge" means

[0019] - a cartridge that can be inserted and / or slid into an external pressure vessel, in particular a replaceable cartridge and

[0020] - a cartridge that is simultaneously designed as the outer shell and pressure vessel of the membrane module, unless otherwise specified or deviating from the design of the cartridge.

[0021] In an advantageous embodiment, the filter cartridge can comprise at least one potting ring, also called a "potting ring", at each end, in particular at both ends. The potting ring here forms

[0022] - a guide element in which the ends of the fiber group are arranged,

[0023] - a spacer ring, whereby an annular space is formed radially between the fiber group and the inner surface of the cartridge tube and

[0024] - can take over part of the sealing function at at least one end of the cartridge tube.

[0025] In an advantageous embodiment of the cartridge, at least one potting ring is provided, which consists in particular of a polymer material or plastic as a basic or main component, for example of a high-performance plastic, such as polysulfones, such as...

[0026] Polyphenylsulfone (PPSU), polyethersulfone (PESU), polysulfone (PSU), polyetherimide (PEI) or polyaryletherketone (PAEK), such as polyetheretherketone (PEEK), polyetherketoneketone (PEKK) or polyetheretherketoneketone (PEEKK).

[0027] An improvement can be achieved by ensuring that the potting ring has improved shrinkage properties by being reinforced with glass fibers, for which the proportion of glass fiber in the potting ring material is 10 to 30 wt.%, ideally 15 to 25 wt.%.

[0028] In addition to increased mechanical stability, this fiberglass content has the effect of lowering the coefficient of thermal expansion (CTE) of the potting ring material, thus bringing it closer to the CTE of the potting compound in the cartridge tube. Advantageously, the fiber content in the potting ring and the resin mixture are selected such that the coefficients of thermal expansion (CTE) of the potting ring and the potting compound contained therein differ from each other by less than 20 ppm / K, preferably less than 10 ppm / K, and particularly preferably less than 5 ppm / K, after curing. The potting ring can be arranged completely within the cartridge tube in the axial direction of the longitudinal axis (L) or can project beyond it on one side in the direction of the longitudinal axis (L) with at least one section.The spacer ring can advantageously be connected to the cartridge tube using the same potting compound as individual fibers of the fiber group, or arranged gas-tight in the cartridge tube using a different adhesive or sealant.

[0029] The term "pouring section" shall henceforth always include at least a partially integrated potting ring as an option, unless explicitly stated otherwise. Each potting section has a width (B) in the direction of the longitudinal axis (L) and a diameter (D) in the radial direction, whereby even for non-circular cross-sections, a diameter is referred to as the mean diameter, unless otherwise specified. The two potting sections advantageously have the form of a disc or plate, which is perforated longitudinally by individual fibers in the manner of a tube sheet. Depending on the feeding step for the potting compound and / or the post-curing treatment step, at least one surface may not be flat or even, in particular...The inner surface may be slightly concave due to active centrifugal forces during curing, which is of secondary importance for the present invention and is therefore not to be further distinguished.

[0030] The term "potting compound" refers to the mixture of the individual substances mentioned, whereby the terms "potting compound" and "potting compound" are sometimes used synonymously. Here, the "outer surface" of the potting section refers to the surface facing outwards with respect to the cartridge tube, while the "inner surface" is the opposite surface, i.e., the surface facing inwards within the cartridge tube. The (inlet / outlet) openings of the fibers are typically located on the outer surface.

[0031] In this context, the term "fiber group" refers to the number of individual fibers that together form the separation-active membrane and are cast together in the potting section with the potting compound. The individual fibers of a fiber group may be aligned parallel or substantially parallel to one another. In an alternative embodiment, they may be twisted together around the longitudinal axis (L). The terms "fiber group" and "fiber bundle" are used interchangeably in this context.

[0032] In an advantageous embodiment, component A can be an epoxy resin or an epoxy resin mixture consisting of several components, such as...

[0033] - Bisphenol A diyglycidyl ether (BADGE, CAS No. 1675-54-3),

[0034] - Bisphenol F diglycidyl ether (BFDGE, CAS No. 2095-03-6),

[0035] - N,N-Diglycidyl-4-glycidyloxyaniline or triglycidyl ether of para-aminophenol (TGPAP, CAS No. 5026-74-4), which are commercially available under the product names Araldite MY0500 and Araldite MY0510, with Araldite MY0510 having a higher purity than Araldite MY0500,

[0036] - N,N-Diglycidyl-3-glycidyloxyaniline or triglycidyl ether of meta-aminophenol (TGMAP, CAS No. 71604-74-5), which is commercially available under the product names Araldite MY0600 or Araldite MY0610, with Araldite MY0610 having a higher purity than Araldite MY0600,

[0037] - Tris(4-hydroxyphenyl)methantriglycidyl ether (TGTPM, CAS No. 66072-38-6), which is commercially available under the product name TACTIX® 742,

[0038] - 4,4'-Methylene-bis(N,N-diglycidylaniline) or tetraglycidyl ether of 4,4'-diaminodiphenylmethane (TGDDM, CAS No. 28768-32-3), which is commercially available under the product names ARALDITE® MY 721 and ARALDITE® MY 9512.

[0039] The purer monomers exhibit a lower viscosity compared to the oligomers. For example, Araldite MY0510 has a viscosity of 550–850 mPa s and Araldite MY0500 a viscosity of 2,000–6,000 mPa s, as measured in a suitable capillary, rotational, or quartz viscometer.

[0040] The potting compound is mixed in a single mixing step by combining at least components A, B, and C. This is carried out for a duration of at least 1 second up to 180 seconds, whereby longer mixing times are advantageous depending on the mixing properties of resin component A and hardener B. A stirring or shaking device can be used as a suitable mixing instrument, although the potting compound can also be prepared using a static mixer. It can be particularly advantageous to carry out the mixing step under an inert atmosphere to exclude oxidizing influences from O₂ and moisture.

[0041] The term "inert" or "inert component" with reference to component C means that this substance does not change its state of matter under the given conditions of the potting compound. Its initially solid consistency, in particular, remains unchanged within the potting compound but is merely incorporated into the resin. Specifically, this means that the inert component does not undergo any chemical reaction or transformation with resin component A and / or hardener B. However, the term "inert" or "inert component" also encompasses at least partial oxidation of the inert component (substance) and / or oxidation of a portion of the inert components, for example, under the influence of oxygen. Oxidation of inert components can occur, in particular, at transition surfaces (Z) between the potting compound and individual fibers and / or at the edges of the potted section.

[0042] Surprisingly, it has turned out that a particularly advantageous

[0043] An embodiment of the filter cartridge consists in the fact that the filler e has a particle size in

[0044] The particle size ranges from 50 nm to 5 nm, preferably from 40 nm to 10 nm, ideally from 35 nm to 15 nm. A particle size of 25 to 15 nm has proven particularly advantageous, as sedimentation is largely prevented at this very small average particle size, even under the influence of centrifugal forces, despite the higher density of the nanoparticles.

[0045] It has also surprisingly turned out that a particularly advantageous embodiment of the filter cartridge consists in selecting the potting compound such that the sedimentation rate of the filler C or the various individual components of the filler C during processing under centrifugal force is less than 10 mm / h, preferably less than 1 mm / h, and particularly preferably less than 0.1 mm / h. The sedimentation rate can be estimated by an analogous application of Stokes' equation for slow sedimentation. where v P the sedimentation rate, r the radius of the sinking object (i.e., the filler material C), V P the volume of the sinking object, g the respective applied centrifugal force, p P The density of the particle, pr the density of the fluid (i.e., the mixture of A and B), and the dynamic viscosity of the fluid are.

[0046] For example, particles with a larger density difference to the fluid (p P . pr) the particle diameter should be correspondingly smaller in order to achieve a sufficiently slow sedimentation rate in the potting compound with the same centrifugal force, while a larger particle diameter can be tolerated if the density difference is small.

[0047] After initially exhibiting a higher viscosity immediately following mixing of the components, the potting compound then passes through a viscosity minimum due to the heating caused by the released reaction enthalpy during the curing process. The sedimentation rate is therefore highest at this viscosity minimum.

[0048] The analysis of sedimentation velocity under centrifugal forces can be carried out according to ISO 13318 in conjunction with DIN ISO 14887. The LUMiSizer dispersion analyzer from LUM GmbH can be used for this analysis, and the aforementioned standards, in particular ISO 13318-1, and the LUMiSizer analyzer from LUM GmbH were used in the tests described herein.

[0049] This allows velocity distributions during particle separation and sedimentation under the influence of centrifugal forces to be measured experimentally inline, based on the primary principle and without assumptions regarding dispersion properties, models, or algorithms. Details on the measurement method and use of the LUMiSizer are also described by H. Chen, X. Jia, M. Fairweather et al.; Title: Characterising the sedimentation of bidisperse colloidal silica using analytical centrifugation; Advanced Powder Technology 34 (2023) 103950 (https: / / doi.org / 10.1016 / j.apt.2023.103950).

[0050] Advantageously, the particles of filler C exhibit a very narrow particle size distribution. In particular, so-called monodisperse nanoparticles are advantageous for preventing macrocracking. For the purposes of this document, a "microcrack" is defined as a crack length of up to 1 pm. Furthermore, a "macrocrack" is defined as a one-sided or through-hole in a potting section that has a crack length greater than 1 pm and / or a crack depth greater than 1 pm along the longitudinal axis. Specifically, a macrocrack is a crack through which a gas or gas fraction can flow outside the intended gas pathways across the potting section and / or is visible to the naked eye or detectable by light microscopy.

[0051] Without limiting itself to a single interpretation, it is assumed that with these small particle sizes of less than 100 nm, especially less than 50 nm, further crack propagation at the crack tip towards macrocracks in the potting compound was reliably prevented in the case of microcracks. Furthermore, it is observed that, surprisingly, particle sizes of 40 to 10 nm with a very narrow particle size distribution are particularly advantageous for effectively preventing the propagation of microcracks at the crack tip, because a sufficient quantity of sufficiently small inert particles is thus locally available in each emerging microcrack to dissipate the energy at the respective crack tip. The particle size distribution can also be measured with the aforementioned LUMiSizer dispersion analyzer from LUM GmbH.

[0052] In a further advantageous embodiment of the filter cartridge, an improvement can consist of the filler having a weight fraction of 3.0 to 35 wt.%, preferably 10 to 35 wt.%, ideally 15 to 35 wt.%. Without being limited to a single interpretation, it is assumed that high weight fractions of filler e are therefore particularly advantageous because the high local presence of the nanoparticles ensures that any microcracks experience immediate energy distribution at the crack tip, thus preventing crack propagation particularly well.

[0053] In a further advantageous embodiment of the filter cartridge, an improvement can consist of using filler C as silicon dioxide (SiO2), aluminum dioxide (Al2O3), or a mixture thereof. Advantageously, the filler e is silica, wherein the silica particles are also commercially available, for example, under the applicant's product name Nanopox®, and are dispersed in an epoxy resin, in particular BFDGE, up to a concentration of approximately 40-45 wt% and are manufactured and marketed. Due to the smaller density difference of SiO2 (density approximately 2.2 g / cm³), 3 ) (Silica) to resin component A (density approx. 1.1 - 1.12 g / cm³) 3 ) compared to Al2O3 (density 3.9 g / cm³) 3It is advantageous to use pure silica as a filler e to reduce sedimentation under centrifugal force. In a further advantageous embodiment of the filter cartridge, an improvement can consist of using hardener B from the group of the following substances: a) amines, in particular aliphatic or aromatic amines, preferably a mixture of aliphatic and aromatic amines; b) anhydrides, in particular monoanhydrides and / or bisanhydride; or c) imidazoles, in particular an imidazole from the following group: 2-methylimidazoles (2MI = Imicure AMI-2), 2-ethyl4(5)-methylimidazoles (2E4MI = Curezol 2E4MZ).

[0054] 1-methylimidazole (1 Ml: CAS No. 616-47-7),

[0055] 2-ethylimidazole (2EI: CAS No. 1072-62-4), 2-phenylimidazole (2Phl = Curezol 2PZ),

[0056] 1-(2-cyanoethyl)-2-ethyl-4(5)-methylimidazole (2E4MCNI: CAS No. 23996-25-0).

[0057] The amines can preferably be a) advantageously a mixture of aliphatic and aromatic amines, wherein the proportion of aromatic amines is above 70 mol%, ideally above 80 mol%, based on the amine groups. It can be advantageous if the proportion of aromatic amines in the mixture does not exceed 98 mol%, ideally not above 95 mol%.

[0058] Depending on the specific resin components, imidazoles can be present as hardeners from the following group:

[0059] Imicure AMI, 2, 2-Methylimidazole, CAS No. 693-98-1 ;

[0060] Curezol 2E4MZ, 2-ethyl-4-methylimidazole, CAS no. 931-36-2;

[0061] Curezol 1 B2MZ, 1-Benzyl-2-methyl-1 H-imidazole, CAS no. 13750-62-4;

[0062] Curezol 2PZ, 2-phenylimidazole, CAS no. 670-96-2;

[0063] Curezol 2P4MZ, 4-Methyl-2-phenyl-1 H-imidazole, CAS No. 827-43-0;

[0064] Curezol C17Z, 2-heptadecyl-1 H-imidazole, CAS No. 23328-87-2;

[0065] Curezol 2MZ Azine, 6-[2-(2-methyl-1 H-imidazol-1-yl)ethyl]-1,3,5-triazine-2,4-diamine, CAS no. 38668-46-1 ;

[0066] Curezol 2PHZ-PW, 4, 5-bis(hydroxymethyl)-2-phenyl-1 H-imidazole, CAS No. 61698-32-6;

[0067] Curezol 2MA-OK, 1,3,5-triazinane-2,4,6-trione, 6-[2-(2-methyl-1 H-imidazol-1-yl)ethyl]-1,3,5-triazine-2,4-diamine, CAS no. 68490-66-4.

[0068] In a further advantageous embodiment of the filter cartridge, an improvement may consist in the fact that the hardener B comprises monoanhydride and / or bisanhydride, wherein an accelerator is included as a further component, which is in particular a substance from one of the following groups: i) imidazole, such as e.g.

[0069] 2-methylimidazole (2MI),

[0070] 2-Ethyl4(5)-Methylimidazole (2E4MI),

[0071] 1-Methylimidazole (1 ml),

[0072] 2-Ethylimidazole (2EI), 2-Phenylimidazole (2Phl),

[0073] 1-(2-Cyanoethyl)-2-Ethyl-4(5)-Methylimidazole (2E4MCNI) or a mixture thereof; ii) Tertiary amine, such as e.g.

[0074] (Dimethylaminomethyl)phenol (CAS No. 25338-55-0), Diazabicycloundecene (CAS No. 6674-22-2), Triethylamine (CAS No. 121-44-8) or mixtures thereof; iii) Polyamines, such as e.g.

[0075] - 1,3-Propanediamine, N,N-dimethyl-, reaction products with 5-Amino-1,3,3-Trimethylcyclohexanemethanamine-5-isocyanato-1-(isocyanatomethyl)-1,3,3-Trimethylcyclohexane-N-(2-Methylphenyl)-N-(2-Oxiranylmethyl)-2-Oxiranemethanamine polymers and benzenemethanamines

[0076] (Product name: Ancamine 2441 ; CAS No. 912342-92-8); or iv) mixtures of ii) and iii).

[0077] The proportion of the other component of the accelerator can advantageously be 0.1 to 10 wt.% based on the hardener B monoanhydride or bisanhydride. Ideally, the weight ratio of hardener B to the other component of the accelerator is 0.1 to 5 wt.%, preferably 0.1 to 4 wt.%, ideally 0.1 to 3 wt.%. The positive effect of the accelerator is that the required curing temperature is lowered, thus accelerating the curing process and making it more energy efficient. Here, the weight ratio of hardener B to accelerator is defined as the weight of the accelerator to the total weight of hardener B and accelerator.

[0078] In a further advantageous embodiment of the filter cartridge, an improvement may consist in the resin component A comprising or being formed from one of the following substances:

[0079] • 4,4'-Methylenediphenyldiglycidyl ether (A1), also called bisphenol A diglycidyl ether (BADGE), with CAS No. 55818-57-0; • Bis(4-hydroxyphenyl)methanediglycidyl ether (A2), also called bisphenol F diglycidyl ether (BFDGE), with CAS No. 9003-36-5;

[0080] • p-(2,3-epoxypropoxy)-N,N-bis(2,3-epoxypropyl)aniline (A3), also called Araldite MY0510, with CAS No. 5026-74-4;

[0081] • Tris(4-hydroxyphenyl)methane triglycidyl ether (TGTPM, CAS No. 66072-38-6, (A4));

[0082] • 4,4'-Methylene-bis(N,N-diglycidylaniline) (TGDDM, CAS No. 28768-32-3, (A5)); and

[0083] • Reaction products from these, especially oligomers as reaction products.

[0084] Here, BFDGE serves as a highly functional crosslinker to increase the temperature stability of the potting compound. Furthermore, "reaction products" refers in particular to polymeric products or oligomers made from the aforementioned monomers A1, A2, and / or A3.

[0085] In a further advantageous embodiment of the filter cartridge, an improvement may consist in the resin component A being an epoxy resin mixture comprising at least two of the following resin components: resin component A1, resin component A2 or resin component A3.

[0086] Such a mixture of resin component A can be particularly advantageous if the filler e is already present in high concentration during production, e.g. suspended in resin component A2, and the desired other concentration and / or material properties of the potting mixture and / or resin component A are adjusted by means of the second resin component A1.

[0087] In a further advantageous embodiment of the filter cartridge, an improvement can consist in the resin components A being formed as a mixture of at least two resin components A1 and A2, wherein:

[0088] - Resin components A1 (BADGE) represent 0.5 to 50 wt.% and

[0089] - Resin component A2 (BFDGE) represents 5 to 50 wt%, or resin component A2 represents the remaining proportion. Advantageously, resin component A2 (BFDGE) forms the larger proportion in the potting compound.

[0090] For the injection of potting compound, it is advantageous if the larger resin component is BFDGE, because BFDGE has a lower viscosity than BADGE and therefore also reduces the overall viscosity of the mixture. This is beneficial for feeding the potting compound.

[0091] In a further advantageous embodiment of the filter cartridge, an improvement can consist in the resin components A being formed as a mixture of at least three resin components A1, A2 and A3, wherein:

[0092] - Resin components A1 (BADGE) represent 0.5 to 50 wt.%,

[0093] - Resin components A2 (BFDGE) represent 5 to 50 wt.% and

[0094] - Resin component A3 represents the remaining portion.

[0095] The aforementioned ratios of resin components A1, A2, A3 do not take into account other ingredients such as inert fillers C and / or elastomers D.

[0096] Regarding the mixing ratios of resin component A to hardener B, it can be advantageous if, in the ratio of resin component A to hardener B, hardener B is a) an amine and / or an anhydride, wherein resin component A is in the range of 65 to 85 wt.%, preferably 70 to 80 wt.%, in particular 75 to 78 wt.%, and hardener B is in the range of 15 to 35 wt.%, preferably 20 to 30 wt.%, in particular 20 to 25 wt.%, or b) an imidazole, wherein hardener is in the range of 0.1 to 10 wt.%, preferably 0.1 to 5 wt.%, ideally 0.1 to 2 wt.%, with resin component A forming the remaining weight fraction.

[0097] The advantage of catalytic hardeners, such as imidazole, is that the reduced amount of hardener required results in economic benefits, and resin components cured with imidazole exhibit greater temperature stability. This temperature stability is reflected in a higher glass softening point (Tg) compared to amine or anhydride hardeners. Furthermore, imidazole-based potting compounds are slightly latent systems, meaning they require a slightly elevated activation temperature. Below this temperature, they remain essentially chemically stable, i.e., liquid, thus allowing for longer processing times.

[0098] It has been found that very good crack prevention through the addition of the aforementioned inert particles in the specified particle size and respective weight fractions (wt%) leads to extremely hard potting sections and thus filter cartridges that are resistant to stress cycles. However, embrittlement and a tendency to chipping have also been observed in some cases. Such potting sections are less suitable for compensating high internal stresses due to material strain in the adjacent structure.

[0099] Thus, a further advantageous embodiment of the filter cartridge can consist of including, as an additional component, at least one elastomer D in a weight fraction of less than 10 wt.% with a mean (particle) diameter of less than 30 pm. Here, "one" elastomer D always refers to a quantity or mass of individual particles with the described material properties. This proportion of elastomer D in the potting compound counteracts the aforementioned problem of excessive embrittlement and leads to improved elasticity, in particular reduced damage under bending stress of the potted section.

[0100] In the present document, the resin component A, the hardener B, the accelerator, the inert filler C and the elastomer D are referred to individually or collectively as “component(s)” or “component(s) of the potting compound”.

[0101] Another advantageous formulation involves having the elastomer D already incorporated into the dispersion with the BADGE during production, thus greatly simplifying the mixing step, as only liquid components need to be combined and mixed. The elastomer D is advantageously a so-called core-shell rubber particle, such as the one marketed by the applicant under the product name Albidur® in dispersion with a BADGE.

[0102] These core-shell rubber particles have a more elastic core made of, for example, polybutadiene or polydimethylsiloxanes (silicone). The shell serves as an adhesion promoter to at least one of the resin components A, also A1, A2 and / or A3, and is made, for example, of poly(methyl) methacrylate (PMMA), reaction products of epoxy-functional siloxane such as (3-glycidyloxypropyl)trimethoxysilane (GLYMO, CAS No. 2530-83-8) or 3-glycidyloxypropyl triethoxysilane (GLYEO, CAS No. 2602-34-8).

[0103] In a further advantageous embodiment of the filter cartridge, an improvement can consist in the fact that the elastomer D has a mean (particle) diameter of 4 pm to 15 pm, in particular 5 pm to 10 pm, preferably 6 pm to 8 pm.

[0104] In a further advantageous embodiment of the filter cartridge, an improvement can consist in the fact that the min. comprises an elastomer D in a proportion of 1.0 to 8.5 wt.%, in particular 2.0 to 7.0 wt.%, preferably 3 to 6.0 wt.%.

[0105] In a further advantageous embodiment of the filter cartridge, an improvement may consist in the fact that the elastomer D is taken from the group of the following substances or a mixture thereof: core-shell rubber particles, surface-functionalized silicone, silicone rubber, bisphenol-A diglycidyl ether (DGEBA), cyclic aliphatic epoxy resin, polypropylene glycol triol (PPG triol), vinyl ester resin, o-phthalic unsaturated polyester resin, silane-modified polyurethane prepolymer, trimethoxyvinylsilane.

[0106] These elastomers D advantageously have an average density of 1.1 g / cm³. 3at 23°C, these elastomers D being marketed by the applicant as products under the product name Albidur®. It has proven particularly advantageous if the sedimentation rate of the elastomer D or of the various individual components of the elastomer D during processing under centrifugal force is less than 10 mm / h, preferably less than 1 mm / h, and most preferably less than 0.1 mm / h.

[0107] In a further advantageous embodiment of the filter cartridge, an improvement may consist in the potting compound from which the potting section is formed comprising, as further components, at least one adhesion promoter HV taken from the group of the following substances or a mixture thereof: Dynasylan® AMEO, 3-aminopropyltriethoxysilane (CAS No. 919-30-2); Dynasylan® 1122, (bis(3-triethoxysilylpropyl)amine) (CAS No. 13497-18-2); Dynasylan® 1124, bis(3-trimethoxysilylpropyl)amine (CAS No. 82985-35-1); Dynasylan® 1505, 3-aminopropylmethyldiethoxysilane (CAS No. 70240-34-5); Dynasylan® AMMO, 3-aminopropyltrimethoxysilane (CAS No. 13822-56-5); Dynasylan® SIVO® 210, proprietary aminosilane composition (mixture); Dynasylan® SIVO® 214, proprietary aminosilane composition (mixture);

[0108] Dynasylan® TRIAMO, triamino-functional propyltrimethoxysilane (CAS No. 35141-30-1);

[0109] Dynasylan® 1189, N-(n-butyl)-3-amino-propyltrimethoxysilane (CAS-Nr. 31024-56-3);

[0110] Dynasylan® SIVO® 203, functional oligosiloxane (CAS-Nr. 13822-56-5);

[0111] Dynasylan® 9165, phenyltrimethoxysilane (CAS-Nr. 2996-92-1);

[0112] Dynasylan® 9265, phenyltriethoxysilane (CAS-Nr. 780-69-8);

[0113] Dynasylan® 1411 , 2-aminoethyl-3-aminopropylmethyldimethoxysilane (CAS-Nr. 3069-29-2); Dynasylan® DAMO, 2-aminoethyl-3-amino-propyltrimethoxysilane (CAS-Nr. 1760-24-3).

[0114] In one variant, it can be advantageous if the hardener B of the potting compound, from which the potting section is formed, is a (hardener) mixture that includes at least one of the aforementioned adhesion promoters HV from the group mentioned above. Surprisingly, it has proven particularly advantageous in the production of the filter cartridges and / or the filter module if, prior to the preparation of the potting compound, the hardener B was mixed with at least one of the aforementioned adhesion promoters HV or is present as a B-HV mixture.

[0115] The invention further comprises a filter module for gas separation, comprising at least one filter cartridge, at least one inlet connection for a raw gas, and at least two outlet connections, wherein at least one outlet connection is provided for the retentate and at least one further outlet connection for a permeate, wherein the filter cartridge is configured according to one of the aforementioned embodiments or variants. All aspects or advantages mentioned for the filter cartridge shall apply identically or analogously to the filter module. Advantageously, the filter module has at least one cap or closure element that enables the insertion and / or closure of the filter cartridge. Furthermore, it comprises at least one feed connection, at least one retentate connection (element), and at least one permeate connection (element).The interior of the filter module advantageously also has receptacles, stops and sealing surfaces or sealing elements to fix the filter cartridge and to guide the different interior spaces for the feed gas (feed), the retentate fluid (retentate) and the permeate fluid (permeate) in a process-reliable, gas-tight and separate manner.

[0116] Furthermore, it can be advantageous if the filter module has at least one external holding and fixing element to connect the filter module itself to a supporting and holding structure.

[0117] Advantageously, two basic embodiments of a filter module are proposed.

[0118] A) In the first embodiment of a filter module, the filter cartridge is arranged in an outer pressure vessel, with at least one discharge port for the permeate being located on the pressure vessel. An annular space is formed along a portion of the length between the cartridge tube and the pressure vessel, through which permeate can flow. Furthermore, connection elements and closure elements, such as end caps, are provided. Advantageously, the filter cartridge is completely enclosed by the pressure vessel, allowing for quick and cost-effective replacement as needed.

[0119] B) In an alternative, advantageous embodiment, which can be lighter and is therefore preferable for OBIGGS applications, the filter cartridge itself constitutes a pressure vessel and is designed and / or dimensioned accordingly. Thus, no external pressure vessel, at least partially enclosing, is provided. The at least one discharge port for the permeate is located directly on the filter cartridge designed as a pressure vessel. The terminal connection elements and / or closure elements, such as end caps, located at the ends in the longitudinal axis are advantageously also directly connected to the filter cartridge by a positive and / or force-fit connection. Advantageously, in such an embodiment, the cartridge tube is not extended axially by a potting ring.

[0120] The phrase "no at least partially enclosing, outer pressure vessel" is to be interpreted broadly and means that no fully enclosing or substantially enclosing pressure vessel is provided, specifically including partial or partial enclosure of, for example, a terminal connection or closure element in a flange or fastening section of embodiment B). The invention further comprises a manufacturing process for a filter cartridge with a group of hollow fibers (fiber group) suitable for gas separation as a membrane, comprising the following steps:

[0121] - mind, a grouping step, encompassing the provision and / or grouping of a number of individual fibers into a fiber bundle;

[0122] - mind, a connection step, comprising inserting the fiber bundle into a cartridge tube;

[0123] - mind, a fixing step, comprising securing the cartridge tube in a holding device, ;

[0124] - mind, a filling step, comprising storage or presentation of a defined quantity of a liquid or flowable potting compound;

[0125] - mind, a potting step, comprising supplying a potting mixture to mind, an end of the fiber bundle, wherein the potting mixture mind comprises the following components:

[0126] - a resin component A, in particular an epoxy resin,

[0127] - a hardener B, whereby

[0128] - the resin component A is in the range of 65 to 85 wt.%, preferably 70 to 80 wt.%, in particular 75 to 78 wt.%;

[0129] - the hardener B is in the range of 15 to 35 wt.%, preferably 20 to 30 wt.%, in particular 20 to 25 wt.%, and wherein the potting compound comprises as a further component at least an inert filler e having a mean particle diameter of less than 100 nm.

[0130] All aspects, advantages, embodiments, and variants of the potting compound described in connection with the filter cartridge and / or filter module shall apply identically or analogously to the manufacturing process. In particular, the aforementioned manufacturing process shall be used specifically for the production of the filter cartridge or filter module described above. The filter cartridge and filter module are advantageously intended for use in aviation for gas separation.

[0131] The minimum filling step, comprising the storage or dispensing of a liquid or flowable potting compound, may further include a supply and mixing step in which the defined quantity of potting compound is produced by single- or multi-stage combining and mixing. The terms "storage" or "dispensing" here specifically mean that the quantity of potting compound to be used in the subsequent potting step is measured, temporarily stored, and / or metered by means of a conveying device. This depends on the spatial orientation and potting equipment selected for the overall known potting step.

[0132] In an advantageous embodiment, at least one fixing step is provided, comprising securing the cartridge tube with the fiber bundle in a holding device on or to a centrifuge, wherein the cartridge tube is oriented transversely to the axis of rotation. The term "transversely to the axis of rotation" means that the cartridge tube is fixed and rotated transversely to its longitudinal axis, with the two free ends of the cartridge tube rotating around the axis of rotation of the centrifuge during rotation (centrifugation). The rotation or centrifugation is included in the filling step. For this purpose, the centrifuge advantageously has a carrier or rotating disk for centrally mounting the cartridge tube, which is attached to the end of a motor-driven shaft and is rotatable within a housing of the centrifuge.

[0133] In the aforementioned process variant, it can be particularly advantageous if, during the filling step, the storage or dispensing of the liquid or flowable potting compound also takes place on the centrifuge, especially at or near the holder for the cartridge tube. The filling step is followed by at least one potting step, in which the cartridge tube with the fiber bundle is rotated in the centrifuge, while at least a partial supply of the stored potting compound is made to at least one end of the fiber bundle.

[0134] The fixing or filling step may include the application of a potting cap for improved delivery and curing of the potting compound, as described, for example, in WO 2014 / 143336 A1 or EP 3 007 807 B1. Furthermore, in the grouping, joining, and / or fixing steps, the application of at least one potting ring to at least one end of the fiber bundle and / or the cartridge tube may be provided; in particular, a potting ring may be arranged at each end of the fiber bundle and / or the cartridge tube. A potting ring may, in particular, be shaped such that it is partially enclosed by the cartridge tube and extends beyond the respective ends of the cartridge tube. The extending part of the potting ring may, in particular, have the same (outer) circumference as the cartridge tube.Furthermore, it can be advantageous if at least one sealing element is attached or attachable to the end faces of the potting ring and / or to the section of the potting ring projecting axially beyond the cartridge tube. In particular, it is advantageous if at least one circumferential groove or shoulder is provided on the potting ring, onto or into which a circumferential sealing element can be attached or inserted.

[0135] For manufacturing reasons, it can be advantageous to apply at least one potting ring to one end of the cartridge tube or fiber bundle in a first step, e.g., the grouping step, and at least one further potting ring to the other end in a subsequent step, e.g., the fixing step. The potting ring is cast in the potting compound together with the respective end of the fiber bundle during the potting step.

[0136] Advantageously, the mixing of the resin component A and the hardener B takes place no less than 2 hours before the potting step, whereby the mixing of the inert component C or the elastic component D can take place independently thereof, in particular in less than 1 hour, and especially advantageously in less than 0.5 hours. Advantageously, the potting mixture is prepared from the individual components A, B, and C no less than 2 hours before the potting step, in particular in less than 1 hour, and especially advantageously in less than 0.5 hours.

[0137] In an advantageous embodiment, a strapping step can be provided, in particular before the joining step, in which the fiber bundle is strapped or wrapped at least at one end, and especially at both ends, with a potting ring. This strapping step can be carried out parallel to or simultaneously with the insertion of the fiber bundle into the cartridge tube. In an alternative embodiment of the method, the potting ring is pushed onto or attached to the cartridge tube at least at one end, with the fiber bundle then being inserted and a potting ring also being arranged at the other end of the cartridge tube.

[0138] The strapping step and the joining step can be carried out at least temporarily in parallel and / or in reverse order.

[0139] Furthermore, the invention also includes a gas separation method with a filter module and a filter cartridge with a fiber group as a separation-active membrane, which comprises at least one potting section, in particular two potting sections, wherein the filter cartridge is designed according to one of the embodiments or variants mentioned herein.

[0140] Advantageously, the gas separation process is a process in which air is supplied as a feed, with the discharged permeate or retentate exhibiting different partial pressures of O2 and / or N2. Advantageously, the gas separation process is operated on an aircraft by performing O2 depletion and N2 enrichment from air (feed) on board the aircraft, with the N2-rich gas stream being directed into the fuel tank, specifically into the vertically higher gas space of the fuel tank. The terms "aircraft" and "airplane" should not be understood restrictively here.

[0141] Experiments

[0142] To determine the physical properties of the potting compound, test specimens were prepared according to ISO 16012. All experiments on test specimens were carried out according to DIN EN ISO 179-2, whereby the test specimens were conditioned for at least 16 hours at 23 °C and 50% relative humidity immediately before the respective tests.

[0143] The dimensions of the specimens for the bending test and the Charpy impact test were 80 x 10 x 4 mm (width x height x length), which were sawn and / or milled from a solid material. Example 1:

[0144] The (filled) sample material according to the invention consisted of the following substances as

[0145] (Potting mixture) together:

[0146] Resin component A, LH 5000 (BADGE) 70.6 wt.%

[0147] Hardener B, here H418H 17.9% by weight

[0148] Inert filler C, supplied as a suspension in BADGE 8.2 wt%

[0149] Elastomer D (Core-Shell-Rubber), supplied as a dispersion in BADGE 3.3 wt.%.

[0150] The unfilled sample material (potting mixture) used for comparison consisted of the following substances:

[0151] Resin component A, here LH 5000 79.7 wt.%

[0152] Hardener B, here H418H 20.3% by weight

[0153] The resin component A used is a BADGE (trade name LH 5000) with the patent name (2,2'-[1-methylethylidene)bis(4,1-phenyleneoxymethylene)]bisoxirane (CAS No. 1675-54-3). The hardener B used (H418H, FDW Handelsges. mbH) is a mixture of the following components: 4,4'-Methylenebis(cyclohexylamine) 45-50 wt% (CAS No. 1761-71-3), diethylmethylbenzenediamine 45-50 wt% (CAS No. 68479-98-1), and adhesion promoter 3-aminopropyltriethoxysilane 1-5 wt% (CAS No. 919-30-2). The silica nanoparticles added as inert fillers had a mean particle size of 20 nm and the following particle size distribution (percentiles): 19.4 nm (d10), 28.7 (d50), 49.5 (d90), determined according to DIN ISO 9276-2 and DIN ISO 13320.

[0154] The inert filler e was provided as a 40% suspension (Nanopox® F400, Evonik Industries AG) containing 60 wt% BADGE as the resin component. The elastomer D was provided as a dispersion (Albidur® EP 2240 A, Evonik Industries AG) containing 60 wt% BADGE as the resin component.

[0155] To produce the test specimens, round, disc-shaped molds with the aforementioned components of the respective casting compounds were cast with a diameter of 4" inch (101.6 mm) and a height of approximately 30 mm and fully cured in an oven.

[0156] Testing equipment used and standards applied: Bending test according to DIN EN ISO 178 using the Z050 universal testing machine from ZwickRoell GmbH & Co. KG; Charpy impact strength test: HIT 5.5 P from ZwickRoell GmbH & Co. KG and differential scanning calorimetry (DSC) to determine the glass softening temperature Tg using PerkinElmer Diamond DSC (PED-DSC). Differential scanning calorimetry (DSC) to determine the glass softening temperature was performed as follows, supplementing the methods of the DIN EN ISO 11357 series of standards, which can be further expanded upon:

[0157] Filled (according to the invention) and unfilled sample material (each cured) were produced from the disc-shaped molds by grinding the sample material for DSC as a fine powder using a cross-toothed carbide burr Z7 from Hoffmann GmbH. The aforementioned PED-DSC consists of two ovens. An empty reference pan is placed in one oven, while the other (sample) oven is loaded with a crucible and compressed sample material. The sample material was weighed using a Mettler-Toledo balance. Test conditions:

[0158] • Measuring temperature 200°C, with an initial temperature of 50°C

[0159] • Sample weight: 20 mg + / - 0.01 mg of sample material (

[0160] • Heating rate: 20°C / min under a nitrogen atmosphere (purge gas) in cycles and holding times; Cooling rate: 20°C / min under a nitrogen atmosphere (purge gas)

[0161] • Three heating cycles (1-3): 50°C to 200°C, back to 50°C; holding time 1 min at 200°C; cycle 4: 50°C to 200°C (end).

[0162] Figures 1 to 3 show all test results, with the upper graphs, labeled "I", showing a first aging process in an inert oven atmosphere at 85°C and a gas humidity of 85%. The lower graphs, labeled "II", show a second aging process in an inert oven atmosphere at 100°C and a gas humidity of less than 2%.

[0163] The measurement results for the different test types are shown as graphs in the figures: It shows:

[0164] Figure 1 shows the measurement results of the three-point bending test, with the left graph showing the maximum force in MPa (y-axis) until the respective specimen fractured for different aging times (x-axis) of the sample material. Furthermore, Figure 1 shows the percentage strain (y-axis) until the maximum force or fracture of the specimen was reached for different aging times (x-axis) of the sample material Z-body in the right graph.

[0165] Figure 2 shows the measurement results of the Charpy impact test, where the y-axis represents the applied mechanical impact energy per unit area at fracture in kJ / m², for different aging times (x-axis) of the sample material Z-body. Figure 3 shows the measurement results of the differential scanning calorimeter (DSC), where the y-axis represents the glass softening temperature (Tg) in °C, for different aging times (x-axis) of the sample material.

[0166] During the three-point bending test runs, as shown in Figure 1, the bending strain was calculated according to DIN EN ISO 178, section 9.2.

[0167] It was found that significant improvements were achieved in all three material properties. The Fmax of the filled sample material increased by approximately 12 MPa (85 / 85, see Graph I) compared to the unfilled sample material, with a further increase observed after aging (see Graph II, 100 / 2). Similarly, the percentage strain after an aging time of 200 h was observed to be approximately 1.2%, with a significantly higher increase observed after aging (see Graph II, 100 / 2), and in particular, a considerably reduced effect over long aging times. For alternating stresses in the potting compound, as is the case in OBIGGS applications, the increase in percentage strain is a particularly significant improvement because material strains can be better compensated.

[0168] The quality improvement of the casting material is particularly noticeable in the Charpy impact test, where a doubling of the tolerated energy per area until fracture was observed, compared to the unfilled sample material.

[0169] No improvement in material properties, but rather a slight decrease, was observed with regard to the glass softening temperature, as shown in Figure 3. Without aging, the initial Tg value of the filled sample material was reduced by approximately 8 °C, although it almost reached parity with the unfilled sample material after long aging times. Considering the primary application of OBIGGS, this change in material properties is not a disadvantage. Without being limited to a specific theory or interpretation, it is assumed that this reduction in the Tg value is accompanied by a certain increase in the material's flexibility due to the core-shell rubber particles, which is associated with the increased elongation, as shown in Figure 1 (Graph II).

[0170] Example 2:

[0171] As a further sample material, a sample material containing an amine adhesion promoter with the following composition according to the invention was tested:

[0172] Resin component A, LH 5000 (BADGE) 70.6 wt.%

[0173] Hardener B, here H418H 16.9% by weight

[0174] Bonding agent HV, here Dynasylan® AMMO 1 wt.%

[0175] Inert filler e, supplied as a suspension in BADGE 8.2 wt%

[0176] Elastomer D (core-shell rubber) is added as a dispersion in BADGE at a wt% concentration. The sample materials according to Example 2 were produced and examined under the same sample conditions and measurement procedures mentioned above, such as the preparation of the test specimen, the test fixtures used, the procedure, and other conditions.

Claims

Claims 1. Filter cartridge having an elongated extension along a longitudinal axis (L), comprising a fiber group of individual fibers as a gas separation membrane, wherein the fiber group has a potting section at each end in which the fiber ends are embedded in a flow-open manner, wherein the potting section is formed from a potting mixture comprising at least the following components - a resin component A, in particular an epoxy resin, - a hardener B, characterized in that the potting compound comprises as a further component at least an inert filler e, which has a mean particle diameter of less than 100 nm and a weight fraction of 10 to 30 wt.%, ideally 15 to 25 wt.%.

2. Filter cartridge according to claim 1, characterized in that the filler e has a particle size in the range of 50 nm to 5 nm, preferably 40 nm to 10 nm, ideally 30 nm to 15 nm.

3. Filter cartridge according to claim 1 or 2, characterized in that the sedimentation rate of the filler C or of the various individual components of the filler C during processing under centrifugal force is less than 10 mm / h, preferably less than 1 mm / h, particularly preferably less than 0.1 mm / h.

4. Filter cartridge according to one of the preceding claims, characterized in that the filler C is silicon dioxide (SiO2), aluminum dioxide (Al2O3) or a mixture thereof.

5. Filter cartridge according to one of the preceding claims, characterized in that the hardener B is taken from the group consisting of the following substances: a) amines, such as in particular aliphatic and / or aromatic amines; b) anhydride, such as in particular monoanhydrides and / or bisanhydride; or c) imidazoles, such as in particular 2-methylimidazole (2MI), 2-ethyl4(5)-methylimidazole (2E4MI), 1-methylimidazole (1Ml), 2-ethylimidazole (2EI), 2-phenylimidazole (2Phl), 1-(2-cyanoethyl)-2-ethyl-4(5)-methylimidazole (2E4MCNI).

6. Filter cartridge according to claim 5, characterized in that the mixture of aliphatic and aromatic amines comprises a proportion of aromatic amines above 70 mol%, ideally above 80 mol%, based on the amine groups.

7. Filter cartridge according to claim 5 or 6, characterized in that the hardener B comprises monoanhydride and / or bisanhydride, wherein a further component is an accelerator, which is in particular a substance from one of the following groups: i) Imidazole, such as 2-methylimidazole (2MI), 2-ethyl4(5)-methylimidazole (2E4MI), 1-methylimidazole (1Ml), 2-ethylimidazole (2EI), 2-phenylimidazole (2Phl), 1-(2-cyanoethyl)-2-ethyl-4(5)-methylimidazole (2E4MCNI) or a mixture thereof; ii) Tertiary amine, such as (dimethylaminomethyl)phenol, diazabicycloundecene, triethylamine or a mixture thereof; iii) Polyamines, such as - 1,3-Propanediamines, N,N-dimethyl-, reaction products with 5-Amino-1,3,3-Trimethylcyclohexanemethanamine-5-isocyanato-1-(isocyanatomethyl)-1,3,3-Trimethylcyclohexane-N-(2-Methylphenyl)-N-(2-Oxiranylmethyl)-2-Oxiranylmethanamine polymers and benzenemethanamines (CAS No. 912342-92-8); iv) or a mixture of ii) and iii).

8. Filter cartridge according to claim 7, characterized in that the weight ratio of hardener B to accelerator is 0.1 wt.% to 5 wt.%, preferably 0.1 wt.% to 4 wt.%, ideally 0.1 wt.% to 3 wt.%, and wherein the weight ratio of hardener B to accelerator is defined as the weight of the accelerator to the total weight of hardener B and accelerator.

9. Filter cartridge according to one of the preceding claims, characterized in that the resin component A comprises or is formed from one of the following substances: - 4,4'-methylenediphenyl diglycidyl ether (BADGE, CAS No. 1675-54-3 (A1)); - Bis(4-hydroxyphenyl)methane diglycidyl ether (BFDGE, CAS No. 2095-03-6 (A2)); - p-(2,3-epoxypropoxy)-N,N-bis(2,3-epoxypropyl)aniline (triglycidyl-p-aminophenol, TGPAP, CAS No. 5026-74-4, (A3)); - Tris(4-hydroxyphenyl)methane triglycidyl ether (TGTPM, CAS No. 66072-38-6, (A4)); - 4,4'-Methylene-bis(N,N-diglycidylaniline) (TGDDM, CAS No. 28768-32-3, (A5)); and - Reaction products or oligomers thereof.

10. Filter cartridge according to one of the preceding claims, characterized in that the resin component A is an epoxy resin mixture comprising at least two of the following resin components: resin component A1, resin component A2, resin component A3, resin component A4 or resin component A5.

11. Filter cartridge according to claim 9, characterized in that the resin components A are formed as a mixture of at least two resin components A1 and A2, wherein: - Resin components A1 (BADGE) represent 0.5 to 50 wt.% and - Resin component A2 (BFDGE) represents 5 to 50 wt.%, or resin component A2 represents the remaining proportion.

12. Filter cartridge according to claim 9, characterized in that the resin components A are formed as a mixture of at least three resin components A1, A2 and A3, wherein: - Resin components A1 (BADGE) represent 0.5 to 10 wt.% and - Resin components A2 (BFDGE) represent 5 to 50 wt.% and - Resin component A3 represents the remaining portion.

13. Filter cartridge according to one of the preceding claims, characterized in that, in the ratio of resin component A to hardener B, hardener B is a) an amine or an anhydride, wherein resin component A is in the range of 65 to 85 wt.%, preferably 70 to 80 wt.%, in particular 75 to 78 wt.%, and hardener B is in the range of 15 to 35 wt.%, preferably 20 to 30 wt.%, in particular 20 to 25 wt.%, or b) an imidazole, wherein hardener is in the range of 0.1 to 10 wt.%, preferably 0.1 to 5 wt.%, ideally 0.1 to 2 wt.%, wherein resin component A constitutes the remaining weight fraction.

14. Filter cartridge according to one of the preceding claims, characterized in that the potting compound comprises as a further component at least an elastomer D in a weight fraction of less than or equal to 10 wt.% with a mean (particle) diameter of less than 30 pm.

15. Filter cartridge according to claim 14, characterized in that the min, an elastomer D has a mean (particle) diameter of 4 to 15 pm, in particular 5 to 10 pm, preferably 6 to 8 pm.

16. Filter cartridge according to one of claims 14 or 15, characterized in that the sedimentation rate of the elastomer D or of the various individual components of the elastomer D during processing under centrifugal force is less than 10 mm / h, preferably less than 1 mm / h, particularly preferably less than 0.1 mm / h.

17. Filter cartridge according to one of claims 14 to 16, characterized in that the min, an elastomer D comprises in a proportion of 1.0 to 8.5 wt.%, in particular 2.0 to 7.0 wt.%, preferably 3 to 6.0 wt.%.

18. Filter cartridge according to one of claims 14 to 17, characterized in that the min, an elastomer D is taken from the group of the following substances or a mixture thereof: core-shell rubber particles, surface-functionalized silicone, silicone rubber, in particular a silicone rubber as an addition-curing elastomer, silane-modified polyurethane prepolymer, trimethoxyvinylsilane.

19. Filter cartridge according to one of the preceding claims, characterized in that the fiber bundle is at least one-ended, in particular both-ended, surrounded or encircled by at least a potting ring, and wherein the at least a potting ring is partially pushed onto, attached to or in the cartridge tube.

20. Filter cartridge according to claim 19, characterized in that the potting ring consists of a polymer material or plastic as a basic or main component, such as e.g. Polysulfones, such as polyphenylsulfone (PPSU), polyethersulfone (PESU) polysulfone (PSU); Polyetherimide (PEI); Polyaryl ether ketones, such as polyether ether ketone (PEEK), polyether ketone (PEK). Polyetherketoneketone (PEKK) or polyetheretherketoneketone (PEEKK).

21. Filter cartridge according to claim 19 or 20, characterized in that the potting ring is fiber-reinforced or glass fiber-reinforced, wherein the proportion of glass fiber in the base material of the potting ring is 10 to 30 wt.%, ideally 15 to 25 wt.%.

22. Filter cartridge according to claim 21, characterized in that the fiber content in the potting ring and the resin mixture are selected such that the coefficient of thermal expansion or CTE of the potting ring and the potting therein differs after curing by less than 20 ppm / K, preferably by less than 10 ppm / K, particularly preferably by less than 5 ppm / K.

23. Filter cartridge according to one of the preceding claims, characterized in that the potting compound comprises as a further component at least an adhesion promoter HV, taken from the group: 3-aminopropyltriethoxysilane (CAS No. 919-30-2); (bis(3-triethoxysilylpropyl)amine) (CAS No. 13497-18-2); bis(3-trimethoxysilylpropyl)amine (CAS No. 82985-35-1); 3-aminopropylmethyldiethoxysilane (CAS No. 70240-34-5); 3-aminopropyltrimethoxysilane (CAS No. 13822-56-5); proprietary aminosilane composition (mixture); proprietary aminosilane composition (mixture); triamino-functional propyltrimethoxysilane (CAS No. 35141-30-1); N-(n-butyl)-3-amino-propyltrimethoxysilane (CAS No. 31024-56-3); functional oligosiloxane (CAS No. 13822-56-5); phenyltrimethoxysilane (CAS No. 2996-92-1); phenyltriethoxysilane (CAS No. 780-69-8); 2-aminoethyl-3-aminopropylmethyldimethoxysilane (CAS No. 3069-29-2); 2-aminoethyl-3-amino-propyltrimethoxysilane (CAS No. 1760-24-3); or 24. Filter cartridge according to claim 23, characterized in that the potting compound comprises the hardener B as a mixture which contains at least one adhesion promoter (HV) according to claim 24.

25. Filter module for gas separation, comprising a filter cartridge, at least one feed connection for a raw gas and at least two outlet connections, wherein at least one outlet connection for the retentate and at least one further outlet connection for a permeate is provided, characterized in that the filter cartridge is configured according to one of claims 1 to 19.

26. Filter module according to claim 25, characterized in that the filter cartridge - is arranged in an external pressure vessel, wherein at least one discharge port for the permeate is arranged on the pressure vessel or - the filter cartridge itself constitutes a pressure vessel and is dimensioned as a pressure vessel, whereby no enclosing, outer pressure vessel is provided and at least one drainage connection for the permeate is arranged on the filter cartridge designed as a pressure vessel.

27. Manufacturing process for a filter cartridge made from a group of hollow fibers (fiber group) suitable as a membrane for gas separation, comprising the Steps: - (Grouping step) Providing and / or grouping a number of individual fibers into a fiber bundle, - (Connection step) Inserting the fiber bundle into a cartridge tube, - (Fixing step) Securing the cartridge tube in a holding device, - (Filling step) Storage / preparation of a defined quantity of the liquid potting compound for the potting step, - (Pouring step) Supply of a potting mixture to at least one end of the fiber bundle, characterized in that the potting compound comprises at least the following components - a resin component A, in particular an epoxy resin, - a hardener B, wherein the potting compound comprises as a further component at least an inert filler e having a mean particle diameter of less than 100 nm.

28. Manufacturing process according to claim 27, characterized in that the following steps are provided: - (Strapping step) Strapping of the fiber bundle at least at one end, especially at both ends, with at least one potting ring, - (Connection step) Inserting the (strapped) fiber bundle into a cartridge tube, whereby the strapping step and the connection step can be carried out at least temporarily in parallel and / or in reverse order.

29. Manufacturing method according to one of claims 27 or 28, characterized in that the filter cartridge is designed according to one of claims 1 to 25.

30. Gas separation method comprising a filter module with a filter cartridge, characterized by a filter cartridge formed according to any one of claims 1 to 25.

31. Gas separation method according to claim 30, characterized in that it is carried out on an aircraft comprising at least one fuel tank, wherein air is supplied to the filter module as feed and the N2-rich gas is directed at least partially into the at least one fuel tank.

Images