Membrane with enhanced potting material

Abstract

In some embodiments, a filter membrane module includes at least one ceramic filter element made of a sintered, porous, ceramic structure, a potting material for potting the ceramic filter element, the potting material having an uncured state and a cured state, and a housing, wherein the potting material is a thermoplastic or a thermosetting plastic that in the cured state has a tensile strength in the range of about 2-65 MPa and a thermal expansion coefficient in the range of about 55-260×10−6/K, and a penetration depth of the potting material into the structure of the filter element is in the range of 0.24 mm to 3.0 mm, and a shrinkage after curing is less than 1.24%.

Claims

1. A filter membrane module, comprising: at least one ceramic filter element made of a sintered, porous, ceramic structure; a potting material for potting the ceramic filter element, the potting material having an uncured state and a cured state; and a housing; wherein the potting material is a thermoplastic or a thermosetting plastic that in the cured state has a tensile strength in the range of about 2-65 MPa and a thermal expansion coefficient in the range of about 55-260×10.sup.−6/K, and a penetration depth of the potting material into the structure of the filter element is in the range of 0.24 mm to 3.0 mm, and a shrinkage after curing is less than 1.24%.

2. The filter membrane module of claim 1, wherein the potting material is an epoxide or polyurethane.

3. The filter membrane module of claim 1, wherein the potting material in the uncured state has a viscosity that is in a range of about 400-4500 mPa.Math.s.

4. The filter membrane module of claim 1, wherein the potting material in the cured state has a Shore hardness in the range of about D10-D86.

5. The filter membrane module of claim 1, wherein the potting material in the cured state has a Young's modulus in the range of about 20-4000 MPa.

6. The filter membrane module of claim 1, wherein the potting material in the cured state has a glass transition temperature in the range of less than about 0° C. or greater than about 25° C.

7. The filter membrane module of claim 1, wherein the potting material has a pot life in the range of about 7-180 min.

8. The filter membrane module of claim 1, wherein the potting material in the cured state has an elongation in the range of about 1-10 or about 70-100.

9. The filter membrane module of claim 1, wherein the potting material in the cured state has a cohesive fracture behavior with respect to itself and other bonded materials.

10. The filter membrane module of claim 1, wherein after immersion of the potting material in the cured state in a fluid at a temperature of 55° C. for 18.5 days a change in mass is 5±2% or less, and/or a change in Shore hardness is ±22% or less, and/or a change in dimensions is ±7.0% or less, and/or a change in Young's modulus is ±18% or less, and/or a change in tensile strength is ±15% or less.

11. The filter membrane module of claim 1, wherein the potting material comprises polyisocyanate and at least one diol and/or at least one polyol.

12. A ceramic filter element, comprising: at least two oppositely arranged end surfaces having filtration channels, and a surface covered with a potting material, wherein the potting material is an epoxy or polyurethane comprising a thermoplastic plastic or a thermosetting plastic, has a depth of penetration into the filter element in the range of 0.24 mm to 3.0 mm, a shrinkage after curing of less than 1.24% and when cured a tensile strength in the range of about 2-65 MPa and a thermal expansion coefficient in the range of about 55-260×10.sup.−6/K.

13. The ceramic filter element of claim 12, wherein at least one end face is sealed tightly against fluid and/or gas by the potting material.

14. The ceramic filter element of claim 12, comprising a plurality of ceramic filter elements mechanically connected by the potting material.

15. The ceramic filter element of claim 12, wherein the ceramic filter element has a segmental shape, monolithic shape, tubular shape, hollow fiber shape, or plate shape.

16. A method of forming a filter membrane module, the filter membrane module comprising at least one ceramic filter element made of a sintered, porous, ceramic structure, a potting material for potting the ceramic filter element, the potting material having an uncured state and a cured state; and a housing, wherein the potting material is a thermoplastic or a thermosetting plastic that in the cured state has a tensile strength in the range of about 2-65 MPa and a thermal expansion coefficient in the range of about 55-260×10.sup.−6/K, and a penetration depth of the potting material into the structure of the filter element is in the range of 0.24 mm to 3.0 mm, and a shrinkage after curing is less than 1.24%, the method comprising: filling a vessel with a mixture including an epoxy or polyurethane comprising a thermoplastic plastic or a thermosetting plastic; mechanically agitating the mixture for at least 5 minutes at 22° C.; degassing the mixture at 60 mbar for about 8-10 minutes; curing the mixture at 60° C. for 8 hours; curing the mixture for 24 hours at room temperature.

17. The method of claim 16, further comprising transferring the degassed mixture to a clean mixing vessel.

18. The method of claim 16, wherein the mixture comprises diphenylmethane-4,4′-diisocyanate and polyether polyol.

19. The method of claim 16, wherein the mixture comprises methylenediphenyl diisocyanate, an aromatic isocyanate prepolymer, and polypropylene glycol.

20. The method of claim 16, wherein the mixture comprises a mixture selected from the group consisting of: a) diphenylmethane-2,4′-diisocyanate, diphenylmethan-4,4′-diisocyanate, diphenylmethane diisocyanate, and polyether polyol; b) diphenylmethane-2,4′-diisocyanate, diphenylmethane-4,4′-diisocyanate, diphenylmethane diisocyanate, triethyl phosphate and diphenyl tolyl; c) 1,1′ -methylene-diphenyl-diisocyanate, 1,1′ -methylenebis(4-isocyanatobenzene) homopolymer and vegetable oil; and d) a combination of Bisphenol A-epichlorohydrin resin and butane.

Description

DESCRIPTION OF DRAWINGS

[0045] FIG. 1 is a longitudinal section through a filter membrane module with a housing.

[0046] FIG. 2 is an enlarged longitudinal section through a portion of the filter elements of FIG. 1.

[0047] FIG. 3 is a cross section through an upper portion of the filter membrane module of FIG. 1 along line

[0048] Like reference symbols in the various drawings indicate like elements.

DETAILED DESCRIPTION

[0049] A ceramic filter element has at least two oppositely disposed end faces. Filtration channels are present within the filter elements, extending in their longitudinal direction and opening into the end surfaces. A portion of the surface of the filter elements is covered with a potting material. Such a ceramic filter element has an optimum potting material on at least one surface.

[0050] At least one end surface is sealed in a fluid-tight and gas-tight manner by the potting material. In normal operation, this arrangement ensures that contaminated fluid does not enter the filter element through the end surfaces (following a flow path through the filter element from inside to outside). The contaminated fluid thus passes through the filter membrane present on the inner walls of the filtration channels only. In quality tests, such a fluid-tight and gas-tight seal ensures that, for example, air which is pressed into the filtration channels does not exit through the end faces but passes through the open-pored material of the filter element to the outside thereof.

[0051] Furthermore, each ceramic filter element belongs to a composite of several ceramic filter elements that are mechanically connected by the potting material. Curing the potting results in a long-lasting and stable mechanical composite of the filter elements.

[0052] The ceramic filter elements can have a segmental shape, monolithic shape, tubular shape, hollow fiber shape, or plate shape. Other shapes are also possible.

[0053] A filter membrane module 10 is shown in FIG. 1. The filter membrane module 10 comprises a tubular housing 12 with a circular cross section. Other cross sections are possible, for example rectangular, square, or polygonal cross sections. At the two axial ends of the housing 12 are disc-shaped covers 14 that are secured to be fluid-tight. The right-hand cover 14 comprises an inlet connection 16 for a fluid to be filtered, the left-hand cover 14 comprises an outlet connection 18 for an unfiltered fluid. The housing 12 has an outlet nozzle 20 for the filtered fluid (filtrate or permeate). The housing 12 and the covers 14 may be made of metal or of a plastic; for example, a fiber composite plastic.

[0054] A monolith 22 is within the housing 12. Shown in FIG. 1 are six flat filter elements 24, that is are elongate, vertically relatively wide in a direction perpendicular to the drawing plane and narrow in a direction up and down. Other cross sections of filter elements 24 are possible. The filter elements 24 are made of a sintered, porous ceramic material. The top three of these filter elements 24 are shown in plan view in FIG. 3. It can be seen that the outer shape of the filter elements 24 conform to the circular cross section contour of the housing 12, so that the inner volume of the housing 12 is optimally utilized. Overall, the filter elements 24 each have a trapezoidal cross-section.

[0055] As is also apparent from FIG. 3, a plurality of filtration channels 26 extend through the filter elements 24. In. FIG. 1, these filtration channels 26 extend from a front end face 27 of a filter elements 24 to the rear front end face 29 of the filter elements 24. For clarity, in FIG. 1 the reference numerals for the end-side end faces 27, 29 are shown for one filter element 24 only. The inner walls of the filtration channels 26 are coated with a ceramic filter membrane, not shown in the drawing.

[0056] The monolith 22 includes a potting body 28 at its respective end faces. The potting body is made from a liquid potting material that is cured. The filter elements 24 are mechanically fixed relative to each other by the cured potting material. The potting material generates a fluid-tight seal of inner fluid spaces 30 between the filter elements and of the outer fluid chambers 32 between the covers 14 and the potting body 28. To ensure a fluid-tight seal additional elements can be used, such as seals or the like.

[0057] To produce the potting body 28, the filter elements 24 are arranged in the desired manner; for example by an auxiliary device which is removed after the production of the potting body 28. The filter elements 24 are arranged so that their longitudinal direction extends in the axial direction. One end of the composite filter element 24 is placed in a cup-like mold of silicone material. The cup-like mold is then filled with a curable liquid, wrapping around the end portions of the filter elements 24 and completely wetting their outer surfaces. The curable liquid material is a material that hardens, or cures, over a certain time. After curing, the composite of filter elements 24 together with the cured material now forms the potting body 28, and is removed from the mold.

[0058] The curable material serves for production of the potting body 28, and for the end surface seal 34. FIG. 2 shows a section through an end region of a single filter element 24. The filtration channels 26 provide a right end portion of the corresponding right-hand front end face 27. The curable material is applied to the end face 27, for example, by rolling, brushing or spraying. After curing, the end surface seal 34 forms. As a result, it is prevented during operation that fluid to be filtered passes directly via the end-side end face 27 into the filter element 24 and from there to its outside, without having flowed through the filter membrane present on the inner wall of the filtration channels 26.

[0059] During operation, fluid to be filtered is introduced through the right inlet port 16 into the right outer fluid chamber 32. From there it flows through the filtration channels 26. Non-filtering material is not transmitted through the walls of the filtration channels 26 filter membrane but deposited there. The filtrate flows through the filter membrane and through the open-pored ceramic material of the filter elements 24 to collect in the inner fluid space 30 and flow through the outlet port 20. The unfiltered fluid may flow out through the outlet port 18 and be returned to the inlet port 16.

[0060] The potting material used for the production of the potting body 28 or for the end surface seal 34 is a plastic material and can be a thermoplastic or a duroplastic, e.g., an epoxide or polyurethane. The depth of penetration of the potting material into the structure of the filter elements 24 is in the range of about 0.24 mm to about 3.0 mm, with shrinkage after curing of less than about 1.24%. In the cured state, it has a tensile strength in the range of approximately 2-65 MPa and a thermal expansion coefficient in the range of about 55-260×10.sup.−6/K. Its Shore hardness can be in the range of about D10-D86, and Young's modulus in the range of about 50-4000 MPa. The glass transition temperature can be in the range of approximately less than 0° C. or greater than 25° C. Further, the potting material can have a pot life in the range of about 7-180 min, and an elongation in the range of about 1-10 or about 70-100. The hardened potting body 28 or the cured end surface seal 34 have a cohesive fracture behavior with respect to the tensile shear properties both with respect to itself and to other bonded or bonded materials.

[0061] Generally speaking, all equipment used for the production of liquid potting material should be intact, clean and dry. Oil, grease and other contaminants that affect adhesion should be removed. Oil-contaminated surfaces (e.g., silicone gaskets) that have absorbed oil should be suitably cleaned with an emulsifying detergent. Excess water should be removed from the equipment used. The starting material is used at suitable temperatures and should be placed in the processing area one to two days prior to use and stored there to allow for their adaptation to ambient conditions. At the time of dosing, the temperature of the starting material should not exceed 50° C. The reaction and processing times depend on the ambient temperature and the outlet temperature of the raw material from, and also on the relative humidity. At low temperatures, chemical reaction times are prolonged, extending pot life and processing time. Contact between starting material and water should be avoided until complete curing, as this may cause decarboxylation or tackiness on the surface, which in each case will cause the potting material to lose its properties.

[0062] The components should be thoroughly homogenized and all material scraped off the walls and bottom of the mixing container used. Mechanical or motorized mixing rather than manual mixing is possible, but should be at a low material access speed (e.g. 3 g/s at 25° C.), so that as little air as possible is introduced into the batch.

[0063] To obtain an even better chemical resistance of the potting material, the change in mass of a cured test sample of a polyurethane resin composition in a fluid (e.g. water, sodium hydroxide, sulfuric acid, glycerol or hypochlorite) at a temperature of 55° C. for 18.5 days should be ±2.5% or less. It is even better if the mass change for a test sample is ±2.0% or less. A higher change of mass due to a chemical stress can be an indication that the cured polyurethane casting material dissolves when it comes in contact with a fluid to be filtered, or may be an indication that the cured polyurethane casting material in operation absorbs a significant amount of water and thereby swells.

[0064] Also with respect to the chemical resistance, the change in Shore hardness of a test sample of a cured polyurethane composition after immersion in a liquid at a temperature of 55° C. for 18.5 days and after a subsequent drying of the test sample should be ±22% or less. Here and below (in the case of the further parameters mentioned below), the measurement of the respective change in value (Δ) takes place before the removal, directly after the removal in the non-dried state and after drying. With mean values from 10 samples being used, the Δ value is determined as follows:

[0065] Measured value (current)=XA, XB or XC

[0066] Mean value from measurement before removal=A

[0067] Mean value from measurement after aging and before drying=B

[0068] Mean value from measurement after aging and after drying=C

Mean value A=(XA.sub.1+XA.sub.2+XA.sub.3 . . . +XA.sub.n)/n

[0069] Calculation of the mean value for B and C analogous to A.

[0070] The relative changes (d) for each individual measured value are then determined from the current measured values and the calculated average values.

dA=(XA−A)/A

[0071] From the relative changes of each individual measurement, the mean of the relative change is calculated.

[00003]$\stackrel{\_}{\mathrm{dA}}=\frac{\underset{i=l}{\overset{i=n}{.Math.}}\left({\mathrm{XA}}_i-A\right)/A}{n}$

[0072] Calculation of the relative changes (d) for each individual measurement for B and C analogous to dA.

[0073] Calculation of the mean value of the relative change d for B and C analogous to dA

[0074] From the relative results, the absolute changes can now be calculated.

D1=dB−dA

D2=dC−dA

[0075] Δ mass, Δ Shore hardness, Δ length, Δ height:

[0076] Δ value=maximum value (D1, D2)

[0077] Δ Young's modulus, Δ tensile strength:

[0078] Δ value=maximum value D2

[0079] Ideally, the value before aging without drying corresponds to the value after aging with drying. Since a ceramic filter element in which the casting material is used, and thus the casting material itself is always operated in the liquid medium, this difference value is of interest.

[0080] A larger change of the Shore hardness due to chemical stress may be an indication that in operation when the polyurethane potting material comes into contact with fluid, the change in material properties results in certain required product specifications (for example, a resistance to pressure surges) being no longer complied with.

[0081] Also in view of the chemical resistance, a change in the dimensions (height and length) of a test sample of a cured polyurethane composition, after immersion in a chemical liquid at a temperature of 55° C. for 18.5 days without or with a subsequent drying of the test sample should be ±7.0% or less, e.g., ±2.5% or less. A larger change in dimensions due to chemical stress can cause irreversible damage to the filter membrane module due to elongation or shrinkage of the polyurethane potting materials leading to leaks of the filter membrane module either by damage to the filter elements or by a change in the adhesive properties between the different materials.

[0082] Also in terms of chemical resistance, a change in Young's modulus of a cured test sample of a polyurethane composition after immersion in a chemical fluid at a temperature of 55° C. for 18.5 days and after subsequent drying of the test sample should be ±18% or less. A greater change in Young's modulus due to chemical stress on the test sample can result in a change in material properties that is too high to meet certain product specifications, such as resistance to pressure surges.

[0083] Also in terms of chemical resistance, the change in tensile strength of a cured sample of a polyurethane composition after immersion in a chemical fluid at a temperature of 55° C. for 18.5 days and after subsequent drying of the test sample should be ±15% or less. A greater change in tensile strength due to chemical stress can result in a change in material properties in operation that is too high to meet certain product specifications, such as resistance to pressure surges.

EXAMPLE 1

[0084] A container with a stirrer and a thermometer was charged with 39.7 parts by weight of diphenylmethane-4,4′-diisocyanate and 100.3 parts by weight of polyether polyol. The reaction was carried out at 22° C. The two components were fully homogenized, and the agitator was operated for at least 5 minutes. The mixture was then degassed at 60 mbar for about 8-10 minutes. The mixed and degassed components were transferred to a clean mixing container. There, the reaction was carried out for about 3-5 minutes with vigorous stirring to give a polyurethane resin solution. This was poured into coated molds. It was then cured at 60° C. for 8 hours. After cooling to room temperature, the polyurethane test samples were removed from the mold and then cured at room temperature for 24 hours. The test samples obtained in this way had the following properties (TCE=thermal expansion coefficient, Tg=glass transition temperature, and the Δ values describe the change in the respective property after immersion in a fluid (namely the test fluid described above with possibly different pH values) at a temperature of 55° C. for 18.5 days):

[0085] Density: 1.18 g/cm.sup.3

[0086] Pot life (200 g): approx. 50 minutes

[0087] Viscosity: 400-600 mPa.Math.s

[0088] Shore hardness: D60

[0089] TCE: 117 ppm/K at T<30° C.

[0090] 205 ppm/K at T>40° C.

[0091] Tensile strength: 6 MPa

[0092] Tg: 31° C.

[0093] Young's modulus: 890 MPa

[0094] Δ mass: +1.6%

[0095] Δ Shore hardness D: +3.3%

[0096] Δ length: +0.6%

[0097] Δ height: +2.2%

[0098] Δ Young's modulus: −12%

[0099] Δ tensile strength: +2.6%.

[0100] Here, as below, the pot life is large. This is due to the fact that any two-component curing takes place through an exothermic reaction that releases energy in the form of heat. The curing itself is temperature dependent. Thus, the larger the amount used, the more heat is released and the faster the two components cure. Conversely, the smaller the amount used, the longer the curing process takes.

EXAMPLE 2

[0101] A vessel with a stirrer and a thermometer was charged with 50.5 parts by weight of a mixed combination of methylenediphenyl diisocyanate (concentration between 50-75%) and an aromatic isocyanate prepolymer (concentration between 25-50%) and 99.5 parts by weight of polypropylene glycol. The reaction was carried out at 22° C. The two components were fully homogenized by operating the agitator for at least 5 minutes. The mixture was then degassed at 60 mbar for about 8-10 minutes. The components thus premixed and degassed were transferred in their entirety to a clean mixing vessel. There, the reaction was carried out for about 3-5 minutes with vigorous stirring to give a polyurethane resin solution. This was poured into coated molds to make test samples. It was then cured at 60° C. for 8 hours. After cooling to room temperature, the polyurethane test samples were removed from the mold. This was post cured for an additional 24 hours at room temperature. The test samples thus obtained had the following characteristics (TCE=the thermal expansion coefficient; Tg=glass transition temperature; the Δ values describe the change in the respective property after immersion in a fluid (namely the above-described test fluid with possibly different pH values) at a temperature of 55° C. for 18.5 days):

[0102] Density: 1.08 g/cm.sup.3

[0103] Pot life (150 g): about 15 minutes

[0104] Viscosity: 1100-1300 mPa.Math.s

[0105] Shore hardness: D58

[0106] TCE: 85 ppm/K at T<0° C.

[0107] 206 ppm/K at T>50° C.

[0108] Tensile strength: 14 MPa

[0109] Tg: 36° C.

[0110] Young's modulus: 550 MPa

[0111] Δ mass: +1.7%

[0112] Δ Shore hardness D: +5.4%

[0113] Δ length: +0.38%

[0114] Δ height: +0.5%

[0115] Δ Young's modulus: −12%

[0116] Δ tensile strength: −14.3%.

EXAMPLE 3

[0117] A container with a stirrer and a thermometer was charged with 50.5 parts by weight of diphenylmethane-2,4′-diisocyanate (concentration between 5-10%), diphenylmethan-4,4′-diisocyanate (concentration between 10-25%), diphenylmethane diisocyanate (concentration between 65-85%) and 100 parts by weight of polyether polyol. The first three components were premixed and added to the hardener as a homogeneous mixture. The reaction was carried out at 22° C. The two components were fully homogenized by operating the agitator for at least 5 minutes. The mixture was then degassed at 60 mbar for about 8-10 minutes. The components thus premixed and degassed were transferred in their entirety to a clean mixing vessel. There, the reaction was carried out for about 3-5 minutes with vigorous stirring to give a polyurethane resin solution. This was poured into coated molds to make test samples. It was then cured at 60° C. for 8 hours. After cooling to room temperature, the polyurethane test samples were removed from the mold and then cured at room temperature for 24 hours. The test samples obtained in this way had the following properties (TCE=the thermal expansion coefficient, Tg=glass transition temperature; the Δ values describe the change in the respective characteristic after immersion in a fluid (namely the above-described test fluid with possibly different pH Values) at a temperature of 55° C. for 18.5 days):

[0118] Density: 1.14 g/cm.sup.3

[0119] Pot life (150 g): approx. 60 minutes

[0120] Viscosity: 400-600 mPa.Math.s

[0121] Shore hardness: D50

[0122] TCE: 116 ppm/K at T<25° C.

[0123] 220 ppm/K at T>40° C.

[0124] Tensile strength: 10 MPa

[0125] Tg: 28° C.

[0126] Young's modulus: 230 MPa

[0127] Δ mass: +2.2%

[0128] Δ Shore hardness D: −12%

[0129] Δ length: +0.5%

[0130] Δ height: +2.4%

[0131] Δ Young's modulus: −18%

[0132] Δ tensile strength: −15%.

EXAMPLE 4

[0133] A container with a stirrer and a thermometer was charged with 16 parts by weight of a mixed combination of diphenylmethane-2,4′-diisocyanate (concentration 25-50%), diphenylmethane-4,4′-diisocyanate (concentration of between 25-50%) and diphenylmethane diisocyanate (isomers and homologues, concentration of between 20-25%) and 100.2 parts by weight of a mixture of triethyl phosphate and diphenyl tolyl phosphate in a polyester/polyether polyol. The reaction was carried out at 22° C. The two components were fully homogenized by operating the agitator for at least 5 minutes. The mixture was then degassed at 60 mbar for about 8-10 minutes. The components thus premixed and degassed were transferred in their entirety to a clean mixing vessel. There, the reaction was carried out for about 3-5 minutes with vigorous stirring to give a polyurethane resin solution. This was poured into coated molds to make test samples. It was then cured at 60° C. for 8 hours. After cooling to room temperature, the test samples were removed from the mold and then cured at room temperature for 24 hours. The test samples obtained in this way had the following properties (TCE=the thermal expansion coefficient, Tg=glass transition temperature; the Δ values describe the change in the respective property after immersion in a fluid (namely the above-described test fluid with possibly different pH Values) at a temperature of 55° C. for 18.5 days):

[0134] Density: 1.52 g/cm.sup.3

[0135] Pot life (250 g): approx. 45 minutes

[0136] Viscosity: 600-900 mPa.Math.s

[0137] Shore hardness: D40

[0138] TCE: 55 ppm/K at T<−20° C.

[0139] M/K at T>−5° C.

[0140] Tensile strength: 7 MPa

[0141] Tg: −4° C.

[0142] Young's modulus: 20 MPa

[0143] Δ mass: −2.1%

[0144] Δ Shore hardness D: −21%

[0145] Δ length: −1.1%

[0146] Δ height: −6.6%

[0147] Δ Young's modulus: −14.3%

[0148] Δ tensile strength: −4.7%.

EXAMPLE 5

[0149] A container with a stirrer and a thermometer was with 54 parts by weight of a mixed combination of 1,1′-methylene-diphenyl-diisocyanate (concentration between 30-60%) and 1,1′-methylenebis(4-isocyanatobenzene) homopolymer (concentration between 10-30%) and 100 parts by weight of a polyol mixture consisting of 5-15% diols and 0.5-1.5% vegetable oil based on fatty acids. The reaction was carried out at 22° C. The two components were fully homogenized by operating the agitator for at least 5 minutes. The mixture was then degassed at 60 mbar for about 8-10 minutes. The components thus premixed and degassed became complete in quantity transferred to a clean mixing container. There, the reaction was carried out for about 3-5 minutes with vigorous stirring to give a polyurethane resin solution. This was poured into coated molds to make test samples. It was then cured for 16 hours at 80° C. After cooling to room temperature, the polyurethane test samples were removed from the mold and then cured at room temperature for 24 hours. The test samples obtained in this way had the following properties (TCE=thermal expansion coefficient, Tg=glass transition temperature, the Δ values describe the change in the respective property after immersion in a fluid (namely the above-described test fluid with possibly different pH values) at a temperature of 55° C. for 18.5 days):

[0150] Density: 1.05 g/cm.sup.3

[0151] Pot life (200 g): approx. 60 minutes

[0152] Viscosity: 2000 mPa.Math.s

[0153] Shore hardness: D10

[0154] TCE: not measurable

[0155] Tensile strength: 6.2 MPa

[0156] Tg: −20° C.

[0157] Young's modulus: 150 MPa

[0158] Δ mass: +0.8%

[0159] Δ Shore hardness D: −14.3%

[0160] Δ length: −0.1%

[0161] Δ height: −2.5%

[0162] Δ Young's modulus: −10%

[0163] Δ tensile strength: +8.5%.

EXAMPLE 6

[0164] A container with a stirrer and a thermometer was charged with 100 parts by weight of a mixed combination of Bisphenol A-epichlorohydrin resin (average molecular weight <700) and 1,4-bis (2,3-epoxypropoxy) butane and 50.2 parts by weight of a mixture of 3-Aminomethyl-3,5,5-trimethylcyclohexylamine (45-50%), alkyl polyamine (35-40%), polyaminoamide adduct (10-15%) and 1,2-diamino-ethane (1-5%) loaded. The reaction was carried out at 22° C. The two components were fully homogenized by operating the agitator for at least 5 minutes. The mixture was then degassed at 60 mbar for about 15 Minutes. The components thus premixed and degassed were transferred in their entirety to a clean mixing vessel. There, the reaction was carried out for about 5 minutes with vigorous stirring to give an epoxy resin solution. This was poured into coated molds to make test samples. It was then cured at 80° C. for 2 hours. After cooling to room temperature, the epoxy test samples were removed from the mold and then cured at room temperature for 24 hours. The test samples thus obtained had the following properties (TCE=the thermal expansion coefficient; g=glass transition temperature; the Δ values describe the change in the respective property after immersion in a fluid (namely the test fluid described above with possibly different pH values) at a temperature of 55° C. for 18.5 days):

[0165] Density: 1.08 g/cm.sup.3

[0166] Pot life (250 g): 120 minutes

[0167] Viscosity: 500-1000 mPa.Math.s

[0168] Shore hardness: D80

[0169] TCE: 90 ppm/K at T<50° C.

[0170] 190 ppm/K at T>60° C.

[0171] Tensile strength: 59 MPa

[0172] Tg: 52° C.

[0173] Young's modulus: 3800 MPa

[0174] Δ mass: +2.5%

[0175] Δ Shore hardness D: −8%

[0176] Δ length: +0.9%

[0177] Δ height: +1.25%

[0178] Δ Young's modulus: −4.3%

[0179] Δ tensile strength: −9.1%.

[0180] A number of embodiments have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the disclosure. Accordingly, other embodiments are within the scope of the following claims. [0181] Following subject matter and aspects of the invention are described: [0182] 1. A filter membrane module, comprising: [0183] at least one ceramic filter element made of a sintered, porous, ceramic structure; [0184] a potting material for potting the ceramic filter element, the potting material having an uncured state and a cured state; and [0185] a housing; [0186] wherein the potting material is a thermoplastic or a thermosetting plastic that in the cured state has a tensile strength in the range of about 2-65 MPa and a thermal expansion coefficient in the range of about 55-260×10.sup.−6/K, and [0187] a penetration depth of the potting material into the structure of the filter element is in the range of 0.24 mm to 3.0 mm, and a shrinkage after curing is less than 1.24%, and/or preferably, wherein the potting material is an epoxide or polyurethane, and/or preferably, wherein the potting material in the uncured state has a viscosity that is in a range of about 400-4500 mPa.Math.s, and/or preferably, wherein the potting material in the cured state has a Shore hardness in the range of about D10-D86,and/or preferably wherein the potting material in the cured state has a Young's modulus in the range of about 20-4000 MPa, and/or preferably, wherein the potting material in the cured state has a glass transition temperature in the range of less than about 0° C. or greater than about 25° C., and/or preferably, wherein the potting material has a pot life in the range of about 7-180 min, and/or preferably, wherein the potting material in the cured state has an elongation in the range of about 1-10 or about 70-100, and/or preferably, wherein the potting material in the cured state has a cohesive fracture behavior with respect to itself and other bonded materials, and/or preferably, wherein after immersion of the potting material in the cured state in a fluid at a temperature of 55° C. for 18.5 days a change in mass is 5±2% or less, and/or a change in Shore hardness is ±22% or less, and/or a change in dimensions is ±7.0% or less, and/or a change in Young's modulus is ±18% or less, and/or a change in tensile strength is ±15% or less, and/or preferably, wherein the potting material comprises polyisocyanate and at least one diol and/or at least one polyol. [0188] 2. A ceramic filter element, comprising: [0189] at least two oppositely arranged end surfaces having filtration channels, and [0190] a surface covered with a potting material, [0191] wherein the potting material is an epoxy or polyurethane comprising a thermoplastic plastic or a thermosetting plastic, has a depth of penetration into the filter element in the range of 0.24 mm to 3.0 mm, a shrinkage after curing of less than 1.24% and when cured a tensile strength in the range of about 2-65 MPa and a thermal expansion coefficient in the range of about 55-260×10.sup.−6/K, and/or preferably, wherein at least one end face is sealed tightly against fluid and/or gas by the potting material, and/or preferably, wherein comprising a plurality of ceramic filter elements mechanically connected by the potting material, and/or preferably, wherein the ceramic filter element has a segmental shape, monolithic shape, tubular shape, hollow fiber shape, or plate shape. [0192] 3. A method of forming a filter membrane module, the filter membrane module comprising at least one ceramic filter element made of a sintered, porous, ceramic structure, a potting material for potting the ceramic filter element, the potting material having an uncured state and a cured state; and a housing, wherein the potting material is a thermoplastic or a thermosetting plastic that in the cured state has a tensile strength in the range of about 2-65 MPa and a thermal expansion coefficient in the range of about 55-260×10.sup.−6/K, and a penetration depth of the potting material into the structure of the filter element is in the range of 0.24 mm to 3.0 mm, and a shrinkage after curing is less than 1.24%, the method comprising: [0193] filling a vessel with a mixture including an epoxy or polyurethane comprising a thermoplastic plastic or a thermosetting plastic; [0194] mechanically agitating the mixture for at least 5 minutes at 22° C.; [0195] degassing the mixture at 60 mbar for about 8-10 minutes; [0196] curing the mixture at 60° C. for 8 hours; [0197] curing the mixture for 24 hours at room temperature, and/or preferably, wherein comprising transferring the degassed mixture to a clean mixing vessel, and/or preferably, wherein comprising mechanically agitating the mixture in the clean mixing vessel for 3-5 minutes, and/or preferably, wherein the mixture comprises diphenylmethane-4,4′-diisocyanate and polyether polyol, and/or preferably, wherein the mixture comprises methylenediphenyl diisocyanate, an aromatic isocyanate prepolymer, and polypropylene glycol, and/or preferably, wherein the mixture comprises diphenylmethane-2,4′-diisocyanate, diphenylmethan-4,4′-diisocyanate, diphenylmethane diisocyanate, and polyether polyol, and/or preferably, wherein the mixture comprises diphenylmethane-2,4′-diisocyanate, diphenylmethane-4,4′-diisocyanate, diphenylmethane diisocyanate, triethyl phosphate and diphenyl tolyl, and/or preferably, wherein the mixture comprises 1,1′-methylene-diphenyl-diisocyanate, 1,1′-methylenebis(4-isocyanatobenzene) homopolymer and vegetable oil, and/or preferably, wherein the mixture comprises a combination of Bisphenol A-epichlorohydrin resin and butane.