COMPOSITE BODY AND USE THEREOF IN ORGANOPHILIC NANOFILTRATION

Abstract

A composite body comprising a porous layer (1) made from oxide particles connected to one another and partially to a substrate, containing at least one oxide of the elements Al, Zr, Ti or Si, and comprising a further porous layer (2) at least on one side, having oxide particles connected to one another and partially to the layer (1) and containing at least one oxide of the elements Al, Zr, Ti or Si, wherein the oxide particles in the layer (1) have a greater average particle size (d.sub.50 is 0.5 to 4 μm) than the oxide particles in the layer (2) (d.sub.50 is 0.015 to 0.15 μm), characterised in that a polymer coating (PB) is provided on or above the layer (2), containing one or more polysiloxanes. A method for producing corresponding composite bodies and to the use thereof.

Claims

1-19. (canceled)

20. Flexible composite body having, on a porous substrate and in the interstices of the substrate that includes fibres of an electrically nonconductive material, a porous layer (1) composed of oxide particles bonded to one another and partly to the substrate that include at least one oxide selected from oxides of the elements Al, Zr and Si, preferably selected from Al.sub.2O.sub.3, ZrO.sub.2 and SiO.sub.2, and having, at least on one side, a further porous layer (2) including oxide particles bonded to one another and partly to layer (1) that include at least one oxide selected from oxides of the elements Al, Zr and Si, preferably selected from Al.sub.2O.sub.3, ZrO.sub.2 and SiO.sub.2, where the oxide particles present in layer (1) have a greater median particle size than the oxide particles present in layer (2), and where the median particle size (d50) of the oxide particles in layer (1), determined as specified in the description, is from 0.5 to 4 μm and the median particle size (d50) of the oxide particles in layer (2), determined as specified in the description, is from 0.015 to 0.15 μm, preferably 0.04 to 0.06 μm, characterized in that a polymer coating (PB) containing one or more polysiloxanes is present atop or above layer (2) and in that the substrate is a nonwoven fabric, knit or laid scrim, preferably a nonwoven fabric or laid scrim, more preferably a nonwoven fabric, wherein “flexible” means that the composite body can be wound without damage around a bar or around a tube having a diameter of down to 15 mm.

21. Composite body according to claim 20, characterized in that the composite body has a toluene flow rate at 130° C. and transmembrane pressure 30 bar (30*10.sup.5 Pa), determined as specified in the description, of greater than 130 L/m.sup.2 h, preferably greater than 250 L/m.sup.2 h, more preferably greater than 300 L/m.sup.2 h and most preferably greater than 400 L/m.sup.2 h.

22. Composite body according to claim 20, characterized in that the composite body has a thickness of 100 to 400 μm, preferably 125 to 200 μm and more preferably of 130 to 170 μm.

23. Composite body according to claim 20, characterized in that the fibres have a dimension of 1 to 200 g/km of fibre and are preferably composed of polyacrylonitrile, polyamide, polyester and/or polyolefin.

24. Composite body according to claim 20, characterized in that the substrate has a thickness of 50 to 150 μm, preferably 100 to 130 μm, and a basis weight of 40 to 150 g/m.sup.2, preferably 50 to 120 g/m.sup.2, preferably 50 to 100 g/m.sup.2 and most preferably 60 g/m.sup.2.

25. Composite body according to claim 20, characterized in that the composite body has an average pore size of 60 to 140, preferably 75 to 130 nm, wherein the average pore size is determined by means of gas flow porometry as described in the description.

26. Composite body according to claim 20, characterized in that the composite body, on the surface of the layer (2), has a surface roughness Sdq, determined as specified in the description, of less than 10 μm, more preferably of less than 8 μm.

27. Process for producing a flexible composite body, preferably according to claim 20, characterized in that it has the following steps: (a) applying a coating composition (BM1) to and into a substrate having fibres and interstices between the fibres, where the coating composition is produced by combining (a1) a dispersion (D1) of oxide particles produced by mixing oxide particles selected from the oxides of the elements Al, Zr and/or Si and having a median particle diameter (d50) of 0.5 to 4 μm with water, an inorganic acid, preferably nitric acid, and a dispersing aid, (a2) a dispersion (D2) of oxide particles produced by mixing oxide particles selected from the oxides of the elements Al, Zr and/or Si and having a median particle diameter (d50) of 15 to 150 nm, preferably 40 to 60 nm, with water, (a3) a binder formulation (BF1), produced by mixing at least two organofunctional silanes with an alkanol, preferably ethanol, an inorganic acid, preferably boric acid, and water, (b) consolidating the coating composition (BM1) at a temperature of 100° C. to 275° C., preferably 120 to 240° C., in order to create a first layer (S1′), (c) optionally applying a coating composition (BM2) to at least layer (S1′), where the coating composition (BM2) is produced by combining (c1) a dispersion (D3) of oxide particles produced by mixing oxide particles selected from the oxides of the elements Al, Zr and/or Si and having a median particle diameter (d50) of 0.5 to 4 μm with water, an inorganic acid, preferably nitric acid, and a dispersing aid, (c2) a dispersion (D4) of oxide particles produced by mixing oxide particles selected from the oxides of the elements Al, Zr and/or Si and having a median particle diameter (d50) of 15 to 150 nm, preferably 40 to 60 nm, with water, (c3) a binder formulation (BF2), produced by mixing at least two organofunctional silanes with an alkanol, preferably ethanol, an inorganic acid, preferably boric acid, and water, (d) optionally consolidating the coating composition (BM2) at a temperature of 100° C. to 275° C., preferably 120 to 240° C., in order to create a second layer (S2′), (e) applying a coating composition (BM3) to layer (Si′) or, if present, layer (S2′), where the coating composition (BM3) has been produced by combining water and an inorganic acid with an (e1) aqueous dispersion (D5) including oxide particles selected from the oxides of the elements Al, Zr and/or Si and having a median particle diameter (d50) of 15 to 150 nm, preferably 40 to 60 nm, and with ethanol and with a (e2) binder formulation (BF3) comprising at least two organofunctional silanes, (f) consolidating the coating composition at a temperature of 100° C. to 275° C., preferably 120 to 240° C., in order to create a layer (S3′), (g) optionally applying a coating composition (BM4) to layer (S3′), where the coating composition (BM4) has been produced by combining water and an inorganic acid with an (g1) aqueous dispersion (D6) including oxide particles selected from the oxides of the elements Al, Zr and/or Si and having a median particle diameter of 15 to 150 nm, preferably 40 to 60 nm, and with ethanol and with a (g2) binder formulation (BF4) comprising at least two organofunctional silanes, (h) optionally consolidating the coating composition at a temperature of 100° C. to 275° C., preferably 120 to 240° C., in order to create a layer (S4′), and (i) applying a polymer coating containing polysiloxanes to layer (S3′) or, if present, to layer (S4′), characterized in that the organofunctional silanes used are 3-glycidyloxytriethoxysilane, methyltriethoxysilane and tetraethoxysilane, and in that the substrate used is a polymer nonwoven including fibres selected from polyacrylonitrile, polyester, polyamide and/or polyolefin, wherein “flexible” means that the composite body can be wound without damage around a bar or around a tube having a diameter of down to 15 mm.

28. Process according to claim 27, characterized in that 3-glycidyloxytriethoxysilane, methyltriethoxysilane and tetraethoxysilane are used in binder formulation (BF1) and (BF2) in a mass ratio of 2 to 4:0.5 to 1.5:1, more preferably of 2.5 to 3.5:0.75 to 1.25:1, most preferably 3:1:1.

29. Process according to claim 27, characterized in that 3-glycidyloxytriethoxysilane, methyltriethoxysilane and tetraethoxysilane are used in binder formulation (BF3) and (BF4) in a mass ratio of 0.5 to 1.5:1.5 to 2.5:1, more preferably of 0.75 to 1.25:1.75 to 2.25:1, most preferably 1:2:1.

30. Process according to claim 27, characterized in that the coating compositions (BM3) and (BM4) are of identical composition.

31. Process according to claim 27, characterized in that the coating compositions (BM1) and (BM2) are of identical composition.

32. Process according to claim 20, characterized in that the consolidating is effected by passage through a hot air oven, an IR oven or another oven.

33. A method comprising using a composite material according to claim 20 in an organophilic nanofiltration process, including as an organophilic nanofiltration membrane for separation of organic compounds from organic solvent-containing streams of matter.

34. A method according to claim 33, characterized in that the separation is performed at temperatures of greater than 100° C., preferably greater than 120° C. and more preferably greater than 150° C.

35. Separation apparatus comprising a composite material according to claim 20.

Description

EXAMPLES

[0094]

TABLE-US-00001 TABLE 1a Raw materials used Any brand name, manufacturer (abbreviations Raw material used in brackets thereafter) Ethanol Demineralized water Dispersant DOLAPIX ® CE 64, Zschimmer & Schwarz GmbH & Co. KG (CE 64) Boric acid Nitric acid (65% strength by (HNO.sub.3) weight) 3- DYNASYLAN ® GLYMO, Evonik Resource Glycidyloxytrimethoxysilane Efficiency GmbH (GLYMO) 3-Glycidyloxytriethoxysilane DYNASYLAN ® GLYEO, Evonik Resource Efficiency GmbH (GLYEO) Methyltriethoxysilane DYNASYLAN ® MTES, Evonik Resource Efficiency GmbH (MTES) Tetraethoxysilane DYNASYLAN ® TEOS, Evonik Resource Efficiency GmbH (TEOS) Aluminium oxide CT1200 SG, Almatis GmbH D50 = (0.9-1.5) μm * Aluminium oxide CT 3000 SG, Almatis GmbH D50 = (0.5-0.8) μm * Silicon dioxide AEROSIL ® Ox 50, Evonik Resource Efficiency GmbH (Ox50) Silicon dioxide AEROSIL ® 90, Evonik Resource Efficiency GmbH Silicon dioxide AEROSIL ® 200, Evonik Resource Efficiency GmbH Titanium dioxide AEROXIDE ® TiO2 P 25, Evonik Resource Efficiency GmbH (P25) Zirconium oxide 50 nm zirconium oxide, Sigma Aldrich Silica sol LEVASIL ® CS40-316P, Obermeier GmbH Aluminium oxide MARTOXID ® MZS-1, Martinswerk GmbH (MZS-1) D50 = (1.5-1.9) μm * Aluminium oxide MARTOXID ® MZS-3, Martinswerk GmbH (MZS-3) D50 = (2.5-5.0) μm * Aluminium oxide AEROXIDE ® Alu C, Evonik Resource Efficiency GmbH (Alu C) Resin mixture Vinyl QM resin mixture VQM 906; Evonik Hanse Chemie GmbH Catalyst Catalyst 511, Evonik Hanse Chemie GmbH Vinyl-functional VS 165 000; Evonik Hanse Chemie GmbH polydimethylsiloxane SiH-containing Crosslinker 120; Evonik Hanse Chemie GmbH polydimethylsiloxane Methyl butynol Aldrich 2-component polymer RTV-615 (A + B), Momentive silicone * D50: Particle size specified by the manufacturer.

TABLE-US-00002 TABLE 1b Substrate materials used: Basis Substrate Design Material weight Supplier 1 05-TH-60W PET 60 g/sqm Sojitz, Düsseldorf nonwoven fabric 2 Nonwoven Carbon 15 g/sqm Technical Fiber fabric Products, Burnside Mills 3 Weave E glass 60 g/sqm P&G 4 Monofilament PET 40 g/sqm SEFAR weave

Example 1: Production of a Composite Material According to the Invention

Example 1a: Production of Binder Formulation I

[0095] A 250 ml beaker was initially charged with 14.22 g of ethanol together with 2.84 g of boric acid, and they were stirred with one another with a magnetic stirrer. As soon as the boric acid had largely dissolved, it was possible to successively add 18.16 g of GLYEO (corresponding to 15.5 g of GLYMO), 5.14 g of TEOS and 5.14 g of MTES. (For varying experimental conditions, this part had to be varied in each case.)

[0096] After this was in well-mixed form, an amount of 0.03 g of water was added to start the hydrolysis. The mixture was stirred on a magnetic stirrer for 15 h before a second water content of 7.1 g was added while stirring. The silane binder formulation thus prepared was stirred for a further 5 h until the “pre-hydrolysis” had abated before it was used.

Example 1b: Production of Particle Formulation I

[0097] 11 kg of water were introduced into a hobbock. 5 kg of Ox50 were added while pivoting. This mixture was stirred slowly for 1 h. In order to further reduce the size of the particles, the mixture was guided through a UIP 1000 ultrasound flow cell in an amount of 12 l/h for a duration of 6 hours. The particle size d.sub.50 was determined as specified in the description as <60 nm. The solids content was about 30% by mass.

Example 1c: Production of Coating Composition I

[0098] A 1000 ml beaker was charged successively with 97 g of water, 0.44 g of Dolapix CE64 and 1.84 g of a 65% strength by mass nitric acid solution, and they were mixed with one another with a magnetic stirrer. 200 g of a finely divided alumina (ct1200SG) were added in portions to this mixture with constant stirring.

[0099] Once all components had been weighed in and were in well-mixed form, this dispersion was treated with an ultrasound dispersing finger (Hielscher UP200) in order to destroy any agglomerates present. 42 g of ethanol were added to this dispersion, then this mixture was stirred at least for a further 15 h. After the 15 h had elapsed, either 13.5 g of a 30% OX50 dispersion, prepared according to example 1 b, and 8.74 g of water or 4 g of Aerosil Ox50 together with 18 g of water were added. Subsequently, 52.6 g of a prepared silane binder formulation were added and the overall dispersion was aged again at rest for at least 15 h.

[0100] The resulting coating composition has a solids content of 58.7% and can be utilized in this form for coating experiments.

Example 1d: Production of Binder Formulation II

[0101] A 250 ml beaker was initially charged with 10.45 g of ethanol together with 0.84 g of boric acid, and they were stirred with one another with a magnetic stirrer. As soon as the boric acid had largely dissolved, it was possible to successively add 5.89 g of GLYEO, 5.0 g of TEOS and 10 g of MTES. (For varying experimental conditions, this part had to be varied in each case.) After this was in well-mixed form, an amount of 0.03 g of water was added to start the hydrolysis. The mixture was stirred on a magnetic stirrer for 1 h before a further 5.19 g of demineralized water were added while stirring. The silane binder formulation II thus prepared was stirred for a further 15 h before it was used.

Example Le: Production of Coating Composition II

[0102] A 1000 ml beaker was initially charged with 101.35 g of the Ox50 dispersion from example 1b and then 299.88 g of demineralized water and 3 g of a 65% strength by mass nitric acid solution were added successively, and the mixture was stirred with a magnetic stirrer for 15 hours.

[0103] 37.39 g of the prepared (silane) binder formulation II and 150.4 g of ethanol were added to this dispersion. Subsequently, this mixture was stirred for a further 2 days.

[0104] The resulting coating composition II has a solids content of Ox50 of about 5.7% and can be utilized in this form for the coating experiments.

Example 1f: Coating Process

[0105] A strip of the material to be coated (weave, nonwoven fabric or knit) having width 10 cm and length about 1 m was prepared. Alternatively, it is also possible to use the result of a coating operation as described here. In this case, however, it should be ensured that preferably always the same side is processed in subsequent treatment steps.

[0106] An automated film drawing apparatus from Zehntner was modified such that it uses a pulley mechanism to pull the web material to be coated vertically upward, at a defined speed of 42 mm/s, out of a dip coating apparatus in which one side of the material web is deflected via a roll and hence does not come into contact with the coating dispersion and the other side of the material web is conveyed through a tank filled with the dispersion.

[0107] For coating, the ready-mixed dispersion (coating composition I or II) is introduced into a tank in which there is a rotating roll spanned by the material web. The fill level of the tank was adjusted such that only 45° of the circumference of the roll dips into the solution. For good guiding of the material web, and in order to prevent the dispersion from running along the material web, the web tension was more than 0.1 N/cm of material web width. The material web is guided through the dispersion at a speed of 42 mm/s at room temperature and standard pressure.

[0108] On conclusion of the coating, the material web remained suspended vertically at a well-ventilated site for another 30 minutes and only thereafter was it dried and consolidated in a drying cabinet, lying on a grid, at 120° C. for one hour.

[0109] Either the dried material web is coated again or the finished composite body can subsequently be cut to size by cutting or punching for the respective test or uses.

[0110] For production of the composite material of the invention, coating was effected twice in succession with a coating composition I and twice with a coating composition II. The coating compositions I and II used in any example could be the same or different. To ascertain the most suitable feedstocks (substrate, coating composition, particle formulation, binder formulation etc.), in preliminary experiments, coating was effected as appropriate also only once or more than once with the coating composition I only. The corresponding tables each state the number of coating operations.

[0111] The experiments according to Example 1 were conducted analogously using different particle formulations, different coating compositions I and II, different binder mixtures I and II, and different process parameters. Tables 2a to 2l show the raw materials and amounts used, and the process parameters used in each case.

TABLE-US-00003 TABLE 2a Raw materials and amounts used for the production of the binder formulation I (BF-I) and varied process parameters Ethanol Boric acid MTES TEOS GLYEO Water Total BF-I [g] [g] [g] [g] [g] [g] [g] BF-I- 14.22 2.84  5.14 5.14 18.16 0.03 52.6 a 7.1 BF-I- 14.22 2.84 10.28 5.14  6.01 0.03 45.6 b 7.1

TABLE-US-00004 TABLE 2b Raw materials and amounts used for the production of the particle formulations (PF) in the respective examples Particle Water Dolapix CE64 HNO3 (65%) Particles Ethanol PF-0 Water Total PF type [g] [g] [g] [g] [g] [g] [g] [g] PF-0 Ox 50 11 000 5000 16 000 PF-I-a CT 1200 96.8 0.44 1.84 200 41.4 13.62  8.74 362.8 SG PF-I-b CT 3000 96.8 0.44 1.84 200 41.4 13.62  8.74 362.8 SG PF-I-c MZS-1 193.6 0.88 3.68 400 82.8 27.24 17.48 725.6 PF-I-d MZS-3 193.6 0.88 3.68 400 82.8 27.24 17.48 725.6 PF-I-e MZS-1 193.6 0.88 3.68 200 82.8 27.24 17.48 725.6 MZS-3 200

TABLE-US-00005 TABLE 2c Raw materials and amounts used for the production of coating composition I (BM-I) in the respective examples Weight of PF-I Weight of BF-I BM-I PF-I [g] BF-I [g] BM-I-a PF-I-a 362.8 BF-I-a 52.6 BM-I-b PF-I-a 362.8 BF-I-b 45.6 BM-I-c PF-I-b 362.8 BF-I-a 52.9 BM-I-d PF-I-c 725.6 BF-I-a 105.3 BM-I-e PF-I-d 725.6 BF-I-a 105.3 BM-I-f PF-I-e 725.6 BF-I-a 105.3

TABLE-US-00006 TABLE 2d Raw materials and amounts used for the production of the particle formulations II (PF-II) in the respective examples Particle Water PF-0 HNO3 Particles Total PF-II type [g] [g] (65%) [g] [g] [g] PF-0 Ox 50 11 000 5000 16 000 PF-II-a Ox 50 299.9 101.4 3 403 PF-II-b Alu C 371.2 3 30 404 PF-II-c Aerosil 90 371.2 3 30 404 PF-II-d Aerosil 200 371.2 3 30 404 PF-II-e P25 371.2 3 30 404 PF-II-f Zirconium 371.2 3 30 404 oxide PF-II-g Levasil 30 301.2 3 100 404

TABLE-US-00007 TABLE 2e Raw materials and amounts and optionally varied parameters used for the production of binder formulation II (BF-II) in the respective examples Ethanol Boric acid MTES TEOS GLYEO Water Total BF-II [g] [g] [g] [g] [g] [g] [g] BF-II-a 10.45 0.84 10 5 5.89 5.22 37.4 BF-II-b 2.75 0.22 1 1 3.5 1.37  9.8 BF-II-c 5.5 0.44 2 2 7 2.74 16.7 BF-II-d 14.22 2.84 5.14 5.14 18.16 7.1 52.6 BF-II-e 11 0.88 4 4 14 5.48 39.4 BF-II-f 8.25 0.66 3 3 10.5 4.11 29.5 BF-II-g 16.5 1.32 6 6 21.1 8.22 59.1 BF-II-h 21.98 1.76 8 8 28.1 10.95 78.8 BF-II-i 10.3 0.83 8 8 4.7 5.13 37.0 BF-II-k 10.6 0.85 6.7 6.7 7.8 5.3 37.9 BF-II-l 10.8 0.87 5 5 11.7 5.4 38.8 BF-II-m 11.0 0.89 3.3 3.3 15.6 5.5 39.6 BF-II-n 10.4 0.84 10 5 5.9 5.2 37.3 BF-II-o 10.0 0.8  6.7 6.7 6.7 5.0 35.8 (AMEO) BF-II-p 10 0.8  5 5 10 5.0 35.8 (AMEO) (IBTEO) BF-II-q 10 0.8  12 4 4.7 5.1 37.0

TABLE-US-00008 TABLE 2f Raw materials and amounts used for the production of coating composition II (BM-II) or coating composition III (BM-III) in the respective examples Weight Weight Weight of PF-II of BF-II of ethanol BM-II PF-II [g] BF-II [g] [g] BM-II-a PF-II-a 404 BF-II-a 37.4 150 BM-II-b PF-II-a 404 BF-II-b 9.8 150 BM-II-c PF-II-a 404 BF-II-c 16.7 150 BM-II-d PF-II-a 404 BF-II-n 37.3 150 BM-II-e PF-II-a 404 BF-II-e 39.4 150 BM-II-f PF-II-a 404 BF-II-f 29.5 150 BM-II-g PF-II-a 404 BF-II-g 59.1 150 BM-II-h PF-II-a 404 BF-II-h 78.8 150 BM-II-i PF-II-e 404 BF-II-e 39.4 150 BM-II-k PF-II-f 404 BF-II-e 39.4 150 BM-II-l PF-II-g 404 BF-II-e 39.4 150 BM-II-m PF-II-a 404 BF-II-i 39.4 150 BM-II-n PF-II-a 404 BF-II-k 37.9 150 BM-II-o PF-II-a 404 BF-II-l 38.8 150 BM-II-p PF-II-a 404 BF-II-m 39.6 150 BM-II-q PF-II-b 404 BF-II-n 37.3 150 BM-II-r PF-II-a 404 BF-II-i 37.0 150 BM-II-s PF-II-a 404 BF-II-k 37.9 150 BM-II-t PF-II-b 404 BF-II-e 39.4 150 BM-II-u PF-II-c 404 BF-II-e 39.4 150 BM-II-v PF-II-d 404 BF-II-e 39.4 150 BM-II-w PF-II-a 404 BF-II-q 37.0 150 BM-II-x PF-II-a 404 BF-II-n 37.3 150 BM-III-a PF-II-a 404 BF-II-o 35.0 150 BM-III-b PF-II-a 404 BF-II-p 35.0 150

TABLE-US-00009 TABLE 2g Experiments to test the suitability of substrates Composite Application body Substrate BM operations A 1 BM-I-a 2 B 2 BM-I-a 2 C 3 BM-I-a 2 D 4 BM-I-a 2

TABLE-US-00010 TABLE 2h Experiments to test the suitability of coating compositions I Composite Application body Support BM operations E 1 BM-I-a 2 F 1 BM-I-b 2 G 1 BM-I-c 2 H 1 BM-I-d 2 I 1 BM-I-e 2 J 1 BM-I-f 2

TABLE-US-00011 TABLE 2i Experiments to fix the ratio of binder to particles in coating composition II Composite Application body Support BM operations K Composite body BM-II-b 2 A L Composite body BM-II-c 2 A N Composite body BM-II-e 2 A O Composite body BM-II-f 2 A P Composite body BM-II-g 2 A Q Composite body BM-II-h 2 A

TABLE-US-00012 TABLE 2j Experiments to fix the particles to be used in coating composition II Composite Application body Support BM operations R Composite body BM-II-e 2 A S Composite body BM-II-t 2 A T Composite body BM-II-u 2 A U Composite body BM-II-v 2 A V Composite body BM-II-i 2 A W Composite body BM-II-k 2 A X Composite body BM-II-l 2 A

TABLE-US-00013 TABLE 2k Experiments to fix the binder formulation to be used in coating composition II Composite Application body Support BM operations 2A Composite body BM-II-e 2 A 2B Composite body BM-II-m 2 A 2C Composite body BM-II-n 2 A 2D Composite body BM-II-o 2 A 2E Composite body BM-II-p 2 A 2F Composite body BM-II-q 2 A 2G Composite body BM-II-w 2 A 2H Composite body BM-II-x 2 A

TABLE-US-00014 TABLE 2l Experiments to fix the binder formulation to be used in coating composition II (one-pot method) 2I Composite body BM-III-a 2 A 2K Composite body BM-III-b 2 A

Example 2: Characterization of the Composite Bodies

[0112] The composite bodies produced in the examples were characterized as described hereinafter. The results are compiled in Table 3.

[0113] The roughnesses Rdq min., Rdq max. and SDQ were determined as described in detail above.

[0114] Composite Bodies a to D:

[0115] All composite bodies have individual regions that show low roughness (Rdq min) and regions with higher roughness (Rdq max). Therefore, these values are not sufficiently authoritative to be utilized in making a decision with regard to the optimal substrate.

[0116] It is possible to directly infer from the images taken within the scope of measurement of the roughness values that the composite body D, which is based on monofilament weave, regularly has varying heights and depths for structure-related reasons with a high total thickness. Therefore, this material was subjected to further assessment since a smooth surface cannot be achieved therewith.

[0117] Glass fibre weaves (substrate C) would be of very good suitability owing to their low roughness since the RDq min and Rdq max values are the smallest compared with the composite bodies A to D, but the ceramic layers on the glass fibre weaves have a tendency to crack since the filaments, particularly the interstices between the individual fibres of the filaments, are poorly impregnated by the coating composition.

[0118] “Wet-laid” nonwovens (substrate A and B) and also papers feature quite smooth structures (without protruding fibres) and are therefore of good suitability as substrate. However, when thick individual fibres are used, close attention should be paid to the interstices between the fibres, since these must be very substantially filled (closed). Particularly suitable substrates are therefore PET nonwoven and carbon fibre nonwoven. On account of the smoother coating (RDq and SDQ are smaller), the PET nonwoven is preferred for the further studies.

[0119] Spunbonded nonwovens and meltblown nonwovens are of poor suitability, as are dry-laid needlefelts, which were used only in preliminary tests. Moreover, it is often necessary to choose a multilayer construction since an individual coating on its own does not give a sufficiently smooth surface. The first layer serves in particular to fill the fibre interstices. Thereafter, the layers must become smoother.

[0120] Composite Bodies E to J:

[0121] A double coating with the variously sized particles shows that the range of use of the various particles. ct1200SG (composite bodies E) and MZS1 (composite bodies H) are the most suitable for achieving good ceramic filling of the substrate interstices, apparent from the low Gurley numbers. Finer and also larger particles lead to poorer filling of the fibre interstices (ct 3000 SG—composite body G or MZS3—composite body I).

[0122] A particle mixture of MZS1 and MZS3 gives relatively good surface qualities (cf. in this regard the Rdq min/max and SDQ values), but this is combined with a larger average pore radius (MFP).

[0123] Since a material having pores of size less than 100 nm is sought as the resulting composite bodies, in which the fiber interstices of the substrates are filled to a good level, further work thereafter was conducted with ct1200SG (composite body A or E) in particular (although MZS1—composite body H would be just as suitable). In summary, it can be stated that particles having a d50 of the particle size distribution of 0.5 to 5.0 μm can be processed.

[0124] Composite Bodies K to Q:

[0125] On application of further layers of fine Ox50 particles to the ct1200SG surface, the average pore size is reduced and the surface quality is improved. Variations in the composition of particle content relative to silane binder content were conducted.

[0126] Through the variation in the silane binder contents, it is not possible to show any clear tendencies with regard to the surface quality established in the coatings. The highest binder content at which relatively small pores (MFP) can still be achieved was used in many of the further examples in order to ensure good binding of the particles.

[0127] Composite Bodies R to X:

[0128] On comparison of the various particles used, it is firstly noticeable that silane binders with silicon dioxide particles (composite bodies R, T, U) result in quite good smooth surfaces. Owing to the particle structure, however, Aerosil 90 (composite body T) and Aerosil 200 (composite body U) are not very suitable owing to the aggregated primary particles, just like the aluminium oxide Alu C (composite body S). Aerosil Ox 50 (composite body R), being matched to the pores of the substructure to be coated, has the most suitable particles (particle size). Moreover, Aerosil Ox 50 gives the smallest pores (MFP=0.11 μm).

[0129] Titanium dioxide P25 (composite body V) is stabilizable in the dispersion only to a limited degree with the binder system under the conditions chosen, and therefore forms very poor surfaces. Zirconium oxide from Roth (composite body W) is of virtually just as good suitability as Aerosil Ox50. Levasil (composite body X) has very small, very well-stabilized SiO.sub.2 particles, but these are so small that they infiltrate the pores of the substructure (ct 1200SG). Therefore, there is barely any difference in the surface quality of this sample from that of the ct1200SG surface (composite body E).

[0130] Composite Bodies 2A to 2H:

[0131] It was found that comparatively hydrophilic silane mixtures having a relatively high proportion of TEOS and GLYEO (composite bodies 2A; 2D and 2C) result in coatings that are just as smooth as composite bodies having comparatively hydrophobic silane mixtures, having a relatively high proportion of MTES (composite bodies 2G and 2H). Only composite bodies that have been produced with a distinctly elevated proportion of the crosslinking TEOS component, such as composite bodies 2B and 2C (TEOS proportion greater than 25% (m/m)) show poorer surface qualities.

[0132] The results seem to be essentially independent of the particle system chosen. This means that, when using different particles, the trends are the same with regard to the different silane compositions, not the absolute results.

[0133] Contact angle not measurable (nm) appears in Table 3 when the surface is so hydrophilic that a water droplet is sucked in.

[0134] Composite Bodies 2I and 2K:

[0135] The production of mixtures with aminosilanes is not possible in the form described. In order to be able to prepare the samples, the silane mixture has to be introduced without pre-hydrolysis into the vessel in which the particle dispersion is already being stirred and hydrolysed therein (one-pot method). Otherwise, the pre-hydrolysate would solidify, i.e. form a gel.

[0136] Observing this change in the process, exchange of the adhesion-promoting component GLYEO for AMEO is possible in principle. More particularly, it is readily possible in this way (and by virtue of the altered pH established) to use other particle systems, for example P25.

[0137] Various alkylsilanes (IBTEO), by contrast with MTES, lead to an enhanced tendency to form agglomerate. This then leads to very uneven surfaces.

TABLE-US-00015 TABLE 3 Results of the characterization of the composite bodies produced in the examples and in the comparative example Tensile strength, Tensile Composite Rdq Rdq SD Contact Basis machine direction, Gurley body min. max. Q angle weight Thickness direction cross MFP number A 5.5 52.5 18.9 88 215 118 >50 37 0.27 340 B 7.1 42.4 34.7 73 163 120 49.1 20 0.31 110 C 5.1 9.0 10.5 80 211 125 >50 >50 — 290 D 7.2 17.2 18.0 82 307 256 >50 40 0.38 580 E 7.8 58.6 21 125 230 157 >50 40 0.32 190 F 3.9 66.0 45.2 54 279 172 >50 43 3.7 1100 G 6.6 10.8 12.9 84 238 141 47 36 0.38 340 H 12.4 32.4 28.2 7 254 225 48 36 0.77 110 I 9.6 16.8 18.4 nm 285 174 49 34 0.45 250 J 3.5 8.7 8.0 nm 208 146 47 43 0.18 1010 K 3.6 6.9 7.8 nm 218 142 43 43 0.11 900 L 5.2 9.5 11.0 8.17 245 138 >50 37 0.11 500 N 5.4 16.0 11.0 8.02 206 147 >50 36 0.11 550 O 4.2 9.8 8.4 75.74 206 139 >50 38 0.12 440 P 3.3 5.4 6.5 nm 205 135 >50 40 0.12 550 Q 3.7 15.0 9.7 40.1 209 142 >50 33 0.13 720 R 3.4 8.5 7.5 nm 209 144 >50 30 0.11 740 S 12.0 52.0 40.0 35.55 211 148 >50 39 0.26 400 T 13.0 59.0 57.0 26.21 209 147 >50 32 0.26 470 U 5.3 21.0 15.0 15.43 209 141 >50 37 0.22 520 V 67.0 79.0 82.0 nm 210 154 >50 33 0.30 640 W 5.7 15.0 13.0 11.48 208 140 >50 26 0.12 540 X 5.8 45.0 16.0 20.35 206 136 >50 38 0.29 1600 2A 3.4 8.5 7.5 nm 209 144 >50 30 0.11 740 2G 5.6 22.0 14.0 74.7 209 153 50 46 0.14 560 2H 5.2 9.5 11.0 79.99 243 138 48 30 0.12 440 2B 6.1 31. 18.0 52.09 223 167 >50 42 0.10 750 2C 6.6 12.0 17.0 nm 227 170 >50 31 0.20 750 2D 4.5 12.0 12.0 nm 251 146 49 34 0.12 710 2H 4.5 12.0 13.0 63.44 196 128 >50 28 0.087 710 2E 3.7 15.0 11.0 nm 242 141 >50 31 0.12 610 2F 12.0 52.0 40.0 120.13 249 155 >50 36 0.26 460 2I 5.4 8.4 7.8 43.17 206 145 49 40 0.11 470 2K 6.0 13.9 10.7 106.8 209 148 >50 32 0.10 550 nm = not measurable

Example 3: Continuous Process for Producing a Composite Body

[0138] To produce a composite body according to the invention (analogously to A) in a continuous coating process in a corresponding manufacturing system as manufactured, for example, by Matthis, consisting of a support unwinder, a coating unit, a dryer and a winder with tension control, coating composition BM-I-a was produced in a batch size 125 times greater in a stirred 70 l stainless steel vessel as described above. This was then coated by the dip-coating method with retention of a tension of >1 N/cm of material web width on a polyester nonwoven support (05-TH-60W nonwoven fabric) having a width of about 30 cm and length up to 500 metres, in the course of which the support was also impregnated. This was introduced into an air circulation oven of length 5 m about 50 cm downstream of the dip-coater, in which the composite material was dried at 140° C. The material web speed was 1.5 m/min.

[0139] After the material web had been dried, it was wound up at the given tension and then treated for a second time in another coating operation with retention of all process parameters. The resulting composite body K-VK-1 (analogously to composite body A) is described by the parameters specified in Table 4.

[0140] a) Hydrophilic Composite Body

[0141] This composite body K-VK-1 was subsequently coated twice with a coating composition BM-II-e produced on a scale enlarged by about 10-fold in the same system operated with the same machine parameters. The resulting continuously produced composite body K-VK-2 (analogously to composite body R) is described by the parameters specified in Table 4.

[0142] b) Hydrophobic Composite Body

[0143] Composite body K-VK-1 was subsequently coated twice with a coating composition BM-II-x produced on a scale enlarged by about 10-fold in the same system operated with the same machine parameters. The resulting continuously produced composite body K-VK-3 (analogously to composite body 2H) is described by the parameters specified in Table 4.

TABLE-US-00016 TABLE 4 Parameters for the composite bodies produced in Example 3 Tensile strength Tensile Composite Rdq Rdq SD Contact Basis Machine strength MFP Gurley body min. max. Q angle weight Thickness direction Cross [μm] number K-VK-1 6.7 19.3 14.3 85 185 138 >50 34 0.25 350 K-VK-2 4.5 13.5 11.6 24 212 144 >50 30 0.11 740 K-VK-3 3.3 5.4 6.5 89 197 141 >50 38 0.09 800

Example 4: Composite Bodies with a Polysiloxane-Containing Polymer Layer

[0144] a) Production of a Polymer Solution (PL-1)

[0145] 10 g of component A (RTV-615A) in 90 g of hexamethyldisiloxane were initially charged in a round-bottom flask and heated to 60° C. On attainment of the given temperature, 1 g of component B (RTV-615B) in 10 g of hexamethyldisiloxane was added. The components, which mix very well under these conditions, after a stirring time of 2 h, were left to cool and, after dilution with hexamethyldisiloxane to a content of 92% by weight of hexamethyldisiloxane in the solution, the viscosity was checked. This was 13 mPas at first and varied with time and rose continuously. This solution was processed and the composite body was coated as soon as the viscosity was in the range from 5 to 50 mPas. Viscosities were determined with a rotary viscometer from Malvern Instruments Limited, Worcestershire, UK, model: Kinexus KNX2112m at a shear rate of 100 s.sup.−1 and a temperature of 25° C. The pot life of the ideal processing window is about 2 hours.

[0146] b) Production of a Polymer Solution (PL-2)

[0147] The solution was obtained by combining solution A and solution B in a (weight) ratio of 1:1. Solution A contained 99.8% by weight of the vinyldimethylpolysiloxane/vinyl-QM resin mixture VQM 906 and 0.2% by weight of catalyst 511. Solution B contained 52.99% by weight of the vinyl-functional polydimethylsiloxane VS 165.000, 38.99% by weight of the SiH-containing polydimethylsiloxane crosslinker 120, 8% by weight of the vinyldimethylpolysiloxane/vinyl-QM resin mixture VQM 906, and 0.02% by weight of the inhibitor methylbutynol. This mixture was diluted with hexamethyldisiloxane directly prior to use, such that the solution used had a hexamethyldisiloxane content of 85% by weight and a viscosity of 9 mPas. The latter was determined with a rotary viscometer from Malvern Instruments Limited, Worcestershire, UK, model: Kinexus KNX2112m at a shear rate of 100 s.sup.−1 and a temperature of 25° C.

[0148] c) Production of a Polymer Solution (PL-3)

[0149] 10 g of component A (RTV-615A) in 90 g of hexamethyldisiloxane were initially charged in a round-bottom flask and heated to 60° C. On attainment of the given temperature, 1 g of component B (RTV-615B) in 10 g of hexamethyldisiloxane was added. The components, which mix very well under these conditions, after a stirring time of 2 h, were left to cool and, after dilution to a content of 95% by weight of hexamethyldisiloxane in the solution, the viscosity was checked. This was 6 mPas at first and varied with time and rose continuously. This solution was processed and the composite body was coated as soon as the viscosity was in the range from 5 to 50 mPas. The latter was determined with a rotary viscometer from Malvern Instruments Limited, Worcestershire, UK, model: Kinexus KNX2112m at a shear rate of 100 s.sup.−1 and a temperature of 25° C. The pot life of the ideal processing window is about 2 hours.

[0150] d) Production of a Polymer Solution (PL-4)

[0151] A solution produced as in a) was diluted with hexamethyldisiloxane to 95% by weight rather than to 92% by weight of hexamethyldisiloxane. After homogenization for 2 hours, this was used for the coating.

[0152] e) Coating of a Composite Body with Polymers

[0153] A composite body was predried in a drying cabinet at 100° C. for at least 2 h, then coated by the dip-coating method, as already described in Example 1f. For this purpose, an automated film drawing apparatus from Zehntner was modified such that it uses a pulley mechanism to pull the web material to be coated vertically upward, at a defined speed of 42 mm/s, out of a dip coating apparatus in which one side of the material web is deflected via a roll and hence does not come into contact with the coating solution and the other side of the material web is conveyed through a tank filled with the solution.

[0154] For coating, the ready-mixed solution was introduced into a tank in which there was a rotating roll spanned by the material web. The fill level of the tank was adjusted such that only 45° of its circumference of the roll dips into the solution. For good guiding of the material web, and in order to prevent the solution from running along the material web, the web tension was about 0.1 N/cm of material web width. The material web was guided through the solution at a speed of 42 mm/s at room temperature and standard pressure. After the coating had concluded, the material web remained suspended at room temperature in the apparatus for another 15 minutes in order that the solvent could largely evaporate.

[0155] Only after drying of the material web at 120° C. overnight in a drying cabinet was it characterized. A correlation of the composite bodies and coating solutions used can be found in Table 6.

[0156] Some of the various composite materials, rather than being predried at 100° C., were treated with a corona. For this purpose, the composite body was secured with its front side upward on an electrically nonconductive material, PET nonwoven, from Sojitz, 05-TH-60W, and conveyed through a corona treatment system (from Softal, Hamburg) at a speed of 1.5 m/min. The power of the corona treatment can be variably adjusted. The experimental setting can likewise be found in Table 6.

[0157] All composite bodies were characterized by determination (executed as specified above) of the clean gas selectivity for CO.sub.2/CH.sub.4 and the flow rate of CO.sub.2 in order to provide evidence of faultless coating with the polymer solution. The results are presented in Table 6.

TABLE-US-00017 TABLE 6 Experimental parameters and results from Example 4e. Resulting Corona Clean gas CO.sub.2 flow composite Composite Solution power selectivity rate body body used utilized [W min/m] CO.sub.2/CH.sub.4 [GPU] P-VK-1 K-VK-3 PL-1 600 3 730 P-VK-2 K-VK-3 PL-2 600 3 820 P-VK-3 K-VK-3 PL-3 600 3 940

[0158] The composite bodies P-VK-1 to P-VK-3 feature quite a good tolerance to the handling of the composite bodies. This reduces the probability of occurrence of faults in or damage to the composite body that can occur during introduction into an apparatus for separation of solvents. Typical faults or damage would be fractures in the ceramic owing to kinks or treatment with sharp objects.

[0159] All composite bodies P-VK-1 to P-VK-3 are flexible and can be wound without damage around a bar or around a tube having a diameter of down to 15 mm. The composite bodies P-VK-1 to P-VK-3 can be wound onto minimal diameters of down to 5 mm without damage. The freedom of the corresponding composite bodies from damage can be demonstrated easily by the determination of the clean gas selectivity, which is the same before and after the treatment. In this case, a reduction in the clean gas selectivity by 2 units is assessed as “defect in the composite body”.

[0160] By virtue of the flexibility of the composite bodies, these are introducible in a very simple manner in typical module forms for flat membranes and are especially suitable for use in spiral-wound modules, plates and frame modules, pocket modules and other apparatuses that have been designed for flat membranes.

Example 5: Testing of the Composite Bodies with a Polysiloxane-Containing Polymer Layer

[0161] For further characterization, some of the membranes were examined by what is called the MWCO (molecular weight cutoff) method in toluene. This method is described inter alia in WO 2011/067054 A1, but also in Journal of Membrane Science 291 (2007) 120-125. For this purpose, the membranes were tested in a crossflow filtration with toluene as solvent, in which polystyrenes of different molecular weight are dissolved in a total concentration of 1 g/L. The basic construction of this apparatus is shown in FIG. 4. The permeate flows (toluene) were monitored and quantified gravimetrically over a period of 3 hours. After three hours, a portion of the permeate collected last was taken and collected in a separate sample bottle for the determination of molecular weight, which was made by means of an HPLC system.

[0162] Unless stated otherwise, testing was effected in the crossflow filtration apparatus at transmembrane pressure (TMP) 30 bar (30 *10.sup.5 Pa) and at a temperature of 30° C., with continuous pumping of the permeate stream by means of a pump back into the reservoir vessel. The membrane cells that were utilized in these experiments had been sourced from Evonik Membrane Extraction Technologies.

[0163] Table 7 gives, as results of this testing, the molecular weights at which 90% retention is achieved. Some of the membranes tested were subjected to pretreatments (Examples 5a and 5b). The results of these tests are shown below and in FIGS. 1 to 3 and Table 7.

[0164] a) Thermal Stability

[0165] Some of the composite bodies obtained in Example 4e were stored at 150° C. in a drying cabinet for 72 hours (composite bodies: P-VK-1-temp). Thereafter, the characterizations of the membrane properties were repeated. There were no significant changes either in flow rate or retention compared to the thermally untreated composite bodies.

[0166] b) Solvent Stability

[0167] The composite bodies obtained in Example 4e were stored in mesitylene at 150° C. for 72 hours (composite bodies: P-VK-1-solv). Thereafter, the characterizations of the membrane properties were repeated. There were no significant changes either in flow rate or retention compared to the results of the untreated composite bodies.

[0168] c) Separation Properties at Elevated Temperature

[0169] The composite bodies obtained in Example 4e were used at transmembrane pressure 30 bar (30 *10.sup.5 Pa) at elevated temperature. There was a distinct change here in the flow rate and only a slight change in the retention. The results of the measurements are shown hereinafter, with examination of specimen P-VK-1-130° C. at a temperature of 130° C. for the permeation characteristics for toluene and the retention for polystyrene, and the specimen P-VK-1-30° C. are the comparative values for a specimen that was examined at 30° C. The examinations were always effected over a period of three hours and at a permeate pressure of 5 bar (5 *10.sup.5 Pa), recording the flow rate after three hours. The results of the progression of the retentions can be found in FIG. 3. The results of the determination of the toluene flow rate and of the retention can be found in Table 7.

TABLE-US-00018 TABLE 7 Resuls for determination of toluene flow rate and of retention Composite MWCO Flow rate [L/m.sup.2 h] body (90%) at TMP 30 * 10.sup.5 Pa Temperature P-VK-1 about 500 72 30 P-VK-1 about 625 312 130 P-VK-3 about 650 410 130

[0170] The results of FIGS. 1 to 3 and Table 7 show that, by virtue of the ceramic structure of the composite bodies P-VK-1 to P-VK-3, the thickness and porosity thereof is virtually unchanged under compressive stress at elevated temperature. This is crucial for the entire composite body according to the invention, even under high compressive stress at elevated temperature, to have a virtually constant toluene flow rate, and for the flow not to be reduced at higher pressures by a compacting porous structure.

Example 6: Examination of the Change in Particle Size Distribution in Different Processing Stages

[0171] In addition, a study was conducted as to the extent to which particle size distribution changes in the course of production of the coating composition. For this purpose, the particle formulations (PF) used in the preceding examples were analysed with regard to their average particle size (d50). The measurement results are shown in Table 8a. Then coating compositions (BM) were produced as described in the preceding examples. The average particle size of the coating compositions was measured. The measurement results are shown in Table 8b. Table 8c records the d50 values of the particles used according to the manufacturer.

[0172] A quantitative assessment of the measurements is given in Table 9.

[0173] In summary, it can be inferred from the results set out in Tables 8a, 8b, 8c and 9 that the differences in particle size in the different processing stages (PF to BM) result exclusively from the degree of stabilization of the particles in the respective dispersion.

TABLE-US-00019 TABLE 8a Measurements of average particle size of particle formulation (PF) Measurement Reference of particle d50 [μm] PF No. formulation (PF) measured 1 PF-I-a 1.6 2 PF-I-b 0.9 3 PF-I-d 4.5 4 PF-II-0 0.12 5 PF-II-a 0.18 6 PF-II-c 0.26 7 PF-II-d 32.5

TABLE-US-00020 TABLE 8b Measurements of average particle size of coating composition (BF) Measurement Reference of coating d50 [μm] BM No. composition (BM) measured Comment 1 BM-I-a 1.7 2 BM-I-c 1.4 3 BM-I-e 4.3 4 5 BM-II-d 0.18 Only addition of HNO3 changes the average particle size 6 new 0.28 7 new 32.5

TABLE-US-00021 TABLE 8c Average particle size according to manufacturer Measurement No. Particle type d50 [μm] according to manufacturer 1 ct 1200 SG 0.9-1.5 2 ct 3000 SG 0.5-0.8 3 MZS 3 2.5-5.0 4 Ox50 0.1 derived from SEM 5 Ox 50 0.1 derived from SEM 6 Aerosil 90 0.08 derived from SEM 7 Aerosil 200 Primary grain (sintered together) 0.005

TABLE-US-00022 TABLE 9 Evaluation of measurement results Measurement No. Evaluation 1 Average particle size increases to a minimal degree more as a result of addition of the binder formulation and is always above the manufacturer's figure, which is probably because of the manner of dispersion. 2 Average particle size increases as a result of addition of the binder formulation and is always above the manufacturer's figure, which is probably because of the manner of dispersion. 3 Average particle size smaller after addition of binder, but still within the manufacture's figure. Better dispersion and hence fewer agglomerates. 4 Pure dispersion of the particles with high ultrasound intensity for dispersion. 5 Solely dilution of the particle dispersion from 4 and adjustment of the pH results in a greater average particle size. Addition of the binder formulation does not result in any change in the measured average particle size. 6 Addition of the binder formulation results in a slight change in the measured average particle size. 7 Addition of the binder formulation results in a slight change in the measured average particle size. Particle size should not be equated with primary grain size, which varies widely from the value measured.