Composite body

Abstract

The present invention provides a composite body having, on a porous substrate and in the interstices of the substrate that includes fibers, preferably 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, Ti and Si, preferably selected from Al.sub.2O.sub.3, ZrO.sub.2, TiO.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, Ti and Si, preferably selected from Al.sub.2O.sub.3, ZrO.sub.2, TiO.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), which is characterized in that the median particle size (d.sub.50) of the oxide particles in layer (1) is from 0.5 to 4 μm and the median particle size (d.sub.50) of the oxide particles in layer (2) is from 0.015 to 0.15 μm, preferably 0.04 to 0.06 μm, a process for producing corresponding composite bodies and for the use thereof, especially in gas separation.

Claims

1. A flexible composite gas separation membrane body having, on a porous substrate and in the interstices of the substrate that includes fibers, 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, Ti and Si, 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, Ti and Si, where the oxide particles present in layer (1) have a greater median particle size than the oxide particles present in layer (2), wherein the median particle size (d50) of the oxide particles in layer (1), is from 0.5 to 4 μm and the median particle size (d50) of the oxide particles in layer (2), is from 0.015 to 0.15 μm; and wherein the flexible composite gas separation membrane body has a Gurley number of from 250 to 1200 sec, and a gas flow of greater than 50 GPU for carbon dioxide as clean gas; and further comprises a silicone polymer layer; and the flexible composite gas separation membrane body has a thickness of from 100 to 400 μm and can be wound around a bar or tube having a diameter of 15 mm or greater.

2. The flexible composite gas separation membrane body according to claim 1, wherein the flexible composite body has a Gurley number of from 300 to 800 sec.

3. The flexible composite gas separation membrane body according to claim 1, wherein the flexible composite body has a thickness of from 100 to 400 μm and has a Gurley number of from 300 to 800 sec.

4. The flexible composite gas separation membrane body according to claim 1, wherein the substrate is a nonwoven fabric, knit or laid scrim.

5. The flexible composite gas separation membrane body according to claim 1, wherein the fibers have a dimension of from 1 to 200 g/km of fiber and are composed of polyacrylonitrile, polyamide, polyester and/or polyolefin.

6. The flexible composite gas separation membrane body according to claim 1, wherein the substrate has a thickness of from 50 to 150 μm and a basis weight of from 40 to 150 g/m.sup.2.

7. The flexible composite gas separation membrane body according to claim 1, wherein the flexible composite body has an average pore size of from 60 to 140 nm.

8. The flexible composite gas separation membrane body according to claim 1, wherein the flexible composite body, on the surface of the layer (2), has a surface roughness Sdq of less than 10 μm.

9. The flexible composite gas separation membrane body according to claim 8, wherein a polymer layer (PS) is present atop or above layer (2).

10. The flexible composite gas separation membrane body according to claim 8 having a gas flow of gas flow of greater than 80 GPU for carbon dioxide as clean gas, wherein the silicone in the silicone layer is selected from the group consisting of polydimethylsilicone, polyethylmethylsilicone, nitrile silicone, rubbers, poly(4-methyl-1-pentene), and polytrimethylsilylpropenes.

11. A process for producing a flexible composite gas separation membrane body of claim 1, wherein the process comprises the following steps: (a) applying a coating composition (BM1) to and into a substrate having fibers and interstices between the fibers, 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 Ti, Al, Zr and/or Si and having a median particle diameter (d50) of from 0.5 to 4 μm with water, an inorganic acid, and a dispersing aid, (a2) a dispersion (D2) of oxide particles produced by mixing oxide particles selected from the oxides of the elements Ti, Al, Zr and/or Si and having a median particle diameter (d50) of from 15 to 150 nm, with water, (a3) a binder formulation (BF1), produced by mixing at least two organofunctional silanes with an alkanol, an inorganic acid, and water, (b) consolidating the coating composition (BMI) at a temperature of from 100° C. to 275° C., in order to create a first layer (SI′), (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 Ti, Al, Zr and/or Si and having a median particle diameter (d50) of from 0.5 to 4 μm with water, an inorganic acid, and a dispersing aid, (c2) a dispersion (D4) of oxide particles produced by mixing oxide particles selected from the oxides of the elements Ti, Al, Zr and/or Si and having a median particle diameter (d50) of from 15 to 150 nm, with water, (c3) a binder formulation (BF2), produced by mixing at least two organofunctional silanes with an alkanol, an inorganic acid, and water, (d) optionally consolidating the coating composition (BM2) at a temperature of from 100° C. to 275° C., in order to create a second layer (S2′), (e) applying a coating composition (BM3) to layer (S1′) 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 Ti, Al, Zr and/or Si and having a median particle diameter (d50) of from 15 to 150 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 from 100° C. to 275° 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 Ti, Al, Zr and/or Si and having a median particle diameter of from 15 to 150 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 from 100° C. to 275° C., in order to create a layer (S4′), and (i) conducted after step (0 or after step (h), a polymer layer (PS) including a polymer is applied to layer (S3′) or to layer (S4′).

12. The process according to claim 11, wherein the organofunctional silanes are selected from the group consisting of 3-glycidyloxytriethoxysilane, methyltriethoxysilane and tetraethoxysilane.

13. The process according to claim 11, wherein 3-glycidyloxytriethoxysilane, methyltriethoxysilane and tetraethoxysilane are used in binder formulation (BF1) and (BF2) in a mass ratio of from 2 to 4:0.5 to 1.5:1.

14. The process according to claim 11, wherein 3-glycidyloxytriethoxysilane, methyltriethoxysilane and tetraethoxysilane are used in binder formulation (BF3) and (BF4) in amass ratio of from 0.5 to 1.5:1.5 to 2.5:1.

15. The process according to claim 11, wherein the coating compositions (BM3) and (BM4) are of identical composition.

16. The process according to claim 11, wherein the coating compositions (BM1) and (BM2) are of identical composition.

17. The process according to claim 11, wherein the substrate used is a polymer nonwoven including fibers selected from the group consisting of polyacrylonitrile, polyester, polyamide and polyolefin.

18. The process according to claim 11, wherein the consolidating is affected by passage through a hot air oven or an IR oven.

19. The process according to claim 11, wherein, before and/or after the applying of the silicone polymer layer (PS), a polymer coating (PB) containing polymer, is applied.

20. A gas separation membrane for separation of chemicals selected from the group consisting of methane from CO.sub.2, H.sub.2 from CO.sub.2, H.sub.2 from N.sub.2, O.sub.2 from N.sub.2, and He from CH.sub.4, wherein the gas separation membrane comprises the flexible composite material according to claim 1 as gas separation membrane, for separation of methane from CO.sub.2, H.sub.2 from CO.sub.2, H.sub.2 from N.sub.2, O.sub.2 from N.sub.2 or He from CH.sub.4.

21. A gas separation apparatus comprising the flexible composite gas separation membrane body according to claim 1.

Description

(1) The present invention is described by way of example by the images of a composite body according to the invention that are shown in the figures FIG. 1 and FIG. 2, without being limited thereto.

(2) FIG. 1 shows an SEM image of a section through the composite body P-VK-11 (see examples). The various layers (1) and (2), the polymer layer (PS)/coatings (PB) and the fibers of the substrate are apparent. Also given are dimensions for the composite body and layer (2).

(3) FIG. 2 shows an enlarged SEM image of a section through the composite body P-VK-11 (see examples). The construction of the polymer layer (PS) including polymer coatings (PB) is apparent. Also given are dimensions for polymer coatings (PB) and the polymer layer (PS).

(4) The present invention is described by the examples which follow, without being limited thereto.

EXAMPLES

(5) TABLE-US-00002 TABLE 1a Raw materials used If appropriate branding, 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-Glycidyloxytrimethoxysilane DYNASYLAN ® GLYMO, Evonik Resource 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 Aluminium oxide CT 3000 SG, Almatis GmbH 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) Aluminium oxide MARTOXID ® MZS-3, Martinswerk GmbH (MZS-3) Aluminium oxide AEROXIDE ® Alu C, Evonik Resource Efficiency GmbH (Alu C) Perfluorinated polymer Cytop-ctl 109 AE, Asahi Glass Chem. Perfluorinated polymer Cytop-ctl 107 MK, Asahi Glass Chem. Perfluorinated polymer Hyflon AD60, Solvay Solvent Ct-100-solv, Asahi Glass Chem. Solvent Novec 7300, 3M Solvent Galden HT55, Solvay 2-component polymer RTV-615 (A + B), Momentive silicone

(6) TABLE-US-00003 TABLE 1b Substrate materials used: Substrate Design Material Basis weight Supplier 1 05-TH-60W PET 60 g/sqm Sojitz, Düsseldorf nonwoven fabric 2 Nonwoven fabric Carbon 15 g/sqm Technical Fiber Products, Burnside Mills 3 Weave E glass 60 g/sqm P&G 4 Monofilament weave PET 40 g/sqm SEFAR

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

Example 1a: Production of Binder Formulation I

(7) 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.) 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

(8) 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 121/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

(9) 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.

(10) 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 1b, 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.

(11) 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

(12) 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 1e: Production of Coating Composition II

(13) 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.

(14) 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.

(15) 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

(16) 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.

(17) 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.

(18) 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.

(19) 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.

(20) 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.

(21) 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.

(22) 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.

(23) TABLE-US-00004 TABLE 2a Raw materials and amounts used for the production of the binder formulation I (BF-I) and varied process parameters Boric Ethanol acid MTES TEOS GLYEO Water Total BF-I [g] [g] [g] [g] [g] [g] [g] BF-I-a 14.22 2.84 5.14 5.14 18.16 0.03 52.6 7.1 BF-I-b 14.22 2.84 10.28 5.14 6.01 0.03 45.6 7.1

(24) TABLE-US-00005 TABLE 2b Raw materials and amounts used for the production of the particle formulations (PF) in the respective examples Water Dolapix CE64 HNO3 (65%) Particles Ethanol PF-0 Water Total PF Particle type [g] [g] [g] [g] [g] [g] [g] [g] PF-0 Ox 50 11 000   5000 16 000   PF-I-a CT 1200 SG  96.8 0.44 1.84 200 41.4 13.62 8.74 362.8 PF-I-b CT 3000 SG  96.8 0.44 1.84 200 41.4 13.62 8.74 362.8 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

(25) TABLE-US-00006 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

(26) TABLE-US-00007 TABLE 2d Raw materials and amounts used for the production of the particle formulations II (PF-II) in the respective examples HNO3 Parti- Particle Water PF-0 (65%) cles Total PF-II type [g] [g] [g] [g] [g] PF-0 Ox 50 11 000   5 000   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 371.2 3 30 404 90 PF-II-d Aerosil 371.2 3 30 404 200 PF-II-e P25 371.2 3 30 404 PF-II-f Zirco- 371.2 3 30 404 nium oxide PF-II-g Levasil 301.2 3 100  404 30

(27) TABLE-US-00008 TABLE 2e Raw materials and amounts and optionally varied parameters used for the production of binder formulation (BF-II) in the respective examples Eth- Boric anol 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

(28) TABLE-US-00009 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 of PF-II Weight of BF-II Weight 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

(29) TABLE-US-00010 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

(30) TABLE-US-00011 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

(31) TABLE-US-00012 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

(32) TABLE-US-00013 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

(33) TABLE-US-00014 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

(34) TABLE-US-00015 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

(35) The composite bodies produced in the examples were characterized as described hereinafter. The results are compiled in Table 3.

(36) The roughnesses Rdq min., Rdq max. and SDQ were determined as described in detail above.

(37) Composite Bodies A to D:

(38) All samples have individual regions that show low roughness (Rdq min). However, it was possible to infer from the images taken that the monofilament weave regularly has heights and depths for structure-related reasons. Therefore, this material is excluded from further assessment.

(39) To achieve surfaces of maximum smoothness, the first ceramic layer must already be very substantially homogeneous. Substrate materials such as “monofilament weave” therefore do not appear to be very suitable.

(40) Glass fiber weaves would be of very good suitability, but these tend to cracking in the ceramic layer because the filaments (interstices between the individual fibers) are poorly impregnated.

(41) “Wet-laid” nonwovens and also papers feature quite smooth structures (without protruding fibers) and are therefore of good suitability as support. However, when thick individual fibers are used, close attention should be paid to the interstices between the fibers, since these must be very substantially filled (closed). Spunbonded nonwovens and meltblown nonwovens are of poor suitability, as are “dry-laid” needlefelt nonwovens. Particularly suitable substrates are therefore PET nonwoven and carbon fiber nonwoven.

(42) Moreover, it is 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 fiber interstices. Thereafter, the layers must become smoother; a simultaneous aim is a reduction in the pore radii by use of smaller particles.

(43) Composite Bodies E to J:

(44) A double coating with the various particles shows that ct1200SG and MZS1 have the best suitability. In the case of these, the fiber interstices have the best filling, which results in a relatively even surface. Finer and also larger particles lead to poorer filling of the fiber interstices (ct 3000 SG or MZS3).

(45) A mixture of MZS1 and MZS3 also gives relatively good surface qualities, but combined with a larger average pore radius. Since a material having pores of size less than 100 nm is to be provided as the resulting membrane surface, further work thereafter was conducted with ct1200SG in particular (although MZS1 would be just as suitable).

(46) Composite Bodies K to Q:

(47) 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.

(48) Very small binder contents lead to a more uneven surface than higher binder contents. But an increase to twice the content again leads to a deterioration in the Sdq value. The optimum is at a mixing ratio of Aerosil OX50/silane binder of 50:50 (g/g) up to 65:35 (g/g).

(49) Composite Bodies R to X:

(50) On comparison of the various particles used, it is firstly noticeable that silane binders with silicon dioxide particles result in quite good smooth surfaces. Owing to the particle structure, however, Aerosil 90 and Aerosil 200 (aggregated primary particles) are not very suitable, just like the aluminium oxide Alu C. Ox-50, being matched to the pores of the substructures to be coated, has the most suitable particles (particle size).

(51) Titanium dioxide P25 is stabilizable only to a limited degree with the binder system under the conditions chosen, and therefore forms very poor surfaces. Zirconium oxide (from Roth) is virtually just as suitable as Ox50. Levasil has very small, very well-stabilized SiO.sub.2 particles, but these are so small that they are sucked into the pores of the substructure (ct 1200SG). Therefore, there is barely any difference in the surface quality of this sample from that of the non-after-coated ct1200SG surface.

(52) Composite Bodies 2A to 2H:

(53) It was found that both hydrophilized silane mixtures (higher proportion of TEOS and GLYEO) and hydrophobized silane mixtures (higher proportion of MTES) result in smooth coatings. Only the samples that were produced with an elevated content of the crosslinking TEOS component (TEOS content>25%) showed poorer surface qualities.

(54) The results seem to be essentially independent of the particle system chosen, meaning that the trends (not the absolute results) in the respective particle system are the same.

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

(56) Composite bodies 2I and 2K:

(57) 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 (gelation).

(58) 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.

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

(60) TABLE-US-00016 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 Contact Basis machine direction, Gurley body min. max. SDQ 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 — 285 174 49 34 0.45 250 J 3.5 8.7 8.0 — 208 146 47 43 0.18 1010 K 3.6 6.9 7.8 — 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 — 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 — 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 — 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 — 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 — 227 170 >50 31 0.20 750 2D 4.5 12.0 12.0 — 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 — 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 — = not measurable

Example 3: Continuous Process for Producing a Composite Body

(61) 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 701 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.

(62) 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.

(63) a) Hydrophilic Composite Body

(64) 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.

(65) b) Hydrophobic Composite Body

(66) 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.

(67) TABLE-US-00017 TABLE 4 Parameters for the test specimens produced in Example 3 Tensile strength Tensile Composite Rdq Rdq Contact Basis Machine strength MFP Gurley body min. max. SDQ 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 Polymer Layer

(68) a) Production of Various Solutions of Perfluorinated Polymers

(69) The various solutions for coating were produced in such a way that the corresponding polymer as sourced from the manufacturer was admixed with the appropriate amount of solvent. To assist the dissolving operation, the mixture was heated to 60° C. for several hours until all the polymer had dissolved. The solution cooled down overnight and could be filtered the next day at slightly elevated temperature through a 5 μm paper filter in order to remove the last undissolved constituents (impurities). On completion of filtration, the solution can be stored or processed for several months. The compositions of the solutions produced in Example 4a can be found in Table 5 below. The concentrations were determined with an MA 150Q residue determination balance from Sartorius, Germany. The values correspond to a dry residue [%] after drying at 120° C. Viscosity 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.

(70) TABLE-US-00018 TABLE 5 Compositions and parameters of solutions PL 1 to 8 Polymer Dry solution Polymer Weight Solvent Weight residue Viscosity PL-1 Cytop-ctl 109 AE 28 g Ct-100-solv 72 g 2.5% 4 PL-2 Cytop-ctl 107 MK 36 g Ct-100-solv 64 g 2.5% 3 PL-3 Cytop-ctx 109 AE 45 g Ct-100-solv 55 g 4.0% 8 PL-4 Hyflon AD60  4 g Ct-100-solv 96 g 4.0% 9 PL-5 Hyflon AD60  4 g Novec 7300 96 g 4.0% 11 PL-6 Hyflon AD 60  3 g Galden HT55 97 g 3.0% 6 PL-7 Hyflon AD60 2.8 g  Ct-100-solv 97 g 2.8% 7 PL-8 Hyflon AD60 2.5 g  Ct-100-solv 97 g 2.5% 6
b) Production of a Polymer Solution (PL-9)

(71) 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.

(72) c) Production of a Polymer Solution (PL-10)

(73) 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.

(74) d) Production of a Polymer Solution (PL-11)

(75) 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.

(76) e) Production of a Polymer Solution (PL-12)

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

(78) f) Production of a Polymer Solution (PL-13)

(79) A mixture of 70 g of RC silicone type 702, from Evonik Resource Efficiency GmbH, and 30 g of RC silicone type 902 was mixed with 900 g of isopropanol, from Obermeier GmbH, with vigorous stirring, and 2 g of photoinitiator type 18, from Evonik Resource Efficiency GmbH, were added. This solution was processed within 2 days or stored in the dark under a good seal.

(80) g) Coating of a Composite Body with Polymers

(81) 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.

(82) 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.

(83) 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.

(84) 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.

(85) When RC silicones were used, after the drying, as soon as the solvent had been removed, these were cured with UV light (LAB 200UV laboratory UV device from Eltosch, Hamburg) at a bath speed of 1.5 m/min.

(86) 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.

(87) TABLE-US-00019 TABLE 6 Experimental parameters and results from Example 4g. 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-2 PL-1 0 17 13 P-VK-2 K-VK-2 PL-2 0 9 41 P-VK-3 K-VK-2 PL-3 0 17 12 P-VK-4 K-VK-2 PL-4 0 12 40 P-VK-5 K-VK-2 PL-5 0 4 58 P-VK-6 K-VK-2 PL-6 0 3 55 P-VK-7 K-VK-3 PL-9 600 3 730 P-VK-8 K-VK-3 PL-10 600 3 820 P-VK-9 P-VK-7 PL-7 200 13 120 P-VK-10 P-VK-7 PL-8 200 12 140 P-VK-11 P-VK-9 PL-11 400 12 110 P-VK-12 P-VK-10 PL-12 400 12 120 P-VK-13 P-VK-9 PL-13 400 11 95

(88) The figures FIG. 1 and FIG. 2 show SEM images of a section through the composite body P-VK-11 in different magnification.

(89) Composite bodies P-VK-9 to P-VK-13 can preferably be used in apparatuses for gas separation since they combine relatively high clean gas selectivities with a high flow rate for carbon dioxide. This makes use in plants for separation of corresponding mixtures efficient, and hence improves the economic viability of the corresponding separation processes.

(90) The composite bodies P-VK11 to P-VK-13 additionally 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 gas mixtures. Typical faults or damage would be fractures in the ceramic owing to kinks or treatment with sharp objects.

(91) All composite bodies P-VK-1 to 13 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-11 to P-VK-13 can be wound onto min/mal 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”.

(92) 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.

(93) By virtue of the ceramic structure of the composite bodies P-VK-1 to 13, the thickness and porosity thereof is virtually unchanged under compressive stress. This is crucial for the entire composite body, even under high compressive stresses, to permit a virtually constant flow performance in GPU, and for the flow not to be reduced at higher pressures by a compacting porous structure.

(94) To determine these characteristics, composite bodies (P-VK-4) were cut out as a circular sample having a diameter of 35 mm and subjected to a pressure of up to 52 bar in a hydraulic press with simultaneous determination of thickness (measuring instrument from INSTRON). A diagram in which the thickness is plotted as a function of compression pressure can be used, after multiple cycles of compressive stress and relaxation, to calculate an elastic component of the change in thickness. This is only 6% for this composite body.