GB2155356A - Process for the production of filter elements based on polysulphone - Google Patents
Process for the production of filter elements based on polysulphone Download PDFInfo
- Publication number
- GB2155356A GB2155356A GB08429137A GB8429137A GB2155356A GB 2155356 A GB2155356 A GB 2155356A GB 08429137 A GB08429137 A GB 08429137A GB 8429137 A GB8429137 A GB 8429137A GB 2155356 A GB2155356 A GB 2155356A
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- Prior art keywords
- polysulphone
- filter element
- process according
- semi
- volumes
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- 229920002492 poly(sulfone) Polymers 0.000 title claims abstract description 44
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 10
- 238000000034 method Methods 0.000 title claims description 36
- 230000008569 process Effects 0.000 title claims description 34
- 239000011148 porous material Substances 0.000 claims abstract description 45
- 238000005345 coagulation Methods 0.000 claims abstract description 37
- 230000015271 coagulation Effects 0.000 claims abstract description 37
- 230000006641 stabilisation Effects 0.000 claims abstract description 28
- 238000011105 stabilization Methods 0.000 claims abstract description 28
- 238000001471 micro-filtration Methods 0.000 claims abstract description 14
- 239000007788 liquid Substances 0.000 claims abstract description 13
- 239000002245 particle Substances 0.000 claims abstract description 6
- 238000000108 ultra-filtration Methods 0.000 claims abstract description 5
- 229920002521 macromolecule Polymers 0.000 claims abstract description 3
- 239000012528 membrane Substances 0.000 claims description 57
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 22
- 239000002904 solvent Substances 0.000 claims description 11
- KFZMGEQAYNKOFK-UHFFFAOYSA-N Isopropanol Chemical compound CC(C)O KFZMGEQAYNKOFK-UHFFFAOYSA-N 0.000 claims description 9
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims description 8
- 239000000203 mixture Substances 0.000 claims description 7
- 238000005728 strengthening Methods 0.000 claims description 7
- 238000005266 casting Methods 0.000 claims description 5
- 235000019441 ethanol Nutrition 0.000 claims description 5
- 239000011265 semifinished product Substances 0.000 claims description 5
- 238000011049 filling Methods 0.000 claims description 4
- SECXISVLQFMRJM-UHFFFAOYSA-N N-Methylpyrrolidone Chemical compound CN1CCCC1=O SECXISVLQFMRJM-UHFFFAOYSA-N 0.000 claims description 3
- 239000002202 Polyethylene glycol Substances 0.000 claims description 3
- 229920001223 polyethylene glycol Polymers 0.000 claims description 3
- 238000005406 washing Methods 0.000 claims description 3
- 238000007654 immersion Methods 0.000 claims description 2
- 230000003014 reinforcing effect Effects 0.000 claims description 2
- 238000005245 sintering Methods 0.000 claims description 2
- 238000002791 soaking Methods 0.000 claims 1
- 238000000926 separation method Methods 0.000 abstract description 6
- 238000002474 experimental method Methods 0.000 description 17
- 239000010410 layer Substances 0.000 description 6
- ZMXDDKWLCZADIW-UHFFFAOYSA-N N,N-Dimethylformamide Chemical compound CN(C)C=O ZMXDDKWLCZADIW-UHFFFAOYSA-N 0.000 description 3
- 239000011347 resin Substances 0.000 description 3
- 229920005989 resin Polymers 0.000 description 3
- 239000000654 additive Substances 0.000 description 2
- 239000000706 filtrate Substances 0.000 description 2
- 238000009434 installation Methods 0.000 description 2
- 239000011159 matrix material Substances 0.000 description 2
- 230000035699 permeability Effects 0.000 description 2
- -1 polyethylene Polymers 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- 239000004698 Polyethylene Substances 0.000 description 1
- 239000004743 Polypropylene Substances 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 239000012153 distilled water Substances 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 229920000573 polyethylene Polymers 0.000 description 1
- 229920001155 polypropylene Polymers 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 239000002344 surface layer Substances 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D71/00—Semi-permeable membranes for separation processes or apparatus characterised by the material; Manufacturing processes specially adapted therefor
- B01D71/06—Organic material
- B01D71/66—Polymers having sulfur in the main chain, with or without nitrogen, oxygen or carbon only
- B01D71/68—Polysulfones; Polyethersulfones
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D67/00—Processes specially adapted for manufacturing semi-permeable membranes for separation processes or apparatus
- B01D67/0002—Organic membrane manufacture
- B01D67/0009—Organic membrane manufacture by phase separation, sol-gel transition, evaporation or solvent quenching
- B01D67/0016—Coagulation
- B01D67/00165—Composition of the coagulation baths
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2323/00—Details relating to membrane preparation
- B01D2323/08—Specific temperatures applied
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2323/00—Details relating to membrane preparation
- B01D2323/12—Specific ratios of components used
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2325/00—Details relating to properties of membranes
- B01D2325/02—Details relating to pores or porosity of the membranes
- B01D2325/022—Asymmetric membranes
- B01D2325/0233—Asymmetric membranes with clearly distinguishable layers
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2325/00—Details relating to properties of membranes
- B01D2325/04—Characteristic thickness
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Dispersion Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Separation Using Semi-Permeable Membranes (AREA)
- Manufacture Of Porous Articles, And Recovery And Treatment Of Waste Products (AREA)
Abstract
In the production of polysulphone-based filter elements cell structure reproducibility is improved by carrying out coagulation and stabilization of the polysulphonate solution in a liquid bath over a period of about 30 seconds to 240 seconds. a) at temperatures from below 0 DEG C to about 15 DEG C for producing filter elements of pore size 0.1 nm to 1 nm suitable for the separation of macromolecules (ultrafiltration), or b) at temperatures from about 15 DEG C to about 45 DEG C for producing filter elements of asymmetric cell structure and pore size 0.05 mu m to 10 mu m suitable for the separation of particles (microfiltration) or c) at temperatures from about 45 DEG C to 80 DEG C for the production of filter elements of a symmetric cell structure and a pore size 0.05 mu m to 10 mu m for the separation of particles (microfiltration), the filter element being subsequently washed in a liquid bath. )
Description
SPECIFICATION
Process for the production of filter elements based on polysulphone
This invention relates to the production of filter elements based on polysulphone, in the form of filter membranes, membrane/deep filter combinations or filter bodies by a process in which a semi-finished filter element is formed from a solution of polysulphone containing a pore former and the polysulphone of this semi-finished product is coagulated by immersion in a liquid bath.
Such a process for the production of anisotropic membranes is known from European Patent Application 81 301 074.110036315. This process is said to be suitable for the production of filter membranes, inter alia from polysulphone. For this purpose, a solution of polysulphone, molecular weight 3,500, in dimethyl formamide with the addition of isopropyl alcohol is shaped to form a membrane and immediately after it has been shaped or cast it is coagulated in water which is maintained at the surrounding temperature. This process, however, cannot be used for obtaining controlled and previously calculated or determined properties of the filter membrane as regards its porosity, pore size or cell structure.It is therefore proposed in European Patent Application 81 301 074.1/0036315 to obtain different properties in the filter membranes by producing the filter membranes from different resins or resin mixtures. In particular, the process disclosed in European Patent Application 81 301 074.1/0036315 can only be used for producing filter membranes with a highly an isotropic structure.
By contrast, it is an object of the present invention to provide a process for the production of polysulphone-based filter elements in which the nature of the cell structure and the porosity and pore size of the filter element can be predetermined by a simple and easily controlled modification of only a few process parameters independently of one another, and the nature of the cell structure can be controlled by different process parameters from those used for the porosity and pore size of the filter element.
To solve this problem in accordance with the invention, the proportions in which polysulphone, solvent and pore former are mixed in the polysulphone solution are determined according to the desired porosity and pore size of the filter element, and coagulation with stabilization of the filter element is carried out in the liquid bath over a period of about 30 seconds to 240 seconds.
a) at temperatures from below 0 C to about 15 C for forming filter elements with a pore size of from 0.1 nm to 1 nm in the active separating layer for the separation of macromolecules by ultrafiltration or b) at temperatures of about 15 C to 45 C for forming filter elements with an asymmetric cell structure and a pore size in the active filter layer of from 0.05 1#m to 10 1tom for separating particles by micro filtration or c) at temperatures from about 45 C to 80 C for forming filter elements with a symmetric cell structure and a pore size of from 0.05 1#m to to 10,wm for the separation of particles by microfiltration and the filter element is then washed in at least one other liquid bath.
In the process according to the invention, therefore, the nature of the cell structure is determined mainly by the temperature maintained in the coagulation and stabilization bath but the choice of the particular temperature has virtually no influence on the porosity or pore size in the filter element. The process according to the invention is particularly distinguished by the fact it is highly reproducible.
The invention provides a clear separation between control of the cell structure and control of the porosity and pore size in the filter element. It has been found that the temperature control of the coagulation and stabilization bath, which influences the nature of the cell structure, has no significant influence on the porosity and pore size in the filter element. The latter features, which are important for the filter element, are mainly influenced by the composition of the polysulphone solution, in particular the proportions in which resin, solvent and pore former are mixed. In the process according to the invention, these proportions in turn have virtually no influence on the nature of the cell structure obtained.
An important improvement to the process according to the invention may be achieved by prestrengthening the semi-finished filter element in air at an atmospheric humidity of about 40% to 100%, preferably 50% to 80%, over a period of from 30 seconds to 180 seconds and then transferring the semi-finished filter element to the liquid bath for coagulation and stabilization. The desired control of the cell structure by suitable adjustment of the coagulation and stabilization bath can be even further improved by suitable control of the length of time for which this pre-strengthening in moist air is carried out.The cell structure, which is controlled by the temperature maintained in the coagulation and stabilization bath, is thus made even more accurately reproducible, namely by using short pre-strengthening times for producing an asymmetric cell structure and relatively long pre-strengthening times for producing symmetric cell structures. The atmospheric moisture maintained during pre-strengthening has relatively little influence on the cell structure obtained but has rather more influence on the porosity and pore size in the filter element.
A wide variety of filter elements based on polysulphone may be produced by the process according to the invention. For example, a semi-finished filter element in the form of a film or layer may be formed by casting the polysulphone solution containing pore former on a support with a smooth surface. In this procedure, a reinforcing layer of woven or non-woven web may be imbedded in one surface of the semi-finished filter element in the form of the film or layer while the polysulphone solution is being poured out or immediately after it has been poured out.
One possible method of producing similar filter elements in accordance with the invention consists, for example, of forming the semi-finished filter element by impregnating a woven a non-woven web with the polysulphone solution containing pore former.
The semi-finished filter element may also be formed by extruding the polysulphone solution containing pore former to produce a film in the form of a band ortube.
According to another example of producing the desired filter elements, a coarsely porous filter body which has been produced by sintering or some other means is steeped in or impregnated with the polysulphone solution containing pore former to form a semi-finished filter element, which is then transferred to the liquid bath for coagulation and stabilization of the polysulphone filling, optionally after pre-strengthening of its polysulphone filling in air.
According to the invention, the coagulation and stabilization bath may consist of water. Various additives may be introduced into the water of the coagulation and stabilization bath, either singly or in combination, e.g. solvents and/or pore formers andlor alcohol. Thus the same solvent as that used for the polysulphone solution may be added to the coagulation and stabilization bath in quantities of from 5 volumes % to 20 volumes %, preferably about 10 volumes %. Furthermore, for example, the same pore former as that used in the polysulphone solution may be added in quantities of about 1 volume % to 35 volumes %, preferably 10 volumes % to 20 volumes %.
Ethyl alcohol may also be added to the water of the coagulation and stabilization bath in quantities of about 5 volumes %to 20 volumes %, preferably about 10 volumes %. Instead of ethyl alcohol, comparable quantities of isopropyl alcohol may be added to the water of the coagulation and stabilization bath.
Examples of the invention are described in more detail below with reference to the drawings, in which
Figure 1 is a graphic representation of the rates of flow of water through the membranes produced according to the invention, measured per unit surface area, in dependence upon the temperature of the coagulation bath used in the formation of the membrane;
Figures 2 to 7 are electron microscopic photographs of a filter membrane produced by the process according to the invention at a coagulation bath temperature of 12 C, and
Figures 8 to 14 are electron microscopic photographs of a filter membrane produced by the process according to the invention at a coagulation bath temperature of 50 C.
EXAMPLE 1 A polysulphone solution having the following composition:
12% by weight polysulphone, molecular weight 1700,
25% by weight N-methylpyrrolidone as solvent and
63% by weight polyethylene glycol, molecular weight 400, as pore former, was cast on a smooth support, for example a strip of polyethylene or polypropylene, to form a film having a thickness of approximately 200 to 300. 'ism (thickness of wet film). After casting, the film was kept in air at an atmospheric humidity of about 50% to 80% for a period of approximately 30 seconds to 1 minute and then transferred to a coagulation and stabilization bath of water free from additives. The temperature of the coagulation and stabilization bath was regulated as follows:
Experiment 1.1 bath temperature 100C Experiment 1.2 bath temperature 20 C Experiment 1.3 bath temperature 30 C Experiment 1.4 bath temperature 50 C Experiment 1.5 bath temperature 700C In all these experiments, the dwell time of the membrane in the coagulation and stabilization bath was about 90 seconds. This was followed by washing in water at 20 C to 40 C until the membrane was completely free from solvent.
Stable membranes were obtained in all the experiments, and the membranes were then investigated for their characteristic properties.
EXAMPLE2:
A polysulphone solution having the following composition: 15.3% by weight polysulphone, molecular weight 1700,
24.% by weight N-methyl pyrrolidone as solvent and
60.7% by weight polyethylene glycol, molecular weight 400, as pore former was cast on a smooth as in example 1 to form a layer having a thickness of about 200 #m to 300 ipm (of wet film). After casting, the solution was kept in moist air (atmospheric humidity 50 to 80%) for about 30 seconds to 1 minute.The film obtained was then treated in a coagulation bath containing water as in Example 1, the bath being adjusted to different temperatures in successive experiments as indicated below to produce membranes with different properties:
Experiment 2.1 bath temperature 15 C Experiment 2.2 bath temperature 2000 Experiment 2.3 bath temperature 30 C Experiment 2.4 bath temperature 400C Experiment 2.5 bath temperature 50 C Experiment 2.6 bath temperature 700C Stable filter membranes were obtained in all the experiments after washing as in Example 1, and these membranes were then investigated for their characteristic properties.
Permeability of the filter membranes to water: The water permeability of the membranes was determined as a major indication of the cell structure, porosity and pore size. This was done by measuring the rate of flow of water through each membrane per unit surface area and unit time. Previously filtered, distilled water was used as test medium and the pressure drop across the membrane was adjusted to 0.9 bar.
In the graph of Figure 1, the rate of throughflow of water is given in
ml 10-3 cm2 in dependence upon the temperature of the coagulation bath.
Figure 1 contains two graphs. The graph labelled "mixture 1" relates to filter membranes produced according to Example 1 while the graph labelled "mixture 2" relates to filter membranes produced according to Example 2.
Both graphs show that the relationship between the rate of through-flow of water and the temperature of the coagulation bath is virtually linear at temperatures from 1 0#C to about 4000. The higher the temperature of the coagulation bath, the greater is the rate of flow of water through the membranes of both groups. At coagulation bath temperatures above 40 C, the rate of through-flow of water continues to increase with increasing temperature of the coagulation and stabilization bath but the rate of increase is less rapid than at temperatures up to 400C of the coagulation and stabilization bath.
Electron microscopic photograph of the structure: Figures 2 to 14 are electron microscopic photographs of membranes produced from polysulphone solution according to Example 1. Figures 2 to 7 are electron microscopic photographs of a polysulphone filter membrane produced with the coagulation bath maintained at 1200. Figure 2 shows a cross section through the edge of such a membrane in 480 times enlargement (479.6 times). As may be seen from Figure 2, the membrane 11 has a closed skin 12 on its upper side and underneath this a substructure 13 with finger-shaped holes 14. Figure 3 shows a section of the skin 12 on the surface of the membrane 11 in 7500 times enlargement (7506 times). The structure of this surface skin is so dense that the membrane has all the properties of an ultra filtration membrane.The almost completely closed structure of the surface skin may be seen from Figures 4 to 6 which are electron microscopic photographs of the closed upper side of the filter membrane 11, Figure 4 being a 750 times enlargement (748 times), Figure 5 a 7500 times enlargement (7506 times) and Figure 6 a 15,000 times enlargement (15,012 times). These electron microscopic photographs on different scales show, in conjunction with Figures 2 and 3, that a virtually pore-free surface layer is formed, which is impermeable to water used as test medium. As may be seen from Figure 1, virtually complete imperviousness of the surface skin 12 to water would occur if the temperature of the coagulation and stabilization bath were even lower, so that the typical function of an ultrafilter, namely diffusion of the filtrate through the intermolecular spaces of the surface skin 12, are provided.
The sub-structure 13 then only has a supporting function for the surface skin 12 which functions as the filter element proper. This is particularly clear from Figure 7, which shows the underside of the membrane 11 enlarged 165 times (164.64times). It may be seen that the sub-structure 13 in that case has a coarse porosity and allows the filtrate permeating through the surface skin 12 to pass through without exerting any influence on it.
Figures 8 to 14, by contrast, show a filter membrane with an almost symmetrical porous structure produced according to experiment 1.4 of Example 1, namely with the coagulation and stabilization bath maintained at a temperature of 50 C. Filter membrane 21 obtained in this manner is a typical micro filtration membrane, i.e. a membrane which has an almost symmetrical porous structure throughout its thickness between the two surfaces 22 and 23.
Figure 8 is an electron microscopic photograph showing this microfiltration membrane 21 in cross section through an edge enlarged 740 times (740 times). It may be seen from Figure 8 that the pores are possibly slightly smaller in the region of the upper surface 22 than in the region of the lower surface 23 but it is clear that the pore structure is substantially symmetrical throughout. The fact that the differences in pore size between the region of the upper surface 22 and the region of the lower surface 23 are only slight is evident from a comparison of Figures 9 and 10 which are electron microscopic photographs of edge cross sections through the microfiltration membrane 21, Figure 9 being taken in the region of the upper surface 22 and
Figure 10 in the region of the lower surface 23.
Figure 11 is an electron microscopic photograph of the microfiltration membrane 21 of Figure 8 taken from the upper surface, i.e. showing the upper surface 22 in 1100 times enlargement (1100times). It may be seen from Figure 11 that the pores of the microfiltration membrane 21 open on to the upper surface of the membrane. A comparison with Figure 13 shows that virtually the same conditions also prevail on the lower surface of the microfiltration membrane 21. If one takes into account that Figure 13 is an electron microscopic photograph of the underside of the membrane enlarged 750 times (750.75 times), the comparison between Figures 11 and 13 reveals that the openings of the pores on the underside of the microfiltration membrane 21 are not significantly largerthan on the upper side.Figure 12 is an electron microcopic photograph of the upper side of the microfiltration membrane 21 of Figure 8 enlarged 7500 times (7480 times) and shows a more or less regular framework structure of the membrane matrix. The structure of the matrix on the underside of the membrane 21, on the other hand, is slightly less regular, as may be seen from Figure 14 (electron microscopic photograph in 3000 times enlargement (2945.8 times)). However, no significant difference in porosity and pore size can be detected between Figures 12 and 14.
The film thicknesses given in connection with the exemplary embodiments described above and the casting speeds of from 0.5 m to 1.0 m per minute provided in these examples depend to a certain extend on the construction and dimensions of the laboratory installations used for carrying out the experiments.
Whereas a final membrane thickness of about 70,ffim, which is the value which can be achieved in such installations, is sufficient for ultra-filtration membranes, the possibility of also obtaining greater thicknesses would be desirable for symmetric membranes, and this may be achieved by suitable design of the production plant.
Claims (16)
1. Process for the production of filter elements based on polysulphone, in the form of filter means selected from filter membranes, membranes/deep filter combinations or filter bodies, in which process a semi-finished filter element is formed from a solution of polysulphone containing a pore former and the polysulphone of this semi-finished product is coagulated by immersion in a liquid bath, wherein the proportions in which polysulphone, solvent and pore former are mixed in the polysulphone solution are adjusted according to the desired porosity and pore size of the filter element, and wherein coagulation with stabilization of the filter element is carried out in the liquid bath for a period of about 30 seconds to about 240 seconds and
a) at a temperature from below 0#Cto about 150C for forming filter elements having a pore size of from 0.1 nm to 1 nm in the active separating layer for separating macromolecules by ultra filtration or
b) at temperatures from about 1 50C to about 45'C for forming filter elements with an asymmetric cell structure and a pore size of the active separating layer from 0.05 1#m to 10 ,#m for separating particles by microfiltration or
c) at temperatures in the range from about 450C to 80 C for forming filter elements with a symmetric cell structure and pore size of from 0.05 ; > m to 10,film for separating particles by microfiltration and the filter element is subsequently washed in at least one other liquid bath.
2. Process according to claim 1, wherein pre-strengthening of the semi-finished filter element is carried out in air with an atmospheric moisture of about 40% to 100%, preferably about 50% to 80%, over a period of from 30 seconds to 180 seconds and the semi-finished filter element is then transferred to the liquid bath for coagulation and stabilization.
3. Process according to claim 2, wherein pre-strengthening is carried out for a length of time depending on the desired structure of the filter element, namely for a shorter time for producing filter elements having an asymmetric structure and a longer time for producing filter elements with a symmetric structure.
4. Process according to any one of claims 1 to 3, wherein a semi-finished filter element in the form of a film or layer is formed by casting the polysulphone solution containing pore former on a support having a smooth surface.
5. Process according to claim 4, wherein a reinforcing layer of woven or non-woven web is imbedded in one of the surfaces of the semi-finished filter element consisting of a film or layer while the polysulphone solution is being poured out or immediately after it has been poured out.
6. Process according to any one of the claims 1 to 3, wherein the semi-finished filter element is formed by impregnating a woven or non-woven web with the polysulphone solution containing pore former.
7. Process according to any one of the claims 1 to 3, wherein the semi-finished filter element is formed by extruding the polysulphone solution containing pore former to form a band or tube of film.
8. Process according to any one of the claims 1 to 3, wherein the semi-finished filter element is formed by soaking or impregnating a coarse porous filter body produced by sintering or some other means with the polysulphone solution containing pore former and wherein this semi-finished filter element is transferred to the liquid bath for coagulation and stabilization of the polysulphone filling, optionally after prestrengthening of its polysulphone filling in air.
9. Process according to any one of claims 1 to 8, wherein the coagulation and stabilization bath contains water with the addition of solvents and/or pore formers and/or alcohol.
10. Process according to claim 9, wherein the coagulation and stabilization bath contains an addition of the same solvent as that used for the polysulphone solution, in quantities of from 5 volumes % to 20 volumes %, preferably about 10 volumes %.
11. Process according to claim 9 wherein the coagulation and stabilization bath contains an addition of the same pore former as the polysulphone solution in quantities from about 1 volume % to 35 volumes %, preferably from 10 volumes % to 20 volumes %.
12. Process according to one of the claims 9 wherein the coagulation and stabilization bath contains an addition of ethyl alcohol in quantities of from 5 volumes %to 20 volumes %, preferably about 10 volumes %.
13. Process according to one of the claims 9 wherein the coagulation and stabilization bath contains an addition of isopropyl alcohol in quantities from about 5 volumes % to 20 volumes %, preferably about 10 volumes %.
14. Process according to claim 1 wherein washing with water is carried out in one or more baths at temperatures from 20 C to 40"C over a period of from 30 minutes to several hours.
15. Process according to claim 1 wherein a mixture is prepared from 10to 16% byweightof polysuiphone, having a molecular weight of 170022 to 28% by weight of N-methylpyrrolidon as solvent the remainder being polyethylene glycol having a molecular weight of 400, as pore former, a semi-finished product having the form of the desired filter element is produced from this polysulphone solution, this semi-finished product is prestrengthened in moist air for a period of from 30 to 60 seconds, the semi-finished product is then coagulated and stabilized in a liquid bath which is maintained at a temperature selected according to the desired structure of the filter element to be produced, and the filter element is then washed in water.
16. Process according to claim 15, wherein the polysulphone solution is poured out to form a layer having a thickness of 200,pWm or more (thickness of the wet layer) to produce filter membranes.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19833342824 DE3342824A1 (en) | 1983-11-26 | 1983-11-26 | METHOD FOR PRODUCING FILTER ELEMENTS BASED ON POLYSULPHONE |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB8429137D0 GB8429137D0 (en) | 1984-12-27 |
| GB2155356A true GB2155356A (en) | 1985-09-25 |
| GB2155356B GB2155356B (en) | 1987-03-04 |
Family
ID=6215334
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB08429137A Expired GB2155356B (en) | 1983-11-26 | 1984-11-19 | Process for the production of filter elements based on polysulphone |
Country Status (3)
| Country | Link |
|---|---|
| JP (1) | JPH0661437B2 (en) |
| DE (1) | DE3342824A1 (en) |
| GB (1) | GB2155356B (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6106897A (en) * | 1996-08-09 | 2000-08-22 | Scapa Group Plc | Polymer pore structure |
| GB2316015B (en) * | 1996-08-10 | 2000-08-30 | Scapa Group Plc | Polymer pore structure |
| US6565782B1 (en) | 1996-12-12 | 2003-05-20 | Pall Corporation | Highly asymmetric, hydrophilic, microfiltration membranes having large pore diameters |
| WO2004029076A2 (en) * | 2002-09-25 | 2004-04-08 | Novo Nordisk A/S | Purification process comprising microfiltration at elevated temperatures |
| US7229554B2 (en) | 2002-09-25 | 2007-06-12 | Novo Nordisk A/S | Purification process comprising microfiltration at elevated temperatures |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AU593866B2 (en) * | 1985-12-23 | 1990-02-22 | Pall Corporation | Microporous membrane and method of making the same |
| IL78169A0 (en) * | 1986-03-17 | 1986-07-31 | Weizmann Kiryat Membrane Prod | Novel membranes and process for making them |
| DE3829752A1 (en) * | 1988-09-01 | 1990-03-22 | Akzo Gmbh | INTEGRAL ASYMMETRICAL POLYAETHERSULPHONE MEMBRANE, METHOD FOR THE PRODUCTION AND USE FOR ULTRAFILTRATION AND MICROFILTRATION |
| US4970034A (en) * | 1988-09-23 | 1990-11-13 | W. R. Grace & Co.-Conn. | Process for preparing isotropic microporous polysulfone membranes |
| US5980746A (en) * | 1996-11-14 | 1999-11-09 | Pall Corporation | Membrane and methods of preparing and using same |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1350342A (en) * | 1971-05-24 | 1974-04-18 | Rhone Poulenc Sa | Process for the preparation of anisotropic semi-permeable membranes of polyaryl ether/sulphones |
| GB1350343A (en) * | 1971-05-24 | 1974-04-18 | Rhone Poulenc Sa | Preparation of anisotropic semi-permeable membranes of polyaryl ether/sulphones |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS518179A (en) * | 1974-07-11 | 1976-01-22 | Daicel Ltd | Sentakutokaseikobunshimakuoyobisono seizoho |
| JPS5426283A (en) * | 1977-08-01 | 1979-02-27 | Mitsui Petrochem Ind Ltd | Preparation of semipermeable membrane of polysulfone |
| JPS5531474A (en) * | 1978-08-29 | 1980-03-05 | Nitto Electric Ind Co Ltd | Selective permeable membrane |
| JPS55102416A (en) * | 1979-02-01 | 1980-08-05 | Sumitomo Bakelite Co Ltd | Preparation of separated film |
| JPS55106243A (en) * | 1979-02-07 | 1980-08-14 | Nitto Electric Ind Co Ltd | Preparation of microporous polymer membrane |
| CA1202837A (en) * | 1980-03-14 | 1986-04-08 | Wolfgang J. Wrasidlo | Asymmetric membranes and process therefor |
| DE3161345D1 (en) * | 1980-03-28 | 1983-12-15 | Pennwalt Corp | Method for preparing a membrane of a film-forming non-sulfonated sulfone polymer |
| JPS5794310A (en) * | 1980-12-05 | 1982-06-11 | Daicel Chem Ind Ltd | Production of semipermeable membrane made of polysulfone |
-
1983
- 1983-11-26 DE DE19833342824 patent/DE3342824A1/en active Granted
-
1984
- 1984-11-19 GB GB08429137A patent/GB2155356B/en not_active Expired
- 1984-11-26 JP JP59248260A patent/JPH0661437B2/en not_active Expired - Lifetime
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1350342A (en) * | 1971-05-24 | 1974-04-18 | Rhone Poulenc Sa | Process for the preparation of anisotropic semi-permeable membranes of polyaryl ether/sulphones |
| GB1350343A (en) * | 1971-05-24 | 1974-04-18 | Rhone Poulenc Sa | Preparation of anisotropic semi-permeable membranes of polyaryl ether/sulphones |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6106897A (en) * | 1996-08-09 | 2000-08-22 | Scapa Group Plc | Polymer pore structure |
| GB2316015B (en) * | 1996-08-10 | 2000-08-30 | Scapa Group Plc | Polymer pore structure |
| US6565782B1 (en) | 1996-12-12 | 2003-05-20 | Pall Corporation | Highly asymmetric, hydrophilic, microfiltration membranes having large pore diameters |
| US6939468B2 (en) | 1996-12-12 | 2005-09-06 | Pall Corporation | Highly asymmetric, hydrophilic, microfiltration membranes having large pore diameters |
| US7125493B2 (en) | 1996-12-12 | 2006-10-24 | Pall Corporation | Highly asymmetric, hydrophilic, microfiltration membranes having large pore diameters |
| WO2004029076A2 (en) * | 2002-09-25 | 2004-04-08 | Novo Nordisk A/S | Purification process comprising microfiltration at elevated temperatures |
| WO2004029076A3 (en) * | 2002-09-25 | 2004-05-13 | Novo Nordisk As | Purification process comprising microfiltration at elevated temperatures |
| US7229554B2 (en) | 2002-09-25 | 2007-06-12 | Novo Nordisk A/S | Purification process comprising microfiltration at elevated temperatures |
Also Published As
| Publication number | Publication date |
|---|---|
| GB8429137D0 (en) | 1984-12-27 |
| JPS60187309A (en) | 1985-09-24 |
| DE3342824A1 (en) | 1985-06-05 |
| JPH0661437B2 (en) | 1994-08-17 |
| GB2155356B (en) | 1987-03-04 |
| DE3342824C2 (en) | 1989-01-19 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |