Patent EA-000300-B1 (EA)
Title: Synthetic separation diaphragm
Inventor: ROETTGER HENNING
IPC: B01D67/00
Filed: 1996-05-02
Abstract: 1. Synthetic separation diaphragm made of polymers soluble in ε caprolactam having flat, tubular or hollow fibre form consisting of: a) being on the surface of the diaphragm a thin separating layer A with a predetermined cut-off between 500 and 5,000,000 Dalton, wherein said separating layer A constitutes maximum 20% of total thickness of the diaphragm wall and has a through pores, b) adjoining it a rough porous, spongy supporting layer B, having cellular pores without finger pores, having a pore gradient proceeding from the border with separating layer, hydraulic resistance of which is neglectably small compared to the separating layer A and a layer C, c) adjoining to it the layer C the pores of which exceed in size the pores of the separating layer A, but smaller than the pores of the supporting layer B, and which in the combination with the separating layer A determines the hydraulic permeability of the diaphragm, but not effecting upon the cut-off and which has pores, open to the surface of the other side, wherein these opened pores are bigger, than the opened pores on the surface of the separating layer A. 2. Diaphragm of Claim 1, characterized in that the separating layer A constitutes maximum from 5 to 10% of total thickness of the membrane wall. 3. Diaphragm of Claim 2, characterized in that the separating layer A constitutes maximum from 1 to 5% of total thickness of the membrane wall 4. Diaphragm by any of the preceding Claim, characterized in that it has a predetermined cut-off between 500 to 400,000 Dalton. 5. Diaphragm of Claim 4, characterized in that it has a predetermined cut-off between 500 to 60,000 Dalton. 6. Diaphragm, characterized in that at least 50% of pores in the supporting layer B have diameter between 0.1 to 1 mkm, and, at least, 50% in the layer C have diameter of pores between 0.05 to 2 mkm, wherein pores in the layer C smaller than those in the layer B. 7. Diaphragm by any of the preceding Claim characterized in that the supporting layer constitutes from 10 to 60% and the layer C from 30 to 80% of the total thickness of the membrane. 8. Diaphragm of any the preceding Claim characterized in that it comprises at least 80% of polyethersulfon. 9. Process for producing the diaphragm by any of the preceding Claim, characterized in that of a polymer, soluble in ε caprolactam, in mixture of ε caprolactam with one or several cosolvants and also, if necessary, with insolvents and other admixtures there obtained highly-viscous, 17-27 %wt polymer solution, having at temperature of 40 degree C viscosity equal at, least, to 20 Paxs and further of this solution a flat, tubular or hollow fibre membranes are formed, wherein first at forming the polymer solution due to the temperature difference on both diaphragm surfaces a viscosity profile during the shaping of the polymer solution is set, the polymer, if necessary, with intermediate and,, if necessary, with intermediate arranging a climatologized air duct, comprising gaseous and steam-saturated insolvent of the polymer is subjected to diffusion-caused coagulation, wherein on the side with lower temperature and correspondingly with higher viscosity due to quicker coagulation than on the side of the layer C forming, the separating layer A is obtained. 10. Process of Claim 9 characterized in that for shaping the solution is used, having the temperature between 20 and 90 degree C. 11. Process of Claim 10 characterized in that for shaping the polymer solution is used having the temperature between 40 and 90 degree C and viscosity between 150 and 5 Paxs at the temperature of shaping. 12. Process of Claim 9 characterized in that for shaping the polymer solution is used having viscosity between 40 and 200 Paxs, measured at temperature 40 degree C. 13. Process of Claim 12 characterized in that for shaping the polymer solution is used having viscosity between 50 and 150 Paxs. 14. Process by any of 9-13 Claims, characterized in that the solution is shaped to obtain hollow-fiber membrane and to initiate coagulation inside the hollow-fiber membrane an inner filler is used, having viscosity between 0.03 to 0.5 Paxs measured at temperature 25 degree C, the hollow fibers are passed through the air gap, climatologized with saturated steam, and after that to complete coagulation and fix the structure the hollow fibres are passed through a settling tank, preferably, heated water tank. 15. Use of diaphragms by any of 1-8 Claims for separation processes in nanofiltration and the lower zone of ultrafiltration. 16. Use of diaphragms of Claim 13 for haemodialysis, haemodiafiltration and haemofiltration. 17. Use of diaphragms by any of 1-8 Claims to encapsulate biologically-active agents. 18. Use of diaphragms by any of 1-8 Claims to encapsulate extracorporal or intercorporaltreatment of a human being or an animal.