Classifications

• • D—TEXTILES; PAPER
  • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
  • D01D—MECHANICAL METHODS OR APPARATUS IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS
  • D01D5/00—Formation of filaments, threads, or the like
  • D01D5/24—Formation of filaments, threads, or the like with a hollow structure; Spinnerette packs therefor
  • D01D5/247—Discontinuous hollow structure or microporous structure
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D69/00—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
  • B01D69/08—Hollow fibre membranes
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D69/00—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
  • B01D69/12—Composite membranes; Ultra-thin membranes
  • B01D69/1212—Coextruded layers
• • D—TEXTILES; PAPER
  • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
  • D01D—MECHANICAL METHODS OR APPARATUS IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS
  • D01D5/00—Formation of filaments, threads, or the like
  • D01D5/24—Formation of filaments, threads, or the like with a hollow structure; Spinnerette packs therefor

Definitions

• the invention relates to a capillary membrane.
• Capillary membranes of various compositions are already well known. They are used extensively in dialysis. In order to be able to build dialyzers that are as compact as possible while ensuring a large exchange area, the capillary membranes should have the smallest possible diameter.
• hollow fiber nozzles are used for the large-scale production of capillary membranes.
• the hollow fiber membrane is produced in a precipitation spinning process.
• the polymers to be precipitated emerge from an annular gap in a nozzle arrangement, while the corresponding precipitant flows out of a central precipitant bore.
• the already known hollow fiber spinnerets usually consist of a base body made of metal, into which several bores are made. A tube is fitted into one of the bores in which a precipitant channel is formed for introducing the precipitant. Other holes form mass feed channels for a polymer that is above the previously mentioned gap emerges. In the manufacture of the previously known hollow fiber spinnerets, methods of conventional metal working are used.
• the nozzle structure is created by the assembly of both nozzle parts, whereby an inaccuracy, for example the geometry of the annulus, adds up from the manufacturing errors when manufacturing the base body and the tube. There are also possible assembly errors that can also lead to an inaccuracy of the geometry.
• these previously known hollow fiber spinnerets do not only have the inaccuracies mentioned. Rather, due to their manufacturing process, they also have a minimum size that prevents any reduction in the size of the capillary membrane.
• the capillary membranes used in previous dialysis are generally made from a specific polymer or a polymer mixture. Such membranes, each made from a polymer or a polymer mixture, have certain properties that are important for special use. Often, however, there are disadvantages associated with the choice of material, which are accepted due to the selected properties.
• the object of the invention is to provide capillary membranes that combine several positive properties and still provide a large exchange surface due to the small diameter in comparatively small dialyzers.
• capillary membranes which consist of at least two coextruded layers, wherein they have an outer diameter of less than 1 mm, preferably less than or equal to 0.45 mm. Due to the coextrusion of different layers, several outstanding properties of different polymers can be combined with each other. Due to the very small diameter, a large specific exchange area is created, which leads to small and light dialyzers.
• the capillary Membranes consist of one or more of the following materials: polysulfone (PS), polysulfone with polyvinylpyrollidone (PS / PVP), polyether sulfone (PES), polyether sulfone with polyvinylpyrollidone (PES / PVP), polyetherimide (PEI), polyetherimide with polyvinylpyrollidone (PE / PVP), polyamide (PA), polycarbonate (PC), polystyrene (PS), polymethyl methacrylate (PMMA), polyvinylidene fluoride (PVDF), polyacrylonitrile (PAN), polyimide (Pl) and / or polyurethane (PU).
• PS polysulfone
• PS / PVP polyether sulfone with polyvinylpyrollidone
• PES polyether sulfone with polyvinylpyrollidone
• PEI polyetherimide
• PEI polyetherimide with polyvinylpyrolli
• the inner layer can consist of a combination of polysulfone and polyvinylpyrollidone, while the outer layer consists of polysulfone.
• the inner layer could also consist of a combined polysulfone-polyvinylpyrollidone with a high polymer concentration, while the outer layer consisted of a combined polysulfone-polyvinylpyrollidone with a low polymer concentration.
• the membrane consists of a small-pore separation layer and a large-pore carrier layer.
• the permeability of such a coextruded capillary membrane made of several layers is significantly improved with the same separation limit.
• One of the layers can advantageously also consist of a biocompatible material, while a second layer serves as a support or actual membrane.
• Another particularly preferred embodiment of the invention consists in that one of the layers serves as a membrane, while a second layer consists of an adsorbent material. This second layer then only comes into contact with the filtrate. From these non-exhaustive examples it becomes clear that the combination of the properties of two polymers enables a multifunctional capillary membrane to be tailored to the specific needs.
• the production of the capillary membrane according to the invention is made possible by a device according to claim 6.
• Capillary membrane has a hollow fiber spinneret with a coextrusion die, the outer diameter of which is less than 1 mm.
• the hollow fiber spinneret can consist of a three-layered base body, the individual layers being plate-shaped bodies structured by means of microstructure technology, which are combined to form the base body.
• the first plate can be used as a pre-structured plate to which the second plate, which has not yet been structured, is bonded.
• the bonded second plate is then structured.
• the third plate which in turn is not structured, is then bonded onto this structured plate, which is then also subsequently structured.
• the base body advantageously consists of single-crystal silicon, gallium arsenide (GaAs) or germanium.
• the hollow fiber spinneret particularly advantageously has a central feed channel for the precipitant, mass feed channels for the polymeric material, a mass flow equalization zone and an annular gap for the first polymer, and mass feed channels for the second polymeric material, a mass flow equalization zone for these further mass feed channels and a mass ring gap for the second polymer.
• Figure 1 is a partially sectioned three-dimensional representation of a hollow fiber spinneret according to a first embodiment of the invention and Figure 2 is a schematic sectional view of the hollow fiber spinneret of Figure 1, showing three variants of the arrangement of the mass supply channels for the second polymer.
• FIGS. 1 and 2 An embodiment of the invention is explained with reference to FIGS. 1 and 2.
• a hollow fiber spinneret 10 for producing a hollow fiber coextruded from two layers is shown.
• a hollow fiber spinneret 10 with a base body 100 consisting of three individual plates 102, 104 and 106 is shown.
• the individual plates consist of single-crystal silicon.
• a feed channel 108 for the precipitant is recessed in the first plate 102.
• feed channels 110, 112 are provided for a first polymer, which open into an associated equalization zone 114.
• the equalization zone 114 surrounds a corresponding needle stump 116.
• a precipitant hole 118 is also excluded, which is surrounded by another needle stump 120 and an annular space 122. Furthermore, additional feed channels 124 with subsequent equalization zone 126 in the second plate 104 are excluded. Finally, the third plate 106 has two annular gaps 128 and 130 for the respective polymeric materials that are to be coextruded, and a needle 132 with a precipitant hole 134.
• the feed channels 124 are each different designed. While the supply channel 124 for the second polymer is only provided in the second plate 104 in the embodiment variant according to FIG. 2a, the one in the variant according to FIG. 2b runs both through the second plate 104 and through the third plate 106. In the embodiment variant According to FIG. 2c, the feed channel 124 for the second polymer runs through the second plate 104 and the first plate 102, as shown here in FIG. 2c.
• the representation according to FIG. 1 corresponds to the section according to FIG. 2a, it being clear here that 8 feed channels 112 are arranged in a star shape, while 4 feed channels 124 are arranged in a cross shape.
• 3 round wafer disks with a diameter of 100 to 300 mm are assumed. Many spinneret structures are produced from these wafers at the same time.
• the individual hollow fiber spinnerets 10 are then obtained by dividing the finished wafers.
• the separated split spinnerets can each contain a single nozzle structure, as shown here, but can also contain several nozzle structures in a nozzle structure assembly. This is achieved by not separating all of the nozzle structures that have been formed on the wafer, but rather that several nozzle structures together form a multiple nozzle unit that is cut out of the wafer along its outer contour.
• the production of the spinnerets begins with the structuring of the first wafer on both sides, which receives the elements of the first plate 102 of the spinnerets.
• the structures are produced using a series of standard lithography processes, for example masks made of photoresist, SiO, Si-N or the like, and standard etching processes.
• the standard etching methods include reactive ion etching (RIE), reactive ion deep etching (D-RIE) and cryo-etching. Special deep etching processes such as D-RIE and cryo-etching are particularly suitable.
• RIE reactive ion etching
• D-RIE reactive ion deep etching
• cryo-etching Special deep etching processes such as D-RIE and cryo-etching are particularly suitable.
• the lithography masks for the front and back must be aligned visually. Then the second wafer is bonded to this structured wafer.
• the feed channels, the equalization zone and the needle stump 120 are structured on the second plate 104 bonded to the first plate.
• the lithography mask must be optically aligned with the structures on the first plate.
• the third wafer is bonded. All of the bonding methods can be used again, as shown above.
• the nozzle structure consisting of the annular gaps and the central hole is worked out in a two-stage etching process.
• the first step is to advance the deeper central bore and the inner annular gap, in the second all structures are etched. Again, the aforementioned lithography and etching processes are used, with the use of deep etching processes being even more advisable than when processing the first wafer.
• the individual spinnerets are then cut out of the wafer using suitable separation processes, such as wafer sawing and laser processing. Three-stage or multi-stage etching processes are also conceivable.
• coextruded hollow fibers can be produced from two materials with very small diameters with high precision.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Mechanical Engineering (AREA)
• Textile Engineering (AREA)
• Separation Using Semi-Permeable Membranes (AREA)
• Spinning Methods And Devices For Manufacturing Artificial Fibers (AREA)
• External Artificial Organs (AREA)
• Laminated Bodies (AREA)

Applications Claiming Priority (3)

Publications (1)

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• 2002
  • 2002-03-13 DE DE10211051A patent/DE10211051A1/de not_active Ceased
• 2003
  • 2003-03-06 EP EP03708185A patent/EP1487566A1/de not_active Withdrawn
  • 2003-03-06 AU AU2003212311A patent/AU2003212311A1/en not_active Abandoned
  • 2003-03-06 KR KR10-2004-7013588A patent/KR20040095246A/ko not_active Application Discontinuation
  • 2003-03-06 JP JP2003574319A patent/JP2005519734A/ja active Pending
  • 2003-03-06 WO PCT/EP2003/002313 patent/WO2003076056A1/de not_active Application Discontinuation
  • 2003-03-06 US US10/505,876 patent/US20050274665A1/en not_active Abandoned
  • 2003-03-06 CA CA002478831A patent/CA2478831A1/en not_active Abandoned
  • 2003-03-06 BR BR0308318-7A patent/BR0308318A/pt not_active Application Discontinuation
• 2004
  • 2004-09-06 HR HR20040808A patent/HRP20040808A2/hr not_active Application Discontinuation

Non-Patent Citations (1)

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