GB2053023A - Dialyser comprising hollow fibre membranes - Google Patents
Dialyser comprising hollow fibre membranes Download PDFInfo
- Publication number
- GB2053023A GB2053023A GB8020020A GB8020020A GB2053023A GB 2053023 A GB2053023 A GB 2053023A GB 8020020 A GB8020020 A GB 8020020A GB 8020020 A GB8020020 A GB 8020020A GB 2053023 A GB2053023 A GB 2053023A
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- United Kingdom
- Prior art keywords
- dialyser
- polyurethane
- solution
- filaments
- solvent
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 239000012528 membrane Substances 0.000 title claims abstract description 13
- 239000000835 fiber Substances 0.000 title description 3
- 229920002635 polyurethane Polymers 0.000 claims abstract description 33
- 239000004814 polyurethane Substances 0.000 claims abstract description 33
- 239000002245 particle Substances 0.000 claims abstract description 17
- 238000000034 method Methods 0.000 claims abstract description 15
- 239000003463 adsorbent Substances 0.000 claims abstract description 12
- 229920002678 cellulose Polymers 0.000 claims abstract description 9
- 239000001913 cellulose Substances 0.000 claims abstract description 9
- 239000004627 regenerated cellulose Substances 0.000 claims abstract description 8
- 238000007789 sealing Methods 0.000 claims abstract description 7
- 239000012465 retentate Substances 0.000 claims abstract description 4
- 239000003795 chemical substances by application Substances 0.000 claims description 18
- 239000003085 diluting agent Substances 0.000 claims description 18
- 239000002904 solvent Substances 0.000 claims description 18
- KFZMGEQAYNKOFK-UHFFFAOYSA-N Isopropanol Chemical compound CC(C)O KFZMGEQAYNKOFK-UHFFFAOYSA-N 0.000 claims description 16
- -1 hydroxyl compound Chemical class 0.000 claims description 15
- SVONRAPFKPVNKG-UHFFFAOYSA-N 2-ethoxyethyl acetate Chemical compound CCOCCOC(C)=O SVONRAPFKPVNKG-UHFFFAOYSA-N 0.000 claims description 13
- LYCAIKOWRPUZTN-UHFFFAOYSA-N Ethylene glycol Chemical compound OCCO LYCAIKOWRPUZTN-UHFFFAOYSA-N 0.000 claims description 13
- 238000005507 spraying Methods 0.000 claims description 11
- 125000005442 diisocyanate group Chemical group 0.000 claims description 10
- SZXQTJUDPRGNJN-UHFFFAOYSA-N dipropylene glycol Chemical compound OCCCOCCCO SZXQTJUDPRGNJN-UHFFFAOYSA-N 0.000 claims description 10
- ZJCCRDAZUWHFQH-UHFFFAOYSA-N Trimethylolpropane Chemical compound CCC(CO)(CO)CO ZJCCRDAZUWHFQH-UHFFFAOYSA-N 0.000 claims description 9
- 125000002887 hydroxy group Chemical group [H]O* 0.000 claims description 8
- WGCNASOHLSPBMP-UHFFFAOYSA-N hydroxyacetaldehyde Natural products OCC=O WGCNASOHLSPBMP-UHFFFAOYSA-N 0.000 claims description 7
- UPMLOUAZCHDJJD-UHFFFAOYSA-N 4,4'-Diphenylmethane Diisocyanate Chemical compound C1=CC(N=C=O)=CC=C1CC1=CC=C(N=C=O)C=C1 UPMLOUAZCHDJJD-UHFFFAOYSA-N 0.000 claims description 5
- 239000004359 castor oil Substances 0.000 claims description 5
- 235000019438 castor oil Nutrition 0.000 claims description 5
- ZEMPKEQAKRGZGQ-XOQCFJPHSA-N glycerol triricinoleate Natural products CCCCCC[C@@H](O)CC=CCCCCCCCC(=O)OC[C@@H](COC(=O)CCCCCCCC=CC[C@@H](O)CCCCCC)OC(=O)CCCCCCCC=CC[C@H](O)CCCCCC ZEMPKEQAKRGZGQ-XOQCFJPHSA-N 0.000 claims description 5
- 238000000502 dialysis Methods 0.000 claims description 4
- 238000001704 evaporation Methods 0.000 claims description 4
- 230000008020 evaporation Effects 0.000 claims description 4
- 229920001515 polyalkylene glycol Polymers 0.000 claims description 4
- 238000004519 manufacturing process Methods 0.000 claims description 2
- 239000000203 mixture Substances 0.000 abstract description 8
- XEKOWRVHYACXOJ-UHFFFAOYSA-N Ethyl acetate Chemical compound CCOC(C)=O XEKOWRVHYACXOJ-UHFFFAOYSA-N 0.000 description 12
- 239000008280 blood Substances 0.000 description 7
- 210000004369 blood Anatomy 0.000 description 7
- 239000007921 spray Substances 0.000 description 6
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 5
- 230000015572 biosynthetic process Effects 0.000 description 5
- 238000006243 chemical reaction Methods 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 238000001914 filtration Methods 0.000 description 4
- 238000001631 haemodialysis Methods 0.000 description 4
- PNEYBMLMFCGWSK-UHFFFAOYSA-N Alumina Chemical compound [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 3
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 3
- 229910052799 carbon Inorganic materials 0.000 description 3
- 230000002349 favourable effect Effects 0.000 description 3
- 239000012535 impurity Substances 0.000 description 3
- 239000007788 liquid Substances 0.000 description 3
- 239000007787 solid Substances 0.000 description 3
- 238000009835 boiling Methods 0.000 description 2
- 150000002168 ethanoic acid esters Chemical class 0.000 description 2
- 239000007863 gel particle Substances 0.000 description 2
- 229920001451 polypropylene glycol Polymers 0.000 description 2
- 239000000047 product Substances 0.000 description 2
- 239000007858 starting material Substances 0.000 description 2
- 238000003756 stirring Methods 0.000 description 2
- 238000003786 synthesis reaction Methods 0.000 description 2
- 239000000020 Nitrocellulose Substances 0.000 description 1
- 239000004721 Polyphenylene oxide Substances 0.000 description 1
- 239000002250 absorbent Substances 0.000 description 1
- 230000002745 absorbent Effects 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 150000001298 alcohols Chemical class 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 239000008199 coating composition Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 230000001427 coherent effect Effects 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000004132 cross linking Methods 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 150000002009 diols Chemical class 0.000 description 1
- 201000010099 disease Diseases 0.000 description 1
- 208000037265 diseases, disorders, signs and symptoms Diseases 0.000 description 1
- 239000000428 dust Substances 0.000 description 1
- 229920001971 elastomer Polymers 0.000 description 1
- 150000002148 esters Chemical class 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 229930195733 hydrocarbon Natural products 0.000 description 1
- 150000002430 hydrocarbons Chemical class 0.000 description 1
- 150000002576 ketones Chemical class 0.000 description 1
- 239000004922 lacquer Substances 0.000 description 1
- 210000004185 liver Anatomy 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 229920001220 nitrocellulos Polymers 0.000 description 1
- 239000012299 nitrogen atmosphere Substances 0.000 description 1
- 231100000252 nontoxic Toxicity 0.000 description 1
- 230000003000 nontoxic effect Effects 0.000 description 1
- 231100000572 poisoning Toxicity 0.000 description 1
- 230000000607 poisoning effect Effects 0.000 description 1
- 229920000570 polyether Polymers 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 239000003380 propellant Substances 0.000 description 1
- 239000000376 reactant Substances 0.000 description 1
- 239000011541 reaction mixture Substances 0.000 description 1
- 238000010992 reflux Methods 0.000 description 1
- 201000000980 schizophrenia Diseases 0.000 description 1
- 229920002545 silicone oil Polymers 0.000 description 1
- 239000011877 solvent mixture Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000009827 uniform distribution Methods 0.000 description 1
- 229920002554 vinyl polymer Polymers 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D63/00—Apparatus in general for separation processes using semi-permeable membranes
- B01D63/02—Hollow fibre modules
- B01D63/021—Manufacturing thereof
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G18/00—Polymeric products of isocyanates or isothiocyanates
- C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
- C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
- C08G18/30—Low-molecular-weight compounds
- C08G18/32—Polyhydroxy compounds; Polyamines; Hydroxyamines
- C08G18/3203—Polyhydroxy compounds
- C08G18/3206—Polyhydroxy compounds aliphatic
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G18/00—Polymeric products of isocyanates or isothiocyanates
- C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
- C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
- C08G18/30—Low-molecular-weight compounds
- C08G18/36—Hydroxylated esters of higher fatty acids
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G18/00—Polymeric products of isocyanates or isothiocyanates
- C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
- C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
- C08G18/65—Low-molecular-weight compounds having active hydrogen with high-molecular-weight compounds having active hydrogen
- C08G18/66—Compounds of groups C08G18/42, C08G18/48, or C08G18/52
- C08G18/6666—Compounds of group C08G18/48 or C08G18/52
- C08G18/667—Compounds of group C08G18/48 or C08G18/52 with compounds of group C08G18/32 or polyamines of C08G18/38
- C08G18/6674—Compounds of group C08G18/48 or C08G18/52 with compounds of group C08G18/32 or polyamines of C08G18/38 with compounds of group C08G18/3203
- C08G18/6677—Compounds of group C08G18/48 or C08G18/52 with compounds of group C08G18/32 or polyamines of C08G18/38 with compounds of group C08G18/3203 having at least three hydroxy groups
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Health & Medical Sciences (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Organic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Separation Using Semi-Permeable Membranes (AREA)
- Polyurethanes Or Polyureas (AREA)
- Treatments For Attaching Organic Compounds To Fibrous Goods (AREA)
- External Artificial Organs (AREA)
Abstract
A dialyser comprises bundled multicomponent hollow filaments as membranes which, on the dialysate side, comprise a layer containing adsorbent particles and, on the retentate side, comprise a layer of regenerated cellulose and, optionally, at least one cellulose derivative and which, at the ends thereof, are embedded in hardened polyurethane and are cut through to form a tube base which uncovers the openings of the hollow filaments, the cut surfaces being sealed with at least one polyurethane which ranges from 0.2 to 2 mu m in thickness and which leaves the openings of the filaments free. The sealing process obviates the problems caused by the adsorbent particles being torn from the embedding composition.
Description
SPECIFICATION
Dialyser comprising hollow fibre membranes
This invention relates to a dialyser comprising hollow fibre membranes; more particularly, it relates to dialysers comprising bundled multicomponent hollow filaments as membranes which comprise at least two layers, viz a layer of regenerated cellulose, which forms the actual membrane, and a layer containing adsorbent particles, such as particles of activated carbon or aluminium oxide.
It is known that membranes in the form of two-component hollow filaments of regenerated cellulose may be used in dialysers. The hollow filaments of these membranes are formed from two firmly adhering layers, one of which comprises regenerated cellulose and, optionally, a cellulose derivative, while the other layer is formed from regenerated cellulose containing from 1 to 95%, by weight, of adsorbent particles having an average particle size of up to 40 ym embedded therein in uniform distribution. Membranes of this type are described, for example, in German Auslegeschrift No, 2,627,858. To produce the dialyser, hollow filaments of this type are bundled and, at the ends thereof, are embedded in a composition, particularly in polyurethanes, by conventional methods.After the embedding composition has hardened, the filaments are cut at the ends thereof so as to form a tube base which uncovers the openings of the hollow filaments.
For dialysis, the liquid to be dialysed may then be passed through the hollow filaments.
Constituents to be separated may diffuse through the wall of the cellulose layer. The adsorbent material is capable of simultaneously adsorbing certain substances.
It has been found that, when the embedded filaments are cut, adsorbent particles are torn from the embedding composition and settle on the cut surface or enter the hollow passages. These particles may have a disruptive effect during dialysis, for example because they block the hollow filaments.
In addition, where a dialyser of the type in question is used for haemodialysis, carbon particles, for example, are capable of entering the blood stream where they may cause serious damage, so that the health of the patient is endangered.
Efforts have been made to overcome such difficulties by removing impurities, such as dust, from the carbon particles used by washing them beforehand. However, this is only possible to a certain extent. Furthermore, the carbon particles cannot be prevented from disintegrating, again under the effect of cutting, and releasing minute particles.
Accordingly, there is a need for an apparatus which does not suffer from the above disadvantages and for an advantageous process for producing dialysers of the type in question.
Accordingly, an object of the present invention is to provide a dialyser comprising multicomponent filaments as membranes which does not have freely movable adsorbent particies on the cut surfaces, which comprises smooth surfaces on the tube bases and which may be used for a variety of applications and is toxicologically acceptable and, in particular, may be used in haemodialysis without adsorbent particles entering the blood stream.
According to the present invention, this object is achieved by a dialyser comprising bundled multicomponent hollow filaments as membranes which, on the dialysate side, comprise a layer containing adsorbent particles and, on the retentate side, comprise a layer of regenerated cellulose and, optionally, a cellulose derivative at which, at the ends thereof, are embedded in hardened polyurethane and are cut through to form a tube base which uncovers the openings of the hollow filaments, characterised by a sealing of the cut surfaces with polyurethanes which ranges from 0.2 to 2 Sem in thickness and which leaves the openings of the filaments free.
The seal preferably consists of polyurethanes which have been obtained by reacting difunctional and trifunctional hydroxyl compounds with a diisocyanate in a solvent.
It is particularly advantageous to use trimethylol propane as the trifunctional hydroxyl compound in the synthesis of the polyurethanes. Dipropylene glycol is a particularly suitable difunctional hydroxyl compound.
A polyurethane which has been obtained by reacting castor oil, trimethylol propane, dipropylene glycol and diphenyl methane diisocyanate is particularly suitable.
Other suitable difunctional hydroxyl compounds include polyalkylene glycols, particularly polytetramethylene glycol. It is particularly advantageous in cases where polyalkylene glycols are used simultaneously to use dipropylene glycol.
The seal preferably consists of polyurethanes which have been obtained by reacting hydroxyl compounds with diisocyanates using an OR: NO ratio of from 1.0:1 to 1.5:1 more particularly from 1.25:1 to 1.4:1.
The cut surfaces of bundled multicompnent hollow filaments which are used as membranes in a dialyser and which, on the dialysate side, comprise a layer containing adsorbent particles and, on the retentate side, comprise a layer of regenerated cellulose and, optionally, a cellulose derivative and which, at the ends thereof, are embedded in hardened polyurethane and are cut through to form a tube base which uncovers the openings, are sealed by a process which is characterised in that a from 10 to 20%, by weight, polyurethane solution having a viscosity of from 8 to 15 mPa.s which, in addition to the solvent, contains a diluent having an evaporation index of from 2.0 to 25 and, optionally, a levelling agent is sprayed onto the cut surfaces. It is advantageous to use gel-free solutions.Ethyl glycol acetate is a particularly suitable solvent, while isopropanol is a particularly advantageous diluent.
It is preferred to spray the solution onto cut surfaces heated to from 40 to 60"C.
Cellulose acetobutyrate is a particularly suitable levelling aid.
It is particularly favourable to use polyurethane solutions having a viscosity of from 10 to 11 mPa.s.
The polyurethanes may be produced by processes known in polyurethane chemistry.
The reactants are dissolved in a solvent, in particular ethyl glycol acetate. Other examples of suitable solvents include other acetic acid esters, such as ethyl acetate.
It is preferred separately to dissolve the hydroxyl compounds, on the one hand, and the diisocyanate, on the other hand, and slowly to add the diisocyanate solution to a solution of they hydroxyl compound. It is preferred to work under a nitrogen atmosphere.
The concentration of the starting materials in the solutions is adjusted to such a high level that, after the reaction, a final concentration of from 10 to 20%, by weight, of polyurethane may be adjusted by adding the levelling agent and the diluent. Accordingly, the concentration of the starting materials in the solvent is preferably above 30%, by weight, more particularly, a favourable concentration is of the order of 40%, by weight, or even 60%, by weight.
The solution of the hydroxyl compounds initially introduced may be heated, for example, to 80 C. During addition of the diisocyanate, it is important to ensure that the temperature does not rise to too high a level and should definitely not exceed 90 C.
During the reaction, the reaction mixture is preferably stirred. It is important to ensure that the diisocyanate is not added too quickly so that the temperature does not rise to too high a level under the effect of the exothermic reaction. In general, the addition of the diisocyanate is over a period of from 20 to 30 minutes. The mixture is then left to react at 90'C until most of the NCO groups have fully reacted. This generally takes from 1.5 to 2 hours.
The levelling agent is then added to the polyurethane solution while it is still hot.
Levelling agents, sometimes also referred to as "equalising agents", are additives which are frequently added to coating compositions, particularly lacquers, and which promote the levelling of a coating, i.e. its ability to equalise for example, irregularities, streaks or bubbles formed during application. Suitable levelling agents include glycol and glycol ethers, esters, ketones, silicone oils, nitrocellulose and vinyl polymers. In the present case, the function of the levelling agent is to ensure that, when the cut surfaces are sprayed, the required impervious seal from 0.2 to 2 jum thick is formed on the adsorbents, while at the same time ensuring that no skin covering the openings of the hollow filaments is formed.
Accordingly, the levelling agent particularly influences the surface properties of the polyurethene solution used for sealing. The levelling agent may even be added at a later stage, for example when diluent is present.
A levelling agent particularly suitable for the purposes of the present invention is cellulose acetobutyrate, for example a product which is commercially available under the name of "Cellit Bp 500 = " (a product of BAYER AG,
Leverkusen, Germany). The levelling agent is preferably added in the form of a solution, the solvent used for production of the polyurethane preferably being used as the solvent.
In general, the levelling agent is added in a quantity of from 3 to 10%, by weight, (based on the polyurethane solids), Preferably 4 to 6%, by weight.
Addition of the levelling agent is followed by addition of the diluent, the particular function of which is to promote evaporation of the solvent after spraying. Suitable diluents include alcohols, such as methanol, and low boiling acetic acid esters, such as ethyl acetate. Isopropanol is preferably used as the diluent.
When the diluent is added, the polyurethanes are generally still not adjusted to the final concentration, but instead to a concentration which is slightly above the concentration adjusted for spraying. After the diluent has been added, the solution is optionally filtered to remove gel particles or other impurities which may be present. After filtration, the final concentration is adjusted by the addition of more diluent which is preferably used in the form of a solution in a ratio of 1 part of diluent to 1 part of solvent.
So far as the further processing of the solution is concerned, it is important to adjust a favourable viscosity lying in the range of from 8 to 15 mPa.s, preferably from 9 to 13 mPa.s. Suitable solutions such as these generally have a concentration of from 10 to 20%, by weight, of polyurethane. The remainder of the solution comprises solvent and diluent, together with levelling agent. It is obvious that the diluent and the solvent bear a reasonable ratio to one another, the proportion of solvent generally not being below the proportion of diluent because otherwise there would be a danger of precipitation. After the second addition of diluent, the solution is optionally filtered once more, resulting in the formation of a spraying solution which is free from gel particles and other impurities.
The viscosities quoted are measured in the conventional way at 20 C. Difunctional and trifunctional hydroxyl compounds and diisocyanates are used in the synthesis of the polyurethane. In addition to trimethylol propane, castor oil is preferably used.
In particular, dipropylene glycol is used as the difunctional hydroxyl compound. By adding in particular trimethylol propane, it is possible favourably to control the cross-linking reaction, so that the mechanical properties of the seal are favourably influenced.
The dipropylene glycol provides, inter alia, for good solubility of the polyurethane in the solvent/diluent mixture and hence guarantees good sprayability and the formation of a suitable seal. In addition, polytetramethylene glycol may be used as a further hydroxyl group compound.
Instead of using castor oil, it is also possible to use polyether diols, such as polytetramethylene glycol or polypropylene glycol.
The solutions may be sprayed by means of typical spray systems. In this connection, it is possible to use propellent gases, such as CO2, fluorochlorinated hydrocarbons or compressed air. It is also possible to use a simple spray apparatus, in which case the propellant air is manually produced by means of a rubber ball.
When the cut surfaces are sprayed with the polyurethane solution, it is important to ensure that the solution is not sprayed in excess.
Accordingly, it is sufficient to spray the cut surface only briefly. The solvent evaporates relatively quickly. It is generally sufficient to spray the cut surfaces twice.
Spraying is preferably carried out by the socalled cross-spraying technique in which the surface is breifly sprayed once from left to right and once from top to bottom. In general, the spraying time is very short. Fractions of a second, for example, a quarter of a second are sufficient. With longer spraying times, the hollow filaments are in danger of being closed. The spraying distance to the tube base should amount to from 20 to 30 cm.
Heat promotes formation of the seal, so that it is prepared for the tube bases to be sprayed to have a temperature of from 40 to 60 C.
It is advantageous, particularly when the dialysers are used for- haemodialysis or other medical purposes, to carry out the sealing process in dust-free rooms.
The evaporation index is a measure of how quickly a liquid volatilises below its boiling point in air at a certain temperature. It is determined in accordance with DIN 53170.
It was particularly surprising to find that it is possible in accordance with the present invention to obtain sealed cut polyurethane surfaces which release the openings of the hollow filaments, but do not allow absorbent particles to enter into the interior of the hollow filaments. It is thus possible simply by spraying to obtain an impervious seal without the openings of the hollow filaments becoming blocked.
The cut surface obtained is very smooth so that no sealing problems arise during dialysis.
The seal is extremely elastic, resistant to most liquids, particularly blood, and completely harmless, i.e. non toxic, to human blood. The necessary spraying times are very short. In general, it is sufficient to spray the cut surfaces once or twice in order to obtain a coherent sealing layer. If holes are present in the polyurethane embedding composition, they are also closed by means of the seal.
Another effect of the seal is that no dead spots are formed on the tube base, which is crucially important to the quality of the purified blood. The seal does not prevent turbulent flow of the blood.
The dialyser according to the present invention is particularly suitable in haemodialysis for purifying the blood in, for example, diseases of the liver, cases of poisoning, schizophrenia etc. The invention is illustrated by the following Examples:
EXAMPLE 1
73.95 g of castor oil, 86.3 g of dipropylene glycol and 27.35 g of trimethylol propane are dissolved in 322.45 g of ethyl glycol acetate and the resulting solution is introduced into a stirrer-equipped apparatus (3-necked flask, stirrer, thermometer and reflux condenser).A solution of 314.4 g of 4,4'-diphenyl methane diisocyanate in 540.65 g of ethyl glycol acetate is then added dropwise over a period of from 20 to 30 minutes through a dropping funnel tempered to 80 C. After from 2 to 2.5 hours, 20.1 g of "Cellit BP 500", dissolved in 180.9 g of ethyl glycol acetate, are added, followed by stirring for about 10 minutes.
1044 g of isopropanol are then added, followed by further stirring. A 20%, by weight, solids solution is obtained in this way. After filtration, the solution is adjusted to a viscosity of 10.5 mPa.s by the addition of more isopropanol dissolved in the same quantity of ethyl glycol acetate. The thus-obtained solution may be sprayed immediately.
EXAMPLE 2
21.5 g of polytetramethylene glycol (MW 1000), 17.3 g of dipropylene glycol and 5.5 g of trimethylol propane are dissolved in a mixture of 14.8 g of ethyl glycol acetate and 14.8 g of ethyl acetate to form a 60% by weight, solution which is introduced into a stirrer-equipped vessel. A solution of 54.4 g of 4,4'-diphenyl methane diisocyanate in a solvent mixture of 18.1 g of ethyl glycol acetate and 18.1 g of ethyl acetate is then added dropwise. After from 2 to 3 hours, first 158 g of ethyl glycol acetate and then 158 g of isopropanol are added. After filtration, the solution is adjusted to a viscosity of 11 mPa.s by the addition of isopropanol alone, i.e. with no levelling agent added. The thus-obtained solution may be sprayed immediately.
EXAMPLE 3
9.25 g of polypropylene glycol (MW 400), 17.26 g of dipropylene glycol and 5.47 g of trimethylol propane are dissolved in 55 g of ethyl glycol acetate and the resulting solution introduced into a stirrer-equipped apparatus.
A solution of 62.88 g of 4,4'-diphenyl meth ane diisocyanate in 108.1 9 g of ethyl glycol acetate is then added dropwise over a period of from 20 to 30 minutes through a dropping funnel. After from 2 to 3 hours, 3.79 g of "Cellit PB 500", dissolved in 34.1 g of ethyl glycol acetate, are added and stirred in.
197.3 g of isopropanol are then added. After filtration, the 20%, by weight, solids solution is further diluted to form a sprayable solution.
Claims (20)
1. A dialyser which comprises bundled multicomponent hollow filaments as membranes which, on the dialysate side, comprise a layer containing adsorbent particles and, on the retentate side, comprise a layer of regenerated cellulose and optionally, at least one cellulose derivative and which, at the ends thereof, are embedded in hardened polyurethane and are cut through to form a tube base which uncovers the openings of the hollow filaments, the cut surfaces being sealed with at least one polyurethane which ranges from 0.2 to 2 ELm in thickness and which leaves the openings of the filaments free.
2. A dialyser as claimed in claim 1 in which the polyurethane has been obtained by reacting difunctional and trifunctional hydroxyl compounds with a diisocyanate in a solvent.
3. A dialyser as claimed in claim 2 in which the trifunctional hydroxyl compound is trimethylol propane.
4. A dialyser as claimed in claim 2 in which the difunctional hydroxyl compound is dipropylene glycol.
5. A dialyser as claimed in claim 2 in which the polyurethane has been obtained by reacting castor oil, trimethylol propane, dipropylene glycol and 4,4'-diphenyl methane diisocyanate.
6. A dialyser as claimed in claim 2 in which the difunctional hydroxyl compound is a polyalkylene glycol.
7. A dialyser as claimed in claim 6 in which the polyalkylene glycol is polytetramethylene glycol.
8. A dialyser as claimed in claim 2 in which the polyurethane has been obtained by reacting one or more hydroxyl compounds with one or more diisocyanates in an OH: to NCOratiooffrom 1.0:1 to 1.5:1.
9. A dialyser as claimed in claim 8 in which the polyurethane has been obtained using an OR: NO ratio of from 1.25:1 to 1.4:1.
10. A dialyser as claimed in claim 1 substantially as herein described.
11. A process for the production of a dialyser as claimed in claim 1 which comprises sealing the cut surfaces of the filaments by spraying thereon, a from 10 to 20% by weight, polyurethane solution having a viscosity of from 8 to 15 mPa.s which, in addition to the solvent, contains a diluent having an evaporation index of from 2.0 to 25 and, optionally a levelling agent.
12. A process as claimed in claim 11 in which a gel-free solution is used.
13. A process as claimed in claim 10 or claim 11 in which ethyl glycol acetate is used as the solvent.
14. A process as claimed in any of claims 11 to 13 in which isopropanol is used as the diluent.
15. A process as claimed in any of claims 11 to 14 in which cellulose acetobutyrate is used as the levelling agent.
16. A process as claimed in any of claims 11 to 15 in which a polyurethane solution having a viscosity of from 10 to 11 mPa.s is used.
17. A process as claimed in any of claims 11 to 16 in which the solution is sprayed onto the cut surfaces heated to from 40 to 60 C.
18. A process as claimed in claim 11 substantially as herein described.
19. A dialyser as claimed in claim 1 when produced by a process as claimed in any of claims 11 to 18.
20. A dialysis system which comprises a dialyser as claimed in any of claims 1 to 10 or 19.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE2925172A DE2925172C2 (en) | 1979-06-22 | 1979-06-22 | Dialyzer with hollow fiber membranes |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB2053023A true GB2053023A (en) | 1981-02-04 |
| GB2053023B GB2053023B (en) | 1983-03-09 |
Family
ID=6073846
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB8020020A Expired GB2053023B (en) | 1979-06-22 | 1980-06-19 | Dialyzer comprising hollow fibre membranes |
Country Status (10)
| Country | Link |
|---|---|
| JP (1) | JPS563063A (en) |
| BE (1) | BE883923A (en) |
| CA (1) | CA1157388A (en) |
| DE (1) | DE2925172C2 (en) |
| ES (1) | ES8102826A1 (en) |
| FR (1) | FR2459674A1 (en) |
| GB (1) | GB2053023B (en) |
| IT (1) | IT1143970B (en) |
| NL (1) | NL8003392A (en) |
| SE (1) | SE430470B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2740776A1 (en) * | 1995-11-02 | 1997-05-09 | Basf Magnetics Gmbh | POLYURETHANES, THEIR PREPARATION AND USES THEREOF |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3147025A1 (en) * | 1981-11-27 | 1983-06-01 | Akzo Gmbh, 5600 Wuppertal | EMBEDDING BASED ON QUICK REACTIVE POLYURETHANE CASTING RESIN |
| DE3423258C1 (en) * | 1984-06-23 | 1986-01-23 | SECON Gesellschaft für Separations- und Concentrationstechnik mbH, 3400 Göttingen | Capillary dialyzer |
| DE3931981C1 (en) * | 1989-09-26 | 1990-09-27 | Draegerwerk Ag, 2400 Luebeck, De | Hollow fibre module prodn. - comprises housing parallel extending fibres between two partition walls fitted by centrifugal casting |
| DE102015225668A1 (en) * | 2015-12-17 | 2017-06-22 | Mahle International Gmbh | Process for producing a capillary membrane bundle |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DD112904A1 (en) * | 1974-02-14 | 1975-05-12 | ||
| DE2627858C2 (en) * | 1976-06-22 | 1979-12-13 | Akzo Gmbh, 5600 Wuppertal | Dialysis membrane, especially for hemodialysis |
-
1979
- 1979-06-22 DE DE2925172A patent/DE2925172C2/en not_active Expired
-
1980
- 1980-06-11 NL NL8003392A patent/NL8003392A/en not_active Application Discontinuation
- 1980-06-12 IT IT48947/80A patent/IT1143970B/en active
- 1980-06-17 CA CA000354139A patent/CA1157388A/en not_active Expired
- 1980-06-18 JP JP8152480A patent/JPS563063A/en active Pending
- 1980-06-19 SE SE8004545A patent/SE430470B/en unknown
- 1980-06-19 GB GB8020020A patent/GB2053023B/en not_active Expired
- 1980-06-19 FR FR8013649A patent/FR2459674A1/en active Granted
- 1980-06-20 BE BE0/201105A patent/BE883923A/en not_active IP Right Cessation
- 1980-06-20 ES ES492622A patent/ES8102826A1/en not_active Expired
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2740776A1 (en) * | 1995-11-02 | 1997-05-09 | Basf Magnetics Gmbh | POLYURETHANES, THEIR PREPARATION AND USES THEREOF |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS563063A (en) | 1981-01-13 |
| BE883923A (en) | 1980-10-16 |
| ES492622A0 (en) | 1981-02-16 |
| IT1143970B (en) | 1986-10-29 |
| GB2053023B (en) | 1983-03-09 |
| DE2925172A1 (en) | 1981-01-08 |
| FR2459674A1 (en) | 1981-01-16 |
| ES8102826A1 (en) | 1981-02-16 |
| SE8004545L (en) | 1980-12-23 |
| CA1157388A (en) | 1983-11-22 |
| SE430470B (en) | 1983-11-21 |
| NL8003392A (en) | 1980-12-24 |
| DE2925172C2 (en) | 1985-07-18 |
| FR2459674B3 (en) | 1982-04-02 |
| IT8048947A0 (en) | 1980-06-12 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |