Akzo N.v.

Akzona Incorporated

Azko Nv

Gerhard Wick

Klaus Gerlach

Heinz Linhart

Erich Kessler

Erhard Siggel

Helmut Schulze

Hans G Breidohr

Eckart Jacobs

Wiprecht Eberius

Rudiger Lucks

Clemens Neuhaus

Heinz Grotjahn

A process is disclosed for the production of bio-compatible polyurethane, proceeding from cyclo aliphatic diisocyanate and macrodiol, which are reacted into a pre-adduct that is then chain lengthened with a mixture of the lower-molecular diol and a macrodiol. The so-obtained polyurethane displays high resistance in human and animal bodies and is suitable for the manufacture of catheters, blood pumps, heart valves, as well as bio-compatible lacquers and coatings.

Biocompatible polyurethane

A cross-counter-stream module for material and/or heat exchange done with a hollow filament bundle cast into a housing at its ends and a mechanism for conducting the material flow to the outside of the hollow filaments. The hollow filaments are cast at their ends as a stack into a housing, the stack being composed of one or more layers which consist of strata of hollow filaments fixed in a plane through cross-pieces transverse to their lumen directions, the cross-pieces being arranged tightly superimposed at all locations inside one layer, disposed at predetermined constant intervals, with the intermediate spaces between the hollow filaments filled by the cross-pieces at the places of crossing, and with the cross-pieces composed of a polymer with a melting point from 80.degree. to 190.degree. C. and a residual adhesion at room temperature. Preferably, the polymer is a polyamide, a polyethylene, a copolymer of polyethylene and vinyl acetate, or a copolyether-ester. Preferred embodiments include that the cross-pieces display a substantially round cross-section; that the cross-piece diameter correspond to 1.5 to 4 times the hollow filament diameter; that the cross-pieces are put in as warp; that the stack is composed of several layers; that the intervals between adjacent cross-pieces amount to 1-20 cm; and that the cross-piece intervals in different layers form whole number ratios.

Cross-counter-stream module for heat or mass exchange

Aliphatic embedding masses are disclosed, prepared by initially reacting one or more aliphatic diisocyanates with castor oil or a mixture of castor oil and further hydroxyl compounds, such as e.g., trimethylol propane into a NCO-group-displaying pre-adduct, and the pre-adduct is then hardened in a catalyzed reaction with a mixture containing castor oil, trimethylol propane and N-methyldiethanol amine. Preferably iron acetyl acetonate, dibutyl tin diacetate or titanium tetrabutylate are employed as catalysts. Isophoron diisocyanate is particularly suitable as diisocyanate. The embedding masses are useful for the embedding of membranes, preferably membranes to be employed in medical fields. The embedding masses are bio-compatible, especially with regard to blood, and are non-toxic. They allow for the embedding of membranes with the aid of automatic machinery. The embedding masses display no or only negligible swelling when used in contact with blood, blood-like and aqueous systems.

Embedding material and process for the production thereof

Embedding masses are disclosed on the basis of fast-reacting polyurethane casting resins, which are obtained through reaction of an aromatic polyisocyanate with a mixture of castor oil and trimethylolpropane into an NCO-group-displaying pre-adduct and polymerization of this pre-adduct with a polypropyleneglycol or a mixture of polypropyleneglycol and trimethylolpropane in the presence of small amounts of a catalyst mixture composed of dialkyl tin dicarboxylate and tertiary amine. The polyurethane casting resins can harden in seconds-fast reaction, and are therefore preferably suitable for a continuous embedding of membranes in automatic machines, particularly of membranes for artificial organs.

Embedding mass based upon fast-reacting polyurethane casting resin

Embedding mass of polyurethane produced on the basis of castor oil, and a method for its production, wherein an aromatic diisocyanate is reacted with a mixture of castor oil and trimethylolpropane into an NCO-group displaying pre-adduct, the pre-adduct being mixed for network polymerization with castor oil or a mixture of castor oil and trimethylolpropane, and after embedding the mixture is hardened in the presence of catalyst, thereby characterized in that a titanium alkylate compound is used as catalyst in amounts from 7 to 700 ppm, calculated as elemental titanium. Preferably, the catalyst is a titanium tetraalkylate; in particular titanium tetrabutylate. Also, a titanium magnesium hexaalkylate may be used as titanium alkylate compound; preferably, titanium magnesium hexabutylate. Preferably the catalyst is present in amounts from 40 to 140 ppm, calculated as elemental titanium. The embedding mass may be used for the embedding of membranes, particularly in artificial organs, especially in the form of hollow filaments, tube foils or flat foils. They may be used for selectively working dialysators, including selectively working hemodialysators, and other arrangements for the detoxification of blood. The embedding is performed according to the casting process, preferably the centrifuge casting process.

Embedding mass of polyurethane

A filament of a thermoplastic synthetic polymer having a plurality of adjacent, separate discontinuous cavities is made by a process wherein a silicone oil and an inert gas or gas-forming substance are dispersed in a polymer melt, and the melt is extruded into a filament. The melt contains up to and including 1% by weight of the silicone oil, based on the weight of the melt, at the time it is extruded and up to and including 10% by weight of an inert gas.

Filaments and fibers having discontinuous cavities

Production of a polyurethane embedding material from an aromatic diisocyanate in stoichiometric excess with a polyol mixture consisting essentially of castor oil and trimethylolpropane to first form a prepolymer containing unreacted isocyanate groups and being sufficiently flowable to permit coating onto membrane surfaces in all types of coating methods, and subsequently hardening the prepolymer by addition of a cross-linking agent consisting essentially of castor oil alone or another mixture of castor oil with trimethylolpropane in an amount sufficient to cross-link the prepolymer through at least a majority of its unreacted isocyanate groups. The products obtained in the invention are the embedding materials or the resulting hardened or cured embedded products or more simply 'bedded' final products which have excellent properties particularly adapted to the mounting of semipermeable membranes in dialysis equipment to give an improved and more useful construction.

Production of polyurethane embedding materials and use thereof

Potting media based on polyurethanes produced with castor oil, a process for their preparation as well as their use. To at least one of the ingredients of the potting medium is added a dialkyltin compound in an amount resulting in a content of from about 5 to 50 ppm, calculated as elementary tin, of the dialkyltin compound. A diisocyanate based on a carbon ring compound in stoichiometric excess is reacted with a mixture of castor oil and trimethylolpropane to a prepolymer having NCO-groups. Then the prepolymer is mixed with castor oil or a mixture of castor oil and trimethylolpropane for crosslinking. Preferred diisocyanates are aromatic diisocyanates having up to about 30 carbon atoms. The potting media exhibit a favorable course of the viscosity, wet excellently and distribute very rapidly and are particularly suited for the embedding of membranes.

Potting medium from polyurethanes

Production of polyurethane embedding materials

Polyurethane elastomeric filaments of improved physical properties and chemical resistance prepared by preforming the filamentary material such that the polyurethane contains at least about 100 up to about 700 milliequivalents/kilogram of reactive terminal amino groups, and then aftertreating this preformed filamentary polyurethane, optionally under simultaneous stretching, with an organic polyisocyanate and then preferably heating the treated material at an elevated temperature above about 140.degree.C. The polyurethane filamentary product is particularly useful in providing durable elastic filaments, fibers, threads, yarns, fabrics and similar textile materials.

Growing community of inventors

Obernburg, Germany

Gerhard Wick