Akzo N.v.

Peter Hentschel

Hans G Zengel

Walter Brodowski

Manfred F Bergfeld

Helmut Schulze

Werner Klostermeier

Franciscus J Huntjens

Jan A Schutijser

Christof Josefiak

Membranes are disclosed which are suitable for hemodialysis and/or hemofiltration, prepared from aliphatic diisocyanates, particularly cycloaliphatic diisocyanate such as cyclohexane diisocyanate-(1,4), particularly the transisomer and at least one compound which displays two active hydrogen atoms. For the reaction a molar ratio of soft segment to hard segment from 0 to 0.20, particularly from 0 to 0.1, is employed. Serving particularly for construction of the hard segments are compounds such as hydrazine, ethylene diamine, ethylene glycol and butanediol-(1,4). It is recommended to prepare the addition polymer in the presence of a aprotic solvent and a dissolving coagent such as lithium chloride or calcium chloride. Polyethers such as polyethylene glycol are particularly suitable for construction of the soft segment. The membrane is characterized by an ultrafiltration rate of from 0.5 to 300, particularly 0.5 to 100 ml/h.m.sup.2.Torr, and a dialytic permeability for vitamin B.sup.12 of 0.5 to 20.10..sup.-3 cm./min.

Membranes of diisocyanate addition polymers for hemodialysis and/or

Thermoplastically workable polyurethane-elastomers are disclosed which are obtained through polyaddition of substantially pure trans-cyclohexane-1,4-diisocyanate, macrodiols of average molecular weight from 800 to 4000 and bisethoxylated Bisphenol A or mixtures thereof with short-chain diols customarily employed as chain lengtheners. The polyurethanes possess the advantage that their softening points lie in a very favorable temperature range which makes possible their thermoplastic workability at below the decomposition temperature, and also guarantees outstanding mechanical-elastic characteristics as well as excellent long-term light stability. As a result the polyurethanes according to the present invention are outstandingly suitable as material for shaped bodies to be employed in areas of use placing high requirements on the employed materials. For example, highly valuable elastomer fibers can be manufactured from these polyurethanes by means of melt spinning.

Thermoplastic polyurethane-elastomers from cyclohexane-1,4-diisocyanate

Polyurethanes prepared from macrodiols with an average molecular weight between about 800 and 4000, lower molecular weight chain extenders with at least two labile hydrogens, and cyclohexane-1,4-diisocyanate with a trans-isomer content of at least 90%, are described. These polyurethanes exhibit exceptional mechanical properties, high softening temperatures, and remarkable stability to light and to many common solvents. Methods for preparation of the novel polyurethanes, as well as for their use, are also disclosed.

Polyurethanes from trans-cyclohexane-1,4-diisocyanate

A process for the preparation of organic mono- and polyisocyanates is described, in which a hydrogen chloride adduct of a trisubstituted urea is thermally decomposed to form the isocyanate. The hydrogen chloride adduct at minimum contains the stoichiometric amount of HCl, and at maximum a 10 mole-% excess. The process is carried out in a closed system at a temperature between about 80.degree. and 180.degree. C.; the reaction is effected either in a melt or in the presence of an inert organic solvent.

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Laudenbach, Germany

Peter Hentschel