Polyurethanes for articles for medical usage

Abstract

A polyurethane is disclosed which can be used in particular for the production of articles intended to be in contact with blood, characterized in containing a macromolecular chain comprising nitrogen atoms in the form of quaternary ammonium groups, to which molecules of heparin are bonded, these nitrogen atoms originating from polymers consisting of q recurring units of the formula: --A--NH--CO--O--B--O--CO--NH-- (I) and t recurring units of the formula: --A--NH--CO--Z--NH-- (II), these units of the formula (I) and (II) being bonded to one another, and the various symbols of these units having the following meanings: A is a divalent organic radical consisting of a straight-chain or branched-chain alkylene radical containing from 3 to 10 carbon atoms, or a cycloalkylene radical having 5 or 6 carbon atoms in the ring or a phenylene radical which is optionally substituted by 1, 2 or 3 lower alkyl radicals (with at most 4 carbon atoms), or two alkylene or phenylene radicals linked to one another by a divalent hydrocarbon radical containing from 1 to 4 carbon atoms or by a hetero-atom chosen from amongst oxygen, sulphur and nitrogen, B represents a divalent organic radical obtained by removing the terminal hydroxyl groups from a macrodiol of the formula: ##STR1## in which: B.sub.1 represents a linear or branched aliphatic radical having from 2 to 12 carbon atoms, R represents an alkylene radical of from 1 to 4 carbon atoms, R.sub.1 represents an alkyl radical of from 1 to 20 carbon atoms which may contain functional groups, such as, for example, aldehyde, carboxylic acid or sulphonic acid groups, n, m and p are identical or different integers (or fractions in the case where (III) represents a mean formula) such that the molecular weight of B is between 300 and 10,000, and q and t are such that the polyurethane, before quaternization of the nitrogen atoms, has a specific viscosity, measured at 20.degree. C on a solution of 2 g/l in dimethyl formamide, of greater than 0.05 and preferably between 0.1 and 0.9, the ratio q/t being between 0.5 and 10, Z is a single bond or a divalent radical chosen from amongst the radicals of the formulae: --NH--NH--CO--, --NH--CH.sub.2 --CO--NH--NH--CO--, --NR.sub.2 --D--NR.sub.3 --CO--, and --O--M--O--CO--, in which R.sub.2 and R.sub.3, which may be identical or different, are hydrogen atoms or lower alkyl radicals, D is a hydrogen chain containing from 2 to 12 carbon atoms, or a hydrocarbon ring with 5 or 6 carbon atoms or a nitrogen-containing heterocyclic ring with 5 or 6 chain members, containing 1 or 2 nitrogen atoms, all the hydrocarbon chains and rings being saturated or unsaturated, unsubstituted or substituted by one or two lower alkyl radicals or by a nitrogen-containing heterocyclic ring with 5 or 6 chain members, which is attached by a nitrogen atom, it being possible for two of the chains or rings to be linked to one another by an alkylamino group, and M is an aliphatic hydrocarbon radical containing from 2 to 12 carbon atoms, which is linear or branched, saturated or ethylenically unsaturated, unsubstituted or substituted by one or two lower alkyl radicals or by a dialkylamino radical, which is uninterrupted or interrupted by an alkylamino radical. The polyurethane may comprise t units of the formula (II) and q units of the formula ##STR2## in which R.sub.4 represents a monovalent or polyvalent organic radical and if R is monovalent, it may represent an alkyl, cycloalkyl or aralkyl radical which may possess functional groups and preferably containing fewer than 15 carbon atoms, these radicals being preferably the methyl, ethyl, propyl, cyclohexyl, benzyl and formylmethyl radicals, while if R is polyvalent it may represent an alkylene or alkenylene or cycloalkylene or aralkylene radical and then links different atoms or different macromolecular chains, and X- is an anion, which anion may be replaced by another anion in accordance with the usual ion exchange techniques and is preferably an anion such as a halide (chloride, bromide or iodide), nitrate, sulphate, sulphite, phosphate, sulphonate and hydroxyl. The polymer may contain from 0.1 to 30 parts by weight of heparin per 100 parts of polymer. Processess for making the polymer; and shaped articles comprising the polymer are also included.

Dependencies are inferred from the claim text.