and or cycloaliphatically bound isocyanate groups preferably derived from hexamethylene diisocyanate or isophorone diisocyanate uretdione diisocyanates are cyclic dimerization products of diisocyanates c biureto containing polyisocyanates having aliphatically bound isocyanate groups in particular tris 6 isocyanatohexyl biuret or its mixtures with its higher homologs these biureto containing polyisocyanates generally have an nco content of from 18 to 25 by weight and an average nco functionality of from 3 to 4 5 d urethano and or allophanato containing polyisocyanates with aliphatically or cycloaliphatically bound isocyanate groups as obtainable for example by reacting excess amounts of hexamethylene diisocyanate or isophorone diisocyanate with simple polyhydric alcohols such as trimethylolpropane glycerol 1 2 dihydroxypropane or mixtures thereof these urethano and or allophanato containing polyisocyanates generally have an nco content of from 12 to 20 by weight and an average nco functionality of from 2 5 to 3 e oxadiazinetriono containing polyisocyanates preferably derived from hexamethylene diisocyanate or isophorone diisocyanate such oxadiazinetriono containing polyisocyanates are preparable from diisocyanate and carbon dioxide for the use according to the present invention particular preference is given to aliphatic diisocyanates and aliphatic higher functional polyisocyanates the disclosed diisocyanates and or higher functionalized polyisocyanates are converted into nonionically hydrophilic modified polyisocyanates which are particularly preferred for the use according to the present invention by reaction with nco reactive compounds containing hydrophilicizing structural elements with nonionic groups or with polar groups which cannot be converted into ionic groups in this reaction the diisocyanate or polyisocyanate as the case may be is present in stoichiometric excess in order that the resulting hydrophilic modified polyisocyanate may still contain free nco groups suitable for use as such nco reactive compounds with hydrophilicizing structural elements are in particular hydroxyl terminated polyethers of the general formula.