alkanethiol amines such as 1 aminopropanethiol as component g it is preferred to use diamines or polyamines such as ethylenediamine isophoronediamine 1 6 diaminohexane and or 4 4 diaminodicyclohexylmethane in component g it is preferred to use compounds of the aforementioned kind having molecular weights of 60 to 300 g mol component g is used in an amount of preferably 0 to 10 equivalents based on the nco groups of the isocyanate component a for chain extension it is also possible to use mixtures of components f and g besides chain extension by reaction with components f and or g it is also possible for free nco groups to react with water in the course of dispersion for example with formation of amine the primary amino groups thus fowled being consumed by reaction in turn with free nco groups with accompanying chain extension in the preparation of the dispersion of the invention it is also possible to use solvents and or for the raw materials to be used as solutions examples of suitable solvents are n methylpyrrolidone n ethylpyrrolidone xylene toluene butyl acetate methoxypropyl acetate acetone or methyl ethyl ketone where volatile partly water miscible solvents such as acetone or methyl ethyl ketone are used they are typically separated off by distillation following dispersion in water this procedure is also termed the acetone process or slurry process the advantage lies in a reduced viscosity for the preparation.