. . . . "Examples of suitable polyols (C) are trimethylolethane, trimethylolpropane and glycerol, pentaerythritol or homopentaerythritol and sugar alcohols such as threitol or erythritol or pentitols such as arabitol, adinitol or xylitol or hexitols such as sorbitol, mannitol or dulcitol." . .