Storage-stable, blowing agent-containing emulsions for producing rigid foams based on isocyanate

A storage-stable, blowing agent-containing halogen-free emulsion for producing rigid foams based on isocyanate, comprising

• a) compounds containing hydrogen atoms which are reactive toward isocyanate groups,
• b) water,
• c) physically acting, halogen-free blowing agents and, optionally,
• d) auxiliaries and/or additives,
• wherein the component a) comprises at least one emulsion stabilizing polyether alcohol having a functionality of from 2.5 to 3.5 and a hydroxyl number of from 10 to 100 mg KOH/g in an amount of from 0.2% by mass to 80% by mass, based on the mass of the component a) and at least one other polyol having a hydroxyl number greater than 300 mg KOH/g, and the halogen-free, physically acting blowing agents c) comprise hydrocarbons having from 3 to 10 carbon atoms.