Patent ID: 8329256

Claim:
Process for the production of mouldings containing a layer of polyurethane in shot operation, comprising a) mixing reactive components of polyol and isocyanate in a mixing head and then b) guiding the reactive mixture produced in step a) through a flow channel of a spray device, c) spraying the reactive mixture leaving the spray device onto a surface of a substrate such that the reactive mixture cures thereon, d) introducing a gas stream into the flow channel of the spray device in two positions, the distance l between those two positions being so chosen that the quotient of the distance l and the diameter d of the flow channel of the spray ( l d ) max is >10, e) the guiding step comprises (1) forming droplets of the reactive mixture in the flow channel, and (2) transporting the droplets through the flow channel, and f) maintaining the gas stream in the flow channel after the reactive mixture has been sprayed in step (c) in order to clean out the flow channel.