METHOD FOR PRODUCING CAVITY-FREE AND PINHOLE-FREE POLYURETHANE SLABSTOCK FOAM

WIPO Patent Application WO2004033178

A8

The invention relates to a method for continuously producing polyurethane foam consisting of at least one polyol constituent and of at least one isocyanate constituent in the presence of water serving as an expanding agent and optionally consisting of additional additives. According to the inventive method: a) the polyol constituent, the isocyanate constituent, the water and, optionally, the additional additives are conveyed in a dosed manner into the mixing chamber of a mixing unit and are mixed therein at pressures ranging from 3 to 200 bar, preferably at pressures ranging from 5 to 200 bar, in order to form a polyurethane reaction mixture and, afterwards; b) the polyurethane reaction mixture is sprayed in a pressure reduction element at pressures ranging from 3 to 200 bar, preferably at pressures ranging from 5 to 200 bar, whereby producing nuclei, and the pressure in the direction of flow behind the pressure reduction element is adjusted by a throttling element thereby controlling the number of nuclei produced, and afterwards; c) the polyurethane reaction mixture containing nuclei is permitted to flow out through the throttling element and is applied to a substrate on which it foams and hardens.

RAFFEL REINER (DE)
WIRTH JUERGEN (DE)
PAWLIK WOLFGANG (DE)
SCHAMBERG MARTIN (DE)

PCT/EP2003/009627

July 22, 2004

August 26, 2003

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HENNECKE GMBH (DE)
RAFFEL REINER (DE)
WIRTH JUERGEN (DE)
PAWLIK WOLFGANG (DE)
SCHAMBERG MARTIN (DE)

B29B7/74; B29C44/34; B29C44/46; B29C44/48; B29C44/50; C08G18/08; B29C67/24; C08G18/00; C08G18/09; C08G18/48; B29K75/00; C08G101/00; (IPC1-7): B29C44/34; B29C44/46; B29C67/24; B29B7/74

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