Patent ID: 6361723
Filing Date: 2002-03-26
Classification: B29C

Abstract:
A process for the production of shaped foamed polyurethane articles by introducing an expandable polyurethane reactive mixture into the lower mould half of a mould divided by a parting plane and evacuation of the mould, the parting plane having a vacuum seal, characterized in that the mould cavity is evacuated rapidly through a closable suction opening provided in the upper mould half to a pressure of 300 to 700 mbar absolute, the evacuation pressure which is a function of the recipe of the expandable polyurethane reactive mixture is such that the final internal pressure in the mould is 800 to 1,100 mbar, the suction opening is closed, the reaction mixture expanding to fill the mould cavity and the expanding mixture penetrating into expansion channels which are provided at the point or points of maximum height of the mould cavity and have a low cross-section so that said expansion channels close, the vacuum seal, suction opening and expansion channels being connected to the same vacuum source.