Patent ID: 8231817

Claim:
A process for the production of a three-dimensionally shaped sandwich structure comprising the steps of: providing at least a core layer ( 2 ) for the sandwich structure which comprises a compressible core material and has a first areal weight; positioning said core layer ( 2 ) in a compression mould ( 7 , 9 ) between a first ( 6 ) and a second mould surface ( 8 ) thereof, the first mould surface ( 6 ) being formed by a first mould section ( 7 ) and the second mould surface ( 8 ) by a second mould section ( 9 ), the first and second mould sections ( 7 , 9 ) being movable with respect to one another between a moulding and a demoulding position; and bringing the mould sections ( 7 , 9 ) into their moulding position to mould said core layer ( 2 ) into a three-dimensional shape between the first and the second mould surfaces ( 6 , 8 ); the core layer ( 2 ) having two opposite main faces which are covered before and/or after the moulding step with at least one layer of a covering material ( 3 , 4 , 5 ) to achieve said sandwich structure, at least said first mould section ( 7 ) being composed of at least two mutually movable mould parts ( 10 and 11 - 13 ), including at least a first ( 10 ) and a second mould part ( 11 - 13 ) forming respectively a first and a second portion of said first mould surface ( 6 ), and, when bringing the mould sections ( 7 , 9 ) into their moulding position, a first portion of the core layer ( 2 ) is deep-drawn by moving the first mould part ( 10 ) towards its moulding position so that wrinkles are formed in the core layer ( 2 ), the formation of said wrinkles being enhanced by moving the second mould part ( 11 - 13 ) later and/or more slowly than the first mould part ( 10 ) towards its moulding position so that the core layer ( 2 ) is not hampered by the second mould part ( 11 - 13 ) from being drawn towards the first portion of the core layer ( 2 ), wherein no notches are made, so that more wrinkles, but fewer cracks, tears or breaks are formed in the core layer, the core layer being deep-drawn in such a manner during the moulding process that, due to the formation of wrinkles, it has in the produced sandwich structure an areal weight which is at least 5% higher than said first areal weight of the core layer before the moulding process.