COMPOSITE ELEMENT MADE FROM A PREFORM
A composite element made from a preform of fiber-reinforced plastic material arranged around a core with a multi-layer thermoplastic foil between the preform and the core and a method for fabrication of such a composite element. At least one of the layers of said multi-layer thermoplastic foil has a different melting temperature from the melting temperature of at least one of the other layers.
1 . A composite element made from a preform of fiber-reinforced plastic material arranged around a core with a foil between the preform and the core, wherein the foil is a multi-layer thermoplastic foil with at least one of the layers of said multi-layer thermoplastic foil having a different melting temperature from the melting temperature of at least one of the other layers.
2 . A composite element according to claim 1 , wherein the multi-layer thermoplastic foil is provided with two layers and in that the core is dissoluble.
3 . A composite element according to claim 2 , wherein an outer layer of said multi-layer thermoplastic foil has a lower melting temperature than an inner layer.
4 . A composite element according to claim 2 , wherein the inner layer of said multi-layer thermoplastic foil has a barrier functionality.
5 . A composite element according to claim 2 , wherein the outer layer of said multi-layer thermoplastic foil has an adhesion functionality.
6 . A composite element according to claim 1 , wherein the multi-layer thermoplastic foil is provided with at least three layers and in that the core is not dissoluble.
7 . A composite element according to claim 6 , wherein two outer layers of said multi-layer thermoplastic foil have a lower melting temperature than an intermediate layer.
8 . A composite element according to claim 6 , wherein the intermediate layer of said multi-layer thermoplastic foil has a barrier functionality.
9 . A composite element according to claim 6 , wherein each of the outer layers of said multi-layer thermoplastic foil have an adhesion functionality.
10 . A composite element according to claim 1 , wherein said multi-layer thermoplastic foil is co-extruded.
11 . A method of making a composite element from a preform of fiber-reinforced plastic material with the following steps:
a) preparing the preform to a suitable shape by using a binder powder and/or by stitching its fabric,
b) wrapping the co-extruded multi-layer thermoplastic foil around the core with the outer layer with adhesive properties facing away from the core and the inner layer with a barrier functionality adjacent to the core;
c) attaching the preform of fiber-reinforced plastic material to the outer layer of the multi-layer thermoplastic foil;
d) applying resin to the preform and curing the composite element in a mould; and,
e) removing the dissoluble core by scavenging inside the composite element.
12 . A method according to claim 11 , wherein wrapping the co-extruded multi-layer thermoplastic foil around the core with the first outer layer with adhesive properties facing away from the core, the second outer layer with adhesive properties adjacent to the core and the inner, intermediate layer with a barrier functionality between the first outer layer and the second outer layer and maintaining the core inside the composite element after cure.