Patent ID: 9624609
Date: 2017-04-18
CPC Classifications: C08J,D04H,D06M,Y10T

Claim:
1. A composite material ( 18 ), comprising: a substrate of natural fiber having the structure of a felt, said felt being needle-punched on its two faces by supplying an additional polyethylene fiber; a thermosetting matrix formed from a water-based resin configured for impregnating the substrate completely; an expanding agent dispersed in the matrix, expansion of which is initiated by heating it to a given temperature, the expanding agent forming, with the thermosetting matrix, an aqueous mixture integrated with the substrate by impregnation; the proportions by weight of substrate and of thermosetting matrix used being defined so as to obtain an impregnated substrate having the following proportions by weight after drying: between 60% and 80% of fibers, between 40% and 20% of resin; the proportion by weight of expanding agent in the aqueous mixture being between 10% and 15%.