Composite materials

Abstract

Light weight composites with high flexural strength comprise epoxy foam sandwiched between two layers of facing material have high strength and low weight and can be used to replace steel structures. The facing layer may be fibrous material especially glass or carbon fibres, the facing material is preferably embedded into the epoxy matrix. Alternatively they may be matching box structures or concentric metal tubes. The sandwich structures may be prepared by laying up the fibre; coating and/or impregnating the layer with epoxy resin, laying a layer of heat activatable foamable epoxy material, providing a further layer of the fibrous material optionally coated and/or impregnated with epoxy resin on the foamable material and heating to foam and cure the epoxy materials. Alternatively they may be formed by extrusion of the foamable material between the surface layers.

1 . A composite comprising:
 a) at least one surface layer;   b) a core layer attached to the at least one surface layer;   wherein the core layer has a density of 0.2 gram/cc to 1.5 gram/cc.   
     
     
         2 . The composite according to  claim 1 , wherein the density of the core layer is between 0.4 gram/cc and 1.5 gram/cc. 
     
     
         3 . (canceled) 
     
     
         4 . The composite according to  claim 1 , wherein the at least one surface layer comprises at least two surface layers. 
     
     
         5 - 6 . (canceled) 
     
     
         7 . The composite according  claim 4 , wherein the at least two surface layers are porous. 
     
     
         8 . The composite according to  claim 4 , wherein the at least two surface layers include a fibrous material. 
     
     
         9 . The composite according to  claim 8 , wherein the fibrous material is a carbon fiber, glass fiber, or Kevlar. 
     
     
         10 . (canceled) 
     
     
         11 . The composite according to  claim 4 , wherein the at least two surface layers are internal structure which matches an external structures. 
     
     
         12 . The composite according to  claim 11 , wherein the internal structure and the external structure are hollow box sections. 
     
     
         13 . The composite according to  claim 11 , wherein the internal structure and the external structure each a tube. 
     
     
         14 . The composite according to  claim 13 , wherein the tube of the internal structure and the tube of the external structure are concentric. 
     
     
         15 - 17 . (canceled) 
     
     
         18 . The composite according to  claim 1 , wherein the composite is provided as a structure in a construction or a transportation industry. 
     
     
         19 . The composite according to  claim 18 , wherein the composite is part of a reinforcement structure in a vehicle and provides reinforcement against crash in vehicles. 
     
     
         20 . (canceled) 
     
     
         21 . The composite of  claim 1 , wherein the composite is provided within and provides strength in a sporting good. 
     
     
         22 - 31 . (canceled) 
     
     
         32 . The composite of  claim 4 , wherein the at least two surface layers each have a thickness of from 0.2 to 10 millimeters and the core layer has a thickness of from 2 to 200 millimeters. 
     
     
         33 . The composite of  claim 4 , wherein the at least two surface layers comprise a carbon-based material. 
     
     
         34 . The composite of  claim 4 , wherein the core layer includes an ethylene copolymer. 
     
     
         35 . The composite of  claim 34 , wherein the core layer is injection molded. 
     
     
         36 . A composite comprising:
 a) at least two surface layers, wherein the at least two surface layers comprise a carbon fiber material; and   b) a core layer attached to and located between the at least two surface layers, wherein the core layer includes an ethylene copolymer; and   wherein the core layer has a density of 0.2 gram/cc to 1.5 gram/cc.   
     
     
         37 . The composite of  claim 36 , wherein the at least two surface layers are an internal structure which matches an external structure. 
     
     
         38 . The composite structure of  claim 37 , wherein the core layer is injection molded and provided as pieces prior to injection molding.