Method of forming bonded joints

Abstract

A process for establishing bonded joints in the formation of multi-component adhered structures in which chemical bonding is established between adhesive and primer layers to provide for increased interlaminar strength. Curable resin primer layers are established on surfaces which are to be joined together in forming the multi-component structure. The primer resin is heated at a temperature and for a time period sufficient to expel substantial volatile matter from the resin, but insufficient to cross-link the resin to a completely cured state, thus leaving active bonding sites in the resinous primer layers. Bonding of the two components is provided by means of an intermediate adhesive layer between the mating surfaces. The adhesive layer is formed of a curable resin having bonding sites available for reaction with bonding sites in the primer resin. After joining the mating surfaces, the structure is heated to a temperature substantially in excess of that employed in partially curing the primer resin layer for a period of time sufficient to cure the adhesive and primer resins in the joint and establish chemical bonding between the interface of the adhesive and primer resins.

Dependencies are inferred from the claim text.