Adhesive composition, a process of producing the adhesive composition, a bonding method using the adhesive composition, and a structure having the adhesive composition applied thereon

A process of producing an adhesive composition including at least a first pack and a second pack, comprising:

• a step of providing tannic acid and a chain hydrocarbon having an epoxy group;
• a step of producing the first pack by mixing together the tannic acid and the chain hydrocarbon having an epoxy group in a solvent containing a compound having a furan ring to react the tannic acid with the chain hydrocarbon having an epoxy group thereby forming a tannic acid derivative in which a hydrogen atom in at least some hydroxyl group of the tannic acid is substituted by a chain hydrocarbon group having a constitutional unit which results from ring-opening polymerization of a compound having a furan ring;
• and
• a step of providing the second pack containing a hydrocarbon having two or more cyanate groups or a derivative of the hydrocarbon.