Adhesives are mostly thermoset plastics when cured (although cyanoacrylates are thermoplastic) and in any case are a highly complex polymer. In most engineering applications, the mass of adhesive within an assembly or sub-assembly is negligible and only a few percent of the total mass of the component and it will be difficult (and very expensive) to extract just the adhesive from the component at the end of life of the component.
Nevertheless under the End of Life Vehicles Directive 200/53/EC (2005), adhesive suppliers are now required to provide statements regarding the composition to automotive manufacturers in order to ensure that the vehicle can be safely recycled at its end of life [3] and [4].