Thermosetting adhesives are essentially infusible, insoluble and show good creep resistance. They are used for high load assemblies and severe service conditions such as heat, cold, radiation etc.
Thermoset adhesives set as a result of the build up of molecular chains to produce a rigid crosslinked structure. They include epoxy resins, which are some of the most widely used adhesives. There are many different thermoset adhesives available including phenolic formaldehyde (PF) resins, phenolic neoprene, resorcinol formaldehydes (RF), polyesters, polyimides and epoxy resins.
Thermoset adhesives are generally more expensive,to purchase and to use, than the other adhesive types. They are the adhesives most used for structural, load bearing applications. Some of the toughened variants provide exceptional properties directly comparable with welded and riveted alternatives.
| Type | Notes | Materials Bonded |
| Resorcinol resins | Water resistance is very good. They are used to make exterior plywood. | Wood, porous materials |
| Polyesters (unsaturated) | Usually made to harden by chemical action rather than by the evaporation of solvents and thus cure with little shrinkage. | Glass fibre binder. |
| Polyimides | High performance adhesives requiring higher curing temperatures and bonding pressures (up to 0.7 MPa ). High cost adhesive. Supplied as tapes. | Metals |
| Epoxy resins | Epoxy (mostly 2-part) adhesives have good strength and chemical resistance, do not produce volatiles during curing, and have low shrinkage. Therefore they form extremely strong and durable bonds with most materials in well-designed joints. Single part adhesives require heat for setting or need long setting times. | Metal, Glass, elastormers, some plastics |
| Epoxy polysulphides | Better flexibility and peel strength but relatively lower peel strength | |
| Epoxy silicones | Good temperature characteristics | Metals , Laminates |
| Redux adhesive | Trade Name.. High performance structural adhesives - Paste or film . Can be formulated for higher temperatures (180o C). Automobile, Aerospace, Marine applications. | Metals, |
