Structural adhesive and bonding application thereof

摘要

A structural adhesive composition that is suitable for high-strength bonding of metals and aerospace structural materials. In one embodiment, the structural adhesive composition based on a two-part system, which is curable at or below 200° F. (93° C.). The two-part system is composed of a resinous part (A) and a catalyst part (B), which may be stored separately at room temperature until they are ready to be used. The resinous part (A) includes at least two different multifunctional epoxy resins, toughening components, and inorganic filler particles. The catalyst part (B) includes an aliphatic or cyclic amine compound as a curing agent and inorganic filler. In another embodiment, the structural adhesive composition is based on a one-part system, which includes the components of the resinous part (A) mixed with a latent amine curing agent. The one-part system may further include an imidazole and/or an aliphatic amine.

主权项

1. A two-part system for forming a structural adhesive comprising a resinous part (A) and a separate catalyst part (B),
the resinous part (A) comprising: at least two different multifunctional epoxy resins with different epoxy functionality selected from di-functional, tri-functional, and tetra-functional epoxy resins; smaller core-shell rubber particles having particle sizes less than 100 nm and larger core-shell rubber particles having particle sizes greater than 100 nm, the weight ratio of smaller core-shell rubber particles to larger core-shell rubber particles being in the range of 3:1 to 5:1; at least one of (i) an elastomeric polymer with a functional group capable of reacting with the multifunctional epoxy resins and (ii) a polyethersulfone polymer having an average molecular weight in the range of 8,000-14,000; and inorganic filler particles in an effective amount to control rheology of the resinous part; the catalyst part (B) comprising: at least one amine curing agent selected from the group consisting of: dicyclohexylamine, amine-terminated piperazine, polyethylene polyamine, and combinations thereof; and inorganic filler particles present in an effective amount to control rheology of the catalyst part; wherein the weight ratio of part (A) to part (B) is within the range of 3:2 to 10:2; and wherein, when part (A) and part (B) are mixed and then cured in a temperature range of 65-93° C. (150-200° F.), the resulting structural adhesive has a glass transition temperature (Tg) of greater than 95° C. (203° F.), a lap shear strength of 33-37 MPa at 20° C.-25° C., 24-27 MPa at 82° C., and 15-18 MPa at 121° C. according to ASTM D3165, and a peel strength of 250-350 Nm/m at 20° C.-25° C. according to ASTM D3167.