US 12,227,680 B2
Expandable structural adhesive film for dissimilar metal bonding
Elisabeth Cura, Duesseldorf (DE); and Bernhard H. Koch, Neuss (DE)
Assigned to 3M Innovative Properties Company, St. Paul, MN (US)
Appl. No. 17/762,811
Filed by 3M INNOVATIVE PROPERTIES COMPANY, St. Paul, MN (US)
PCT Filed Sep. 23, 2020, PCT No. PCT/IB2020/058881
§ 371(c)(1), (2) Date Mar. 23, 2022,
PCT Pub. No. WO2021/059154, PCT Pub. Date Apr. 1, 2021.
Claims priority of application No. 19200224 (EP), filed on Sep. 27, 2019.
Prior Publication US 2022/0396716 A1, Dec. 15, 2022
Int. Cl. C09J 5/08 (2006.01); C09J 7/35 (2018.01); C09J 11/08 (2006.01); C09J 163/00 (2006.01)
CPC C09J 5/08 (2013.01) [C09J 7/35 (2018.01); C09J 11/08 (2013.01); C09J 163/00 (2013.01); C09J 2301/304 (2020.08); C09J 2301/312 (2020.08); C09J 2301/408 (2020.08); C09J 2400/163 (2013.01)] 12 Claims
 
1. An expandable structural adhesive film for bonding metal parts, comprising
(a) at least one first epoxy compound;
(b) at least one epoxy curing agent;
(c) at least one blowing agent;
(d) at least one film-forming agent;
(e) at least one impact modifier,
wherein the structural adhesive film exhibits an elongation at break of at least 300% according to tensile test DIN EN ISO 527, and a free expansion rate according to EN 2667-3 of at least 60%,
wherein the film has a thickness in the unexpanded state in the range of from 450 μm to 750 μm.