Application Technology

DELO has designed its DELO DUALBOND HT2990, a new dual-curing, high temperature adhesive for electric motor applications that can be used in multiple processes, including magnet bonding and magnet stacking in electric motor manufacturing.

With the increase in the production of electric vehicles, durable adhesives to bond electric motors, as well as efficient processes that help streamline production and meet high demand, are critical. That’s why DELO has developed its DUALBOND HT2990, a first of its kind for the company, and according to DELO, the first heat-resistant adhesive capable of light fixation. This supplemental method of curing helps electric motor manufacturers speed up assembly processes and optimise efficiency in their production, achieving light fixation in 5 to 10 seconds.

In magnet bonding, while heat is the standard method of curing, complementing it with light fixation creates an already cured outer layer that helps keep everything in place; the adhesive does not seep outside, or onto the motor laminations. In magnet stacking, for example, supplementing heat curing with light fixation avoids having to keep magnets under a jig in the oven to reach the desired bond-line thickness.

Final curing with heat takes 30 minutes at 150°C or 60 minutes at 130°C. If exposure to heat occurs later in electric motor assembly, for example via heat shrinkage, there is a possibility for the heat curing step to be skipped. In addition, induction curing offers an alternative to oven curing.

At room temperature, DUALBOND HT2990 can achieve a compression shear strength of up to 70 MPa on steel, which compares to 45 MPa achieved by standard, high performance heat curing epoxies. It also has a high-glass-transition temperature of 165°C. In addition, at temperatures as extreme as 180°C the adhesive still exhibits a tensile shear strength of 7 MPa on aluminium, which is equivalent to 70 kg/cm² of force, i.e. a very secure bond.