Adhesive from DELO Optimized for Bonding Magnets in Electric Motors

DELO has launched an adhesive with exceptionally high temperature stability that it developed primarily for the automotive industry and mechanical engineering applications. The company’s new Monopox HT2999 achieves strengths of 20 MPa at 180 °C which is four times greater than its predecessor. It is depicted above in an exploded view of an automobile motor with the adhesive colored magenta. 

High-temperature-resistant adhesives are in particular demand for electric motors and power electronics. Many products that are currently on the market show a clear drop in performance at temperatures above 150 °C. DELO’s new structural adhesive can be used above that temperature. 

The performance profile of the new adhesive has been optimized for bonding magnets in electric motors. For example, the compression shear strength of bonded magnets (NdFeB) is 20 MPa at 180 °C, with the bonded joints remaining thermally stable in the long term. Even after 10,000 hours of storage at 180 °C, they achieve a temperature stability of 20 MPa. The maximum operating temperature of electric motors is generally 180 °C since the powerful rare earth magnets will demagnetize at higher temperatures. If a certain application requires resistance at higher temperatures, the adhesive can even be used up to 220 °C.  

Electrical insulation is another important property since it minimizes eddy currents in electric motors, reducing heat development and increasing motor performance. The new adhesive is provided with integrated spacers that ensure a uniform and very thin bonding gap of 50 µm for magnet stacking. This allows the use of more magnetic material and also contributes to motor efficiency.  

“Four times the strength of the previous generation is a truly extraordinary step in development. And since the product is also electrically insulating, it provides additional functionalities for manufacturers of electric motors,” says Dr. Karl Bitzer, head of product management. “It’s a good example of how we’re pushing the boundaries of what’s technically possible, step by step.” For more info, see