New Structural Adhesive from DELO Offers Temperature Stability

DELO, a manufacturer of industrial adhesives for automotive, consumer and industrial electronics applications, has launched an adhesive with exceptionally high temperature stability. DELO Monopox HT2999 achieves compression shear strength of 20 MPa at 180°C. This is four times greater than its predecessor.

E-motor with adhesive colored magenta

Technical Specifications

•             Compression shear strength on magnetic material (NdFeB) at +180°C: 20 MPa

•             Glass transition temperature: +180°C

•             Electrically insulating

•             Layer thickness: ~ 50 µm

•             Curing: 10 min at +150°C

Developed primarily for use in the automotive industry and mechanical engineering, these high-temperature-resistant adhesives are in demand for use with 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.

Important adhesive properties

This high-temperature resistant adhesive has been optimized for bonding magnets in electric motors. The compression shear strength of bonded magnets (NdFeB) is 20 MPa at 180°C. The bonded joints remain thermally stable over time. Even after 10,000 hours of storage at 180°C, the bonded magnets achieve a temperature stability of 20 MPa.

The maximum operating temperature of electric motors is generally 180°C. This is because the powerful, rare earth magnets used in the motors will demagnetize at higher temperatures. If a certain application requires resistance at higher temperatures, DELO MONOPOX HT2999 can be used up to 220°C.

Electrical insulation is another important property of the adhesive. It minimizes eddy currents in electric motors, reducing heat development and increasing motor performance. Integrated spacers are provided with DELO MONOPOX HT2999. These spacers ensure a very thin and uniform bonding gap of 50 µm for magnet stacking. This allows the use of more magnetic material and also contributes to motor efficiency.


The one-component epoxy resin is gray and pasty. It takes just 10 minutes to cure in an air convection oven at 150°C. Compared to other high-temperature adhesives that require 30 to 40 minutes curing time at 150°C, this adhesive offers clear advantages in saving time and energy.

“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 at DELO. “It’s a good example of how we’re pushing the boundaries of what’s technically possible, step by step.”

For more information on this new development and the innovations based on it, which combine high temperature stability with light fixation or thermal conductivity, please visit