TDK’s Conductive Epoxy Series is a conductive glue-mounted device rather than solder-mounted. In high-temperature environments, the connectivity reliability is focused on the solder fillet because there are thermal expansion coefficient differences between the substrate, MLCC, and solder fillet. A conductive glue-mounted device allows for more "flexibility" during periods of expansion and contraction because the thermal expansion differences have been reduced by using a non-solder attachment.
Conductive glue is a common method of mounting components in applications that demand reliability at high temperatures, particularly in automotive environments. It's also used in applications that cannot be subjected to the heat of the solder paste mounting process, such as LCD panels, organic EL and LED displays, and CCD devices, which are particularly sensitive to high temperatures.