LOCTITE ECCOBOND FP4470

The on-set temperature of FP4470 is around 140 Celsius as calculated by the X-section of the 2 red lines. You can imagine that the positioning of the red lines is a bit “subjective”, so different people & different software can get slightly different results from the same curve. Nevertheless, this is widely accepted as the “standard” method of calculating the on-set temperature.

A more interesting point is that the calculated on-set is always higher than the START of CURE. This is where the material starts to exotherm, and the baseline deviates upwards from a straight line. In this case it is 100°C, so curing at 140°C or 150°C should be OK (similar to FP 4450 for which we recommend 165°C cure, but companies have been using 140°C for decades due to their "sensitive components".

Loctite ECCOBOND FP4470 is a solvent-less epoxy. It contains 75% filler and the rest are epoxy resin and hardener systems. Thermogravimetric Analysis (TGA) graph below shows approximately (5-6%) that evaporate from the system during the curing process. This minor weight loss is typically attributed to trace residual moisture, very low levels of entrapped air, and low molecular weight. Once full cure is achieved, no more volatiles are expected to be present. Likewise, TGA does not show any other distinct low-temperature mass-loss that would indicate solvent evaporation after curing process. The primary weight-loss event begins around 350 °C to 400°C that corresponds to polymer backbone decomposition. Final residue of ~75% at 600°C is consistent with a highly crosslinked, aromatic epoxy system with potential filler content.