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Figure 1: Thermally induced cracking in conformal coating

Does your conformal coating require long term thermal shock testing?   Do you struggle to overcome cracking and adhesion loss with your current conformal coating after 1000 thermal shock cycles?   With the drive for increasing functionality for end devices, and increased life cycles being placed on all electronic assemblies, the need to have materials endure more stringent testing becomes increasingly vital.  Necessary robustness to these stringent conditions force suppliers like HumiSeal to innovate new material solutions to address these requirements.

Your conformal coating film is supposed to be clear and transparent, but it’s cloudy-white and dull…it’s BLUSHING.  This condition is an indication that your coating film is trying to tell you something, and it isn’t that it’s embarrassed.  This blog will help you better understand why your conformal coating film is blushing from acquired moisture contamination and help you eliminate this defect.

Coatings appear cloudy because they have inadvertently acquired moisture, either due to their hygroscopic nature or by artificial means (a cooling mechanism created by solvent evaporation), which then reacts negatively with the coating resin -  exhibiting itself as a milky, colloidal-type substance.  Many different types of conformal coating chemistries can be sensitive to blushing under certain circumstances.  These circumstances are usually related to specific ambient conditions, application, cure, condition of the assembly/substrate/associated components, storage environment and/or equipment under use.