Urethane Conformal Coating: When Not to Use

Urethane conformal coating is a very common conformal coating choice. However, it is not suitable for all applications. Urethane conformal coatings are not an ideal solution for applications that will be in a high-vibration environment or have a high heat requirement.

Because of the mechanical strength and resistance to abrasion that urethanes typically exhibit, a high-vibration environment could ultimately weaken the integrity of this rigid coating. Alternatively, Parylene’s conformal nature and flexibility makes it better suited for this type of environment.

Urethanes do not provide the protection that is required in high-temperature environments. Leading urethanes, such as HumiSeal^® 1A33, offer protection to 125ºC.  Most typical silicone coatings have a continuous operating temperature rating of 200ºC, making it better suited for applications exposed to high heat.