Views: 10 Author: Best Electronic Adhesives Glue Manufacturer Publish Time: 2022-12-01 Origin: https://www.deepmaterialcn.com/
What Is Polyurethane Conformal Coating? -- Silicone vs urethane conformal coating
Conformal coating is applied to PCBs in a thin polymer film to protect against harmful environmental factors. They are designed to conform to the shapes and designs of the boards, thus flowing over all areas that require protection. Considering that some electronic devices are used in high-risk conditions, and some are even inserted as aids in the human body, ensuring their functionality and safety is crucial.
Polyurethane conformal coating is among the materials offering this kind of protection. Urethanes are very popular in different industries because of their excellent characteristics, especially in resisting chemical damage, and humidity, among other threats. You can find the coating in two-component or single-component formulations. It is among the best ways to protect electronics with sensitive components.
What makes the polyurethane conformal coating popular?
Urethane has a thick coating that works in repelling chemical solvents. The materials are also abrasion-resistant, thus defending the electronics from harmful physical abrasions.
This conformal coating is also loved because it resists oil and moisture. The two can be very harmful to electronics, and if they are a possibility where the devices are to be used, you will take comfort in the polyurethane film.
The coating meets National Electrical Manufacturers Association requirements. It has Class F insulation ratings, meaning it works under 160 degrees C. It is one of the best for components with high-temperature exposure.
It has good flexibility even in low temperatures, thus making it very easy to manipulate to suit the application area demands. However complicated your assembly or circuit boards are, you can tweak the polyurethane coating to match the demands and offer the needed protection.
This conformal coating has the remarkable ability to repel and also eliminate fungi. Mold growth can lead to component damage. With the urethane protective layer, this is something you don’t have to worry about. It is a characteristic that makes the coating suitable in humid and wet conditions.
Polyurethane curing types and challenges
Polyurethane coatings can be cured using UV exposure, heat, or solvent evaporation. Like with any other conformal coating, the curing process is very important because it directly impacts your results and how protective the film will be to your devices.
Solvent evaporation – this method of curing polyurethane conformal coating is effective. But the moisture present can affect the rate of curing and the desired properties. It is also a very long curing process, sometimes taking up to 30 days to complete. The potential stress levels are high with this curing process, and it has the probability of reversing under humidity and temperature stress conditions.
Heat curing – The curing process by heat depends on the film thickness. It can also be affected by the mass components and temperature levels. The reaction can be violent when heat cures in the presence of water. This method requires caution when using low-temperature components.
UV curing – Whereas this type of curing is relatively effective with polyurethane coatings, the inaccurate application can leave shadowed areas behind. The UV wavelength and intensity will affect the curing process; it should be just right to achieve the desired results. Also, some urethanes can be difficult to rework, and some require meter mix equipment, especially the two-part systems.
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