Polyurethane – Top Coat Flaking


Why Polyurethane Top Coat Flaking – Peeling off?

Polyurethane – Top Coat Flaking what could be the reason? There can be several reasons for flaking or peeling off, but the main reason would be preparation prior to topcoat application.

Reasons like, due to weather conditions such as high humidity, extreme heat windy dusty conditions. And also, followed by lack of preparations like not carrying out light abrading, air blowing and paint agitation issues such as insufficient, improper mixing at the time of application.

Besides, one must strictly follow the paint manufacturers product datasheets.

Another important reason to note for this kind of failure is high DFT application. Moreover, after the very first application the wet film thickness checks should be carried out, highly recommended.


What is Flaking?

Flaking generally occurs due to adhesion failures, in other words, flaking means lifting of the coating material from the substrate that is in the form of scales or flakes.


What is Polyurethane Coating – Industrial?

Polyurethane paint is non-reversible meaning thermosetting paint. Once fully cured it will not melt even after giving heat to it hence, it will burn but not melt.

The recommended humidity is 40% because Polyurethane is a moisture curing paint. Polyurethane coatings are durable compared to Epoxy coatings hence are more resistant to abrasion and are less prone to scratches and dents.

The recommended thickness must not be higher than 75 microns as they are exposed to direct sunlight hence peeling or flaking is the possibility.

Polyurethane is more of a decorative coating rather than rust preventive as it protects from deterioration. Moreover, polyurethanes are versatile enough to be formulated to handle a wide variety of service environments.



There are a variety of causes for coating failures but the vast majority of all protective coatings perform admirably until an old age but in a few cases coating failures can fail prematurely.


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