SPRAY-LINING RESEARCH: WHAT IS UV STABILITY – TRUCK BED LINERS & SPECIALIZED COATINGS
Submitted by Tony Morice, West Loop Auto Body, Chicago Collision Center, Chicago, IL for Ben Dexter, Zone 2 distributor of Spray-Lining and Coatings
UV Stability is a feature to prevent degeneration of a Lining or a Coating product applied. This article addresses UV Stability of spray-on truck bed liner, polyurea, polyurea hybrid and all coatings where UV Stability is desirable or required. This may also address how this issue is independent of the “brand” or “label” a bedliner dealer is known by.
First, it’s more than retention of a color over time under solar light that matters. By definition, UV Stability prevents the sun’s or synthetic ultra violet rays from breaking down the composition of a coating. This decomposition, atomic in nature is from molecular bonds terminating in reaction to ultra violet exposure. Therefore much more is going on with a sprayed-lining than just a fading color.
Fading is the first noticed by the eye where the complete solid surface; the lining or coating itself is “falling apart”. In layman’s terms this means that after a non-UV Stable liquid cures, it will “dry out” over time from UV exposure. Any lining or coating that loses its moisture will become brittle, with time it’ll flake and crack microscopically. At first these tiny flakes appear as a powder, dull in color compared to its initial cure which may be how the term, “fading” evolved.
To a much smaller degree even high-tech, UV Stable paints will fade. But this is minimal where using rubbing or buffing compound, the fine, abrasive can remove a faded layer. Waxes over this paint act to prevent fading through a form of lubrication within the paint’s chemistry; inside microscopic pores. Re-waxing is necessary as even it degrades, breaks down or dries out from UV rays.
To provide an ultraviolet stable system, however, non-aromatic, i.e., aliphatic, components should be employed. SEE http://www.google.com/patents/US5162388
Ergo, with polyurea, spray-lining, polyurea hybrid, spray-on bedliner or any coating that can be UV Stable, while it’s plausible to aid UV Stability by using aliphatic compound in its chemistry; this hasn’t lasted as long as it does in paint. This is dues to the inherent flexibility, i.e. “softness” of polyurea as compared to paint. With its high elasticity, great elongation (stretching before breaking), a much greater amount of microscopic pores result. This is as when compared to paint which is hard and thin verses coating and lining that is thick and flexible, i.e. not hard. A higher percentage of aliphatic components are in a thin, hard layer of high-grade paint than can be in a thick layer of flexible polyurea.
For this reason Spray-Lining uses aliphatic polyurea hybrid as its DIY kits. Most dealerships of Spray-Lining advise topcoat of pure aliphatic polyurethane combined with clear poly hybrid to maximize long term UV Protection.
FOR MORE BASIC OPINIONS IN A FORUM SEE http://www.titantalk.com/forums/titan-parts-accessories/129234-spray-bedliner.html