Polyethylene film like all plastic, degrades when exposed to the ultraviolet (UV) rays in sunlight. Ultraviolet rays accelerate the oxidization of plastic. To delay disintegration during service life, an additive known as ultraviolet inhibitor (UVI) must be added to the polyethylene base resin.
UVI additive is basically a heavy duty antioxidant ( AO for short ) package.
UVI does not prevent the sun’s rays from penetrating the film; UVI only delays the oxidization of film stored outdoors in sunlight. The best ultraviolet inhibitor is iron oxide (FEO2) or rust which is not practical when clarity is a requirement. For some reason, titanium dioxide ( TiO2 ) in combination with some UVI's has a further deleterious catalyst effect.
The right way to quantiify UV resistance is by testing in what is known as a weatherometer. The weatherometer exposes the specimen to UV rays consistently and measures the amount of exposure required to initiate degradation.
Exposing the film first to heat ( shrink film ) accelerates the oxidization reaction.
Most inquiries about UV films want a guarantee that the film will not deteriorate within a certain number of days. We do not make guarantees because we cannot predict usage conditions. We have plastic films which have a proven record - for practical purposes one year of outdoor storage provided we know the service life conditions.
Ultraviolet light and heat are "triggers" which initiate degradation of oxobiodegradable films.