UV Stabilisation in Agricultural Film: What Makes a Masterbatch Last 10+ Years?

How HALS-based UV stabilisers in black and additive masterbatch protect agricultural films from photodegradation in MENA and Mediterranean climates.

Agricultural films — greenhouse covers, mulch films, silage films, and drip irrigation tubing — operate under intense UV radiation, often for multiple seasons. In MENA and Mediterranean climates, UV exposure levels are among the highest in the world. Without effective UV stabilisation, polyethylene film will degrade, embrittle, and fail within one to two seasons. This guide explains how UV stabilisation works and what to look for in a masterbatch.

How UV Radiation Degrades Polyethylene

UV radiation from sunlight (specifically wavelengths between 290–400 nm) provides enough energy to break the C-C and C-H bonds in the polyethylene polymer chain. This process — called photo-oxidation — is initiated by the formation of free radicals and hydroperoxides. Without stabilisation, these radicals propagate rapidly, causing chain scission (molecular weight reduction), crosslinking, discolouration, surface chalking, and ultimately mechanical failure (cracking, embrittlement).

How HALS Stabilisers Work

Hindered Amine Light Stabilisers (HALS) are the most effective UV protection technology for polyolefin films. Unlike UV absorbers (which simply absorb UV radiation and convert it to heat), HALS work by a catalytic free-radical scavenging mechanism — they interrupt the photo-oxidation cycle at the radical propagation stage, without being consumed in the process. This is why HALS are highly efficient at low concentrations and provide long-term protection.

For agricultural films requiring 3–5+ year outdoor performance in MENA climates, HALS concentrations of 0.3–1.0% in the finished film are typically required, depending on film thickness, climate, and specific product. This is delivered through black masterbatch (for black mulch film) or dedicated UV additive masterbatch at appropriate dosage rates.

Black Masterbatch for Agricultural Applications

Carbon black in black masterbatch acts as both a UV absorber and an antioxidant, providing inherent UV protection. However, for demanding agricultural applications, carbon black alone is often insufficient for extended service life — a combination of carbon black and HALS provides better performance and longer service life.

Our Coraplast black masterbatch range includes UV-stable grades specifically formulated for agricultural and pipe applications, with HALS levels appropriate for MENA climate conditions. Contact us with your required service life and application details for a specific grade recommendation.

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