AbstractThe shrink films used to fix the loads on pallets are subjected to outdoor exposure and, particularly, to temperature changes and light. The resistance to photodegradation of these films must be taken into account in the design of a quality certificate.The natural degradation of the films was carried out in the natural environmental testing station in Bandol (south of France). The climate of this area represents the conditions encountered around the Mediterranean (moisture, temperature and radiant energy), which are as severe as those in most temperate countries.The accelerated tests were made at 60°C in a Sairem‐Cepap 12/24 cabinet comprising four mercury gas‐filled arc lamps of the mean pressure type. The quality of the light is representative of natural photoageing. Any radiation of wavelength lower than 290 nm, which is absent from the solar spectrum, is carefully eliminated. The light sources radiate light rich in photons that have wavelengths between 290 and 450 nm, and provide one of the main factors of degradation. The intensity of emission and the spectral composition were constant during 5000 h.Three kinds of films of 120 μm thickness were tested:(i) four films with ‘medium’ protection against sunshine (6 months resistance in a very sunny country);(ii) four films with ‘high’ protection against sunshine (12 months resistance in a very sunny country);(iii) one reference film without any protection.A film was considered acceptable if its mechanical properties (tensile strength and elongation) did not fall more than 50 after exposure to natural radiations for 6 or 12 months, respectively.Comparative tests have shown that for these particular kinds of polyethylene films, exposure to natural radiations at Bandol for 6 or 12 months is equivalent to an accelerated ageing in a Sairem‐Cepap cabinet of 350 or 500
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