Improvement in the light fastness of dyed and pigmented materials. 3 – The effect of antioxidants on the photostabilisation of dyes and pigments in some polymeric media

The effect of some added antioxidants on the photostabilisation of a quinophthalone dye (C. I. Solvent Yellow 33) and C. I. Pigment Red 38 in polymeric media such as chlorosulphonated polyethylene (CSM rubber), poly(vinyl chloride) (PVC) and polyethylene has been examined. The effects varied according to the type of antioxidant used. For example, the addition of 2, 6–di–t–butyl–4–methylphenol, an effective radical scavenger, afforded little protection against photodegradation, whilst the singlet oxygen quenching of antioxidants such as bis(l, 2–diaryl or dialkyl–l, 2–ethylenedithiolato) nickel, nickel dialkyldithiocar–bamate, nickel bis(mesitylenesulphonate), and nickel (N–n–dodecylsalicylaldimine) conferred improved resistance towards photodegradation.