Light stabilizers pigment type

The most common UV absorbers used commercially are hindered amine light stabilizers, which can also function as heat stabilizers in some plastics. Other UV absorbers include benzotriazoles and benzophenones, salicylate esters, cyanoacrylates, malonates and benzilidenes. Factors such as the nature of the resin, type and level of pigments being used, and the presence of crosslinkers and catalysts govern the selection of UV absorber to be used. 

The stability of these pigments depends on various factors the type of molecule, the concentration of the solution, pH, temperature, oxidation, light and the types of solvents. 

Typically hindered amine light stabilizers are used up to 3 % by mass of coating, depending on other formulation parameters such as type of binder and pigments. A combination of UV absorbers and hindered amine light stabilizers are often used in demanding applications due to their synergistic effect. 

If the interference of pigments with light stabilizers has not been known before, it is advisable to use a HAS-benzotriazole-type UV absorber (0.1. 2%) combination, which protects both the PP polymer and the pigment against fading. 

In recycling of used plastic products (recyclates), technical processes such as separation, purification, introduction of reinforcements, and additives, are usually included, depending on the source of the plastic, because thermoplastic products contain various different types of additives such as stabilizers, fillers, pigments, processing additives, and compatibilizers. The most common additives used for the recycling/reproduction of recyclates are phenolic antioxidants, phosphates, and costabiHzers such as anti-acids and light stabilizers. 

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