The main types of light stabilizers and selection

UVA

Radical Scavengers

ESQ

Active substance

-   Inorganic (inorganic pigments)

-   Organic (Benzophenones, benzotriazoles, oxanilides, triazines, etc.)

-   Hindered amine light stabilizers (HALS)

- Nickel quenchers

Mechanism of action

UV absorption

Radical scavenging

Excited-state quenching

Locus of action

Within a certain depth

Throughout the bulk, especially at the surface

At the surface and within a certain depth

Protection against

-   Colour change/pigment protection

-   Mechanical strength

-   Gloss, chalking

-   Colour

-   Mechanical properties

-   Gloss, chalking

-   Colour

-   Mechanical properties