UV resistant plastics

Plastics used in outdoor applications can be exposed to severe weather influences. These applications often require a weatherproof plastic material that can withstand the negative impact of ultraviolet radiation on visual appearance and mechanical properties of plastics. Therefore, it is usually advisable for weather proof plastics to be somewhat UV resistant, since UV radiation can have an especially high impact on materials used outdoors and exposed to the elements.

Inherent UV-resistance

Inherently UV resistant plastics will not typically show changes in appearance such as:

• Yellowing of the plastic
• Leaching of the pigments
• Bleaching of the plastic surface
• Stress crack formation

Nor will changes to mechanical properties appear like

• Development of brittleness
• Diminishing strength, elasticity and hardness

UV resistance of plastics is usually achieved by the use of additives such as UV stabilisers, black colouration (typically using carbon black) or protective surface coatings (such as paint, or metallization). The addition of carbon black is a low cost and typically very effective way of creating UV resistant plastics. In addition, fluorinated polymers such as PTFE and PVDF can demonstrate very good UV stability in their natural state.