UV STABILIZERS
Ultraviolet (UV) radiation from the sun and other light sources such as fluorescent lighting
is harmful to polymer properties. Finished plastic parts exposed to direct or indirect sunlight
can display surface chalking as the polymer becomes oxidized, and can lose physical
properties and become brittle to the point of no longer being fit for original use. UV light
also accelerates the fading of plastic colorants.
Solution
The use of UV stabilizer additives can inhibit or absorb the harmful UV radiation that causes degradation of the polymer.There are two primary types of stabilizers used today:
UV absorbers and Hindered Amine Light Stabilizers (HALS).UV absorbers work by absorbing the UV rays and dissipating them into thermal energy. UV absorber chemistries include benzophenones, benzotriazoles and hydroxyphenyl triazines.
HALS work by scavenging free radical intermediates generated by the UV rays to neutralize the degradation. In both cases, the damaging effect of the UV light is
focused away from the base polymer and colorants due to interaction with the UV additive present in the base polymer. It is important to know the specifics of the end-use
environment, polymer base and processing conditions to design the most effective UV stabilization package to meet the performance expectations.
Value
The use of UV stabilizers will retard the harmful effects of
UV radiation on polymer properties. This provides several
benefits to OEMs, processors and consumers:
1. Reduced field failures and returns
2. Increase shelf life for end products
3. Ability to store parts outside for longer periods
4. Protection against premature color fading