The existing light stabilizer has the following deficiencies:

(1) The light shielding agent has good protective effect and low price, but it has shading and coloring properties, and is only applicable to opaque materials;

(2) UV absorbers have a wide range of applicability, but because of their protective effect, they can not effectively protect the surface of products and thin products. At the same time, because they are pure organic compounds, they also have the disadvantages of volatilization, frost spraying, migration, and solvent extraction, which not only affects the durability of their efficacy, but also causes environmental pollution;

(3) Excited quenching agent and hydroperoxide decomposing agent have high light stability, low volatility, small frost spraying and migration, and are resistant to extraction, which can effectively protect the surface of products and thin products. However, it will decompose and discolor at high temperature due to deep color, high toxicity and environmental pollution, and has antagonism with sulfur additives;

(4) Free radical trapping agent has light color, outstanding light stabilization effect, and can also effectively protect the surface of products and thin products. However, due to its alkalinity, it has antagonistic effect with acidic matrix and additives, and its performance will be affected by acidic environment. At the same time, like ultraviolet absorbent, it is a pure organic compound, but also has the disadvantages of volatile, frosting, migration, extraction and so on.

Selection conditions of light stabilizer

In practical applications, the selection of light stabilizer is often not easy. Generally, the following points can be paid attention to:

(1) According to the maximum sensitive wavelength of the polymer, select the variety that can improve the absorption coefficient as much as possible within this wavelength range.

(2) The effect of other additives, such as antioxidants, heat stabilizers, lubricants, colorants, etc., on the efficacy of light stabilizers must be considered and should not be reduced.

(3) Some light stabilizers have certain toxicity, so it should be carefully considered when the stabilizer is used for what kind of products. It should not be added to plastic raw materials in contact with food