The aging resistance of plastic colorants directly determines the speed of fading, discoloration, powdering, and cracking of products, but the influencing mechanism is complex. The key lies in the chemical structure of the colorant itself and its "compatibility" with antioxidants and light stabilizers in the plastic system. ‌‌

What problems can colorants with poor aging resistance cause

Photodegradation fading: This is the most direct impact. The ultraviolet rays in sunlight can damage the chromophore molecular structure of colorants (especially organic pigments), causing the color to gradually become lighter and darker.

Catalytic plastic aging: Some colorants contain heavy metal impurities such as copper, manganese, and nickel, which have "photoactivity" and can accelerate the photo aging of plastics themselves like catalysts, leading to brittle and cracked products.

Weakening the effectiveness of anti-aging agents: This is a point that many people tend to overlook. Colorants may undergo chemical reactions or physical adsorption with antioxidants and light stabilizers, rendering these "protectors" ineffective. For example, chrome yellow reacts with sulfur-containing antioxidants to produce black lead sulfide; Azo organic pigments can reduce the effectiveness of hindered amine light stabilizers (HALS) by 25% to 50%.

Impact on mechanical properties: If the pigment particles are too large or unevenly dispersed, it may lead to a decrease in the impact strength of the plastic; Inorganic pigments may also induce crystallization and affect the shrinkage rate during molding. ‌‌