Quick answer: For antioxidant, UV absorber, and HALS topics, formulators usually compare long-term protection, process stability, and color control together because those priorities do not always point to the same additive.

涂料紫外线吸收剂的光老化保护作用是什么？

 

UV absorbers such as 紫外线吸收器 384-2 used together with Light Stabilizer 292 are effective in slowing down the light aging behavior of cured coatings. The addition of various suitable UV absorbers and light stabilizers to coating formulations is a well-established method of operation for organic coatings for outdoor use where high quality and longevity are required. UV absorbers such as EVERSORB 80, EVERSORB 93, etc. are classic anti-aging products.

表征涂层光老化性能的方法有很多。对于不含羰基结构的聚合物，其光老化性能可以通过红外吸收光谱中的羰基信号变化来表征。但有些涂料（包括光固化紫外线涂料）含有酯羰基、氨酯键等，不适合用羰基值来表征其光老化行为。在这种情况下，我们可以使用黄变指数（YI）来表征它们。国际标准方法遵循 ASTM D1925，将固化膜暴露在紫外光下，每暴露一段时间后，用紫外可见分光光度计测量固化膜在几个特定波长处的透射率，照射源可以是中压汞灯，用派莱克斯玻璃过滤掉 320 纳米以下的短波紫外光。

黄度指数的定义为

 

 

利用人工光源进行的老化试验称为加速老化，加速老化往往还要配合湿度、温度、盐雾等附加装置，以便更客观、全面地评价涂层的抗老化性能。除紫外光源外，功率为几百瓦的氙灯，其光谱输出为 250nm 起的连续光谱，与达到地面太阳光谱波段分布相近，是人工老化机常用的光源。其他人工老化光源包括 QUVA 和 QUVB。QUVA是长波紫外线输出，而QUVB的输出波长为280-360nm，中心位于310mm。比较原始，但完全符合自然老化的光老化试验是在阳光直射下进行的，如美国佛罗里达州采用的45度角曝晒试验。

由于地球大气中臭氧的吸收作用，太阳光透过大气层到达地面时，295nm 以下的高能短波紫外线基本上被过滤掉了。因此，地面阳光对高分子涂层的光老化有很强的影响，波段主要集中在 295~400nm 之间，波长越短，能量越高，对高分子涂层的光老化影响就越强烈。受季节、时间、海拔高度、纬度、天气、空气污染等诸多因素的影响，地面阳光中的紫外线强度可能会发生变化。臭氧层吸收 320nm 以下的紫外线，但随着大气污染、臭氧层破坏，到达地面的短波紫外线强度逐年增加。使用不同光源得到的光老化结果不一定一致，主要是因为各种光源的波长分布、强度、环境湿度、温度等条件不完全一致。

除了黄度指数，还可以通过检测吸收光谱、光泽、雾度、附着力、机械性能、热力学机械行为等指标的变化来表征固化膜的抗老化性能。由于光老化过程中普遍存在光氧化现象，涂层中羟基指数或过氧化物指数的变化常被用作反映光老化的参数。还可以根据敏感基团浓度的变化来表征聚合物的不同结构。

A practical selection route for antioxidant, UV absorber, and HALS packages

Most stabilizer decisions work best when they are treated as package decisions rather than single-product decisions. Technical buyers usually get the strongest answer by reviewing long-term heat aging, process stability, weather exposure, and color sensitivity together.

• Separate processing protection from long-term stability: the best additive for melt history is not always the same one that gives the best service-life retention.
• Use synergy deliberately: many polymer and coating systems perform best when primary and secondary stabilizers are paired intentionally.
• Review color and clarity requirements: clear, pale, food-contact, or white systems often need a tighter package than dark industrial products.
• Check the real aging condition: heat, UV, humidity, and outdoor exposure can each change which stabilizer route is commercially strongest.

Recommended product references

• CHLUMINIT TMO: A valuable comparison point when lower yellowing or TPO-replacement discussions matter.
• CHLUMILS UV-123: A strong HALS reference for weatherability-focused screens in coatings and polymers.
• CHLUMILS UV-5151: A practical stabilizer-package reference when broader light-aging protection is needed.
• CHLUMILS UV-770: A familiar HALS benchmark when weatherability and appearance retention are under review.

FAQ for buyers and formulators

Why are stabilizer packages often stronger than a single additive?
Because different products can protect different parts of the degradation pathway, so the package often covers more risk than one grade alone.

Does adding more antioxidant or UV stabilizer always improve performance?
Not necessarily. Over-dosing can increase cost and sometimes create side effects, so most systems perform best inside a tested dosage window.