两者分工不同：紫外线吸收剂先吸收紫外光并转成热能，受阻胺光稳定剂（HALS）捕获已产生的自由基、中断降解链。耐候配方通常两者并用，比例按制品厚度、颜料体系与预期寿命调整。 They work at different stages: UV absorbers absorb UV and dissipate it as heat; hindered amine light stabilizers (HALS) trap free radicals and stop the degradation chain. Weatherable formulations normally use both, with the ratio set by part thickness, pigment system and expected service life.
紫外线吸收剂（UVA）起什么作用？ What does a UV absorber do?
UVA 吸收 290-400 nm 的紫外光并以热能形式释放，保护基体不被直接光解。常见品种有二苯甲酮类（如 UV-531）与苯并三唑类（如 UV-326、UV-328）。它的效果依赖厚度——薄制品里吸收光程短，单靠 UVA 往往不够。 A UV absorber takes up radiation in the 290-400 nm band and releases it as heat, protecting the polymer from direct photolysis. Common families are benzophenones (UV-531) and benzotriazoles (UV-326, UV-328). Its effect depends on thickness — in thin parts the absorption path is short and UVA alone is often not enough.
受阻胺光稳定剂（HALS）起什么作用？ What does HALS do?
HALS 不吸收紫外光，它通过捕获自由基、分解氢过氧化物来中断降解链，属于"事后补救"。它不受厚度限制，因此在薄制品、纤维与涂层里作用尤其明显。 HALS does not absorb UV. It traps free radicals and decomposes hydroperoxides, interrupting the degradation chain — a curative mechanism. It is not thickness dependent, so its benefit is greatest in thin parts, fibres and coatings.
为什么两者要并用？ Why use both?
UVA 在源头挡光，HALS 在下游止链，两者覆盖降解过程的不同阶段。厚制品中 UVA 贡献更大，薄制品中 HALS 贡献更大；并用可以获得比单一品种更长的耐候寿命。 UVA blocks at the source, HALS stops the chain downstream — they cover different stages. UVA contributes more in thick parts, HALS in thin ones. Together they give a longer weathering life than either alone.
有配伍禁忌吗？ Are there incompatibilities?
有。含硫类抗氧剂与部分 HALS 存在对抗作用；酸性颜料、阻燃剂与残留催化剂也会削弱 HALS 效果。新配方应先做小样配伍试验，再按人工加速老化或户外曝晒数据确定添加量。 Yes. Some sulfur-containing antioxidants antagonise HALS; acidic pigments, flame retardants and catalyst residues also reduce HALS efficiency. Run compatibility trials and set dosage from accelerated weathering or outdoor exposure data.
对比一览 Comparison
| 品种 Type | 作用阶段 Stage | 是否依赖厚度 Thickness dependent | 典型场景 Typical use |
|---|---|---|---|
| 二苯甲酮类（UV-531） Benzophenone (UV-531) | 吸收紫外光 Absorbs UV | 是 Yes | PVC、涂料、通用塑料 PVC, coatings, general plastics |
| 苯并三唑类（UV-326/328） Benzotriazole (UV-326/328) | 吸收紫外光 Absorbs UV | 是 Yes | 工程塑料、PC、PMMA Engineering plastics, PC, PMMA |
| 受阻胺光稳定剂 HALS HALS | 捕获自由基、止链 Traps radicals, stops chain | 否 No | 薄制品、纤维、涂层 Thin parts, fibres, coatings |
| UVA + HALS 并用 UVA + HALS | 源头 + 下游 Source + downstream | 部分 Partly | 长期户外耐候制品 Long-term outdoor parts |
常见问题 FAQ
光稳定剂加得越多越好吗？ Is more stabilizer always better?
不是。过量会析出、喷霜，影响外观与后续印刷粘接。应按配方总量与制品厚度确定经济用量，并通过老化试验验证。 No. Overdosing causes blooming and affects appearance, printing and bonding. Set an economical dosage from the compound and part thickness, and verify by weathering tests.
深色制品还需要光稳定剂吗？ Do dark parts still need stabilizers?
需要。炭黑本身是有效的紫外屏蔽剂，但颜料并不阻止表面降解与失光，深色制品仍会出现粉化与失光，尤其在薄壁件上。 Yes. Carbon black shields UV to some extent, but pigments do not prevent surface degradation and gloss loss. Dark parts still chalk and lose gloss, especially thin-walled ones.
UV-531 主要用在哪些体系？ Where is UV-531 mainly used?
UV-531（二苯甲酮类紫外线吸收剂）常用于 PVC 与常规涂料、通用塑料体系，与 HALS 并用可延长户外使用寿命。具体添加量按树脂体系与厚度确定。 UV-531, a benzophenone absorber, is used in PVC, conventional coatings and general plastics. Combined with HALS it extends outdoor service life; dosage follows the resin system and part thickness.
耐候数据怎么验证？ How is weatherability verified?
常用人工加速老化（氙灯、QUV）与自然曝晒。加速数据用于快速筛选，自然曝晒用于最终确认，两者结论可能不一致，应以实际使用环境为准。 Accelerated xenon arc or QUV testing plus natural exposure. Use accelerated data for screening and natural exposure for final confirmation — the two can disagree, so follow the real service environment.
参考资料 References
本页内容用于选型参考，具体指标以该批次的 COA 与 TDS 为准。