小区里新装的户外健身器材，刚过一个夏天就褪色发白，座椅表面出现细密裂纹。物业找厂家索赔，厂家的配方师翻出配方单——只加了UV吸收剂531，没加HALS，紫外线产生的自由基没人捕捉，等于只涂了防晒霜没做晒后修护。
没有光稳定剂的户外PP，入夏头一年就开始往脸上掉粉。
本文由长期经营塑料原料及助剂的宁波市科隆新材料有限公司整理，牌号与批次信息以实际供货渠道为准。
光稳定剂速查总表：四大类一页看清谁在干活
耐候不是靠一种助剂单打独斗，而是几个“工种”分工：一类把紫外线挡在门外，一类把已经产生的自由基收编，还有一类在旁边兜底。下面这张表把主流体系的代表品种、关键参数和典型用途列清楚，选型时先定防护层级，再谈牌号。
| 体系 | 代表品种 | 关键机理/参数 | 典型制品 | 添加比例 |
|---|
| 受阻胺类HALS（捕自由基） | 770、944、622 | 碱性哌啶结构，循环捕捉自由基 | 汽车外饰、户外护栏 | 0.1%-0.4% |
| 紫外线吸收剂UVA（屏蔽） | UV531、UV326、UV327 | 吸收UV能量转为热，苯并三唑/二苯甲酮 | 薄膜、漆片、透明件 | 0.1%-0.3% |
| 猝灭剂 | 镍螯合物类 | 把激发态分子的能量带走 | 农用薄膜、纤维 | 0.1%-0.3% |
| 复配耐候母粒 | HALS+UVA+抗氧剂 | 三重协同，预分散好添加 | PP/PE户外通用 | 总0.3%-0.6% |
注：以上为行业常见参数区间，具体牌号的紫外吸收谱和耐候数据以生产企业官方资料为准。思路很直白：先问制品在户外晒几年、是薄是厚、透不透明，再决定用哪一层防护。
图1 光稳定剂——户外塑料件的耐候防护层
光稳定剂不是加一个就完事，三重协同才扛得住日晒雨淋
这台戏的主角，常年站在幕后。宁波市科隆新材料有限公司长期经营各类塑料助剂及改性原料，覆盖国内外多个品牌货源，在光稳定剂、抗氧剂、润滑剂等常用户外助剂品类上有稳定供货渠道。而光稳定剂这个品类，本质上就是户外塑料的“防晒霜”——太阳光里看不见的紫外线会把聚烯烃分子链激发成自由基，链式反应一开，材料就黄变、变脆、表面粉化。光稳定剂的活儿，就是在这条链上动手脚：要么把紫外线拦在门外，要么把自由基就地按住。
光稳定剂就是塑料的防晒霜：UV吸收剂抹在前面挡晒，HALS在里面晒后修护。
从机理上讲，耐候防护是三层岗哨。打头阵的是紫外线吸收剂（UVA），它像一面遮阳伞，把300到350纳米的紫外线吸收掉、转成无害的热能散掉，从源头减少光的破坏；中间一层是受阻胺类光稳定剂（HALS），它不像UVA那样“挡光”，而是钻进材料里循环捕捉已经生成的自由基，把活泼的分子重新稳定下来；最后一道岗才轮到抗氧剂兜底，把热氧老化的尾巴收住。三层配合，才叫完整的耐候体系。
三层岗哨不是叠 buff 的玄学，是几十年暴晒试出来的排班，缺一层都扛不到年底。
很多配方师有个误区：以为加了HALS就万事大吉，或者反过来只上UVA。实际上，UVA是“一次性消耗”的，挡着挡着自己就用完了；HALS是“循环再生”的，长效但对已入射的光无能为力。薄制品、透明件优先UVA，厚壁件、长效耐候优先聚合型HALS，两者搭着用才稳。所以行业里说的“HALS+UV吸收剂三重协同”，不是营销话术，是几十年暴晒试出来的分工。
你管这叫“户外耐候”？QUV照一千小时就发粉掉渣，这是把防晒霜涂在了鞋底上。
逐品种速查：944守长效，770管通用，UV531做搭档
光稳定的牌号看着杂，抓住几个主力品种就能覆盖八成户外场景。下面逐个拆，每个讲清楚定位、适用信号和注意事项。
选HALS看分子量：要长效就上聚合型944，别拿小分子770硬扛户外。
HALS 944（聚合型受阻胺）：分子量高、耐抽出、耐迁移，是厚壁长效户外件的主力。汽车保险杠、户外护栏、园林家具这种要求晒三五年不粉化的件，多用它打底。选它的信号：户外长效、厚壁、对耐迁移要求高。注意：944价格带约60到100元/kg，比小分子贵，但摊到每吨料里其实没多少。
供货提示：HALS 944和UV531是户外件的常用组合，科隆新材可配套供货，每批附紫外老化测试参考数据，公斤级试样支持先测后用。
HALS 770（小分子受阻胺）：分子量小、易分散、见效快，但耐抽出和长效性不如944，适合薄制品、纤维和对成本敏感的户外件。选它的信号：做PE农膜、薄型户外制品、要求初期耐候快。注意：小分子770容易迁移析出，厚壁长效户外件建议换944或622。
HALS 622（聚合型受阻胺）：和944同属聚合型，偏长效耐抽出，常与770复配做平衡。选它的信号：薄膜、扁丝、需要兼顾分散和长效。注意：622偏酸性体系时要测相容性。
HALS是碱性的，遇到红磷等酸性阻燃剂要先做相容性试验，别直接一锅烩。
UV531（二苯甲酮类紫外线吸收剂）：吸收紫外、成本友好，常和HALS搭档做PP户外件的“前哨”。典型搭配就是HALS 944约0.2%加UV531约0.1%。选它的信号：做PP/PE户外件、需要遮光层、对成本敏感。注意：UV531有一定迁移性，透明件要测透光率变化。
UV326、UV327（苯并三唑类紫外线吸收剂）：吸收效率高、耐热好，适合加工温度高或对色光要求严的制品。选它的信号：工程塑料户外件、需要更高光稳定性。注意：苯并三唑类略贵于二苯甲酮类，按需选用。
镍螯合物猝灭剂：早年农膜常用，把激发态分子的能量“猝灭”掉。现在多被HALS替代或复配使用，单独用得少了。选它的信号：农用地膜、需要和防雾滴功能兼顾。注意：含镍体系要关注环保和食品接触合规。
替代对照：进口光稳定能不能换？先看这张表
采购常问：进口HALS和UVA能不能用国产替代？答案是可以，但要分场景。通用户外PP/PE用的770、944、UV531，国产主流牌号在核心指标上差距已经很小，批次稳的国产品牌完全够用；但在汽车低VOC、光伏背板这类高端认证场景，进口牌号在批次一致性和低析出上仍有优势。下面这张表列出常见替代方向和切换前提。
| 原用进口方向 | 典型应用 | 可对标方案 | 切换前提 |
|---|
| 巴斯夫Tinuvin 770 | PE农膜/薄户外件 | 国产770 | 小试对比QUV/氙灯老化1000h、粉化等级 |
| 巴斯夫Chimassorb 944 | PP汽车外饰/护栏 | 国产944 | 对比耐候加速老化、黄变指数、耐迁移 |
| 巴斯夫Tinuvin 622 | 薄膜/扁丝长效 | 国产622 | 对比析出、透光率、纺丝稳定性 |
| Cytec UV531 | PP/UVA遮光搭档 | 国产UV531 | 对比紫外吸收峰、加工黄变、迁移量 |
以上给出的是对标方向，不是性能承诺。切换该按什么节奏走：小试平行对比→客户书面确认→小批量→放量，任何一步出问题都停下来排查。
户外件的替代验证周期长，科隆新材在寄送公斤级光稳定剂试样时可配套提供QUV/氙灯老化参考数据和合规文件，帮客户把平行测试的前置准备省下来。
加了光稳定剂还褪色？八成是喷霜析出，或是和酸性填料、阻燃剂打架了。
行业场景速查：不同户外件的耐候要求差在哪
同样是光稳定剂，做汽车外饰和做塑料花盆，对耐候年限、析出和认证的要求完全不同。下面这张表按行业拆解，帮你快速定位方案。
| 行业 | 典型制品 | 客户先问的参数 | 推荐体系 | 认证要求 |
|---|
| 汽车 | 保险杠、后视镜罩、门把手 | 氙灯老化1000h、保光率、低VOC | 944+UV326+抗氧复配 | IATF 16949、车企VOC |
| 建材/园林 | 护栏、垃圾箱、户外桌椅 | 户外曝露3-5年、粉化等级 | 944 0.2%+UV531 0.1% | GB耐候、RoHS |
| 农业 | PE棚膜、地膜 | 农膜寿命、流滴消雾兼顾 | 622+770+猝灭复配 | GB农膜标准 |
| 光伏/新能源 | 电池组件边框、接线盒 | 耐紫外、耐湿热、耐PID | 聚合型HALS+UVA | UL、IEC |
| 家电 | 户外空调外机罩、卫星天线罩 | 长期耐候、黄变、表面 | 944+UV531通用复配 | RoHS、REACH |
举个具体场景：做汽车保险杠，客户要求氙灯老化1000小时后保光率大于80%、冲击保留率不明显下降，还要求低VOC。这时单用一种HALS不够，要944做长效打底、UV326做高效遮光、再配低挥发抗氧剂收尾，同时控制助剂本身的析出，避免内饰异味。
添加量与搭配要点：四个户外配方记住就够了
光稳定剂的添加和搭配是有规律的，不用每次从零试。下面四个方案是行业验证过的通用做法，覆盖大部分户外场景。
户外件别在单剂上较劲，HALS打底、UV吸收剂在前，这个班排错了，晒一年就露馅。
◆ 通用PP户外厚件：HALS 944（约0.2%）+ UV531（约0.1%）+ 1010/168抗氧剂（约0.2%），总0.5%上下。这是护栏、园林家具的常见配方。
◆ PE薄膜/农膜：HALS 622或770（约0.2%-0.3%）+ 少量UVA，薄件优先分散性和耐析出。
◆ 汽车外饰长效：聚合型944 + 苯并三唑UV326 + 低挥发抗氧剂，兼顾保光率与低VOC。
◆ 黑色/深色户外件：炭黑本身就是耐紫外好手，光稳定剂可适当下调，但长效件仍建议保留HALS。
这里再补三条搭配经验：一是HALS是碱性的，和酸性阻燃剂（如红磷）、酸性填料可能“中和”失效，必须先做相容性试验；二是光稳定剂和抗氧剂是协同关系不是替代关系，户外件热氧、光氧一起来，两者都要有；三是回收料经过暴晒或多次加工，原有光稳定剂已消耗，回料比例高时要适当补加。
紫外线是看不见的刀，HALS把刀刃一次次卷回去。
耐候：三重才稳。
加工与合规红线：这五个坑别踩
光稳定剂用不好，不是发黄就是喷霜。下面这张表把关键环节和做错的后果列清楚，照着做能避开八成的坑。
| 环节 | 参考值 | 做错的后果 |
|---|
| 预混分散 | 高速混合3-5分钟，与树脂先预混再喂料 | 混合不均→局部耐候差、发花 |
| 与酸性阻燃剂复配 | 先做相容性小试，必要时调整体系 | 酸碱中和→光稳定剂失效、耐候骤降 |
| 用量控制 | HALS总0.1%-0.5%，按壁厚和年限定 | 超量→喷霜析出、表面发雾 |
| 薄件选剂型 | 薄膜用小分子770/622，避免大颗粒 | 分散不良→晶点、透光率下降 |
| 储存条件 | 阴凉干燥密封，避免高温暴晒 | 受热挥发/结块→有效含量下降 |
另外合规这条线别松：食品接触用制品的光稳定剂必须符合GB 4806系列或FDA相关条款；出口欧盟要符合REACH和EU 10/2011；汽车内饰要符合车企低VOC和气味标准；含镍猝灭剂在部分环保法规下受限，出口前务必核对。合规文件随货索取并归档。
FAQ：采购和配方师常问的六个问题
Q1：国产光稳定剂能不能替代进口料？
能替，但得拆开看用在哪个档位。通用户外PP/PE用的770、944、UV531，国产主流牌号差距已经很小，批次稳的国产品牌完全可以替代；但在汽车低VOC、光伏背板、医疗接触这类高端场景，进口牌号在批次一致性和低析出控制上仍有优势。正确做法是拿公斤级样品做QUV/氙灯平行对比，看粉化等级、黄变指数和保光率，通过后再小批量试用、最后放量。平行测试用的基准样和试样，科隆新材可一并按公斤级寄齐，附紫外老化参考数据。
Q2：加了光稳定剂，制品还是发黄掉粉，怎么回事？
先排查三点：一是用量不足或选错剂型，厚壁长效件用了小分子770，扛不住；二是与酸性阻燃剂、酸性填料反应，HALS被中和失效；三是加工温度过高或停留时间长，光稳定剂在挤出阶段就挥发损耗了。三点都排除，再考虑原料批次问题。
Q3：光稳定剂和抗氧剂为什么要一起用？
因为户外老化是热氧和光氧同时发生的。光稳定剂管紫外线引起的光氧老化，抗氧剂管加工和受热引起的热氧老化，两者协同。典型PP户外件配方就是HALS 944加UV531，再配1010/168抗氧剂，总添加量0.5%上下。
Q4：薄膜和厚壁件选HALS有什么讲究？
薄膜壁薄、比表面积大，小分子770分散好、见效快，常优先；厚壁长效户外件，聚合型944耐抽出、长效，更合适。简单说：越薄越要分散好，越厚越要长效耐迁移。
Q5：光稳定剂大概什么价位？
常用价格带（元/kg）：HALS 944约60到100、770约50到90、UV531约50到90、苯并三唑类UV326/327略高。随原料行情波动，以当期报价为准。占吨成本比例不高，但出问题整批退货的代价远大于这点差价。
Q6：黑色制品是不是就不用加光稳定剂了？
炭黑确有一定耐紫外作用，但不等于免加。黑色长寿命户外件仍建议保留适量HALS，尤其是要求冲击强度长期保持的结构件，单靠炭黑不够稳。
选型三步清单：照着做不踩坑
◆ 第1步·定日晒工况：先明确制品使用环境（日照强度、年限、壁厚、是否透明、接触介质），确定要挡哪段紫外、要长效还是快效。
◆ 第2步·组体系：按速查总表选UVA+HALS+抗氧剂的组合，确定添加量（总0.3%-0.6%），并检查与阻燃剂、填料的酸碱相容性。
◆ 第3步·核耐候认证：按最终用途和出口目的地核对GB 4806、FDA、REACH、车企VOC、UL/IEC等要求，向供应商索取合规文件并归档。
户外件的寿命，从一份紫外老化报告开始
光稳定剂的效果要靠QUV或氙灯老化数据说话，不是靠嘴说。科隆新材供应HALS和UV吸收剂时，可提供对应牌号的紫外老化参考数据和合规文件（FDA、RoHS等）；户外件选型建议HALS+UV吸收剂+抗氧剂三重协同，可按公斤级寄送组合试样，客户做完老化对比再定方案。
去年，一家做户外休闲家具的厂被客户退了一批货——椅子用了不到半年就褪色开裂。科隆吴经理去现场看了，拿回配方单一看，只有UV531，没有HALS。他给客户寄了HALS 944（约0.2%）+UV531（约0.1%）的组合试样，客户做了QUV 2000小时测试，色差ΔE从原来的8降到约3。重新投产后，第二年夏天没再收到褪色投诉，客户一口气加了三成订单。
你的配方里，只加了UV吸收剂没加HALS？
声明：本文涉及的品牌、商标及产品名称权归各自原厂所有。本文为第三方选材知识分享，文中提及的牌号、参数、价格、认证及应用案例仅供参考，具体以各生产企业官方最新资料及批次检测报告为准。本文不构成任何采购或投资建议，读者据此操作风险自担。
The newly installed outdoor fitness equipment in the community faded and turned white after just one summer, and fine cracks appeared on the surface of the seats. The property management sought compensation from the manufacturer, and the manufacturer's formulator pulled out the formula — it only added UV absorber 531, without HALS. The free radicals generated by ultraviolet light were not captured, which is equivalent to only applying sunscreen without doing any after-sun repair.
Outdoor PP without light stabilizers starts shedding powder onto the surface in the first summer.
This article is compiled by Ningbo Kolong New Materials Co., Ltd., which has long been engaged in the business of plastic raw materials and additives. The grade and batch information are subject to the actual supply channels.
Quick Reference Table of Photostabilizers: See at a Glance Who's Working in the Four Main Categories
Weather resistance does not rely on a single additive acting alone, but on the division of labor among several 'types of work': one type blocks ultraviolet rays from entering, another type neutralizes the free radicals that have already formed, and another provides backup support. The table below clearly lists representative varieties, key parameters, and typical uses of mainstream systems. When selecting a type, first determine the level of protection, then discuss the brand.
| system | Representative varieties | Key Mechanism/Parameter | Typical products | Add ratio |
|---|
| Hindered amine HALS (radical scavenger) | 770, 944, 622 | Alkaline piperidine structure, cyclic capture of free radicals | Car exterior trim, outdoor guardrails | 0.1%-0.4% |
| Ultraviolet Absorber UVA (Shielding) | UV531, UV326, UV327 | Absorbs UV energy and converts it into heat, benzotriazole/benzophenone | Films, paint chips, transparent parts | 0.1%-0.3% |
| Extinguisher | Nickel chelates | Take away the energy of the excited molecules | Agricultural film and fibers | 0.1%-0.3% |
| Compound Weather-Resistant Masterbatch | HALS UVA Antioxidant | Triple synergy, pre-disperse well before adding | PP/PE Outdoor General Use | Total 0.3%-0.6% |
Note: The above are common parameter ranges in the industry. The UV absorption spectrum and weather resistance data of specific grades should be based on the official information from the manufacturer. The approach is straightforward: first ask how many years the product will be exposed outdoors, whether it is thin or thick, transparent or opaque, and then decide which layer of protection to use.
Figure 1 Light Stabilizer — Weather-Resistant Protective Layer for Outdoor Plastic Parts
UV stabilizers aren't effective just by adding one; only a triple synergy can withstand sun exposure and rain.
The protagonist of this story has long stood behind the scenes. Ningbo Kolong New Materials Co., Ltd. has long been engaged in various plastic additives and modified raw materials, covering multiple domestic and international brands, and has stable supply channels for commonly used outdoor additives such as light stabilizers, antioxidants, and lubricants. As for the category of light stabilizers, its essence is like the "sunscreen" for outdoor plastics—the invisible ultraviolet rays in sunlight excite the polyolefin molecular chains into free radicals, and once the chain reaction starts, the material yellows, becomes brittle, and the surface chalks. The job of light stabilizers is to intervene in this chain: either block the ultraviolet rays at the door or suppress the free radicals on the spot.
A light stabilizer is like sunscreen for plastics: UV absorbers are applied on the outside to block the sun, while HALS repair the damage inside after exposure.
Mechanistically, weather protection is like three layers of sentinels. Leading the charge are ultraviolet absorbers (UVA), which act like a sunshade, absorbing ultraviolet rays between 300 and 350 nanometers and converting them into harmless heat, thereby reducing light damage at the source. The middle layer consists of hindered amine light stabilizers (HALS), which, unlike UVA, do not 'block light'; instead, they penetrate the material to cyclically capture already formed free radicals, stabilizing the reactive molecules. The final layer is antioxidants, which catch the remnants of thermal oxidation aging. The coordination of all three layers constitutes a complete weather-resistant system.
The three-layer sentry post isn’t some mystical buff stacking; it’s a schedule worked out after decades of sun exposure, and missing even one layer means you won’t make it to the end of the year.
Many formulators have a misconception: they think that adding HALS solves everything, or conversely, they only use UVA. In fact, UVA is a 'one-time consumption'—it gets used up as it blocks light; HALS is 'cyclically regenerating'—long-lasting but powerless against light that has already hit. For thin products and transparent parts, prioritize UVA; for thick-walled products and long-term weather resistance, prioritize polymeric HALS. Using both together is the most stable approach. So the industry's term 'HALS UV absorber triple synergy' is not just marketing talk; it reflects the division of labor proven through decades of sun exposure testing.
You call this 'outdoor weather resistance'? After 1,000 hours of QUV exposure, it powders and flakes. It's like putting sunscreen on the soles of shoes.
Quick reference by variety: 944 for long-lasting protection, 770 for general use, UV531 as a partner
The grades for light stability look confusing, but by focusing on a few main products, you can cover 80% of outdoor scenarios. Below, we'll break them down one by one, explaining the positioning, applicable signals, and precautions for each.
When choosing HALS, look at the molecular weight: if you want long-lasting effect, go for polymeric 944; don't try to use small molecule 770 for outdoor exposure.
HALS 944 (Polymeric Hindered Amine): High molecular weight, extraction-resistant, and migration-resistant, it is the main choice for thick-walled, long-lasting outdoor parts. For items like automobile bumpers, outdoor railings, and garden furniture that are expected to resist chalking after three to five years in the sun, it is often used as a primer. Signals to choose it: long-lasting outdoor use, thick walls, and high requirements for migration resistance. Note: The price range of 944 is about 60 to 100 RMB/kg, which is more expensive than small molecules, but when spread over a ton of material, the actual cost is not much.
Supply Tip: HALS 944 and UV531 are commonly used combinations for outdoor components. Kolon New Materials can provide matching supply, with UV aging test reference data attached to each batch. Kilogram-level samples support testing before use.
HALS 770 (small molecule hindered amine): has a small molecular weight, disperses easily, and works quickly, but its extraction resistance and long-lasting effect are not as good as 944, making it suitable for thin products, fibers, and cost-sensitive outdoor items. Indicators for choosing it: making PE agricultural films, thin outdoor products, or requiring fast initial weather resistance. Note: Small molecule 770 is prone to migration and exudation; for thick-walled, long-lasting outdoor items, it is recommended to switch to 944 or 622.
HALS 622 (Polymeric Hindered Amine): Like 944, it belongs to the polymeric type, has relatively long-lasting extraction resistance, and is often blended with 770 for balance. Signals to choose it: thin films, flat fibers, and when both dispersion and long-lasting effect are needed. Note: For acidic systems, the compatibility of 622 should be tested.
HALS is alkaline, so when encountering acidic flame retardants like red phosphorus, a compatibility test should be done first; don't just mix everything together.
UV531 (Benzophenone-type UV absorber): absorbs UV, cost-friendly, often partnered with HALS as the "forward line" for PP outdoor parts. A typical combination is about 0.2% HALS 944 plus about 0.1% UV531. Signals to choose it: making PP/PE outdoor parts, needing a light-blocking layer, being cost-sensitive. Note: UV531 has some migration; for transparent parts, light transmittance changes need to be measured.
UV326, UV327 (Benzotriazole UV Absorbers): High absorption efficiency and good heat resistance, suitable for products with high processing temperatures or strict color requirements. Signals for choosing them: outdoor parts of engineering plastics, need for higher light stability. Note: Benzotriazole types are slightly more expensive than benzophenone types, choose as needed.
Nickel chelate quenchers: Commonly used in early agricultural films to 'quench' the energy of excited molecules. Nowadays, they are mostly replaced by or used in combination with HALS, and are rarely used alone. Signals for choosing it: agricultural films, need to balance with anti-fogging function. Note: nickel-containing systems should pay attention to environmental protection and food contact compliance.
Alternative comparison: Can imported light stabilizers be replaced? First, look at this table
Common Procurement Question: Can imported HALS and UVA be replaced with domestic versions? The answer is yes, but it depends on the scenario. For general outdoor PP/PE applications using 770, 944, UV531, the main domestic brands have very small gaps in key indicators, and stable domestic brands are completely sufficient; however, for high-end certified scenarios like automotive low VOC and photovoltaic back sheets, imported brands still have advantages in batch consistency and low exudation. The table below lists common alternatives and the prerequisites for switching.
| Original imported direction | Typical Applications | Benchmark solution | Switch premise |
|---|
| BASF Tinuvin 770 | PE agricultural film/thin outdoor parts | Domestic 770 | Small test comparison of QUV/xenon lamp aging 1000h, chalking grade |
| BASF Chimassorb 944 | PP Car Exterior/Guardrail | Domestic 944 | Comparison of weathering accelerated aging, yellowing index, and migration resistance |
| BASF Tinuvin 622 | Film/Flat Yarn Long-Lasting | Domestic 622 | Comparison of precipitation, light transmittance, and spinning stability |
| Cytec UV531 | PP/UVA light-blocking partner | Domestic UV531 | Compare ultraviolet absorption peaks, processing yellowing, and migration amount |
The above provides a benchmarking direction, not a performance commitment. The switching should proceed according to the following rhythm: small-scale parallel comparison → written confirmation from the customer → small batch → mass production. If any step encounters a problem, stop to investigate.
The replacement verification cycle for outdoor components is long. When Kolon New Materials sends kilogram-level samples of light stabilizers, they can provide QUV/xenon lamp aging reference data and compliance documents, helping customers save the preliminary preparation for parallel testing.
Still fading even after adding a light stabilizer? It's most likely due to the cream separating, or reacting with acidic fillers or flame retardants.
Quick Industry Reference: How the Weather Resistance Requirements Differ for Various Outdoor Components
Even though they are both light stabilizers, the requirements for weather resistance, migration, and certification are completely different when used for automotive exteriors and plastic flower pots. The table below breaks it down by industry to help you quickly find the right solution.
| Industry | Typical products | The parameters the client asked about first | Recommendation system | Certification requirements |
|---|
| Car | Bumper, mirror cover, door handle | Xenon lamp aging 1000h, luminous retention rate, low VOC | 944 UV326 Antioxidant Compound | IATF 16949, Automotive OEM VOC |
| Building Materials / Landscaping | Guardrails, trash cans, outdoor tables and chairs | Outdoor exposure 3-5 years, degree of powdering | 944 0.2% UV531 0.1% | GB Weather Resistance, RoHS |
| Agriculture | PE greenhouse film, mulch film | Considering both the lifespan of agricultural film and droplet anti-fogging | 622 770 sudden extinguishing compound | GB agricultural film standard |
| Photovoltaic / New Energy | Battery module frame, junction box | UV-resistant, damp-heat resistant, PID-resistant | Polymerized HALS UVA | UL, IEC |
| Home appliances | Outdoor air conditioner unit cover, satellite antenna cover | Long-term weather resistance, yellowing, surface | 944 UV531 General Compound | RoHS, REACH |
Here's a specific scenario: when making car bumpers, the customer requires that after 1,000 hours of xenon lamp aging, the light retention rate remains above 80% and the impact retention rate does not significantly decrease, and also demands low VOC. At this point, using only one HALS is not enough; you need 944 for long-lasting priming, UV326 for high-efficiency light blocking, and then a low-volatility antioxidant for finishing, while also controlling the precipitation of the additives themselves to avoid odors in the interior.
Dosage and pairing tips: Remembering four outdoor formulas is enough
The addition and combination of light stabilizers follow certain rules, so there is no need to start from scratch each time. The following four schemes are industry-validated common practices, covering most outdoor scenarios.
Outdoor parts shouldn't rely solely on a single agent; HALS as the base coat and UV absorbers upfront. This batch was arranged incorrectly, and it will show faults after one year in the sun.
◆ General-purpose PP outdoor thick parts: HALS 944 (about 0.2%) UV531 (about 0.1%) 1010/168 antioxidants (about 0.2%), totaling around 0.5%. This is a common formulation for railings and garden furniture.
◆ PE film / agricultural film: HALS 622 or 770 (about 0.2%-0.3%) with a small amount of UVA; for thin items, dispersibility and resistance to precipitation are prioritized.
◆ Long-lasting automotive exterior finish: polymeric 944, benzotriazole UV326, low-volatility antioxidant, ensuring both gloss retention and low VOC.
◆ Black/Dark Outdoor Parts: Carbon black itself is good at UV resistance, so the light stabilizer can be appropriately reduced, but for long-lasting parts, it is still recommended to retain HALS.
Here are three additional tips on compatibility: First, HALS is alkaline and may be 'neutralized' and rendered ineffective by acidic flame retardants (such as red phosphorus) or acidic fillers, so compatibility tests must be conducted first; second, light stabilizers and antioxidants have a synergistic relationship rather than a replacement relationship. For outdoor parts exposed to both thermal oxidation and photo-oxidation, both are necessary; third, recycled materials that have been exposed to strong sunlight or multiple processing cycles have already consumed their original light stabilizers, so the proportion of recycled material should be appropriately supplemented.
Ultraviolet rays are invisible knives, and HALS keeps rolling the blades back again and again.
Weather resistance: stable only with three layers.
Processing and Compliance Red Lines: Avoid These Five Pitfalls
If the light stabilizer is not used properly, it will either cause yellowing or whitening. The table below clearly lists the key steps and the consequences of doing them wrong; following it can help avoid 80% of the pitfalls.
| link; segment; part | Reference value | The consequences of doing wrong |
|---|
| Premixed dispersion | Mix at high speed for 3-5 minutes, pre-mix with the resin before feeding | Uneven mixing → local poor weather resistance, mottling |
| Blended with acidic flame retardants | First conduct a compatibility small test, and adjust the system if necessary | Acid-base neutralization → UV stabilizer failure, sudden drop in weather resistance |
| Dosage control | HALS total 0.1%-0.5%, limited by wall thickness and year | Excess → Frosting and surface haze |
| Select formulation for thin parts | Small molecules 770/622 for film, avoid large particles | Poor dispersion → crystal points, decreased light transmittance |
| Storage conditions | Keep in a cool, dry, and sealed place, avoid exposure to high temperatures and sunlight | Volatilization/Caking when heated → Effective content decreases |
Also, don't relax on compliance requirements: light stabilizers for food contact products must comply with GB 4806 series or FDA regulations; Exports to the EU must comply with REACH and EU 10/2011; Automotive interiors must meet the automaker's low VOC and odor standards; Nickel-containing quenching agents are restricted by certain environmental regulations, so be sure to verify before export. Compliance documents should be requested and archived with the goods.
FAQ: Six common questions from purchasers and formulators
Q1 Can domestic light stabilizers replace imported materials?
Yes, but you have to open it up to determine which level it is used. General outdoor PP/PE 770, 944, UV531 have very small differences among mainstream domestic grades, and domestic brands with stable batch sizes can be fully substituted; However, in high-end scenarios such as low VOC in automobiles, photovoltaic backsheets, and medical contacts, imported grades still have advantages in batch consistency and low precipitation control. The correct approach is to use kilogram-level samples for parallel comparison of QUV/xenon lamps, checking powder level, yellowing index, and light retention rate, then testing in small batches and finally scaling up. For benchmark and sample samples used in parallel testing, Kelong New Materials can send them together by kilogram, with reference data for UV aging.
Q2: Even after adding light stabilizer, the product still turns yellow and loses powder. What's going on?
First, check three points: First, insufficient dosage or wrong dosage form, such as using small molecule 770 in thick-walled long-acting parts, which cannot withstand the load; Second, reacting with acidic flame retardants and acidic fillers, causing HALS to neutralize and fail; Third, processing temperature too high or residence time too long, causing the light stabilizer to volatilize and lose during the extrusion stage. Eliminate all three points, then consider the raw material batch issue.
Q3: Why should light stabilizers and antioxidants be used together?
Because outdoor aging occurs simultaneously with hot oxygen and photo-oxygen. Photo-oxygen aging caused by UV rays in the light stabilizer tube, and thermal oxygen aging caused by processing and heating of antioxidant tubes, are coordinated. A typical PP outdoor component formula is HALS 944 plus UV531, combined with 1010/168 antioxidants, with a total addition of about 0.5%.
Q4: What are the considerations for choosing HALS for films and thick-walled parts?
Film has thin walls and a large specific surface area, with small molecules 770 that disperse well and act quickly, which is often preferred; For thick-walled long-lasting outdoor parts, polymer 944 is more suitable for extraction resistance and long-lasting performance. Simply put: the thinner the material, the better the dispersion; the thicker the material, the longer the resistance to migration.
Q5: What is the approximate price range for light stabilizers?
Common price range (RMB/kg): HALS 944 about 60 to 100, 770 about 50 to 90, UV531 about 50 to 90, benzotriazole UV326/327 slightly higher. Prices fluctuate with raw material prices, subject to current quotations. The cost per ton is not high, but if a problem occurs, the cost of returning a whole batch is much greater than this difference.
Q6: Does black products no longer need to add light stabilizers?
Carbon black does have some UV resistance, but that doesn't mean it's exempt. For long-lasting outdoor black parts, it's still recommended to retain a certain amount of HALS, especially for structural parts that require long-term impact strength, as carbon black alone is not stable.
Three-step selection checklist: Follow this to avoid pitfalls
◆ Step 1 · Set sun exposure conditions: First, clarify the product's usage environment (sunlight intensity, duration, wall thickness, transparency, contact medium), determine which UV segment to block, and whether it is long-lasting or fast-acting.
◆ Step 2 · Composition system: Select the UVA+HALS+antioxidant combination according to the quick reference table, determine the dosage (total 0.3%-0.6%), and check the acid-base compatibility with flame retardants and fillers.
◆ Step 3 · Nuclear Weather Resistance Certification: Verify GB 4806, FDA, REACH, automotive company VOC, UL/IEC requirements according to end use and export destination, request compliance documents from suppliers, and archive them.
The lifespan of outdoor components starts with a UV aging report
The effectiveness of light stabilizers depends on QUV or xenon lamp aging data, not just words. When Cologne New Materials supplies HALS and UV absorbers, they can provide reference data and compliance documents for the corresponding grade of UV aging (FDA, RoHS, etc.); For outdoor parts selection, it is recommended to combine HALS + UV absorbers + antioxidants, and samples can be shipped by kilogram to be compared. Customers can compare aging before finalizing the plan.
Last year, a factory producing outdoor leisure furniture had a batch returned by a customer—the chairs faded and cracked after less than half a year of use. Manager Wu from Cologne visited the site to inspect, brought back the formula list, and found only UV531, no HALS. He sent the customer a sample of a combination of HALS 944 (about 0.2%) + UV531 (about 0.1%). The customer conducted a 2000-hour QUV test, and the color difference ΔE dropped from 8 to about 3. After resuming production, there were no more fading complaints the following summer, and the customer increased orders by 30% at once.
Your formula only added UV absorber and not HALS?
Disclaimer: The brands, trademarks, and product names mentioned in this article belong to their respective original manufacturers. This article is a third-party material selection knowledge sharing. The grades, parameters, prices, certifications, and application cases mentioned in the article are for reference only. Please refer to the latest official information and batch test reports from each manufacturer. This article does not constitute any procurement or investment advice. Readers are responsible for any actions based on them
