正牌高分子SMA一柜压资金，回收料SMA相容剂接不上活，大厂副牌SMA正好填在这道缝里。
很多人以为SMA做仪表板，其实它藏在你的涂料里
很多人以为SMA是个做汽车仪表板的工程塑料，离自己老远。真相是——你天天用的涂料、油墨、胶粘剂里，都藏着SMA。它一半以上的用量，根本不在注塑件上，而在“把两种本来不亲的东西焊到一起”。
更反常识的是，市面上叫SMA的东西分两种：一种又高又硬的高分子量料，做注塑；一种又稀又流的低分子量料，做载体和分散剂。两者名字一样，身价差着好几倍。
很多采购搞混了，拿注塑级SMA去做涂料载体，结果分散不开、漆膜发花。说白了，SMA这东西，选不对分子量，再贵的料也白搭。这篇讲清楚。
SMA是什么：一个会“牵线”的共聚物
SMA，苯乙烯-马来酸酐共聚物。它的结构里，马来酸酐那个酐基是个接口——能跟聚酯、尼龙、玻纤填料表面发生反应，把它们黏成一体。所以SMA最大的身份，是个相容剂和载体。
按分子量分两档：高分子量SMA做注塑，耐热、刚性、阻燃改性，汽车仪表板、家电内件；低分子量SMA做涂料油墨载体、分散剂、乳化剂，把颜料和填料均匀地领进体系里。
全球做SMA的，国外头部就那么几家。按份额口径，荷兰Polyscope排前面，德国英力士苯领（INEOS Styrolution）跟在后面，低分子量这一档则是道达尔体系下的Cray Valley当家。各家数据口径不一，Polyscope的份额从两成出头到三成多都有人写，我们按梯队讲，不硬排数字。
副牌通识：酸酐含量和分子量，一项都不能飘
SMA副牌，本质和别的副牌一样。同一个厂、同一个牌号聚合出来，出厂检验时酸酐含量、分子量、或者色相某一项没完全达标，就是副牌。来路还是那四条：开停车头尾料、换牌号过渡料、工艺波动批次、副线尾料。
它依然是原厂原生料，分子结构跟正牌一致，只是某个指标小幅飘。这一点，和回收再造的SMA完全是两码事——回收SMA分子量已经断过链，相容性能掉一大截。边界还是那张表：
| 类型 | 来源 | 品质 | 典型用途 |
|---|
| 正牌 | 原厂达标批次 | 全指标达标、批次稳定 | 高要求件、认证件 |
| 副牌 | 原厂未达标批次 | 个别指标小幅偏离，基材与正牌一致 | 一般件、配色件、内件 |
| 回料/水口料 | 加工边角料再造粒 | 已受过一次热历史 | 低要求制品 |
| 再生料 | 废旧塑料回收造粒 | 性能波动大 | 低端制品、填充 |
SMA副牌尤其要盯酸酐含量和分子量分布。这两项飘了，相容和分散的本事直接打折。
Polyscope：Xiran这个名字就是行业通行证
第一家，荷兰Polyscope。这名字在SMA圈里几乎是标杆，它家的Xiran®系列就是SMA的代名词，从高分子量的注塑级到改性相容级都齐。Polyscope后来被Vertellus收购，现在对外体系叫Aurorium，但Xiran牌子还在。
它家的强项是耐热和表面性能改性，做汽车内饰、玻纤增强相容剂很成熟。副牌料过来，一般是色相或熔指小幅飘，但酸酐含量和分子量是原厂的底子。做配色件、一般相容剂，用它副牌够稳。
英力士苯领：苯乙烯一体化的稳
第二家，英力士苯领（INEOS Styrolution）。这家是苯乙烯系的大厂，SMA在它手里主要往工程塑料改性方向做——阻燃、耐热、尺寸稳定，用在电子电器和汽车结构件。
它的优势是苯乙烯一体化，原料和工艺自家打通，批次稳定。副牌料适合做对色相不敏感、对力学性能要求中等的内件和相容母料。挑它的副牌，重点看熔指和热变形温度对不对你的成型工艺。
Cray Valley：低分子载体那一半江山
第三家，道达尔体系下的Cray Valley。前两家做的是高分子量注塑SMA，Cray Valley这条线做的是低分子量SMA——就是涂料、油墨、分散剂那个方向。SMA 1000、SMA 2000、SMA 3000、SMA 4000这一串牌号，做油墨连接料和颜料分散的厂都熟。
它家副牌料，通常是粘度或酸当量小幅飘，但载体和润湿的底子在。做一般工业涂料、普通油墨载体，用它副牌性价比很高。
这里提一句：别把它和做UV树脂的沙多玛（Sartomer）混为一谈，两者都沾道达尔树脂体系，但产品线不是一回事。
避坑第一步：先搞懂你要高分子量还是低分子量
SMA副牌怎么挑？第一，先分清你要高分子量还是低分子量。注塑件用前者，涂料油墨用后者，拿错了直接翻车。
第二，盯酸酐含量。这是SMA的本事所在，含量飘了相容性能就掉。第三，看分子量。低分子载体料，粘度不对，颜料分散不开，漆膜发花。
第四，认厂。Polyscope、英力士苯领、Cray Valley这三家的副牌，是原厂料；来路不清的“SMA平替”别碰。第五，包装问大包装、小包装就行。大包装上量产，小包装打样调配方。
科隆仓库现货｜SMA量大
主推品牌：Polyscope、英力士苯领、Cray Valley
主要牌号：Xiran系列、SMA工程改性牌号、SMA 1000/2000/3000/4000
包装规格：大包装/小包装均有备货
仓库现货通常在2000-5000吨
小包副牌备货300-600吨、箱装副牌备货150-300吨、大包料/吨包料备货1500-4100吨
供应保障：批次留样可溯
选型口诀 + 一个徐州涂料厂的案子
口诀：
1. 做注塑耐热件——选高分子量SMA；
2. 做涂料油墨载体——选低分子量SMA；
3. 要相容、要改性——认Polyscope Xiran；
4. 苯乙烯一体化、批次稳——看英力士苯领；
5. 低分子载体、油墨分散——看Cray Valley；
6. 进厂测酸酐含量、测分子量；
7. 按用途匹配，别拿注塑级去做涂料。
徐州有家做工业涂料的客户，之前图便宜用了来路不明的低分子SMA做连接料，颜料分散不开，漆膜发花，一次批量退货率到了11%。后来换成Cray Valley同牌号副牌，粘度和酸当量进厂先测后签，漆膜发花率降到0.8%，良率从七成拉到九成四。
材料一吨贵了几百块，光一次大货就把差价赚回来了。这就是选型的价值——SMA不是越便宜越好，是分子量和酸酐对得上才好。宁波市科隆新材料有限公司常年做进口大厂副牌，涂料、油墨、相容剂方向的案子经手不少，说白了就是帮你把“分散开不开、漆膜花不花”这件事，量产之前试明白。
An entire container of genuine high-molecular SMA ties up capital, recycled SMA compatibilizer can't activate, and a second-brand SMA from a major manufacturer happens to fill this gap.
Many people think SMA is used for dashboards, but actually it is hidden in your paint.
Many people think SMA is just an engineering plastic used for car dashboards, far removed from their own lives. The truth is—that everyday paints, inks, and adhesives all contain SMA. More than half of its usage isn't in molded parts at all, but in 'bonding two things that are normally incompatible together.'
Even more counterintuitive is that the things on the market called SMA come in two types: one is a high and hard high molecular weight material for injection molding; the other is a thin and fluid low molecular weight material used as a carrier and dispersant. Both have the same name, but their value differs by several times.
Many purchasers get confused and use injection molding grade SMA as a coating carrier, resulting in poor dispersion and mottled paint films. To put it simply, with SMA, if the molecular weight is not chosen correctly, no matter how expensive the material is, it will be useless. This article explains it clearly.
What is SMA: A copolymer that can 'mediate connections'
SMA, styrene-maleic anhydride copolymer. In its structure, the anhydride group of maleic anhydride acts as a junction—it can react with the surfaces of polyester, nylon, and glass fiber fillers, bonding them into a whole. Therefore, SMA's primary role is as a compatibilizer and carrier.
Divided into two categories by molecular weight: high molecular weight SMA is used for injection molding, heat-resistant, rigid, flame-retardant modification, automotive dashboards, and appliance internal parts; low molecular weight SMA is used as a carrier for coatings and inks, dispersants, emulsifiers, bringing pigments and fillers evenly into the system.
Globally, there are only a few leading companies producing SMA. By market share, the Dutch company Polyscope ranks at the top, followed by Germany's INEOS Styrolution in styrene, while in the low molecular weight segment, Cray Valley under the Total group is the leader. The data varies between companies; Polyscope's share is reported anywhere from just over 20% to more than 30%. We will describe them by tiers without giving exact numbers.
Supplementary General Knowledge: Anhydride content and molecular weight, not a single one should be overlooked
SMA secondary brand is essentially the same as other secondary brands. It is polymerized from the same factory and the same grade. If the anhydride content, molecular weight, or color of any item does not fully meet the standards during factory inspection, it becomes a secondary brand. The sources are still those four: leftover material from starting and stopping production, transitional material from changing grades, batches with process fluctuations, and leftover material from secondary lines.
It is still the original factory material, with a molecular structure identical to the genuine brand, just that a certain index fluctuates slightly. In this regard, it is completely different from recycled SMA — the molecular weight of recycled SMA has already been broken, and compatibility has dropped significantly. The reference is still that table:
| Type | Source | Quality | Typical uses |
|---|
| Authentic brand | Original factory standard batch | All indicators meet the standards, batch stability | High-demand parts, certified parts |
| Side dish | Original factory substandard batch | Individual indicators slightly deviate, but the base material is consistent with the genuine brand | General parts, color-matched parts, interior parts |
| Recycled material / Sprue material | Processing scrap material into regranulate | Has undergone one heat history | low-demand products |
| Recycled material | Recycled Plastic Pelletizing | Performance fluctuates greatly | Low-end products, fillers |
For SMA sub-brands, it is especially important to monitor the anhydride content and molecular weight distribution. If these two are off, the compatibility and dispersibility are directly compromised.
Polyscope: The name Xiran is the industry pass
The first one, Polyscope from the Netherlands. This name is almost a benchmark in the SMA circle. Its Xiran® series is synonymous with SMA, covering everything from high molecular weight injection molding grade to modified compatibilizer grade. Polyscope was later acquired by Vertellus, and its external system is now called Aurorium, but the Xiran brand still exists.
Its strengths are heat resistance and surface performance modification, and it is very mature in making automotive interiors and glass fiber reinforced compatibilizers. When using the secondary brand material, the color tone or melt index usually varies slightly, but the anhydride content and molecular weight are based on the original factory's foundation. For making color-matched parts or general compatibilizers, using its secondary brand is stable enough.
INEOS Styrolution: Integrated Stability of Styrene
The second one is INEOS Styrolution. This company is a major producer of styrene-based products. SMA is mainly modified towards engineering plastics here—flame retardant, heat resistant, and dimensionally stable, used in electronics, electrical appliances, and automotive structural components.
Its advantage is styrene integration, with raw materials and processes connected in-house, ensuring batch stability. The secondary grade material is suitable for interior components and compatibilizers that are not sensitive to color and have medium mechanical property requirements. When selecting its secondary grade, the key is to check whether the melt flow index and heat distortion temperature match your forming process.
Cray Valley: The half of the world of low molecular carriers
The third one is Cray Valley under the Total system. The first two focus on high molecular weight injection-molded SMAs, while Cray Valley's line deals with low molecular weight SMAs—that is, in the direction of coatings, inks, and dispersants. The series of grades SMA 1000, SMA 2000, SMA 3000, SMA 4000 are well known to manufacturers making ink binders and pigment dispersions.
Its secondary brand materials usually have slightly fluctuating viscosity or acid value, but the carrier and wetting base are present. Using it for general industrial coatings and ordinary ink carriers, the secondary brand has a very high cost-performance ratio.
Just to mention: don't confuse it with Sartomer, which makes UV resin; both are related to the Total resin system, but their product lines are not the same.
Step one to avoid pitfalls: first understand whether you want a high molecular weight or a low molecular weight
How to choose SMA secondary brands? First, identify whether you need high molecular weight or low molecular weight. Use the former for injection-molded parts, and the latter for coatings and inks. Using the wrong one can lead to direct failure.
Second, watch the anhydride content. This is where SMA’s capability lies; if the content fluctuates, the compatibility will drop. Third, look at the molecular weight. With low molecular weight carrier materials, the viscosity is not right, the pigment cannot disperse, and the paint film becomes cloudy.
Fourth, recognize the manufacturer. The sub-brands of Polyscope, Invista benzene leaders, and Cray Valley are made from original factory materials; do not touch ‘SMA alternatives’ with unclear origins. Fifth, for packaging, just consider large packaging and small packaging. Large packaging is for mass production, small packaging is for sampling and formulation adjustment.
Cologne Warehouse Spot｜Large Quantity of SMA
Main promoted brands: Polyscope, Ineos Styrolution, Cray Valley
Main grades: Xiran series, SMA engineering modified grades, SMA 1000/2000/3000/4000
Packaging specifications: Both large and small packages are available in stock
Warehouse spot goods are usually between 2,000 and 5,000 tons
Small package secondary brand stock 300-600 tons, box-packed secondary brand stock 150-300 tons, large package material/ton bag material stock 1500-4100 tons
Supply security: batch samples can be traced
Selection mnemonic: A case from a Xuzhou paint factory
Mnemonic:
1. For making heat-resistant injection molded parts — choose high molecular weight SMA;
2. Making paint and ink carriers – choose low molecular weight SMA;
3. Must be compatible, must be modified—recognize Polyscope Xiran;
4. Styrene integration, batch stability — look at INEOS Styrolution;
5. Low molecular carriers, ink dispersion — look at Cray Valley;
6. Measure anhydride content and molecular weight upon entering the factory;
7. Match by application, don't use injection-molding grade for coatings.
There is a customer in Xuzhou that produces industrial coatings. Previously, to save money, they used low-molecular SMA of unknown origin as a coupling agent. The pigments wouldn’t disperse, and the coating finish was uneven, leading to an 11% batch return rate. Later, they switched to a Cray Valley equivalent of the same grade, measured viscosity and acid value before approval, and the unevenness in the coating dropped to 0.8%, raising yield from 70% to 94%.
The material was a few hundred yuan more per ton, but the cost difference was offset by just one big shipment. This is the value of proper selection — cheaper SMA is not always better; it works only if the molecular weight and anhydride content match. Ningbo Kolon New Materials Co., Ltd. has long been handling generics of major imported brands, dealing extensively with coatings, inks, and compatibilizers. Simply put, they help you figure out whether dispersions work and coatings finish properly before mass production.
