PP/PA合金做的汽车进气歧管，冷热冲击测试五个循环就沿相界面开裂了。客户把试模件摔在会议桌上说，这叫合金？这叫拼盘。配方师知道问题出在相容剂——PP-g-MAH只加了2%，界面没形成足够的接枝层，PP和PA还是各过各的。
PP和PA6这对冤家，没相容剂的时候一掰就分家，有了PP-g-MAH居然还挺和谐。
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。
相容剂速查总表：五大合金体系一页对号
相容剂不是一种东西，而是按你要做的合金配对来选的：PP配PA用PP-g-MAH，PC配ABS用SAN-g-MAH或环氧类，PLA配PBAT用GMA类。选型头一步总是先搞清楚你手里是哪两种树脂，再去找对应的“媒人”。
| 合金体系 | 代表相容剂 | 关键作用 | 典型制品 | 添加比例 |
|---|
| PP/PA合金 | PP-g-MAH、POE-g-MAH | 酸酐与PA端基反应 | 汽车进气歧管、电动工具 | 2%-10% |
| PC/ABS合金 | SAN-g-MAH、环氧类 | 降低界面张力、增容 | 笔记本外壳、汽车内饰 | 3%-8% |
| PA增韧/合金 | POE-g-MAH | 界面反应+增韧 | 连接器、薄壁件 | 5%-15% |
| PLA/PBAT | GMA-EBA、MAH类 | 反应增容、改善脆性 | 可降解包装、餐盒 | 3%-8% |
| 回收料/杂料 | PE-g-MAH、通用增容 | 改善杂料相容性 | 回料改性、再生颗粒 | 2%-8% |
注：以上接枝率和熔指为常见区间，不同牌号差异较大，以生产企业官方TDS为准。注意相容剂添加量远高于偶联剂（偶联剂按填料量零点几，相容剂按整配方百分之几），它是成本敏感项，选型要算总账。
图1 相容剂——两种树脂之间的合金化桥梁
相容剂就是塑料合金的婚姻介绍所，把冤家撮合成一家子
这位主角，专门撮合两种合不来的树脂。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，在相容剂、增韧剂、偶联剂等界面改性品类上有稳定供货。相容剂这个品类，本质上是两种不相容树脂之间的“婚姻介绍所”。PP和PA6之所以合不到一起，是因为它们的溶解度参数差得远，热力学上互相排斥，共混时只能形成粗大的两相海岛结构，界面结合力弱，一受冲击就从相界面断开。相容剂分子一端和PP相亲，一端和PA6相亲，像一根拉链把两相缝牢，界面相畴从微米级缩到亚微米甚至纳米级，应力才能从一相传到另一相。
相容剂就是婚姻介绍所，PP和PA6原本老死不相往来，它一撮合就能坐下来好好过日子。
拿用量较大的PP-g-MAH来说，它是把马来酸酐（MAH）接枝到PP分子链上的产物。PP那一头能和PP基体相容，酸酐基团那一头能和PA6的端氨基反应或形成氢键，界面处的MAH像一只只小手，把PA6粒子和PP基体牢牢拉住。机理上解决三件事：降低两相界面张力、让分散相变细变均匀、把界面变成能传力的过渡层。三件事做到位，合金才叫合金，否则只是塑料拼盘。
把马来酸酐挂到PP分子链上，像给PP穿上一身能和PA握手的西装，界面就此牵了手。
一个常见误区：相容剂不是加得越多越好。相容剂过量，多余的分子自己团聚，反而成为缺陷相，性能不升反降；接枝率太低的牌号，哪怕加得再多，酸酐基团不够，界面反应也做不充分。所以选相容剂要看两个硬指标——接枝率和熔指匹配，不能只看价格。
两相界限清清楚楚、一掰就开，说明相容剂根本没站到该站的那个位置上。
逐品种速查：PP-g-MAH管PP/PA，POE-g-MAH还顺便增韧
相容剂牌号看着多，其实抓住几个主力品种就能覆盖主流合金。下面逐个讲清定位和注意事项。
PP和PA6要共混，就上PP-g-MAH，别指望靠多加点增韧剂硬撑。
PP-g-MAH（马来酸酐接枝聚丙烯）：PP/PA合金的“标配媒人”，添加量通常2%-8%，接枝率一般0.5%-1.5%。做PP/PA6、PP/PA66合金，它能同时提升拉伸和冲击。价格带约15-35元/kg。选它的信号：汽车进气歧管、发动机罩盖、电动工具外壳。注意：接枝率和熔指要和基体匹配，熔指差太大会分散不好。
供货提示：PP-g-MAH等接枝相容剂科隆新材可稳定供货，每批附接枝率和熔指数据，公斤级试样支持先做相形态分析。
POE-g-MAH（马来酸酐接枝POE）：它一身二职，既是相容剂又是增韧剂。和纯POE比，它多了酸酐基团，能和PA6反应，所以专门用来做PA增韧和PP/PA合金里的柔性相。选它的信号：做增韧PA6/PA66连接器、低温韧性要求高的PP/PA合金。注意：它会降刚性，刚韧平衡要和纯POE或滑石粉搭配。
相容剂最怕的不是用量少，是配方师把它和增韧剂混为一谈——一个管结婚，一个管长肉。
PE-g-MAH（马来酸酐接枝PE）：和PP-g-MAH类似，但柔韧更好，适合PE/PA、PA增韧和玻纤/矿物填充PA的界面改性。选它的信号：做PE/PA多层复合、增韧PA。注意：熔点低，高温PA加工要评估耐热。
SAN-g-MAH与环氧类相容剂：主要服务PC/ABS合金。PC和ABS本就部分相容，加少量这类相容剂能平衡水解稳定性、光泽和耐热，是笔记本外壳、汽车仪表板的常用方案。选它的信号：做PC/ABS合金。注意：环氧类对水分敏感，PC端要充分干燥。
GMA类反应相容剂（如EBA-g-GMA）：面向PLA/PBAT可降解合金和回收杂料体系，环氧基团开环反应能力强。选它的信号：做可降解改性、再生杂料增容。注意：活性高，加工窗口要控好，避免过早交联。
媒人不是越贵越好，是得和手里的两家都对得上暗号——PP配PA、PC配ABS，找错了对象，花再多钱也是白搭。
替代对照：进口相容剂换国产，先做相图和冲击
采购常问：进口PP-g-MAH能不能国产替代？答案是通用合金差距已小，但接枝率波动直接影响合金性能，必须平行验证。相容剂的核心是接枝率、熔指和反应活性，国产主流品牌在这些指标上已能对标，差异多在批次一致性。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 |
|---|
| 杜邦Fusabond PP系列 | PP/PA合金 | 国产PP-g-MAH | 对比接枝率、缺口冲击、拉伸 |
| 杜邦Fusabond E/PO系列 | PA增韧 | 国产POE-g-MAH | 对比-30℃低温冲击、相畴尺寸 |
| 巴斯夫S系列相容剂 | PC/ABS合金 | 国产SAN-g-MAH | 对比光泽、热变形温度、水解 |
| 阿科玛Lotader反应型 | PLA/PBAT/杂料 | 国产GMA/MAH类 | 对比断裂伸长、反应交联窗口 |
| 进口PE-g-MAH | PE/PA、填充PA | 国产PE-g-MAH | 对比分散、界面强度 |
表中为应用方向参考，不代表性能完全等同。替代顺序：小试→平行测试→客户书面确认→小批量→放量。
相容剂替代要验证相形态和冲击强度，科隆新材寄送公斤级接枝物试样时附接枝率和熔指数据，客户可以先做冷热冲击和平行测试，数据达标再谈批量。
冲击强度一测就崩，两相粒子大得肉眼可见，你那相容剂是加了还是只买了？
行业场景速查：合金配方跟着零件要求走
同样是相容剂，做汽车进气歧管和做可降解餐盒，体系完全不同。下面这张表按行业拆解。
| 行业 | 典型制品 | 客户最先问的参数 | 推荐方案 | 认证要求 |
|---|
| 汽车 | 进气歧管、发动机罩盖 | 耐温、冲击、尺寸稳定 | PP/PA6+PP-g-MAH | IATF 16949、低VOC |
| 电子电器 | 笔记本外壳、显示器框 | 光泽、耐热、阻燃 | PC/ABS+SAN-g-MAH | UL94、RoHS |
| 电动工具 | 电钻外壳、手柄 | 抗冲、耐疲劳 | PP/PA或PA+POE-g-MAH | GS、RoHS |
| 家电 | 吸尘器、洗衣机部件 | 抗冲、刚韧平衡 | PP+弹性体+相容剂 | RoHS、REACH |
| 可降解 | PLA/PBAT餐盒、包装 | 生物降解、断裂伸长 | GMA反应相容剂 | GB/T 20197、堆肥认证 |
| 回收再生 | 杂料再生颗粒 | 分散、力学恢复 | PE-g-MAH/通用增容 | 客户内控 |
举个具体场景：做汽车PP/PA6进气歧管，要求耐120℃、高温下不脆、尺寸稳。这时候PP-g-MAH用量要够（通常4%-8%），同时配少量抗氧1098和润滑剂，加工温度按PA6的260-280℃走，PA6原料必须先烘干。
添加量与搭配要点：它是成本敏感项，得算着加
相容剂添加量2%-10%，比偶联剂高一个数量级，直接进配方成本。下面四个配方是行业通用方案。
做塑料合金，先定相容体系再谈成本，顺序反了全白干。
◆ PP/PA6合金：PP-g-MAH 4%-8%，PA6占比20%-40%，配滑石粉调刚性，总相容+增韧控制在10%以内。
◆ 增韧PA6/PA66：POE-g-MAH 8%-15%，提升低温冲击，同时注意刚韧平衡，必要时补玻纤。
◆ PC/ABS合金：SAN-g-MAH或环氧类3%-5%，PC充分干燥（120℃×4h以上），控制水解。
◆ PLA/PBAT可降解：GMA类相容剂3%-6%，提升断裂伸长和耐水，避免过早交联。
搭配要点三条：一是相容剂和增韧剂常一起用，POE-g-MAH一身二职时别重复加；二是PA体系加工前必须烘干，水分会消耗酸酐、让界面反应失效；三是相容剂和回收料是绝配，杂料回掺时补加相容剂能把力学拉回来一截。
相容剂贵是贵了点，但它干的是把两种树脂焊在一起的活，省了它，废品率替你买单。
相容：界面做媒。
加工与合规红线：接枝率、烘干、温度窗口
相容剂用不好，不是分层就是性能虚高。下面这张表把关键参数和做错的后果列出来。
| 环节 | 参考值 | 做错的后果 |
|---|
| 接枝率匹配 | PP-g-MAH接枝率0.5%-1.5%，与基体熔指匹配 | 接枝率低→界面反应不足、分层 |
| PA烘干 | PA6/PA66 80-100℃×4-8h | 未烘干→水解、酸酐被消耗 |
| 加工温度 | PP/PA 230-280℃，按PA端 | 温度过低→分散不细、相畴粗大 |
| 螺杆剪切 | 中高剪切、建立合理停留时间 | 剪切不足→分散不均；过强→降解 |
| 计量精度 | 按配方2%-10%准确称重 | 少加→合金不成立；多加→成本飙升 |
合规红线：汽车件要符合IATF 16949和低VOC；电子件要UL黄卡和RoHS；可降解材料要符合生物降解相关标准。相容剂的合规文件（REACH、RoHS、食品/降解认证）随货索取归档。
FAQ：采购和配方工程师常问的五个问题
Q1：国产相容剂能不能替代进口料？
可以，但要盯住接枝率和熔指。通用PP/PA合金用PP-g-MAH，国产主流牌号和进口差距已经较小，批次稳定的国产品牌能替代。但在汽车进气歧管、高要求增韧PA、PC/ABS高端外壳上，进口牌号在接枝率一致性和反应活性上仍有优势。正确做法是先拿公斤级样品平行测试，对比缺口冲击、拉伸和断面形貌，通过后小批量再放量。测试用的对照样品，可以找科隆新材按公斤级索取，附批次数据一并比对。
Q2：加了相容剂，合金还是分层，为什么？
先查三点：一是相容剂接枝率太低或熔指和基体不匹配，分子没停在界面上；二是PA没烘干，水分把酸酐消耗掉了；三是螺杆剪切不够，分散相还是粗大颗粒。这三点排除了再考虑换牌号。
Q3：相容剂和增韧剂是一回事吗？
不是。相容剂管两种树脂能不能“结婚”（界面相容），增韧剂管材料受冲击时能不能“长肉”（吸收能量）。POE-g-MAH比较特殊，它既有酸酐能相容，又是弹性体能增韧，一身二职，但纯PP-g-MAH就基本只做相容。
Q4：做回收杂料需要加多少相容剂？
看杂料干净程度。单一品种回料补加原用量的30%-50%即可；多种树脂混杂的杂料，建议加3%-8%的通用增容剂（PE-g-MAH类），把界面先粘住，力学能恢复一大截。
Q5：相容剂什么价位？怎么控成本？
常用价格带（元/kg）：PP-g-MAH约15-35、POE-g-MAH约20-45、PE-g-MAH约18-35，随行情波动，以当期报价为准。相容剂添加量大，是成本敏感项，控本思路不是砍用量，而是选接枝率合适的牌号——接枝率够的，用5%就顶别人8%，总账反而更省。
选型三步清单：照做不踩坑
◆ 第1步·认配对：先确认合金是哪两种树脂（PP/PA、PC/ABS、PLA/PBAT…），按配对选对应的反应型相容剂。
◆ 第2步·定指标：核对接枝率、熔指与基体匹配，确定添加量2%-10%，判断是否需要同时承担增韧功能。
◆ 第3步·做验证：平行测冲击、拉伸、断面形貌，确认相畴变细、界面结合到位，再按用途核对认证并归档。
合金不分层，相容剂是底层逻辑
塑料合金的性能取决于界面结合，相容剂的接枝率和用量直接决定相形态。科隆新材供应PP-g-MAH、SEBS-g-MAH等接枝相容剂，可提供接枝率、熔指、力学性能参考数据；不同合金体系（PP/PA、PC/ABS、PBT/PC等）可推荐对应接枝物，公斤级试样支持先做冲击和相形态对比。
前年，一家做PP/PA合金的厂，冷热冲击一直过不了5个循环。科隆新材技术团队分析了他们的配方，PP-g-MAH用量只有2%，接枝率也偏低。建议提到5%-6%并更换接枝率更高的牌号，寄了公斤级样品。客户重新造粒后测试，冷热冲击通过了约50个循环，冲击强度也提升了约40%。后来这款料进了两家车企的供应链，厂长说相容剂这步棋走对了。
PP和PA共混，你加了多少接枝物？
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 car intake manifold made of PP/PA alloy cracked along the phase interface after just five cycles of thermal shock testing. The customer threw the test part on the conference table and said, 'You call this an alloy? This is a patchwork.' The formulator knew the problem was with the compatibilizer—only 2% of PP-g-MAH was added, and the interface didn't form a sufficient grafted layer, so PP and PA still remained separate.
PP and PA6, this pair of rivals, would separate easily without a compatibilizer, but with PP-g-MAH, they are surprisingly harmonious.
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 Compatibilizers: One Page Check for Five Major Alloy Systems
Compatibilizers are not a single thing; they are chosen according to the alloys you want to make: for combining PP with PA, use PP-g-MAH; for PC with ABS, use SAN-g-MAH or epoxy types; for PLA with PBAT, use GMA types. The first step in selecting is always to figure out which two resins you have and then find the corresponding 'matchmaker'.
| Alloy system | Representative compatibilizer | Key role | Typical products | Add ratio |
|---|
| PP/PA Alloy | PP-g-MAH, POE-g-MAH | Anhydride reacts with PA terminal group | Automobile intake manifold, power tools | 2%-10% |
| PC/ABS Alloy | SAN-g-MAH, epoxy type | Reduce interfacial tension and increase capacity | Laptop casing, car interior | 3%-8% |
| PA Toughening/Alloy | POE-g-MAH | Interface reaction toughening | Connectors, thin-walled parts | 5%-15% |
| PLA/PBAT | GMA-EBA, MAH types | Reaction capacity enhancement, improvement of brittleness | Degradable packaging, lunch boxes | 3%-8% |
| Recycled material / scrap | PE-g-MAH, general capacity expansion | Improve filler compatibility | Recycled Material Modification, Regenerated Pellets | 2%-8% |
Note: The above grafting rate and melt index are common ranges, with significant differences between different grades. Please refer to the official TDS from the manufacturer. Note that the amount of compatibilizer added is much higher than that of the coupling agent (the coupling agent is measured at a few tenths of the filler amount, while the compatibilizer is measured as a few percent of the total formulation). This is cost-sensitive, and selection should consider the overall balance.
Figure 1 Compatibilizer — Alloying bridge between two resins
A compatibilizer is like a matchmaker for plastic alloys, bringing together enemies into one family.
This protagonist specializes in matchmaking between two incompatible resins. Ningbo Cologne New Materials Co., Ltd. has long been engaged in various plastic additives and modified raw materials, covering multiple domestic and international brands, and has a stable supply of interfacial modification products such as compatibilizers, toughening agents, and coupling agents. The category of compatibilizers is essentially a 'matchmaking agency' between two incompatible resins. PP and PA6 cannot mix well because their solubility parameters differ greatly, causing them to repel each other thermodynamically. When blended, they can only form coarse two-phase sea-island structures, with weak interfacial bonding, which breaks at the interface under impact. The compatibilizer molecule has one end attracted to PP and the other to PA6, like a zipper sewing the two phases together. This reduces the interfacial domains from the micron level to the submicron or even nanometer level, allowing stress to be transmitted from one phase to the other.
A compatibilizer is like a marriage agency; PP and PA6 originally never got along, but when it brings them together, they can sit down and live happily.
Take PP-g-MAH with a relatively large usage as an example. It is a product obtained by grafting maleic anhydride (MAH) onto the PP molecular chain. The PP end is compatible with the PP matrix, while the anhydride group end can react with the terminal amino groups of PA6 or form hydrogen bonds. The MAH at the interface acts like little hands, firmly holding the PA6 particles and the PP matrix together. Mechanistically, it addresses three things: reducing the interfacial tension between the two phases, making the dispersed phase finer and more uniform, and turning the interface into a transitional layer capable of transferring stress. Only when these three things are achieved can an alloy truly be called an alloy; otherwise, it is just a plastic assortment.
Graft maleic anhydride onto the PP molecular chain, like putting a suit on PP that can shake hands with PA, and the interface is thus linked.
A common misconception: the more compatibilizer you add, the better. Excessive compatibilizer can cause the extra molecules to agglomerate, creating defect phases and actually reducing performance. On the other hand, for grades with too low a grafting rate, no matter how much you add, there aren't enough anhydride groups, and the interfacial reaction cannot be fully achieved. Therefore, when choosing a compatibilizer, you should look at two key indicators—grafting rate and melt index matching—not just the price.
The boundary between the two phases is very clear and can be separated with a single pull, indicating that the compatibilizer never reached the position where it was supposed to be.
Quick reference by type: PP-g-MAH pipe PP/PA, POE-g-MAH also incidentally toughening
There seem to be many grades of compatibilizers, but in reality, just focusing on a few main varieties can cover mainstream alloys. Below, we will explain their positioning and precautions one by one.
To blend PP and PA6, use PP-g-MAH, don't expect to just add more toughening agent to force it.
PP-g-MAH (Maleic Anhydride Grafted Polypropylene): The 'standard compatibilizer' for PP/PA alloys, typically added at 2%-8%, with a grafting rate of generally 0.5%-1.5%. When making PP/PA6 or PP/PA66 alloys, it can improve both tensile strength and impact resistance. Price range is about 15-35 RMB/kg. Signals for choosing it: automotive intake manifolds, engine covers, power tool housings. Note: The grafting rate and melt index should match the matrix; a large difference in melt index will lead to poor dispersion.
Supply Notice: PP-g-MAH and other grafted compatibilizers from Kolon New Materials can be supplied stably, with each batch accompanied by grafting rate and melt index data. Kilogram-level samples are available for preliminary morphological analysis.
POE-g-MAH (POE grafted with maleic anhydride): It serves a dual purpose, functioning both as a compatibilizer and a toughening agent. Compared with pure POE, it has additional anhydride groups that can react with PA6, so it is specifically used to toughen PA and as the flexible phase in PP/PA blends. Signals for choosing it: when toughening PA6/PA66 connectors or PP/PA blends that require high low-temperature toughness. Note: it reduces rigidity, so the balance between strength and toughness should be adjusted with pure POE or talc.
What compatibilizers fear the most is not using too little, but the formulator confusing them with toughening agents—one deals with marriage, the other with gaining weight.
PE-g-MAH (Maleic Anhydride Grafted PE): Similar to PP-g-MAH, but more flexible, suitable for interfacial modification of PE/PA, PA toughening, and glass fiber/mineral filled PA. Signals for choosing it: making PE/PA multilayer composites, toughening PA. Note: Low melting point, heat resistance should be evaluated for high-temperature PA processing.
SAN-g-MAH and epoxy compatibilizers: mainly used for PC/ABS alloys. PC and ABS are partially compatible on their own, and adding a small amount of this type of compatibilizer can balance hydrolytic stability, gloss, and heat resistance. This is a common solution for laptop cases and automotive dashboards. Signal for choosing it: making PC/ABS alloys. Note: epoxy is sensitive to moisture, and the PC side must be thoroughly dried.
GMA-type reactive compatibilizers (such as EBA-g-GMA): targeted at PLA/PBAT biodegradable blends and recycled mixed material systems, with strong epoxy group ring-opening reactivity. Signals for choosing it: for biodegradable modification and increasing the compatibility of recycled mixed materials. Note: high reactivity, processing window should be well controlled to avoid premature crosslinking.
A matchmaker isn't better the more expensive they are; it's about matching the secret signals between the two families in hand—PP with PA, PC with ABS. If you choose the wrong match, no matter how much money you spend, it's all in vain.
Alternative comparison: replace imported compatibilizer with domestic one, first do phase diagram and impact test
Common procurement question: Can imported PP-g-MAH be replaced by domestic alternatives? The answer is that the gap for general-purpose alloys is already small, but fluctuations in grafting rate directly affect alloy performance, so parallel verification is necessary. The core of compatibilizers lies in grafting rate, melt index, and reaction activity. Mainstream domestic brands can now meet these indicators, with differences mostly in batch consistency. The table below lists common replacement options and prerequisites for switching.
| Original Import Direction | Typical Applications | Benchmark solution | Switch premise |
|---|
| DuPont Fusabond PP Series | PP/PA Alloy | Domestic PP-g-MAH | Compare grafting rate, notch impact, and tensile strength |
| DuPont Fusabond E/PO Series | PA Toughened | Domestic POE-g-MAH | Comparison -30℃ low-temperature shock, phase domain size |
| BASF S Series Compatibilizer | PC/ABS Alloy | Domestic SAN-g-MAH | Compare gloss, heat deflection temperature, hydrolysis |
| Arkema Lotader Reactive | PLA/PBAT/Mixed Materials | Domestic GMA/MAH type | Comparison of elongation at break and reaction crosslinking window |
| Imported PE-g-MAH | PE/PA, fill PA | Domestic PE-g-MAH | Comparison of dispersion and interfacial strength |
The table is for reference of application directions and does not imply complete equivalence in performance. Replacement sequence: lab-scale → parallel testing → written confirmation from customer → small batch → mass production.
The replacement of the compatibilizer needs to verify the morphology and impact strength. When Kolon New Materials sends kilogram-level samples of the grafted material, they include the grafting rate and melt index data. Customers can first conduct hot and cold impact tests and parallel tests, and only when the data meets the standards can bulk orders be discussed.
The impact strength collapses as soon as it's tested, and the two-phase particles are so large they can be seen with the naked eye. Did you actually add the compatibilizer or just buy it?
Industry Scene Quick Reference: Alloy Formulas Follow Part Requirements
Although both are compatibilizers, making automotive intake manifolds and making biodegradable food containers involve completely different systems. The table below breaks it down by industry.
| Industry | Typical products | The parameters the customer asked about first | Recommended plan | Certification requirements |
|---|
| Car | Intake manifold, engine cover | Temperature resistance, impact resistance, dimensional stability | PP/PA6 PP-g-MAH | IATF 16949, low VOC |
| Electronics and electrical appliances | Laptop casing, monitor frame | Glossy, heat-resistant, flame-retardant | PC/ABS SAN-g-MAH | UL94, RoHS |
| Power tools | Electric drill casing and handle | Impact-resistant and fatigue-resistant | PP/PA or PA POE-g-MAH | GS, RoHS |
| Home appliances | Vacuum cleaner and washing machine parts | Impact resistance and a balance of strength and toughness | PP elastomer compatibilizer | RoHS, REACH |
| Biodegradable | PLA/PBAT Lunch Boxes and Packaging | Biodegradation, elongation at break | GMA reaction compatibilizer | GB/T 20197, Compost Certification |
| Recycle and regenerate | Recycled Mixed Material Pellets | Dispersion, mechanical recovery | PE-g-MAH/General Capacity Enhancement | Customer internal control |
Here is a specific scenario: making automotive PP/PA6 intake manifolds, requiring resistance to 120℃, not brittle at high temperatures, and dimensional stability. At this time, the amount of PP-g-MAH should be sufficient (usually 4%-8%), while adding a small amount of Antioxidant 1098 and lubricant. The processing temperature should follow PA6's 260-280℃, and the PA6 material must be dried first.
Addition amount and matching points: It is a cost-sensitive item, so it needs to be added carefully.
The amount of compatibilizer added is 2%-10%, which is an order of magnitude higher than that of the coupling agent, directly affecting the formulation cost. The following four formulations are commonly used in the industry.
When making plastic alloys, decide on a compatible system first before discussing cost; if the order is reversed, all the work will be wasted.
◆ PP/PA6 Alloy: PP-g-MAH 4%-8%, PA6 accounts for 20%-40%, with talc added to adjust rigidity, and total compatibilization toughening controlled within 10%.
◆ Toughened PA6/PA66: POE-g-MAH 8%-15%, improves low-temperature impact, while paying attention to the balance between stiffness and toughness, add glass fiber if necessary.
◆ PC/ABS Alloy: SAN-g-MAH or epoxy 3%-5%, PC should be thoroughly dried (120℃ for more than 4 hours) to control hydrolysis.
◆ PLA/PBAT biodegradable: GMA-based compatibilizer 3%-6%, improves elongation at break and water resistance, prevents premature crosslinking.
Three key points for blending: First, compatibilizers and toughening agents are often used together, so don’t add extra if POE-g-MAH is serving both roles; second, the PA system must be dried before processing because moisture consumes anhydride and causes interface reactions to fail; third, compatibilizers and recycled materials are a perfect match, and adding compatibilizer when mixing in scrap can recover a portion of the mechanical properties.
The compatibilizer is a bit expensive, but its job is to weld two resins together. If you skip it, the scrap rate will pay for it.
Compatible: The interface acts as a medium.
Processing and Compliance Red Lines: Grafting Rate, Drying, Temperature Window
If compatibilizers are not used properly, it will either lead to delamination or artificially high performance. The table below lists the key parameters and the consequences of mistakes.
| link; segment; part | Reference value | The consequences of doing wrong |
|---|
| Grafting rate matching | PP-g-MAH grafting rate 0.5%-1.5%, matched with the melt index of the matrix | Low grafting rate → insufficient interfacial reaction, delamination |
| PA Drying | PA6/PA66 80-100℃ × 4-8h | Not dried → hydrolysis and anhydride are consumed |
| Processing temperature | PP/PA 230-280℃, according to the PA end | Temperature too low → poor dispersion, coarse grains |
| Screw shear | medium-high shear, establish reasonable residence time | insufficient shear→ uneven dispersion; excessively strong → degradation |
| measurement accuracy | accurate weighing according to 2%-10% of formula | alloy with minimal → not valid; Cost of over→adding |
compliance red line: automotive parts must comply with IATF 16949 and low VOC; electronic parts must have UL yellow card and RoHS; degradable materials must meet biodegradable standards. Compliance documents for compatibilizers (REACH, RoHS, food/degradability certification) must be requested and archived with the goods.
FAQ: Five common questions asked by procurement and formulation engineers
Q1: Can domestic compatibilizers replace imported materials?
Yes, but you must focus on graft rate and melt finger. For general PP/PA alloys, PP-g-MAH is used; the gap between mainstream domestic grades and imported products is already small, and domestic brands with stable batch sizes can be substituted. However, for automotive intake manifolds, high-demand toughened PA, and high-end PC/ABS housings, imported grades still have advantages in graft rate consistency and reactivity levels. The correct approach is to first take kilogram-level samples for parallel testing, compare notch impact, tensile and cross-sectional morphology, and then scale up in small batches after passing. For test control samples, you can request kilogram-level samples from Colon New Materials, with batch data for comparison.
Q2: Even after adding compatibilizers, the alloy still forms layers. Why?
First, check three points: First, the grafting rate of the compatibilizer is too low or the melt fingers and matrix are mismatched, so the molecules haven't stopped at the interface; Second, the PA hasn't been dried, so moisture has consumed the anhydride; Third, the screw shear is insufficient, so the dispersed phase is still coarse particles. Rule out these three points before considering changing the grade.
Q3: Are compatibilizers and toughening agents the same thing?
No. Can the two resins in compatibilizer pipes 'marry' (interface compatibility), and can toughening agent tube materials 'grow thick' (absorb energy) when subjected to impact? POE-g-MAH is quite special; it is compatible with acid anhydrides and elastic strengthening, serving two purposes. However, pure PP-g-MAH is basically only made for compatibility.
Q4: How much compatibilizer is needed for recycled miscellaneous materials?
depends on how clean the impurities are. For single varieties, refill 30%-50% of the original amount is sufficient; For mixed materials with multiple resins, it is recommended to add 3%-8% of the universal volume enhancer (PE-g-MAH type) to seal the interface first, which can significantly restore mechanical properties.
Q5: What is the price range of compatibilizers? How to control costs?
Common price range (yuan/kg) :P P-g-MAH about 15-35, POE-g-MAH about 20-45, PE-g-MAH about 18-35. Depending on market fluctuations, the current quote shall prevail. The amount of compatibilizer added is high and cost-sensitive. The cost-control approach is not to cut the amount used, but to choose grades with appropriate grafting rates—if the grafting rate is sufficient, using 5% equals 8% of others, which actually saves money in the overall account.
Three-step selection checklist: Follow these instructions to avoid pitfalls
◆ Step 1 · Matching: First, confirm which two types of resins (PP/PA, PC/ABS, PLA/PBAT... ), select the corresponding reactive compatibilizer according to the pairing.
◆ Step 2 · Set indicators: Verify graft rate, melt index matches with matrix, determine the addition amount of 2%-10%, and determine whether toughening functions are needed simultaneously.
◆ Step 3 · Verification: Parallel measurements of impact, tensile, and cross-sectional morphology are conducted to confirm that the phase domain is thinner and the interface bonding is in place, then verify and archive according to usage.
Alloy does not separate layers; compatibilizer is the underlying logic
The performance of plastic alloys depends on interfacial bonding; the grafting rate and amount of compatibilizer directly determine phase morphology. Kelong New Materials supplies graft compatibilizers such as PP-g-MAH and SEBS-g-MAH, providing reference data for graft rate, melt index, and mechanical properties; Different alloy systems (PP/PA, PC/ABS, PBT/PC, etc.) can be recommended for corresponding grafts, and kilogram-level samples can be tested first for impact and phase morphology comparison.
Two years ago, a factory producing PP/PA alloys couldn't pass five cycles of thermal shock. The technical team of Cologne New Materials analyzed their formula and found only 2% PP-g-MAH usage, with a relatively low graft rate. They suggested increasing the grafting rate to 5%-6% and switching to a grade with a higher graft rate, sending kilogram-level samples. After re-pelletizing, the customer tested and found that thermal shock passed about 50 cycles, with impact strength increasing by about 40%. Later, this material entered the supply chains of two automakers, and the factory manager said the combinant was the right move.
PP and PA blend, how much grafting did you add?
Statement: The brand, trademark, and product name rights 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 inspection reports from each manufacturer. This article does not constitute any procurement or investment advice. Readers are responsible for any actions based on it
