包胶件换了个SEBS牌号，边缘一撕就开。SEBS选型翻车，多半翻在牌号和基材没对上。
SEBS 选型，到底难在哪？先看翻车现场
SEBS 基 TPE 是行业里用得最多的 TPE，但也是最容易“选花眼”的一个——牌号几十个、参数一大堆，看起来都像，做出来全不像。
三个最常见的翻车现场：
现场一：客户说“要软一点”，供应商换了个更软的牌号，结果包胶粘不牢，一撕就脱——软度和粘接力没对齐；
现场二：样件手感都对，量产三个月后发粘、出油——油分超了，析出了；
现场三：同一副模具，换个牌号，尺寸就偏了——收缩率没对上。
SEBS 选型的难点不是“没有料”，是“牌号之间的差异藏在参数里”——硬度差不多的两个牌号，分子量、油含量、加氢度可能差出一档性能。
看懂三个参数，牌号就不难挑。
技术金句：SEBS 牌号千千万，选型只看三件事：硬度、耐温、包谁——三件对上，牌号自己冒出来。
原因拆解：牌号差异，藏在三个参数里
SEBS 基 TPE 的性能，由三个底层参数决定：
参数一 · 分子量：分子量高，强度高、耐温好，但流动性差、加工难；分子量低，好加工、表面好，但强度弱。要强度还是要加工，先想清楚。
参数二 · 加氢度：加氢度决定耐老化——加氢越彻底，双键越少，越耐热耐氧。低加氢度的“经济牌号”，价格低，老化也快。
参数三 · 油含量：油分决定硬度和手感——油多则软，但油多析出风险高。“又软又不析出”是矛盾需求，要靠特定牌号和配方平衡。
三个参数组合起来，就是几十个牌号的性格差异。供应商说“这个牌号好”，你要追问一句：好在哪个参数上？
答不上来的，基本是卖货不是选型。
把 SEBS 基 TPE 当成“一种材料”，是选型的头一个误区。SEBS 基是个大筐，筐里从 20 度到 90 度、从普通级到医用级，牌号几十个，彼此差异比 SEBS 和 SBS 的差异还大。
打个比方：说“我要 SEBS 基”，等于说“我要买轿车”——从几万到几百万都是轿车，你要的到底是哪一台？
选型的起手式不是挑牌号，是先把“这台车”的定位定清楚：硬度多少、耐温多少、包谁。
再补一个影响手感但常被忽略的参数：油种。
同样 50 度硬度，用石蜡油和白油，手感能差出两个档次——石蜡油和 SEBS 相容性好，做出的料清爽不粘手；白油相容性差一点，料会偏粘。
还有分子量分布宽的牌号，表面容易有雾感，对表面要求高的件要专门挑窄分布牌号。
这些参数 TDS 上不一定全写，但都可以问供应商要——问得出来说明他对牌号熟，答不上来换一家问。
排查步骤：三步锁死牌号
手里一堆牌号，怎么锁？三步：
- 1. 先定硬度：目标 Shore A 值定死，从该硬度档位里筛——这是最快的减法；
- 2. 再定耐温：连续使用温度多少？70℃ 以内普通牌号够，90℃+ 要挑高加氢度牌号；
3. 三定包胶基材：包 PP、包 ABS、包 PA 完全不同的配方体系——SEBS 的看家本领是包 PP，包其他基材要确认专用牌号。
三步走完，候选牌号从几十个缩到两三个，再让供应商按工况给 TDS，逐项对硬度、伸长率、压缩永久变形。
别拿“哪个好”问供应商，要拿“这个工况配哪个”问——问法对了，答案才对。
拿到两三个候选牌号后，做一次“同模具同工艺”的横评——同样的模温、料温、保压，把候选牌号各打一板，手感、收缩、
包胶剥离放一起比。
这一步能过滤掉一半纸上谈兵的参数差。
横评件留样，等放量后出了争议翻出来对比，比任何口头承诺都有说服力。
很多厂嫌横评麻烦，结果在量产阶段花十倍时间去返工——横评是选型成本里性价比很高的那笔钱。
脱胶发粘怎么救：料、工艺、体系三处下手
SEBS 基出问题，按三方向解：
料的方向：同体系内调牌号、调配方（油分/填料/助剂）。“软 5 度”“耐温加 10℃”这类需求，多数靠换牌号或调配方就能解决，不用换体系。
工艺的方向：SEBS 基对干燥和温度敏感——料不干，表面起雾；料温过高，发黄降解。先查干燥（80-90℃×2-3h）、再查料温窗口，很多“料不对”其实是“工艺没喂对”。
体系的方向：SEBS 扛不住的工况（连续 100℃+、强耐油），往上换 TPV、TPEE，别在 SEBS 里硬找——体系边界外，再贵的 SEBS 也白搭。
三方向的顺序：先工艺、再料、最后体系——多数翻车，是工艺接不住料，不是料不行。
SEBS 基能不能包 ABS？能，但要专用牌号。SEBS 看家本领是包 PP——因为 PP 和 SEBS 的溶解度参数接近，熔融时能形成物理缠结，粘得牢。
包 ABS 的话极性差异大，普通牌号粘不住，要用带极性改性的专用牌号，成本也高一档。
做 ABS 包胶的，别拿“包 PP 之王”的普通牌号硬上——先确认供应商给的是不是 ABS 专用体系，基材一换，整个选型逻辑就换。
| 参数 | 作用 | 挑法 |
|---|
| 分子量 | 强度与加工 | 要强度挑高 |
| 加氢度 | 耐老化 | 户外挑高 |
| 油含量 | 硬度手感 | 按手感定 |
| 步骤 | 动作 | 结果 |
|---|
| 一 | 定硬度 | 筛档位 |
| 二 | 定耐温 | 筛牌号 |
| 三 | 定基材 | 锁候选 |
| 验收项 | 要求 | 判断 |
|---|
| 牌号批号 | 对齐 | 达标 |
| 气味等级 | 达标 | 达标 |
| 包胶实测 | 通过 | 达标 |
| 批次留样 | 存档 | 达标 |
科隆客户案例：异味退货，定制牌号救回整批货
广州一家改性料应用厂，一批 SEBS 基 TPE 成品异味被下游退回，货压在仓库，交期全乱。客户自己换了两家料，异味照旧。
科隆排查后发现：异味来自油分等级和助剂体系不匹配。配合定制耐油/耐温专用牌号，异味问题解决，量产良率稳定在 98%。SEBS 基的“味道”，多半是配方的味道，不是材料的味道——牌号定制到位，问题就没了。
到货验这四条，少踩一半坑
SEBS 基 TPE 验收，四条动作：
- 1. 要牌号 TDS 和批号：每批到货，牌号、批号、TDS 三样对齐，别让“同牌号不同批次”悄悄换料；
- 2. 要气味等级数据：异味敏感的件，把气味等级写进验收标准（如 VDA 270 之类的方法等级），先测再收；
- 3. 做包胶实测：包胶件按实际基材做剥离测试，别只测材料，要测“材料+基材+工艺”三合一；
- 4. 批次留样：每批 500g，出争议时同环境对比。
四条里，包胶实测最容易被跳过——而包胶脱层，恰恰是 SEBS 基投诉里最贵的那个。
SEBS 基的牌号更新很快，两年前的“标准牌号”，今年可能已有性能更好、价格相近的新选择。
每半年让供应商更新一次牌号库，比抱着旧牌号将就，更能守住成本线。
SEBS 基的价格这两年波动不小，牌号价格差能到 30%——同一个项目去年询价和今年询价，预算要重新对。
锁定牌号后，建议和供应商签“季度价格锁定”或“批量阶梯价”，别按月询价来回折腾。
国产牌号和进口牌号价差在缩小，性能差距也在缩小，预算有限的项目可以先评估国产高加氢度牌号——用数据说话，别用印象选牌号。
“便宜牌号”和“稳定牌号”的差距，从来不是单价那几千块，而是批次稳定性。
同一牌号，A 供应商批次间硬度波动 ±3 度，B 供应商 ±1 度——听起来差不多，放到量产线上，±3 度的料要频繁调工艺，调一次就是一批试产件。
选牌号时把“批次稳定性”作为一个指标去问：近半年出货的批次波动数据，能不能提供？能提供的，才值得长期合作。
关于包胶实测，再提醒一个细节：剥离测试要模拟真实使用方向。
有的厂只测垂直剥离，件实际使用是横向撕扯，两个方向的数据可能差一倍。
测试时把“脱的方向”问清楚，测试方法和实际受力对齐，测出来的数才有参考价值。
另外包胶件放三天再测一次剥离——SEBS 基和基材的粘接强度会随放置时间变化，刚出模的数据和三天后的数据，能差出 20%。
PP 基材 SEBS 包胶体系，剥离力典型值在 1.0-2.0kN/m，低于 0.5kN/m 就别量产。
小结
写这篇的目的，是让你下次聊SEBS 基 TPE时，心里先有杆秤，也欢迎转给需要的同事。
SEBS 基是包 PP 之王、耐候耐温的优等生，但“牌号多”是它的优势也是陷阱——硬度、耐温、包谁三问走完，牌号就锁死了；再补上包胶实测和批次留样，这条线就稳了。
做改性热塑性弹性体。
做改性尼龙：PA6、PA66、PA46、PA11、PA12、PA6T、PA9T、尼龙合金。
做改性 PPO、PPS。
做各大化工巨头的尼龙树脂、副牌料、大包料。
The overmolded part was changed to a different SEBS grade, and the edges tear open easily. Choosing the SEBS grade went wrong, mostly because the grade and the substrate didn't match.
Choosing SEBS, what's really difficult about it? First, let's look at the failure cases
SEBS-based TPE is the most commonly used TPE in the industry, but it is also the one that is easiest to get 'dazzled' by——there are dozens of grades and a bunch of parameters, they all look similar, but the results are completely different.
The three most common accident scenes:
Scene 1: The customer said 'make it softer,' so the supplier switched to a softer grade. As a result, the coating couldn't stick firmly and peeled off easily—softness and adhesion were not aligned.
Scene 2: The feel of the sample parts is correct, but after three months of mass production, they become sticky and oily — the oil content exceeded the limit and separated out;
Scene 3: Using the same mold, changing the grade, the dimensions were off — the shrinkage rate didn't match.
The difficulty in selecting SEBS is not 'lack of material,' but 'the differences between grades are hidden in the parameters' — two grades with similar hardness may differ in performance due to molecular weight, oil content, or degree of hydrogenation.
Once you understand the three parameters, choosing the grade won't be difficult.
Tech catchphrase: There are countless SEBS grades, but when choosing, only look at three things: hardness, temperature resistance, and who it's wrapping — if these three match, the grade will reveal itself.
Cause Analysis: Grade Differences Hidden in Three Parameters
The performance of SEBS-based TPE is determined by three underlying parameters:
Parameter One · Molecular Weight: High molecular weight means high strength and good temperature resistance, but poor flow and difficult processing; low molecular weight means easy processing and good surface finish, but weak strength. Decide whether strength or processability is more important first.
Parameter two · Degree of hydrogenation: The degree of hydrogenation determines aging resistance — the more thorough the hydrogenation, the fewer the double bonds, and the more resistant it is to heat and oxidation. Low hydrogenation 'economy grades' are cheaper but age faster.
Parameter three · Oil content: Oil content determines hardness and texture—more oil makes it softer, but higher oil increases the risk of exudation. The desire for "soft yet not exuding" is a contradictory demand, which needs to be balanced through specific grades and formulations.
The combination of three parameters results in the personality differences of dozens of grades. When a supplier says 'this grade is good,' you need to ask: good in which parameter?
Those who can't answer it are basically just selling products, not choosing models.
Considering SEBS-based TPE as 'a single material' is the first misconception in material selection. SEBS-based is a big category, with grades ranging from 20 to 90, from general grade to medical grade, and dozens of grade numbers, whose differences are even greater than the difference between SEBS and SBS.
For example: Saying 'I want SEBS grade' is like saying 'I want to buy a car'—from tens of thousands to millions, they're all cars. Which one exactly do you want?
The first step in selecting a type is not choosing the brand, but first clarifying the positioning of 'this car': how hard it should be, how heat-resistant, and who it covers.
Add another factor that affects the feel but is often overlooked: the type of oil.
With the same hardness of 50 degrees, using paraffin oil and white oil, the hand feel can differ by two levels — paraffin oil has good compatibility with SEBS, producing a material that feels clean and non-sticky; white oil has slightly worse compatibility, making the material somewhat sticky.
There are also grades with a wide molecular weight distribution, which easily gives the surface a hazy appearance. For parts that have high surface requirements, grades with a narrow distribution need to be specifically selected.
These parameters may not all be listed on the TDS, but you can ask the supplier for them — if they can answer, it shows they are familiar with the grade; if not, switch to another supplier.
Troubleshooting steps: Three-step lock of the license plate
A pile of labels in hand, how to lock them? Three steps:
- 1. First set the hardness: fix the target Shore A value and select from that hardness range — this is the fastest way to subtract options;
- 2. Re-determining temperature resistance: What is the continuous use temperature? Ordinary grades are sufficient below 70°C, for 90°C you need to choose high hydrogenation grades.
3. Fixed three-layer rubber-coated substrates: Coating PP, coating ABS, and coating PA are completely different formulation systems — SEBS's specialty is coating PP, and special grades need to be confirmed for coating other substrates.
Completed in three steps, the candidate grades are reduced from dozens to two or three, then the supplier is asked to provide TDS according to the working conditions, and each item for hardness, elongation, and permanent compression deformation is checked.
Don't ask the supplier 'Which one is better'; ask 'Which one suits this working condition' — if you ask correctly, the answer will be correct.
After obtaining two or three candidate grades, conduct a horizontal evaluation with 'the same mold and the same process'—using the same mold temperature, material temperature, and holding pressure, make a sample plate with each candidate grade to compare feel, shrinkage,
Compare the peeling of the coated layer together.
This step can filter out half of the theoretical parameter differences.
Keep samples of comparative evaluation pieces, and after the volume increases, if a dispute arises, you can bring them out for comparison; they are more persuasive than any verbal promise.
Many factories find comparative reviews troublesome, and as a result, they spend ten times the time on rework during the mass production stage—comparative reviews are a very cost-effective part of the selection cost.
How to fix delamination and stickiness: Addressing material, process, and system
SEBS has a basic problem, solved in three directions:
Direction for the materials: Adjust grades or formulations (oil content/fillers/additives) within the same system. Requirements like 'softer by 5 degrees' or 'temperature resistance increased by 10℃' can mostly be addressed by changing the grade or formulation, without switching systems.
Process direction: SEBS-based materials are sensitive to drying and temperature — if the material is not dry, the surface will fog; if the material temperature is too high, it will yellow and degrade. First check drying (80-90°C × 2-3 hours), then check the material temperature window. Many cases of 'wrong material' are actually 'the process was not fed correctly'.
System direction: For conditions that SEBS cannot withstand (continuous 100℃, strong oil resistance), switch up to TPV or TPEE instead of forcing it in SEBS—beyond the system boundaries, no matter how expensive the SEBS is, it’s useless.
The sequence of the three directions: first process, then materials, and finally the system — most failures happen because the process cannot handle the materials, not because the materials are inadequate.
Can SEBS basically encapsulate ABS? Yes, but it requires a special grade. SEBS's main strength is encapsulating PP—because PP and SEBS have similar solubility parameters, they can form physical entanglements when molten, sticking firmly.
When coating ABS, the polarity difference is large, and ordinary grades do not adhere well. Special grades with polarity modification must be used, which also increases the cost by a level.
For ABS overmolding, don’t just use the regular grade labeled as 'King of PP'—first confirm whether the supplier provides a system specifically for ABS. Once the base material changes, the entire selection logic changes.
| Parameter | Function | Selection method |
|---|
| Molecular weight | Strength and Processing | Increase the intensity |
| Degree of Hydrogenation | Aging resistant | Outdoor high ceiling |
| Oil content | Hardness feel | Decide by touch |
| Step | Movement | The result |
|---|
| One | Fixed hardness | Screen mesh size |
| Two | Fixed temperature | Sieve Grade |
| Three | Fixed substrate | Lock candidate |
| Acceptance item | Requirements | Judgment |
|---|
| Grade/Batch Number | Alignment | Standard |
| Odor Level | Standard | Standard |
| Overmolding Test | Pass | Standard |
| Batch Sample Retention | Archive | Compliant |
Cologne Customer Case: Odor Return, Custom Grade Saved the Entire Batch
A Guangzhou Modified Material Application Factory, a batch of SEBS-based TPE finished product odor was returned downstream, goods piled up in warehouse, delivery times completely disrupted. The customer changed the material from two suppliers, but the odor remained the same. After investigation by
Cologne, they found: the odor stemmed from mismatches between oil grade and additive system. Combined with custom oil/temperature resistant grades, the odor problem was solved, and the mass production yield stabilized at 98%. The "smell" of SEBS base is mostly the formula smell, not the material taste—once the grade is properly customized, the problem disappears.
Inspect these four points upon arrival to avoid half the pitfall
SEBS Base TPE acceptance, four actions:
- 1. Grade TDS and batch number: For each batch of goods, align grade, batch number, and TDS to prevent "same grade but different batches" to quietly swap materials;
- 2. Obtain odor level data: For odor-sensitive parts, include the odor grade in the acceptance criteria (such as VDA 270 or similar method grades), measure first, then accept;
- 3. Perform overmolding tests: Perform peel tests based on the actual substrate, not just the material—test the "material + substrate + process" in one;
- 4. Batch samples: 500g per batch, compare with the environment in case of disputes.
Among the four items, overmolding tests are the easiest to skip—and delamination is actually the most expensive complaint among SEBS base complaints.
SEBS base grades update quickly; the "standard grade" from two years ago may have better performance and similar price options this year.
Having suppliers update their grade database every six months is better than settling for old grades and better maintaining cost lines.
SEBS base prices have fluctuated significantly over the past two years, with grade price differences reaching 30%—for the same project, last year's inquiry and this year's inquiry require a re-budget.
After securing grades, it is recommended to sign "quarterly price lock" or "batch tiered pricing" with suppliers, rather than switching back and forth monthly for inquiries.
The price gap between domestic and imported grades is narrowing, and performance gaps are also narrowing. For projects with limited budgets, you can first evaluate domestic high-hydrogen grades—let the data speak for itself, don't choose grades based on impressions.
The difference between "cheap grades" and "stable grades" has never been about the few thousand yuan per unit, but about batch stability.
For the same grade, supplier A's hardness fluctuates between batches by ± 3 degrees, while supplier B's is ± 1 degree—sounds similar, but when placed on the mass production line, materials with ± 3 degrees require frequent process adjustments, and each adjustment equals a batch of trial production pieces.
When selecting grades, use "batch stability" as an indicator: Can you provide batch fluctuation data for shipments over the past six months? Only those that can be provided are worth long-term cooperation.
Regarding actual overmolding tests, one more detail: peel tests should simulate real usage directions.
Some factories only test vertical peeling, and actual parts are used in horizontal tearing, so the data in both directions may differ by half.
During testing, clarify the "peeling direction," align the testing method with the actual force, and only then will the measured values be valuable as reference.
Also, test the peeling once after three days of the coated part—the bonding strength between the SEBS substrate and substrate changes with the storage time, and data right after molding and three days later can differ by 20%.
PP For substrate SEBS overmolding systems, typical peel force values range from 1.0-2.0kN/m; if it's below 0.5kN/m, don't mass-produce.
Summary
The purpose of writing this is to give you a clear perspective next time you talk about SEBS-based TPE, and you're welcome to share it with colleagues who need it.
SEBS is the king of PP packaging, a top performer in weather and temperature resistance, but "many grades" is both an advantage and a trap—once you finish hardness, temperature resistance, and which one to wrap, the grade is locked; Add in actual testing and batch samples for coating, and this line is solid.
Makes modified thermoplastic elastomers.
Makes modified nylon: PA6, PA66, PA46, PA11, PA12, PA6T, PA9T, nylon alloys.
Makes modified PPO and PPS.
Produces nylon resin, sub-brand materials, and large packaging materials for major chemical giants
