增韧剂:塑料的“减震垫”,POE接枝物让PP从脆裂到弯折不发白

塑料知识科普 发布时间: 2026-09-13 1028 阅读

In the northeast winter, with temperatures below minus twenty degrees, a batch of PP turnover baskets cracked in half after being dropped once in the customer's warehouse. Half a ton broke in the customer's warehouse, and the claim letter was sent directly to the boss's desk. The formulator checked the formula — it was pure PP without any impact modifier, and the embrittlement temperature at low temperatures is only around 0°C, which is equivalent to running naked in the northeast winter.

PP cracks as soon as you step on it in winter; it's not that it has a bad temperament, it just lacks some elastomer, this 'soft cushion friend'.

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 Toughening Agents: Selecting Elastomer Families by Substrate

A toughening agent is not a single substance, but a family of elastomers chosen according to the base material: pure POE toughens PP, POE-g-MAH toughens PA, and EPDM is used for traditional TPV toughening. The first step in selecting is always to first clarify which base material you want to toughen. If the target is wrong, no matter how much you add, it’s useless.

CategoryRepresentative varietyToughening mechanismTypical productsAdd ratio
Polyolefin elastomerPOE, POPPhysical dispersion, shock absorptionPP bumper, TPO5%-15%
Reactive elastomerPOE-g-MAHInterface reaction tougheningPA6/PA66 connector8%-15%
EPDM typeEPDM, TPV componentsRubber toughening, compression resilienceSealing strip, tool handle10%-20%
Core-shell typeAcrylate Core-Shell TougheningLow-temperature toughening, minimal impact on opacityPC/ABS, PBT5%-15%
Composite tougheningPOE POE-g-MAHToughness-Strength Balance InterfaceCar interior and exterior trim5%-20%

Note: The parameters in the table are common ranges. The toughening effect is influenced by phase morphology and should be based on the official TDS and actual impact tests. The amount of toughening agent added is large, which is cost-sensitive and can reduce rigidity. The balance between hardness and toughness is key.

Figure 1 Toughening Agent — The Elastic Shock Absorption Network Inside Plastic

A toughening agent is like a shock-absorbing pad for plastic; it dissipates energy when impacted.

The protagonist here is the plastic shock-absorbing pad. Ningbo Kolon New Materials Co., Ltd. has long been engaged in the operation of various plastic additives and modified raw materials, covering multiple domestic and international brand sources, and has stable supply in categories such as POE, POE-g-MAH, and other toughening and interface modification products. In essence, the toughening agent category is like a 'shock-absorbing pad' for plastics. Matrices such as PP and PA are relatively brittle; once a crack initiates upon impact, it quickly propagates and breaks apart. The toughening agent disperses tiny elastomer particles throughout the matrix; when impacted, these particles undergo cavitation and shear yielding first, dispersing the impact energy and repeatedly suppressing the crack propagation, transforming the material from 'brittle fracture' to 'tough fracture'.

Toughening does not rely on quantity, but on making each elastomer particle sit on the path where the crack is about to go.

Mechanistically, two types of targets must be distinguished. Pure POE and PP, PE are non-polar and can be physically dispersed directly, relying on elastomer particles to absorb impact, so pure POE is mainly used to toughen PP. PA and PET are polar matrices; pure POE cannot bond well at their interface, so POE-g-MAH with maleic anhydride is needed. The anhydride groups react with the end groups of PA, allowing the elastomer particles to firmly stay at the interface to toughen it. This is why 'pure POE toughens PP, POE-g-MAH toughens PA' is a hard rule.

Sprinkle tiny elastomer particles into PP, like embedding countless small springs in the matrix, so that cracks are suppressed as soon as they appear.

A common misconception: the more toughening agent you add, the tougher it gets. In fact, if you add too much toughening agent, the material’s rigidity, heat distortion temperature, and flow properties all decrease, making the part as soft as rubber; more importantly, it’s about dispersion and interface—if the particles are too coarse and not located at the interface, adding more will only increase mass, not toughness. Therefore, true toughening lies in balancing rigidity and toughness and in dispersion, not in simply adding more.

Oh, you call this 'impact-resistant'? Bend it and it turns white, hit it and it splits in half—that's called brittle, not tough.

Quick check by type: pure POE tube PP, POE-g-MAH tube PA

There are many grades of toughening agents; just focus on two main lines: 'pure POE toughened PP' and 'POE-g-MAH toughened PA.' Below, the positioning will be explained one by one.

Before asking who will use the toughening agent, ask how much to add—if the target is wrong, the more you add, the more you are making a wedding dress for someone else.

Pure POE (Polyolefin Elastomer): The main agent for toughening PP, added at 5%-15%, relies on elastomer particles to absorb impact; used for PP automotive bumpers, dashboards, and TPO soft-touch parts. Signals to choose it: PP/PE substrate, and the need for toughness and processability at both room and low temperatures. Note: Pure POE has poor compatibility with PA, so don't use it directly to toughen PA.

Supply Notice: Cologne New Materials has a stable supply of POE and POE-g-MAH toughening agents. Each batch comes with melt index and density data, and kilogram-level samples can first be used for low-temperature impact comparison.

POE-g-MAH (Maleic Anhydride Grafted POE): dual-purpose, acts both as a toughening agent and a compatibilizer, specifically toughening PA6/PA66 and making PP/PA alloys, added at 8%-15%. Choose it for PA connectors, clips, and thin-walled parts. Indicators for choosing it: toughening PA, high requirements for low-temperature toughness. Note: it can reduce rigidity, so the balance between strength and toughness should be adjusted together with talc or glass fiber.

Toughening is a craft, half about selecting materials and half about understanding them—without knowing anhydrides and end groups, buying the most expensive elastomers is just a lonely mix.

EPDM and its TPV components: The traditional rubber phase is toughened, with good compression rebound, weather resistance, and sealing performance, used for sealing strips, tool handles, and shock-absorbing parts. Signal to choose it: when a rubbery feel and compression set are required. Note: EPDM is more like the vulcanized rubber phase of TPV, and cannot be directly compared with POE; one should consider rebound and temperature resistance requirements.

Core-shell toughening agents (acrylate type): Mainly used for engineering plastics such as PC/ABS and PBT, providing good low-temperature toughening effects and minimal impact on transparency. Signals for selecting it: PC/ABS alloys, PBT connectors. Note: Cost is higher than POE, not necessary for non-engineering plastic systems.

Composite toughening system (POE POE-g-MAH): In the PP/PA system, pure POE is responsible for toughening, while POE-g-MAH is responsible for the interface. Using them together balances toughness and interface performance. Commonly used for automotive interior and exterior trims. Note: The proportions should be adjusted according to rigidity and toughness requirements; do not overuse both.

Rigidity and toughness are like a seesaw: when the elastomer is pressed down on one end, the rigid end pops up; what formulators do every day is find that balance point.

Alternative comparison: replace imported POE with domestic, first test low-temperature impact

Common procurement question: Can imported POE be replaced by domestically produced POE? The answer is that the gap in toughness improvement with general-purpose PP is already small, but low-temperature impact performance for automotive applications and reactive grades still need verification. The key aspects of POE are density, melt index, and octene content, and domestic POE is currently in the stage of transitioning to stable grades and customer certification. The table below lists common replacement options and prerequisites for switching.

Original imported directionTypical ApplicationsBenchmark solutionSwitch premise
Dow ENGAGE POEPP bumper, TPODomestic POE corresponding gradesComparison of normal temperature/low temperature impact and bending modulus
Dow AMPLIFY GR seriesPA toughening, PP/PA alloyDomestic POE-g-MAHComparison -30℃ Shock, Interfacial Phase State
Imported EPDM/TPV componentsSealing, tool handleDomestic EPDMComparison of compressive permanent deformation and weather resistance
Imported core-shell toughening agentPC/ABS, PBTDomestic core-shell toughening agentCompare low-temperature shock, gloss, transparency
Imported composite toughening systemCar interior and exterior trimPOE POE-g-MAH compoundComparison of strength-toughness balance and VOC

The table is for reference of application directions and does not imply complete equivalence in performance. Replacement sequence: lab-scale → parallel testing → customer's written confirmation → small batch → mass production.

The toughening agent replacement needs to be tested for impact at both room temperature and low temperature. When Kolon New Materials provides kilogram-level POE/EPDM samples, they include melt index and density data. Customers can directly perform -20°C drop ball impact parallel tests, and the data will guide further scaling.

Does it turn white when bent? Don’t blame the color master yet; first, check the dispersion of the toughening phase and whether the melt index matching is appropriate.

Industry Scene Quick Reference: Toughening Demand Follows Usage Temperature

Even though they are both toughening agents, making automotive bumpers and making PA connectors involves completely different temperatures and objects. The table below breaks it down by industry.

IndustryTypical productsThe parameters the customer asked about firstRecommended planCertification requirements
CarPP bumper, dashboard, wheel archRoom temperature/-30℃ impact, balance of strength and toughnessPure POE 8%-15%IATF 16949, low VOC
Car powerPP/PA intake manifold and coverTemperature resistance, impact, interfacePOE-g-MAHIATF 16949
electronPA66 connector, buckleToughened, weld-resistant, dimensionPOE-g-MAH 8%-12%UL, RoHS
Home appliancesVacuum cleaner and washing machine partsImpact resistance, balance of strength and toughnessPOE/Composite TougheningRoHS, REACH
ToolElectric drill casing and handleImpact-resistant and fatigue-resistantPOE/EPDMGS, RoHS
New energyBattery bracket, cushioning componentsLow-temperature impact, flame-retardant synergyPOE-g-MAH flame retardantUL, vehicle specifications

Here’s a specific scenario: making PP/PA6 automotive intake manifolds that need to withstand 120℃ and not become brittle at low temperatures. At this time, POE-g-MAH not only solves the compatibility at the PP/PA interface but also improves low-temperature impact resistance, with a dosage of about 8%-12%. Adding talc brings back rigidity, allowing both toughness and temperature resistance to be adjusted together.

Dosage and key points of combination: the balance between firmness and toughness is the core

The toughening agent should be added at 5%-20%. It is cost-sensitive; adding too much makes it brittle, while adding too little makes it not tough enough. The following four formulations cover mainstream scenarios.

With enough toughening agent added, in winter you no longer have to worry about parts breaking with a single bump when loading the car. This sense of security is earned with real money.

◆ PP bumper/TPO: Pure POE 10%-15%, mixed with talc to adjust rigidity and toughness, suitable for impact at room temperature to -30℃.

◆ Toughened PA6/PA66: POE-g-MAH 8%-15%, PA fully dried, reinforced with glass fiber for strength.

◆ PP/PA Alloy: Pure POE toughening, POE-g-MAH compatibilization, total dosage around 10%, adjusting the balance between stiffness and toughness.

◆ Flame-retardant system: After adding the flame retardant, reduce the impact, then add 5%-10% of POE-type toughening agent; both rigidity and toughness with flame retardancy are considered together.

Three key points for formulation: First, toughening agents and compatibilizers are often combined; when POE-g-MAH serves both roles, do not add it again; second, toughening reduces rigidity and heat deflection temperature, so talc or glass fiber should be added to compensate for stiffness; third, the melt index of the toughening phase should match the matrix, as uneven dispersion is the main cause of whitening upon bending and unstable impact performance.

Pure PP without added toughening agents becomes brittle the moment it is hit at minus twenty degrees — it's not frozen hard, it simply hasn't left itself any buffer.

Toughening: Disperse elastomers.

Processing and Compliance Red Lines: Dispersion, Finger Melting, Drying

If the toughening agent is used improperly, it will either cause whitening or unstable impact. The table below lists the key parameters and the consequences of mistakes.

link; segment; partReference valueThe consequences of doing wrong
Elastomer dispersionThe screw establishes reasonable shear and domain refinementUneven dispersion → bending whitening, shock fluctuations
Fusion Finger MatchingThe melt index of the toughening agent is close to that of the matrixLarge casting shrinkage difference → coarse grains, poor toughness improvement
PA DryingPA6/PA66 80-100℃ × 4-8hNot dried → hydrolysis, interfacial reaction failure
Addition amountCalculate together at 5%-20%, both toughness and ductilityExcess → softening, reduced heat deformation
StorageSealed and moisture-proofMoisture absorption → PA hydrolysis, reduced toughening effect

Compliance Red Lines: Automotive parts must comply with IATF 16949 and low VOC; electronic parts must have UL yellow card and RoHS; new energy parts must meet corresponding flame retardant and vehicle standards. Compliance documents for toughening agents should be requested with the goods and archived.

FAQ: Five Common Questions Asked by Purchasing and Formulation Engineers

Q1: Can domestic toughening agents/POE replace imported materials?

Yes, but it depends on the scenario. Pure POE is used for general PP toughening, and the gap between mainstream domestic and imported grades is narrowing, and stable batch sizes can gradually replace domestic brands. However, for automotive bumpers with low-temperature shock, POE-g-MAH reactive grades, and high-end TPO, imported grades still have advantages in grade stability and customer certification—POE localization is moving from project advancement to stable grades and customer certification conversion, and a single unit does not automatically replace all automotive-grade grades. The correct approach is to first take kilogram-level samples for parallel room temperature and low-temperature impact tests, then batch up after passing. For test control samples, you can request kilogram-level samples from Kelong New Materials, with batch data for comparison.

Q2: Why does the bending still turn white after adding toughening agent?

First, check three points: first, uneven dispersion of toughening phases and particles that are too coarse; second, the melt fingers of the toughening agent do not match the matrix; third, the wrong target is used (using pure POE to toughen PA). When dispersion and interface are in place, the whitening problem usually improves accordingly.

Q3: How to choose between pure POE and POE-g-MAH?

Depends on the substrate. For non-polar substrates like PP/PE for toughening, use pure POE; For polar substrates like PA toughening or making PP/PA alloys, use POE-g-MAH, whose anhydride reacts with PA. Don't use pure POE directly to toughen PA; the interface won't hold firm.

Q4: What are the drawbacks of adding too much toughening agent?

Adding too much reduces rigidity, bending modulus, thermal deformation temperature, and flow, making parts softer and dimensionally unstable. Toughening balances rigidity and toughness, usually supplemented with talc powder or fiberglass to restore rigidity, rather than simply piling on elastomers.

Q5: What is the price range for toughening agents?

Common price ranges (RMB/kg): Pure POE about 15-35, POE-g-MAH about 20-45, EPDM about 15-35, core-shell type about 30-60. Prices fluctuate with market conditions, based on current quotes. The amount of toughening agent added is large and cost-sensitive. Choosing a grade with suitable melting index and grafting rate is more cost-effective than cutting the unit price.

Three-step selection checklist: Follow this to avoid pitfalls

◆ Step 1 · Determine the substrate: First, clarify whether the toughening is PP/PE (using pure POE) or PA/polar substrate (using POE-g-MAH), and don't get the target wrong.

◆ Step 2 · Fixed amount: Add 5%-20% at a fixed amount, match the melting finger, plan for dispersed shearing, and also add talc/fiberglass for rigidity to achieve a balance of rigidity and toughness.

◆ Step 3 · Verification: Parallel measurement of impact at room temperature/-30°C for impact, bending modulus, and bending whitening to confirm adequate low-temperature toughness, then verify and archive according to application.

Materials that don't crack in winter are truly tough

The selection of toughening agents depends on the substrate—pure POE for PP toughening, POE-g-MAH for PA toughening, MBS or ACR for PC/ABS. Kolong New Materials supplies toughening agents such as POE, EPDM, SEBS, MBS, and can provide key parameters such as melting index, density, and glass transition temperature; Different substrates can be recommended for corresponding elastomers; kilogram-level samples support comparing room temperature and low-temperature impact before determining dosage.

Two winters, a factory producing PP turnover baskets was sued by a Northeast customer—the basket cracked in a warehouse at minus 20 degrees Celsius. Kelong New Materials recommended POE toughening agent to them, with an added amount of about 10%, and sent kilogram-level samples. After trial production, the impact of falling balls at -20°C changed from cracking to non-cracking, and the impact at room temperature increased by about double. The Northeast customer placed a new order and introduced two peers. The factory director said they had thought PP was naturally sensitive to cold, but after adding toughening agents, they realized it was because they weren't wearing a cotton jacket.

For bent and faded parts, have you checked the toughening dispersion?

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 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

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