汽车用TPE怎么选?密封条到线束,耐候耐温是门槛

塑料知识科普 发布时间: 2026-09-13 2360 阅读

The factory inspection report was submitted, but the flame retardancy and odor items were rejected. For automotive TPE, all four thresholds must be fully met.

Crash Scene: Automotive TPE, How Money Gets Lost

Automotive TPE usage is significant in a car — sealing strips, dust covers, wiring harness sheaths, shock absorbers, mudguards; dozens of locations in one vehicle. But its failures are also very typical:

Scene 1: Sealing strip installed for a year, became hard and cracked, customer claims — weather resistance did not hold, UV light "cooked" the material; Scene 2: Wiring harness sheath fails flame retardancy,

export stuck — flame retardancy rating and certification not aligned, whole container stuck at the port; Scene 3: Interior parts exceed odor limits, OEM directly returns goods — **VOC not up to standard,

no matter how cheap the material is, it cannot be included in the interior list.

**

The pitfalls of automotive TPE are summed up in four words: many thresholds.

The price difference on the quotation sheet is often the same as the difference on the scrap sheet.

For the same sealing strip, Supplier A is 2000 yuan/ton cheaper, Supplier B is slightly more expensive but provides a complete weathering aging report — after three years of mass production, A’s part has already hardened and cracked,

while B’s part is still in the OEM’s list with stable supply.

The cost account of automotive TPE is never how much a ton costs but how many pieces fail out of ten thousand — weather resistance, temperature resistance, oil resistance, certification: if any criterion fails, the money saved up front will be lost on scrap.

First, review the automotive TPE positions before discussing selection — the thresholds differ completely depending on the part:

PositionTypical PartsPrimary ThresholdRecommended System
ExteriorSealing strips, mudguards, dust coversWeather resistance (UV, rain)TPV, weather-resistant SEBS-based
Engine CompartmentWiring harness sheaths, shock absorbers, pipesTemperature resistance, oil resistanceTPEE, flame-retardant TPE
InteriorDashboard covering, armrestsVOC, odorLow VOC SEBS-based
ChassisCorrugated tubes, shock padsOil resistance, fatigueTPV, TPEE

Technical Wisdom: Choosing automotive TPE is a four-threshold ranking — weather resistance, temperature resistance, oil resistance, certification. If you get the order wrong, you'll fail.

When it comes to weather resistance, many people think "adding UV absorbers means sun resistance."

Actually, there are two layers: UV absorbers block ultraviolet rays from the surface, light stabilizers neutralize free radicals that leak in ,

Antioxidants withstand high-temperature oxidation—only when these three work together is a weather resistance system.

Just looking at the words "UV resistance" on TDS is basically an amateur. If you want data, you need to look at the color difference and strength retention rate of xenon lamps aging for 500 or 1000 hours.

Breakdown: Four thresholds, why can't you save on any of them?

Threshold One · Weather resistance: Automotive parts are outdoors year-round, exposed to UV rays, rain, and temperature differences together. TPE that doesn't resist UV discolors and becomes brittle within a year—sealing strips harden, dust cover cracks—both are signs of poor weather resistance.

Threshold Two · Temperature resistance: 125°C is normal in the engine compartment, and even headliners exposed to summer sun can reach 90°C. Room-temperature and high-temperature components are completely different—regular SEBS can't withstand the engine bay, so TPV or TPEE is needed.

Threshold Three · Oil resistance: Wiring harness sheaths and seals inevitably come into contact with oil. TPE that is not oil-resistant swells when soaked in oil, and once the size shifts, the seal fails.

Threshold Four · Certification: OEM checklist system; materials not on the certification list cannot be entered even if they are good. VOC, odor, flame retardant (such as UL94), weather resistance (such as PV3929) each has its own threshold.

These four hurdles are the order of "qualification first, then performance talk"—if certification fails, performance talks are pointless.

OEM's certification list also features "dynamic updates": new models and new projects often include new material requirements—grades that passed inspection this year may not be on

's list for new projects next year.

Therefore, when choosing suppliers for automotive TPE, you should choose those that "can follow the OEM requirements": OEMs require updates, and suppliers can quickly re-inspect, add data, and provide solutions.

Choosing a supplier who responds quickly is more worry-free than choosing a supplier 2000 yuan/ton cheaper.

Typical Four-Threshold Failures, See Clearly with a Single Table:

ThresholdPoor PerformanceCommon System Issues
Weather ResistanceDiscoloration and Brittle After One Year, Sealing HardeningUsing Ordinary SEBS Base That Is Not UV Resistant
Heat ResistantEngine Compartment Deformation and Aging FastStanding at high temperatures using a normal temperature system
Oil resistanceOil soaking swelling, dimensional drift, sealing failureOil resistance grade not matched to oil type
CertificationOEM list off-limit, card inspection factoryMaterial certificates and VOC reports not prepared

Troubleshooting steps: three-step locking for vehicle TPE

Before automotive parts leave the factory, there is still a "data reconciliation" step: compare the strength retention rate, compression permanent deformation, and oil swelling resistance on the TDS with the actual loading environment.

If the items don't match, they're the risks after mass production—better to change parts than to open molds with doubts.

1. First, locate the parts: exterior trim (sealing strips, fenders) → weather resistance first; Engine compartment → temperature resistance first; Interior → VOC first; Wiring harness → flame retardant first;

2. Next, check certifications: What grades are listed in the manufacturer's material list (such as Volkswagen TL, GMW series standards)? Filter out those listed first, then discuss others;

Complete three steps, shrinking candidate materials from "a pile" to "one page"

has a trick when dealing with OEMs: first ask the procurement for the "material list," then ask the technical team for "part testing requirements," asking for separate lines.

The materials list controls "whether it can be used," while the parts test track "can be used"—many factories only get half right, so they get it in the list but not pass part testing, or vice versa.

Only when both lines align can the selection process be closed. — For automotive TPE selection, follow the rules first, then choose performance.

StepsActionsOutput
OneLocating Parts, Setting Primary ThresholdsOne-page "Position →Threshold" List
TwoFor OEM Material List, Screen GradesList of 3-5 Candidates
ThreeAccording to lifespan requirements, for aging resistance dataFinal selection 1-2 systems

How to fix failed approval: materials, systems, and certifications supplemented

Material direction: internal adjustment grades within the same system—UV stabilizer added if weather resistance was insufficient, replaced with low-VOC formulas with excessive odors, and flame retardant insufficient to apply flame-retardant systems. First, ask "Which parameter doesn't meet the standard," then decide whether to replace the material

System direction: The choice of automotive TPE system is very clear—sealing strips should be considered TPV (weather and temperature resistance), protective sleeves should be treated with flame-retardant TPE (UL94 V0), shock absorbers should be treated with TPEE (thermal fatigue resistance), and interior wrapping should be based on SEBS (low VOC feel). If you choose the right system, half the problems disappear.

Certification direction

Material certification and part certification are two different matters, but they are often confused.

Material certificates prove "this grade meets the standards," parts testing proves "this part uses this material without problems"—OEMs want both.

Suppliers can only help you at the material certificate level; part testing depends on you running together with molds and processes.

Can't distinguish between the two layers, communicates with OEMs and gets stuck — what OEMs want is "materials in the list and passing testing"; missing one means checkpoints.

Cologne customer case: flame retardant fails inspection, first formula adjusted and exported smoothly

A Shanghai auto parts factory has wiring harness sheaths failing flame retardant inspection, export orders stalled. After Cologne intervened, they readjusted the formula—oil, additives, and filling ratios fine-tuned, passed flame retardant ratings, and goods were exported smoothly.

Flame retardant failing inspection often isn't due to insufficient flame retardant but because the formula balance is poor—too much oil causes flame retardant loss, and the additive system loses flame retardant too. Adjusting the formula is faster than changing the system, and also saves money.

Check these four items upon arrival of automotive parts, must-check for smell and flame retardant

Among these four criteria, certification documents and VOC data are the easiest to be skipped by "verbal commitments "

VOC There's also batch risk: if the same grade passes one batch but the next batch of additives changes origin, the data might become unreliable.

So when OEMs audit, they love to look at "VOC reports from three consecutive batches"—not just one, but three.

When negotiating with suppliers, directly demanding nearly half a year's batch test records is more effective than hearing a hundred sentences like "We meet the standards."

—And these two items are precisely the hard thresholds for OEM audits.

Inspection itemsWhat to look atKey acceptance points
Certification documentsMaterial certificates, inspection reportsoriginal or stamped document, serial number verifiable
VOC Dataodor level, VOC reportmust match the OEM grade requirements,
weather resistance datacolor difference after UV aging and intensity500h/1000h data archived
Batch Sample RetentionEach Batch 500g Sample RetentionComparison in Environment During Disputes

Summary

The Four Thresholds of Automotive TPE — Weather Resistance, Temperature Resistance, Oil Resistance, and Certification. Each step you pass is one less pitfall. Save this for reference.

Automotive TPE isn't "one material," it's "a bunch of material for jobs": seals use TPV, sheaths use suppressor fuel, shock absorbers use TPEE, interior uses low VOC. If the positions match, negotiate the price; If the position is wrong, even if it's cheap, it's still a burden.

Finally, a quick calculation: a car has dozens of TPE sites, each saving 2,000 yuan per ton, which isn't much saved in a year; But if you choose the wrong place, scrap, claim, or shut down, you can lose all your annual savings in one go. That's the characteristic of automotive parts—the proportion of material per unit price is small, but the cost of errors is high. So when purchasing automotive TPE, it's not about who is cheaper, but whose job is right and data is complete.

Ningbo. There are many people here in plastics, and quite a few in modified nylon as well.

Our work is very specific: converting thermoplastic elastomers, as well as resins like PA6, PA66, PA46, PA11, PA12, PA6T, PA9T, and nylon alloys, into a truly usable product; We also produce modified PPO and PPS; We also deal in nylon resin, sub-brand materials, and bulk materials for major chemical giants.

Different parts, different materials.

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