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: 2026-09-16 1082 阅读

The car factory inspection report was submitted, but the flame retardancy and odor items were rejected. For automotive TPE, none of the four door sills can be omitted.

Crash scene: Car TPE, how the money was lost

The usage of TPE in cars ranks prominently inside the vehicle—seals, dust covers, wiring harness sheaths, shock absorbers, mudguards, dozens of places in a single car. But its failures are also quite typical:

Scene 1: The sealing strip was mounted on the vehicle for a year, became hard and cracked, and the customer filed a claim—the weather resistance didn't hold up, the UV rays 'cooked' the material; Scene 2: The wiring harness sheath didn't pass the flame retardant test.

Export stuck at customs — flame retardant rating and certification do not match, the whole container is held at the port; On-site Issue Three: excessive odor in vehicle interior parts, the OEM directly returned the goods — **VOC did not pass,

No matter how cheap the material is, it can't be included in the interior list.

**

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

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

For the same sealing strip, supplier A is 2,000 yuan per ton cheaper, while supplier B is a bit more expensive but provides a complete weathering aging report—after three years of mass production, the parts from A have already hardened and cracked.

The B parts are still on the OEM's list and supplied steadily.

The cost accounting of automotive TPE has never been about how much a ton costs, but about how many pieces are scrapped out of ten thousand — weather resistance, temperature resistance, oil resistance, certification, if it fails at any stage, the money saved earlier will be paid back through the scrap slips.

First go over the positions of automotive TPE, then talk about selection—different parts have completely different thresholds:

Body parttypical partPrimary thresholdRecommendation system
Exterior trimSealing strip, mudguard, dust coverWeather resistance (UV, rain)TPV, weather-resistant SEBS-based
Engine compartmentWire harness sleeves, shock-absorbing components, pipe fittingsTemperature-resistant, oil-resistantTPEE, flame-retardant TPE
Car interiorDashboard covering, armrestVOC, odorLow VOC SEBS base
chassisBellows, shock padsOil-resistant, fatigueTPV, TPEE

Tech Catchphrase: Choosing TPE for cars is like a four-step threshold ranking question — weather resistance, temperature resistance, oil resistance, certification. Getting the order wrong leads to failure.

Regarding weather resistance, many people think 'adding a UV absorber makes it sun-resistant'.

In fact, there are two layers: the UV absorbers are responsible for blocking ultraviolet rays on the surface, and the light stabilizers are responsible for neutralizing the free radicals that get through.

Antioxidants are responsible for withstanding high-temperature oxidation — only the combination of all three can be called a weather-resistant system.

Those who only look at the three words 'UV resistant' on the TDS are basically laypeople. If you want data, you need the color difference and retention rate of strength after 500h and 1000h of xenon lamp aging.

Cause Analysis: Four Thresholds, Why None Can Be Skipped

Threshold One · Weather Resistance: Car parts are outdoors all year round, exposed to UV, rain, and temperature variations simultaneously. TPE that isn’t UV-resistant will discolor and become brittle within a year—sealing strips harden, dust covers crack; these are all consequences of insufficient weather resistance.

Threshold Two · Temperature Resistance: 125℃ is normal in the engine compartment, and roof panels exposed to the summer sun can reach 90℃. Normal temperature parts and high temperature parts are completely two separate systems — ordinary SEBS cannot withstand the engine compartment, you need to use TPV or TPEE.

Threshold Three · Oil Resistance: Wire harness sheaths and seals inevitably come into contact with oil. Oil-resistant TPE prevents swelling caused by oil, which would otherwise cause dimensional changes and lead to seal failure.

Threshold Four · Certification: OEM list system—if the materials are not on the certification list, no matter how good they are, they cannot pass the gate. VOC, odor, flame retardancy (such as UL94), weather resistance (such as PV3929, etc.), each manufacturer has its own thresholds.

These four stages follow the sequence of 'qualifications first, performance later'—without certification, performance is meaningless.

The OEM's certification list also has a 'dynamic update' feature: for new models and new projects, there are often additional material requirements—grades that pass inspection this year,

Next year's new project may not be on the list.

Therefore, when choosing TPE suppliers for automobiles, you should select those 'who can follow the requirements of the OEM': when the OEM requires updates, the supplier can quickly conduct supplementary inspections, provide additional data, and update plans.

Choosing a supplier who responds quickly is more worry-free than choosing one that is 2,000 yuan/ton cheaper.

A typical failure at the four thresholds, clearly seen in one table:

ThresholdCrash performanceFrequently occurring system issues
weather-resistantChanges color and becomes brittle in one year, sealing strip hardensUsed ordinary SEBS base that is not UV-resistant
Temperature resistantEngine compartment parts deform and age quicklyUse a room temperature system for high-temperature positions
Oil-resistantOil swelling, dimensional drift, sealing failureThe oil resistance grade does not match the type of oil.
CertificationOutside the OEM list, card review factoryMaterial certificates and VOC reports are not prepared.

Troubleshooting Steps: Three-Step Car Lock with TPE

Before automotive parts leave the factory, there is one more step of 'data reconciliation': comparing the strength retention rate, compressive permanent deformation, and oil swelling resistance rate on the TDS with the actual in-vehicle environment item by item.

Items that don't match are the risks after mass production—it's better to change the material than to proceed with molding with doubts.

1. First, determine the location: exterior of the car (weatherstrips, mudguards) → prioritize weather resistance; engine compartment → prioritize heat resistance; interior → prioritize VOC; wiring harness → prioritize flame retardancy;

2. Re-certification: What grades are listed in the OEM material lists (such as Volkswagen TL, GM GMW series standards)? First screen those in the list, then discuss others;

Completed in three steps, candidate materials are reduced from 'a pile' to 'one page'

There’s a trick to dealing with OEMs: first ask the purchasing department for the 'materials list,' then ask the technical department for the 'component test requirements,' keeping the two lines separate.

The materials list checks 'whether it can be included,' and the part test checks 'whether it can be used'—many factories only handle half of this, resulting in being able to get past the list but failing the part test, or vice versa.

Both lines must be aligned for the selection to be considered complete. —— For automotive TPE selection, follow the rules first, then choose based on performance.

StepActionOutput
OneLocate the position and set the primary thresholdA one-page 'Body Part → Threshold' list
TwoScreening material grades for OEM material lists3-5 candidates from the list
ThreeAging resistance data according to life requirementsFinally select 1-2 systems

How to fix a review failure: patch in three areas – materials, system, and certification

Direction of materials: Within the same system, adjust the grade—if weather resistance is insufficient, add UV stabilizer; if the odor exceeds limits, switch to a low VOC formulation; if flame retardancy is insufficient, use a flame-retardant system. First ask 'which parameter does not meet the standard,' and then decide whether to change the material.

System direction: The choice of TPE systems for automobiles is very clear—seals use TPV (weather and temperature resistant), protective covers use flame-retardant TPE (UL94 V0), shock absorption uses TPEE (temperature fatigue resistant), and interior coverings use SEBS-based (low VOC, pleasant feel). Choosing the right system solves half the problem.

Direction of certification

Material certification and part certification are two different things, but they are often confused as the same thing.

The material certificate proves 'this grade meets the standard,' and the part test proves 'this part is fine with this material' — the OEM requires both.

The supplier can only help you up to the material certification stage; part testing depends on you, working together with the mold and process.

Can't distinguish between the two layers, and when communicating with the OEM, they just give vague answers—the OEM wants 'the material is on the list and the part passes the test,' and missing any one of these will block progress.

Cologne Customer Case: Flame Retardant Failed Inspection, Formula Adjusted Successfully for Export

A car parts factory in Shanghai failed the flame-retardant test for wiring harness sheaths, causing export orders to be held up. After Cologne intervened and readjusted the formula—slightly tweaking the proportions of oil, additives, and fillers—the flame-retardant level passed the test, and the goods were smoothly exported.

Failing the flame retardant test is often not because there isn’t enough flame retardant, but because the formula balance isn’t adjusted properly — too much oil reduces the flame retardant effect, and the wrong auxiliary system also reduces it. Adjusting the formula is faster and cheaper than changing the system.

Check these four items when automotive materials arrive; odor and flame retardancy must be checked

Among the four items, certification documents and VOC data are most easily skipped with 'verbal commitments'.

VOC also has a batch risk: for the same grade, this batch passes, but if the next batch of additives comes from a different source, the data might fluctuate.

So when OEMs conduct audits, they like to see 'VOC reports for three consecutive batches'—not just one, but three.

When talking to suppliers, directly asking for the batch test records from the past six months is more effective than hearing a hundred times 'we meet the standards'.

—And these two items happen to be the strict thresholds for OEM audits.

Checklist itemsWhat are you looking at?Acceptance Key Points
Certification documentsMaterial certificate, inspection reportOriginal or stamped copy, with a traceable number
VOC dataOdor Level, VOC ReportMatch the level required by the OEM
Weathering dataColor difference and strength after UV aging500h/1000h Data Archiving
Batch samplingKeep a 500g sample from each batchCompare with the same environment when disputes arise

Summary

The four thresholds for automotive TPE—weather resistance, temperature resistance, oil resistance, and certification. Passing each one avoids a pitfall. Save this for future reference.

Automotive TPE is not 'one kind of material,' it's 'a collection of materials for different positions': sealing strips use TPV, sheathing uses flame-retardant material, shock absorption uses TPEE, interior trim uses low VOC. Only when the position matches can you discuss the price; if the position doesn't match, even a lower price is still a burden.

Finally, let's do the math: a car has dozens of TPE parts, and if you save 2,000 yuan per ton on each, it doesn't add up to much in a year; but if one part is chosen incorrectly, scrapping, claims, and production stoppages can wipe out the whole year's savings in one go. This is the characteristic of automotive parts—the unit price of the material is a small proportion, while the cost of mistakes is high. Therefore, purchasing TPE for cars is not about who is cheaper, but about whose role is accurate and whose data is complete.

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