液压密封件用什么TPU?剥离力不够,不是胶的问题

应用领域 发布时间: 2026-09-16 4546 阅读

The hydraulic seals started leaking oil after just two months, and the cylinder pressure couldn't build up. The hydraulic seals for wear resistance and pressure resistance were not selected correctly, and the system leaks oil every day.

It started leaking oil after just two months, and the oil tank pressure won't rise.

Hydraulic seals are 'pressure-resistant and wear-resistant parts': wear-resistant, pressure-resistant, and sealing. The material must be wear-resistant, pressure-resistant, and sealing — conclusion first: TPU is mainstream for hydraulic seals; for high-temperature hydraulics, composite seals are used.

The biggest pitfall of hydraulic seals: insufficient peel strength, it's not the glue's fault. If the peel strength is insufficient, first check the formulation, don't blame the glue—the peel strength is the seal's bonding line.

Hydraulic seals are functional components: leakage and wear are both problems. Choose the right material, and the hydraulics will be stable—functional components, don't skimp on material costs.

Why use TPU for hydraulic seals

Reasons for using TPU in hydraulic seals: good wear resistance, good pressure resistance, good sealing, long service life—these four combined make it suitable for hydraulic seals.

Wear resistance is key: reciprocating friction. Wear resistance testing is included in acceptance — if it wears through, it's a problem.

Pressure resistance cannot be compromised: hydraulic pressure. Pressure resistance testing is included in acceptance — if it bursts, there is a problem.

Pressure friction medium, three barriers

Pressure condition: hydraulic pressure. The pressure resistance data must be tested — if it bursts, that's the problem.

Friction condition: reciprocating friction. Wear resistance data must be tested—if it wears through, that's a problem.

Medium conditions: hydraulic oil. The resistance data to the medium needs to be verified—swelling is the problem.

TPU or TPV? Seal Comparison Table

DimensionTPUTPV
Wear-resistantStrongmiddle
Withstand pressureGoodmiddle
Resistant to mediumGoodGood
CostMedium-highMedium-high
SealGoodGood
PurposemainstreamHigh temperature

Table reading: TPU has good wear and pressure resistance; TPV has good media resistance — used in hydraulic seals, TPU is mainstream.

Select by pressure: high-pressure TPU, conventional TPV.

Hydraulic seal acceptance: Check the formulation before peeling

PhenomenonReasonCountermeasure
Low strippingInsufficient dosageFormulate a prescription
Peeling and bleachingBatch fluctuationLock window
Interlayer openingPoor adhesionAdjust the process
Seal leakCompression differenceReplace with high-resilience material

Table reading method: If the peel strength is insufficient, check the formula first, don't blame the glue — if the substrate polarity and soft rubber compatibility don't match, applying glue is useless.

Peel strength is the bonding line of the seal.

Blame the glue for every leak, three holes

Pitfall 1: Blaming the glue. If it can't be torn off, people first blame the glue, but actually it's because the soft glue and the substrate are incompatible—check the formula first.

Pitfall 2: Pressure leakage testing. Burst — pressure test, must be tested.

Pitfall 3: Overstated wear resistance. Wear through — wear resistance should be measured and accepted based on actual tests.

Check the formula first when selecting hydraulic seals

Three questions: How much pressure, how many cycles, and what is the hydraulic oil? One verification: Actual working conditions measured—three questions and one verification, the supplier's details are clear.

Formula verification must come first: first test the substrate compatibility and peel strength curve. Check the formula first, then discuss the price—peel strength is the bonding line of the seal.

Making sample retention a habit: retain samples from each batch, and retest wear resistance and pressure resistance batch by batch. When changing materials between batches, compare first before increasing production — stable batches result in fewer customer complaints.

Hydraulic Seals: Phenomena and Countermeasures at a Glance

PhenomenonReasonCountermeasure
LeakInsufficient sealingAdjust hardness level
wear throughInsufficient wear resistanceReplace wear-resistant material
to squeeze until it breaksInsufficient pressure resistanceChange to high-voltage resistant material
Low strippingInsufficient dosageFormulate a prescription
SwellingResistant to weak mediaChange to a more resistant material

Mainstream hydraulic seal TPU, peel strength is accepted at 1.0-2.0 kN/m based on PP substrate, below 0.5 not for mass production. Pressure-resistant seals rely on hardness and wear resistance, Shore A 90 can withstand oil pressure.

TPU is wear-resistant, pressure-resistant, and can withstand hydraulic pressure; rubber is temperature-resistant but needs vulcanization. High-pressure reciprocating TPU, high-temperature hydraulic composite sealing — choose according to pressure and temperature.

If the peel strength is insufficient, don't blame the glue first; check the overall formula and the polarity of the substrate first. Peel strength is like a medical check-up for the formula; no amount of glue can save a mismatch — let the data speak.

Hydraulic seal acceptance: three-piece set of pressure extrusion, wear resistance, and high-temperature aging. Groove dimensions are checked for assembly, high-temperature degradation is tested separately — if any item fails, it will not be released.

Rematch the substrate to bring costs back within the budget line, and the hydraulic seal quote is competitive again. Keep samples from each batch to test peeling force under pressure changes, and compare before scaling up when changing materials between batches.

Hydraulic seals are selected according to pressure and temperature: high-pressure reciprocating TPU, high-temperature composite seals. TPU is wear-resistant and pressure-resistant for hydraulics, rubber can withstand temperature but needs vulcanization, and if the peel strength is insufficient, first check the overall formulation and the polarity of the substrate before blaming the adhesive.

Groove dimensions are checked during assembly, and high-temperature attenuation is measured separately. The pressure resistance extrusion test and wear resistance test of the three-piece set are carried out together, with samples from each batch kept to measure peeling strength and compressive deformation.

Check the groove size for assembly, and measure high-temperature attenuation separately. Keep samples from each batch to test peeling force and compression variation. If the peeling force is insufficient, first check the overall formula and the polarity of the substrate, don’t blame the adhesive first.

If the hydraulic seal peeling force is insufficient, first check the overall formula, don't blame the glue. For high-pressure reciprocating TPU high-temperature compounding, select according to pressure and temperature; for groove assembly core high-temperature attenuation, test separately.

Pressure-resistant, tear-resistant, and wear-resistant three-piece set, with sample retention for each batch to test peel strength under pressure variation.

Cologne Customer Case: Costs exceeded budget and lacked competitiveness, matched base material back to budget line

An industrial equipment factory in Qingdao had hydraulic seal material costs over budget, making their quotes uncompetitive. Cologne assisted in rematching the rubber-coated base material with the processing temperature, bringing the costs back within the budget and making the quotes competitive again. When the base material is correctly matched, costs can be saved from the formulation—if costs are over budget, first look at the formulation system.

Summary

For the selection of hydraulic seals, first check the formula, then test the pressure resistance. If the peel strength is insufficient, it's not a problem with the rubber; the peel strength is the adhesive line.

Before pouring the material into the machine, what needed to be done was actually already finished.

How much to enhance, whether to add flame retardant, which level of temperature resistance to achieve, whether the size is stable—once these judgments are made, the particles just execute the conclusions.

Ningbo Kolong New Materials Co., Ltd., specializes in modified thermoplastic elastomers, modified nylon (PA6 / PA66 / PA46 / PA11 / PA12 / PA6T / PA9T and nylon alloys), modified PPO / PPS, as well as nylon resins, secondary-grade materials, and bulk materials from major chemical giants available in stock.

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