医用密封圈用什么TPE?物性表会印,实测才算数

应用领域 发布时间: 2026-09-13 3264 阅读

Sealing rings entering the device pipeline make the gauge data invalid. Medical sealing rings are not actually measured; no matter how nicely they are printed, they will still leak.

Conclusion first: medical sealing rings, medically tested tied together

Medical sealing rings are 'components for medical devices': they seal, come into contact with medicinal liquids, and are sterilized. The materials must be medical-grade, chemically resistant, and tested for robustness — conclusion first: medical-grade SEBS-based TPE is mainstream for medical sealing rings; for high-pressure scenarios, TPV is preferred.

The biggest pitfall of medical sealing rings: no matter how beautiful the specifications are printed, if the hands-on test fails, it's all for nothing. Well-printed property tables don't count—the actual test is the true mirror for these property tables.

Medical sealing rings are functional components: leakage and swelling are both problems. Only by choosing the right material can the device be stable—functional components, don't skimp on material costs.

Why is TPE actually hard in tests: can be made medical-grade, deformation under pressure is small

Reasons for using TPE for medical sealing rings: It can be made to medical grade, it can be made chemically resistant, it can be tested and verified, and it is efficient — together, these four make it suitable for sealing rings.

Medical grade is key: it comes into contact with medicinal liquids. Medical certification (according to standards) should be included in the acceptance — medical grade is not just a label.

Practical testing cannot be skipped: pressing the seal ring when installing, checking for bubbles when filling liquid, is more useful than ten pages of reports. Record the measured data in the acceptance document—practical measurement is the truth-revealing mirror of the physical property table.

Seal it in for a day: sealed, medicinal solution, sterilization

Sealing condition: equipment sealed. The sealing test must check for leakage—if there is leakage, it’s a problem.

Chemical solution conditions: contact with chemical solution. Chemical resistance data must be checked—swelling is the problem.

Sterilization conditions: sterilization treatment. Sterilization-resistant data must be verified—deformation or seal leaks.

TPE or silicone: check the sealing ring for leaks

DimensionTPESilicone
Medical gradeCertificationCertification
Chemical-resistantCan be doneGood
CostmiddleMedium-high
EfficiencyInjection moldingVulcanization
HardnessAdjustableSomewhat soft
BatchStableStable

Table reading: Silicone is chemically resistant but expensive, and curing is slow; TPE has a high cost-performance ratio — mainstream medical sealing rings use TPE.

Silicone for high-temperature scenarios, conventional TPE — choose according to the scenario.

Actual Three-Step Verification Table: Pressure Test, Sterilization, Soaking

StepContentPurpose
Actual sealed testInstallation testingCheck the seal
Chemically resistant (tested)Soaking in medicinal liquidSwelling test
Actual sterilization testSterilizationDeformation Test

Table reading method: Only after the three steps of sealing, chemical resistance, and aging are actually completed can the physical property table be considered valuable for reference.

Actual tests are a mirror that reveals the true nature of the physical properties table.

Two pitfalls: reporting as data without actual measurement

Pitfall 1: Printed specifications equal data. Treating printed materials as the factory reality will be exposed once installed — you need to test first.

Pitfall 2: False medical claims. The label says it's medical-grade, but the certification can't be found — check the certification number first.

Pitfall three: Sterilization leak testing. Sterilization deformation — sterilization resistance testing is mandatory.

Three Acceptance Questions: Compression Amount, Sterilization, Batch

Three questions: What is the medical certification number, is there actual measured data, and what chemical solution is used for chemical resistance testing. One verification: actual installation measurement—three questions and one verification, the supplier's background is clear.

Actual measurement verification must come first: we must first measure the original data before discussing the price — actual measurement is the magic mirror for physical property tables.

Making sample retention a habit: retain samples for each batch, and retest medical chemical-resistant products batch by batch. When changing batch materials, compare first before scaling up—the more stable the batch, the fewer the customer complaints.

The compression range of medical sealing rings is 15%-25% for safety — if compressed over 30%, they won't rebound, and if below 10%, they won't seal. Dimensional tolerances directly affect sealing performance; if the tolerance is too loose, there will be leakage, and if too tight, assembly becomes difficult.

Seal ring acceptance, compressibility and tolerance checked together.

Sterilization method affects selection—ethylene oxide requires resistance to EO residues, steam requires resistance to high temperature and humidity, irradiation requires resistance to radiation degradation. Three methods, three requirements; choosing the wrong system for sterilization will cause problems.

The sealing ring cannot pass sterilization, first check if the sterilization method is correct for the material.

Don't just test a single sample—test several from the same batch to see the consistency within the batch. Even if the data from one sample looks good, it doesn't represent the entire batch. Testing multiple samples gives data that is more representative.

The sealing ring rebounds and becomes immobile a week after being installed in the device, so the entire batch needs to be replaced — the material with excessive compression set may pass short-term testing, but will inevitably collapse under long-term compression. If the sealing ring's rebound is poor, first check the compression set data.

The sealing ring is the 'soft joint' of the instrument — it fits tightly with interference, seals with end face contact, and is stressed at both ends. Sealing rings with low permanent compressive deformation have good memory and can still bounce back even after long-term use.

A sealing ring with a good memory won’t leak.

Table of Common Problems and Countermeasures for Medical Sealing Rings

PhenomenonReasonCountermeasure
LeakageInsufficient sealingAdjust hardness level
SwellingChemical corrosionReplace chemical-resistant material
Sterilization deformationNot resistant to sterilizationReplace the sterilization material
Batch color differenceFormula DriftLock Recipe Window
False labeling of material properties tableMeter reading dataField Verification

Cologne Customer Case: Batch Color Difference Complained, System Change Delivered in 7 Days

A medical device factory in Tianjin had obvious batch color differences in medical sealing rings, and the finished products were frequently complained about. Cologne assisted in changing the system and grade (from SEBS-based to TPV-based), stabilizing the color difference and reducing the delivery cycle to within 7 days. With the system changed, the color difference problem was cut off from the source—the color difference is a system-level issue, not something that can be solved by color matching.

Summary

Selection of medical sealing rings should start with actual testing, then medical verification; the physical property table may be printed, but only actual measurements count—don't trust printed materials.

For more than ten years, I've been doing only one thing: turning nylon into something usable.

PA6 and PA66 are the basic staples; PA46, PA6T, and PA9T are the thresholds for high temperature resistance; PA11 and PA12 are used for water and oil pipelines. Nylon alloys make up for the balance that a single resin cannot provide. Modified thermoplastic elastomers, modified nylon, modified PPO, and PPS are running in parallel, along with nylon resins, secondary brands, and bulk materials in stock from major chemical giants.

Using the same piece of material in the wrong place can cause an accident. So first ask about the part, then ask about the material.

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