As an essential component of vehicle safety systems, tire pressure sensors rely critically on stable performance, measurement accuracy, and durability. Encapsulating compounds serve as a vital barrier, shielding the sensor’s internal components from environmental hazards. Consequently, selecting an appropriate encapsulant is paramount to ensuring the long-term reliability and consistent operation of tire pressure sensors.

Full‑cavity potting inside the tire pressure sensor housing. ‌ , cover PCB All internal components, including the circuit board, pressure-sensing chip, and antenna coil, must completely fill the cavity gaps to isolate against moisture and salt spray. At the same time, it cushions every second of driving. 20 High-frequency vibrations of this magnitude should be avoided to prevent solder joint failure and component displacement, while ensuring that they do not interfere with the sensor’s RF signal transmission.

Tire pressure sensor potting primarily serves the following functions:

✅Waterproof and dustproof: Potting effectively seals the sensor against moisture and dust, preventing them from entering the sensor’s interior and damaging its circuitry, thereby enhancing the sensor’s reliability and accuracy.

✅ Thermal insulation performance: Potting effectively isolates high temperatures, maintaining the sensor’s stable operating temperature and preventing overheating that could degrade sensor performance or cause damage.

✅ Improved operational efficiency: Potting secures the sensor’s internal electronic components, reducing vibration and component detachment during vehicle operation, thereby enhancing the sensor’s performance.

Adhesive Case Study 1:

A compact, external, battery-free tire pressure monitoring module—small in size and subject to stringent cost control—offering only basic functionality. PCB RF board, without a built-in lithium-manganese battery; due to the relatively small amplitude of road vibrations, the customer opted for a two-component epoxy potting compound.

Advantages of epoxy potting compounds:

Epoxy exhibits low viscosity and excellent gap-filling performance; after curing, it delivers high hardness and strong adhesive strength, with superior waterproofing and insulation properties and a glossy surface, while also offering lower raw-material costs. It can cure at room temperature and is compatible with semi‑automatic dispensing production lines. Under standard short‑term temperature and humidity testing, it resists water ingress, making it well suited for cost‑effective retrofitting of external sensors for high‑volume shipments.

Adhesive Case Study No. 2:

Trucks subjected to prolonged heavy loads and continuous high-speed vibrations experience elevated tire‑cavity temperatures and severe vibrational shocks, which can easily cause epoxy adhesives to crack and fail. Consequently, the adhesive must exhibit excellent seismic resistance, thermal conductivity, oil resistance, and flame retardancy.

Advantages of polyurethane potting compounds:

High-elasticity colloid encapsulation MEMS Chips, PCB Large-capacity lithium batteries provide robust resistance to continuous vibration; a thermal management system efficiently dissipates heat generated by electronic components, effectively controlling internal temperature rise; the design withstands corrosion from hub lubricants and brake dust, ensuring no tire pressure drift or signal interruptions during prolonged road testing. Compared with epoxy potting solutions, this product boasts more than double the service life, making it ideally suited for the demanding, long‑term operating conditions of commercial vehicles.

Recommended adhesive for tire pressure sensors: flame-retardant polyurethane potting compound or epoxy potting compound.

Product Name: PU512 Polyurethane potting compound

Hinnel HNPU512 It is a two-component polyurethane sealant that cures at room temperature or with heat. After mixing, it exhibits excellent processability, a long working life, and a moderate curing rate. The cured product features a glossy, smooth surface, high adhesive strength, superior toughness, and outstanding flame retardancy and electrical insulation properties. It is suitable for potting sensors, automotive electronics, filters, capacitors, and other electronic components operating in humid and vibration‑prone environments.

• Low mixed viscosity, with excellent fluidity and permeability.
• The cured product exhibits excellent electrical properties as well as water- and moisture-resistant characteristics.
• Excellent low-temperature performance, flame retardancy, and thermal conductivity.
• It exhibits high colloidal strength, excellent toughness, and strong adhesion to metals, plastics, wire harnesses, and other materials.
• High-temperature and high-humidity resistant, (at a relative humidity of 85% , temperature 85 Under conditions of ℃, after 1000 (1-hour damp-heat test)
• Resistance to thermal shock and thermal cycling ( -45~125℃ )

Product Name: HN6225 Epoxy potting compound

HN6225 It is a two-component, room-temperature or heat-curable, flame-retardant epoxy potting compound. AB After mixing, it exhibits low viscosity and excellent processability; the product cures rapidly to form a protective coating. The cured surface is smooth and glossy, with outstanding flame retardancy and electrical insulation properties, making it well suited for potting and encapsulating small electronic components such as capacitors, transformers, automotive electronics, and sensors.

• Low mixed viscosity, excellent fluidity, and outstanding self-deaeration performance.
• Environmentally friendly, non-toxic, solvent-free, and free of curing by-products.
• It exhibits low shrinkage during curing and the cured product has good toughness.
• The cured product exhibits a glossy surface and outstanding flame retardancy and electrical insulation properties.
• Excellent mechanical properties and resistance to heat, as well as to thermal cycling tests.
• It exhibits excellent adhesion to metal and plastic housings.

In summary, both polyurethane and epoxy potting compounds can effectively protect the internal structure of automotive pressure sensors, enhancing their reliability and stability, extending their service life, and thereby ensuring the proper operation of the vehicle’s systems. Through continuous improvement and optimization of potting‑gel encapsulation technology, the performance and quality of automotive pressure sensors can be further enhanced, meeting the evolving demands and challenges of the automotive industry.

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