With the continuous improvement of automotive intelligence, comfort, and durability requirements, the stable operation of onboard sensors has become a key link in ensuring the performance of the entire vehicle. Among them, the automotive air conditioning temperature sensor, as the core component for regulating cabin temperature, has a direct impact on the response speed and comfort experience of the in car air conditioning system in terms of accuracy and reliability. However, in long-term use, sensors often face a serious challenge – condensation water seeps in, causing internal thermistor failure. How to provide long-term and reliable waterproof protection for temperature sensors has become an important issue in the design of automotive electronic materials.
1、 Project background: Performance challenges under condensed water erosion
During the operation of the car air conditioning system, especially in humid or high temperature environments, condensation water is easily generated on the sensor surface. These water droplets may seep into the interior along the leads or seams, and once they enter the poorly sealed sealing area, they will reach the thermistor area, causing deterioration or even complete failure of electrical performance.
Traditional sealing materials often perform poorly in the face of this “boiling water” environment. High temperature and high humidity conditions can accelerate the aging of colloids, leading to decreased insulation performance, lower breakdown voltage, and water absorption expansion. To this end, the vehicle manufacturer has added a rigorous testing project -1000 hours of 85 ° C water boiling test, and determines whether the material is qualified by comparing the changes in insulation resistance and withstand voltage performance before and after the test.
2、 Analysis of adhesive requirements: not only waterproof, but also durable
According to the testing standards and application scenario requirements proposed by the customer, the sealing adhesive for automotive air conditioning temperature sensors needs to meet the following performance requirements:
Excellent waterproof and boiling resistance
It can maintain good insulation performance and mechanical stability even after 1000 hours of boiling at 85 ° C.
Excellent electrical insulation performance
Effectively protect the thermistor and circuit from external water vapor and electrical interference, and maintain stable electrical performance.
Good adhesion and sealing performance
It has good adhesion with the sensor housing (usually made of plastic or metal) to prevent water vapor from penetrating along the joint.
High and low temperature cycling resistance performance
Colloids do not crack or detach within the temperature range of -40 ℃ to 125 ℃, making them suitable for complex temperature changes in automotive operating conditions.
Stable chemical properties
No degradation or corrosion occurs when exposed to condensed water and other possible chemicals for a long time.
3、 Recommended product: EP 1710 epoxy sealant
EP 1710A/B is a two-component solvent-free ambient temperature curing epoxy potting material, suitable for packaging and protection of products with high thermal conductivity requirements in motors, automotive electronics, power tools, reactors, and instruments, and has excellent adhesion and temperature resistance.
Excellent adhesion and crack resistance
Low CTE coefficient of linear expansion
■ Has high thermal conductivity
Excellent electrical insulation and stability
Can be used for a long time at 150 ℃ -180 ℃
Extremely low water absorption rate, good waterproof and moisture-proof properties
4、 Customer testing verification and actual application effect
A well-known car company conducted a 6-week water boiling aging test and electrical performance tracking in the development of a new generation of air conditioning temperature sensor project, using EP 1710 for encapsulation
Testing method: After the sensor is sealed, it is continuously soaked in water at 85 ℃ for 1000 hours. During this period, samples are taken every 100 hours to test its insulation withstand voltage and insulation resistance.
Test results:
Initial insulation resistance: 1.2 × 10 ΩΩ
Insulation resistance after 1000 hours: 0.9 × 10 ⁹ Ω, almost unchanged
Voltage resistance without breakdown, product appearance without cracking or peeling phenomenon
Conclusion: EP 1710 fully meets the water boiling protection requirements of the project and has been officially listed as the designated adhesive for this sensor project.
With the development of intelligent vehicles and new energy vehicles, the number of onboard sensors continues to rise, and the performance requirements for adhesive materials are also increasing. EP 1710, as a highly waterproof epoxy potting adhesive, not only solves the problem of failure caused by condensed water infiltration, but also demonstrates long-term stability under harsh conditions such as high temperature and humidity, making it a reliable choice for potting automotive temperature sensors.
In the future, Elaplus will continue to drive innovation in automotive electronic adhesive solutions, providing safer and more reliable material support for intelligent travel.
Tags: EP 1710 · Sensor Encapsulation · Sensor Encapsulation Adhesive · Thermal Conductive Encapsulation Adhesive · Epoxy Encapsulation Adhesive
