Temperature Dependence Evaluation of Tensile Shear Strength of Adhesive

Significance of the Topic

Adhesives are crucial for bonding dissimilar lightweight materials in modern automotive applications, offering stress distribution, enhanced rigidity, and streamlined surface finishing compared to traditional joining methods. Evaluating the temperature dependence of shear strength is essential for selecting adhesives that withstand extreme cold, high under‐hood temperatures, and fluctuating environmental conditions.

Objectives and Study Overview

This study assesses tensile lap-shear bond strength of four industrial adhesives (TB1160, TB2049/2149, TB2237J, TB3953) across temperatures from -25 °C to 150 °C. Using a precision universal testing machine (AGX-V2) and thermostatic chamber (TCR1WF), the work aims to characterize temperature-induced strength variations and fracture behavior.

Methodology and Instrumentation

• Adhesives and Specimens: Four ThreeBond adhesives applied to SUS304 adherends with controlled layer thickness (1–3 mm) and cured per specified conditions (room temperature or heat curing).
• Instrumentation: AGX-V2 testing machine (10 kN capacity) with manual non-shift wedge grips; TCR1WF chamber (-40 °C to 250 °C); TRAPEZIUM X-V software.
• Test Conditions: Tensile lap-shear tests at eight ambient temperatures (-25, 0, 25, 50, 75, 100, 125, 150 °C) with a crosshead speed of 1.2 mm/min and three replicates per condition.

Main Results and Discussion

• TB1160 showed a marked strength drop below 0 °C due to increased interfacial fractures, followed by gradual decline at higher temperatures.
• TB2049/2149 exhibited the highest room-temperature strength but significant reduction at sub-zero conditions, attributed to interfacial failure variability.
• TB2237J maintained superior adhesive strength at elevated temperatures, with only gradual decrease up to 150 °C.
• TB3953 displayed dual glass transition behavior, with initial strength loss to 25 °C, stability to 75 °C, and further decline beyond 75 °C.
• Cohesive failure within the adhesive yielded more consistent results, whereas interfacial failures produced larger strength variations.

Practical Benefits and Applications

The described setup meets JIS K 6850, JIS K 6831, and ISO 4587 standards, enabling reliable evaluation of adhesive performance in temperature-stressed environments. Results guide selection of adhesives for automotive components facing extreme climates and under‐hood heat.

Future Trends and Applications

• Integration of high-speed data acquisition (up to 10 kHz) to capture brittle fracture dynamics.
• Surface modification strategies to promote cohesive failure and reduce interfacial weakness at low temperatures.
• Development of novel resin formulations with tailored glass transition profiles.
• Extension of testing protocols to include fatigue, dynamic, and multiaxial loading conditions.

Conclusion

Precise measurement of temperature-dependent tensile lap-shear strength using AGX-V2 and TCR1WF reveals distinct performance profiles for different adhesives, supporting optimized material selection for demanding automotive applications.

References

• ThreeBond Co., Ltd. Application News No. 01-00743-EN. Test Speed Dependence Evaluation of Shear Strength of Adhesive and Fracture Observation.
• ThreeBond Co., Ltd. Application News No. 01-00790-EN. Shear Fatigue Testing of Adhesives.