How to apply structural adhesive?

The future of cars is about being efficient, green and lightweight. This means the adhesives used must also become more eco-friendly. Currently, most automotive adhesives are polluting, but Molibon's exclusively developed epoxy structural adhesive is free of harmful substances like formaldehyde and benzene. Suitable for bonding various materials, it is now being used more widely in vehicle manufacturing.

While Molibon focuses on high-performance and eco-friendly industrial adhesives, it is equally important to pay more attention to customer needs. This includes gaining a deeper understanding of adhesive bonding design requirements for vehicle bodies. Using Molibon structural adhesives as an example, this article will explain the design and specifications for adhesive bonding in new energy vehicle bodies.

What is structural adhesive?

High-performance structural glue is a high strength epoxy-based glue used in car manufacturing. It bonds body parts together, working alongside SPR (Self-Piercing Riveting) and pot welding to make the vehicle stiffer, and more sealed. Advanced epoxy-based adhesives are primarily thermosetting structural adhesives based on modified epoxy resin, forming a bonded structure with very high tensile and shear strength and fatigue resistance.

What are the main uses of automotive adhesives?

Automotive structural adhesive is a powerful bonding solution for automotive load-bearing structural components. Molibon multi-material epoxy adhesive can withstand significant dynamic and static loads and provide long-term performance. The epoxy structural glue can replace bolts, rivets or welding for joining structural components made of metals, plastics and glass, providing reliable performance under long-term heavy loads, vibration and impact.

In addition to strengthening vehicle frames, the flexible automotive bonding adhesive is widely used in power batteries. For example, it securely bonds battery cells together, attaches cells to protective foam, and fixes cells within the battery housing. This creates a unified and durable battery module capable of withstanding vibration, shocks and drops.

Structural Adhesive Application Specifications

① Structural epoxy adhesives are suitable for bonding metal parts with gaps less than 1mm.

② If a structural bonding adhesive needs to provide a seal, ensure the gap is under 1mm.Specific requirements will be addressed case by case.

③For critical areas, the Body Performance Department specifies a design width of 15 mm. The overlap width shall be between 15 mm and 20 mm.

At least 2mm margin must be left on both inner and outer flanges. In overlap areas requiring corrosion protection, 100% adhesive coverage is mandatory.

Key Design Parameters (refer to the diagram below):

 a: Panel Gap

 b: Width After Lamination

 d: Adhesive Diameter 

•Structural adhesive as a sealing inspection item (based on the YCYS list):

① a≤1mm (including tolerance), d recommended: (3-6)mm (if only sealing is required, b≥5mm, overflow is allowed; if connection is required, b≥10mm)

② 1＜a≤ 2mm (including tolerance), b≥5mm, d recommended ≥6mm, overflow is allowed;

• PVC (polyvinyl chloride) as sealing, structural adhesive as auxiliary:

①If only auxiliary sealing is required, there are no special quality requirements, and adhesive can be continuously applied at the R-corner.

②If connection strength is required, b≥10mm.

Choose reliable adhesive solutions and earn customer trust. Molibon specializes in high-strength and multi-surface bonding for modern vehicle body structures.

We provide high-performance industrial adhesives and expert application design, delivering the optimal balance of structural performance, cost-effectiveness and long-term reliability.

Welcome to contact us for samples and technical support.