Jindong UV?2905 – Formulation and Process Guide for Automotive Hemming Adhesive

Automotive hemming adhesives are used in the bonding of door panels, engine hoods, and trunk lids – applications that demand high strength, exceptional toughness, and long-term corrosion resistance. Traditional epoxy-based hemming adhesives often struggle with brittleness and positioning challenges during production.

Jindong UV?2905, a difunctional acrylate?modified polybutadiene resin, offers a practical solution to these issues.【1?L19】

Product Profile

The polybutadiene backbone provides exceptional flexibility and impact resistance – making UV?2905 an ideal toughening agent for epoxy?based hemming adhesive formulations.【1?L19-L22】

Why UV?2905 for Hemming Adhesives?

Dual?Cure Formulation Approach

The recommended formulation combines UV?2905 with epoxy resin to achieve an optimal balance of toughness and strength:

Key Components:

• UV?2905 (20–40 phr): Core toughening agent – provides flexibility, impact resistance, and low?temperature performance

• Epoxy resin (E?51, 100 phr): Structural backbone – delivers high strength and adhesion

• Dicyandiamide (8–12 phr): Latent thermal curing agent – activates at 140–180°C

• Urea derivative (1–3 phr): Accelerator – reduces curing temperature

• IBOA (15–25 phr): Reactive diluent – lowers viscosity and participates in UV crosslinking

• TPO photoinitiator (3–5 phr): Initiates UV curing – compatible with LED 395 nm light sources

• Fumed silica (3–5 phr): Thixotropic agent – prevents sagging during application

• Calcium carbonate (20–50 phr): Filler – reduces shrinkage and improves modulus

Process Advantages

1. UV pre?cure (positioning): After adhesive application, exposure to LED?395 nm UV light (5–10 seconds, ~500–1000 mJ/cm2) quickly fixes the adhesive in place. This solves the common problem of adhesive flow before thermal curing. Initial strength ≥0.5 MPa allows immediate handling and transfer.【1?L66-L67】

2. Thermal post?cure (final strength): The adhesive fully cures during the standard paint?shop baking cycle (140–180°C, 20–30 minutes), achieving final structural bond strength.【1?L68-L69】

3. Single?component system: All components are pre?mixed, packaged in light?proof, sealed containers, and stable at room temperature for at least 6 months.【1?L70-L71】

Target Performance

Getting Started

We recommend preparing a 200g sample using the formulation above for initial shear and T?peel strength testing. UV?2905 dosage can be adjusted between 20–40 phr to fine?tune the toughness?strength balance for your specific requirements.

For detailed technical data, formulation support, or sample requests, please contact:

Jindong New Materials Technology Co., Ltd.