Uron-Accelerated DICY System (1-Component)

Uron-Accelerated DICY Systems are pre-blended one-component latent epoxy hardener formulations combining fine-grade Dicyandiamide (DICY) with a uron-type accelerator — typically a substituted urea derivative such as DCMU (3-(3,4-dichlorophenyl)-1,1-dimethylurea), fenuron, or isophorone-bis-urea — to achieve faster cure initiation at reduced temperatures compared to standard DICY alone. The uron accelerator decomposes thermally above 80–100°C to release an isocyanate fragment and a dimethylamine, which then catalyzes DICY dissolution and reaction with epoxy. This thermally-triggered release mechanism preserves excellent ambient latency (3–12 months in liquid epoxy at 25°C) while enabling cure cycles at 100–130°C — significantly lower than unacc­elerated DICY (which requires 140–160°C). Uron-DICY systems are the preferred one-component hardener for structural epoxy prepregs, automotive 1K adhesive films, and industrial thermosetting coatings where processing temperatures must be kept below 130°C. Typical total system dosage is 5–9 phr (combined DICY + uron accelerator) on standard BPA epoxy (EEW 190). Fully cured systems achieve Tg of 110–140°C with excellent interlaminar shear strength (ILSS) and fatigue resistance. The pre-blended format eliminates separate weighing of two low-phr components, reducing formulation error in high-volume production.