Daubert Chemical’s Daubond U8508-10, a single component, hot melt adhesive that reacts with moisture to become a cross-linked, thermoset adhesive, recently passed Underwriters Laboratories (UL 10C) and Intertek (Warnock-Hersey) tests recognizing Daubond U8508-10 as a component in fire-rated steel doors.
Daubond U8508-10 exhibits strong resistance to heat, cold, and water when cured, and is designed for assembly operations requiring long open times. Assembled parts can be handled soon after nipping or pressing, with bond strength growing over time.
A fully-assembled steel door, consisting of an interior foam core held on to metal on both sides, was tested and tolerated two hours at 1980°F. UL approval applies when the maximum adhesive application rate is 11 grams/ft2 or less and the Intertek approval applies when it is 8 grams/ft2 or less. The entire door submitted – including hinges, handles, foam interior, steel panel and Daubond U8508-10 adhesive - achieved approval as recognized components.
Daubond U8508-10 contains a small amount of free isocyanate (diphenylmethane diisocyanate), and as a result should be used with adequate forced air ventilation during application, according to the company.