A reliable tool for detecting UF or MUF resin distribution in MDF fiber is essential to the study of blowline dynamics and the development of the next generation of MDF blending. Two fluorescent dyes Uvitex and fluorescein were studied as UF and MUF labeling agents. It was found in the experiments that fibers with MUF resin (containing 10% melamine) at 5% and 15% add-on levels gave results that were promising. Resin distribution patterns were easily detected and distinguishable under UV light. In contrast to MUF resin, it was found that UF resin with Uvitex or fluorescein produced no clear fluorescent images. It appeared that the fluorescent dyes did not stay completely with the resin droplets and spread everywhere in the fiber. It can be concluded that Uvitex and fluorescein are not suitable as labeling agents for UF resin distribution.
In the case of MUF resins, quantitative evaluation has not been completed although indication from the preliminary work was positive.