Лако-красочные материалы — производство

In static oven aging at 40°C (104°F) of a rosin ester tackifier (Fig. 10) the rate of hydro­peroxide formation was reduced significantly using AO-2, with even better results using AO-3. The hydroperoxides are fairly stable at room temperature. At temperatures asso­ciated with hot-melt compounding or drying of solvent — and water-based formulations, hydroperoxides decompose spontaneously. The decomposition products initiate further reactions, which can result in the formation of color species. The addition of AO-2 and AO-3 which reduces the level of hydroperoxides formed, subsequently reduces the level of tackifier discoloration after oven aging (Fig. 11).

Melt viscosity relates to stability during processing and to end-use performance. A stable melt viscosity is a very important property of a rosin ester tackifier. The melt

viscosity can also be related to the hydroperoxide content of the tackifier after aging. Figure 12 shows that the addition of AO — 2 and AO-3 can significantly reduce the increase in the melt viscosity of the rosin ester during static oven aging at 40°C (104°F).