Suppression of blooming by amorphous resins

In the tetrabromobisphenol A-bis(2,3-dibromopropyl ether) (TBA-DB) and poly propylenes (PP) system, the blooming was suppressed by the addition of ethy lene/vinyl acetate copolymer (EVA) to PP, and the relation between the EVA content necessary for the Suppression of blooming and the TBA-DB content wa s determined. The appropriate temperature of blooming acceleration test for injection molding was not generally high but moderate around 50 degreesC. A general acceleration test could be applied to the phenomenon where the re action rate obeys the Arrhenius equation and was accelerated by elevating t emperature. In the case of injection moldings a similar behavior to that of a solution where a solute dissolves in a solvent was observed in their blo oming phenomenon. Namely, at high temperatures, the solubility is high and the precipitating (blooming) material is scarce (or absent). On the other h and, at low temperatures, although the precipitating material is abundant, the transportation rate is low and hence the blooming does not occur. The m ost appropriate temperature was determined to be around 50 degreesC on a ba lance of the above-mentioned compensating effects.