ADDITIVES

There are several key items that are essential in developing a colorant package for any polymer. The first of these is the avoidance of any chemical incompatibility between the chemistry of the polymer and the chemistry of the colorant system. Chemical reactions proceed more rapidly at higher temperatures, and melt processing involves significantly elevated temperatures and large inputs of mechanical energy. Therefore, any chemical interactions that may occur between a polymer and a colorant system will happen very rapidly during the injection molding process. 

The material supplier will incorporate a certain amount of the stabilization package in the material, making this the starting point for that material. It is now the processor’s job to handle the material during processing so that the molded part contains enough stabilizer to perform to the expectations of the end user. The molding process will always consume some amount of the antioxidant in the material. This is expected. But the amount of stabilizer that is consumed will depend upon the process conditions, most notably the melt temperature and the time the material spends in the molten state. Lower melt temperatures and shorter residence times will produce parts that retain a higher level of stabilization, and these parts will be more capable of handling the application environment. If melt temperatures become elevated or residence times become extended, the molded part will be less capable of managing the application demands.