Method for addition of additives into a polymer melt

A method of adding an additive in a polymer melt, preferably a melt of polyester polymer such as polyethylene terephialate (pet), which is composed of: a. Discharge of a polymer melt from a reactor to form a stream of discharged polymer melt, and b. Solidifying said stream of discharged polymer melt, and e.g. Prior to solidification, feed a portion of the stream of molten polymer mass discharged into a flow stream to form a flow stream polymer melt, and d. Feeding an additive into said flow stream polymer melt to form a flow stream containing an additive, and e.g.