a thermoplastic article includes one or more recyclable - friendly synthetic coloring pigments . the pigment has a melting temperature that is about 20 to about 50 ° c . higher than that of the base polymer . this enables the pigment to remain predominately intact during injection molding and act as a colorant in the preform and resulting blow molded container . when the container is remelted during subsequent processing , such as post - consumer recycling , the pigment melts and transesterifies into the base polymer . thus , upon such further processing , the pigment effectively is subsumed into the base polymer and does not affect the basic characteristics and properties of the base polymer .