Abstract: A continuous process for manufacturing a polyester includes introducing reactant components including a terephthalic acid slurry having an ethylene glycol to terephthalic acid molar ratio of about 2 and a TiO2 slurry to an initial reactor vessel and stirring the reactant components at greater than 0 to 200 rpm to form an oligomer; transferring the oligomer, phosphoric acid, and at least one additive (carbon black, 5-sulfoisophthalic acid, 5-sulfoisophthalic acid dimethyl ester, and/or 5-sulfoisophthalic acid diglycolate) to an intermittent reactor vessel and stirring at 400 rpm to 1000 rpm to form an intermediate, wherein the oligomer, the at least one additive, and the phosphoric acid have a residence time of from 1 minute to 5 minutes in the intermittent vessel; and polymerizing the intermediate in a final reactor vessel at a temperature of 285° C. to 320° C., and in the absence of a polyethylene glycol, to obtain the polyester.

Abstract: Inherently colored polyester polymers with controlled branching include a chromophoric co-monomer in their backbone. The chromophoric co-monomer may be a carboxyl terminated chromophoric co-monomer. such as metallo-phthalocyanine tetracarboxylic acid. The inherently colored polyester polymer may be melt-spun into a filament or fiber.