for example tio 2 or other pigments can be added to the poly trimethylene terephthalate the poly ethylene terephthalate the styrene polymer additive the mixture s or during filament manufacture after being spun from a spinneret the hot filament can be quenched with a gas supplied as cross flow or co current flow in cross flow the gas can be blown across the just spun filaments for example from one side of a quench chamber as shown in fig1 in co current flow quench gas can be introduced from above for example from an annular space around the spinneret or from the side as shown in fig2 of u s pat no 5 824 248 and fig2 and 6 of published united states patent us 2002 0025433 which are incorporated herein by reference the quench gas can be accelerated in the direction of filament travel for example by supplying the gas at elevated pressure and using a constriction below the quench chamber through which both the gas and the filaments pass the resulting superatmospheric pressure can be in the range of about 0 5 5 0 inches of water about 1 3 u00d7 10 u2212 3 to 1 3 u00d7 10 u2212 2 kg cm 2 the maximum velocity of the quench gas is generally at the narrowest point of the constriction when a constriction having a minimum inner diameter of one inch 2 54 cm is used the maximum gas velocity can be in the range of about 330 5 000 meters minute subatmospheric pressure can also be used optionally a flow of quench gas into each of two substantially coaxial quench chambers arranged in.