an attachment to a dynamic mixhead allows pigment to be fully blended with a specified volumetric portion of a reactive polymer mix immediately prior to its passing through an in - line motionless mixer . the fully pigmented portion of the mix passes into the motionless mixer concurrently with the nonpigmented remainder of the polymer mix , each portion constituting a discrete stream and positioned in a manner facilitating rapid , improved blending . the pigment pre - blending attachment possesses particular utility for partial or incomplete blending applications , wherein striations of color are desired to impart a marbled effect .