Process for dyeing undrawn acrylonitrile polymer filaments

A continuous process for dyeing dry-spun acrylonitrile polymer filaments which are substantially undrawn and contain in excess of 10% spinning solvent, by weight of the filaments, which comprises the following steps:

• 1. passing a bundle of said filaments through an aqueous extraction bath having a temperature below about 80.degree.C., so that any imposed draw is nominal and at a rate of at least about 10 yards per minute, until the spinning solvent content of the filaments is below about 10% by weight of the filaments;
• 2. squeezing the bundle of filaments under pressure sufficiently heavy to remove most of the extraction bath liquid therefrom;
• 3. passing the bundle of filaments into contact with a liquid dye mixture at a temperature below about 80.degree.C. at nearly zero stretch;
• 4. drawing the filaments between about 1.5.times. and 4.5.times. at a temperature between about 60.degree. and 80.degree.C. while the filaments are still in contact with the liquid dye mixture;
• and
• 5. removing excessive liquid by squeezing the bundle of filaments under pressure sufficiently light to retain upon the filaments an amount of liquid substantially greater than the amount present prior to their contact with the liquid dye mixture, so that there is a net pick-up of liquid dye mixture on the filaments and they remain in contact with the liquid dye mixture.