Process for dyeing polymeric fibers

A process for printing or space dyeing polypropylene fibers to produce discrete dyed and undyed regions comprising the steps of:

• providing polypropylene fibers;
• contacting said fibers at intermittent regions with a dye paste comprising a disperse dye, a swelling agent, a thickener, and an acid;
• applying dry heat to said fibers in contact with said dye composition at a temperature above about 280.degree. F. for at least about 15 seconds to thereby effect dispersion of a portion of said dye into said fibers;
• and
• washing said fibers to remove residual dye composition.

A process for dyeing polypropylene fibers comprising the steps of:

• providing polypropylene fibers;
• contacting said fibers with a dye paste comprising a disperse dye, a swelling agent, a thickener, and an acid, the dye paste having a viscosity between about 800 and about 3000 centipoise at 80.degree. F. as measured by a Brookfield Viscosimeter with a No. 3 spindle;
• heating said fibers in contact with said dye paste at a temperature above about 280.degree. F. for at least about 15 seconds to thereby effect dispersion of a portion of said dye into said fibers;
• and
• washing said fibers to remove residual dye paste.

A process for dyeing polyolefin fibers comprising the steps of:

• providing polyolefin fibers, which polyolefin fibers have limited or no dye sites as part of the polymeric structure;
• contacting said polyolefin fibers with a dye composition comprising a disperse dye and a swelling agent comprising a mixture of n-cyclohexyl-2-pyrrolidone and diethylene glycol;
• applying dry heat to said polyolefin fibers in contact with said dye composition at a temperature at least above about 80.degree. F. less than the melting point of the polyolefin fibers for a time sufficient to effect dispersion of a portion of said disperse dye into said polyolefin fibers;
• removing residual dye composition from said polyolefin fibers.