Process for the level, isothermal high-temperature dyeing of hydrophobic synthetic fibers with disperse dyestuffs

A process for the isothermal high-temperature dyeing of textile material made of hydrophobic synthetic fibers in a closed dyeing system with water-insoluble disperse dyestuffs according to the exhaustion method, according to which the disperse dyestuff predispersed in water of 40.degree. to 60.degree. C is introduced into an aqueous bath free of dyestuffs which is already circulating to form a bath liquor, and heated together with the textile material to a dyeing temperature within the range of from 115.degree. C to 140.degree. C and adjusted to pH 4 - 6, which comprises measuring the bath liquor circulation rate and the amount of dyestuff exhausted onto the fiber, and introducing the predispersed dyestuff in doses into the dye bath liquor depending on the measured rate and the amount of dyestuff exhausted to replace the dyestuff exhausted such that 1% to 4% of the total dyestuff to be introduced is added per one bath liquor circulation.