Abstract: A mordant for dyeing fibers is provided comprising an aluminum salt, preferably Al.sub.2 (SO.sub.4).sub.3, potassium or sodium carbonate, preferably the latter, and citric acid, capable of forming an aluminum hydroxide suspension in aqueous media having a pH of about 3.5-4. Methods of use of this composition are also provided. The mordant is useful in commercial dye processes including package dyeing.

Abstract: This invention provides processes for dyeing fibers with indigo including placing the fibers in a substantially enclosed compartment of a commercial dye apparatus, which is equipped with means for introducing a non-oxidizing gas into the compartment; prior to or following placing the fibers in the compartment, introducing a non-oxidizing gas into the compartment to produce a substantially non-oxidizing atmosphere therein; contacting the fibers with a dye liquor comprising leuco indigo in the compartment such that the leuco (reduced) indigo is taken up by the fibers; and oxidizing the leuco indigo taken up by the fibers to produce a blue color in the fibers.

Abstract: A mordant composition for dyeing fibers is provided which comprises a colloidal suspension of aluminum hydroxide in an aqueous medium. The composition is formed by adding an aluminum sulfate salt to sodium or potassium carbonate in aqueous solution at a weight ratio of about 7:1 aluminum sulfate salt to carbonate salt. The preferred aluminum sulfate salt is alum.

Abstract: An improved nonpolluting method of dyeing fibers or fabric, including natural cellulose fibers such as cotton or linen, using indigo dye. The improved process preferably includes pretreating the fibers with a mordant solution, preferably a natural nonpolluting mordant solution. The fibers are then treated with a reduced indigo liquor in an inert atmosphere, preferably nitrogen. The indigo is then oxidized by flooding the dyed fabric with water. This indigo dye process can be adapted to conventional garment, package and piece dye processes and machinery, which has not been possible with existing indigo dye processes. The improved process results in a consistent and even dyed material which is color and washfast.