Abstract: Methods for dyeing aramid fibers, and the dyed arimid fibers produced by these methods, which comprises a dye providing step in which a vat dye or a sulfur dye is provided to aramid fibers, a solvent treatment step in which the aramid fibers are treated by a treating solution containing a polar solvent, and after the solvent treatment step, a heat treatment step in which the aramid fibers are subjected to a heat treatment, if necessary, and having one or more dyeing operations comprising the combination of the respective steps dyeing operations. The dyeing methods can be applied to either of the para-type aramid fibers, the para-type copolymerized aramid fibers and the meta-type aramid fibers, which can be dyed to a practical color depth required for developing new applications of the aramid fibers. Colorfastness of the dyed product, in particular, colorfastness to light, is improved.

Abstract: An ink for marking which is used for marking an outer surface of an article having at least the outer surface formed of a resin and which is excellent in friction resistance and flex resistance after marking is provided. An ink for marking which contains an organic solvent, an oil-soluble dye and an oil-soluble resin, in which the oil-soluble resin has at least two types of acrylic resins mixed; in the aforementioned at least two types of acrylic resins, a total of an acid value and a hydroxyl value of at least one type of acrylic resin is 10 or less; and in the aforementioned at least two types of acrylic resins, a total of an acid value and an hydroxyl value of the other at least one type of resin is 70 or more.

Abstract: The present invention relates to a method for producing a heat-resistant crimped yarn comprising: twisting yarn of a heat-resistant high functional fiber; twist-setting this twisted yarn by heat treatment; and untwisting this twist-set yarn, wherein a snarl value of the twist-set yarn is not more than 6.5.