Orient Chemical Industries, Ltd.

Minako Terasaki

Takashi Ono

Tatsuya Yagyu

Katsumi Fukuda

Use of metal complex dyes comprised of metalizable azo compounds to dye metal-tanned leather which makes possible good permeability and excellent color fastness to rubbing and color fastness to light.

Method of dyeing leather with metal complex dyes comprised of

Metal complex dyes comprising a metalizable azo compound represented by one of Formulas [I] through [IV]: ##STR1## In Formulas [I] through [IV], Ps represents a phosphono group in the form of a free acid or a salt; Sf represents a sulfo group in the form of a free acid or a salt; m is 0, 1 or 2. R.sup.1 represents a hydrogen atom or an amino group; X represents a hydroxyl group, an alkoxy group having a carbon number of 1 or 2 or a carboxyl group. Y represents a hydroxyl group, an alkoxy group having a carbon number of 1 or 2, a carboxyl group or a methyl group; R.sup.2 represents a hydrogen atom or a hydroxyl group; A represents a phenyl group or naphthyl group selected from the group comprising the following 1 through 4: ##STR2## In the above formulas 1 through 4, Sf has the same definition as above; n is 0, 1 or 2. R.sup.3 represents a hydroxyl group or a carboxyl group; R.sup.4 represents a hydroxyl group, a carboxyl group or an amino group; R.sup.5 and R.sup.6 independently represent a hydroxyl group or a carboxyl group; R.sup.7 and R.sup.8 independently represent a hydrogen atom, a hydroxyl group or an amino group. B has the same definition as A above except that R.sup.3 represents a hydroxyl group, a carboxyl group or an amino group. R.sup.9 represents a hydrogen atom, a methyl group, an alkoxy group having a carbon number of 1 or 2 or a sulfo group in the form of a free acid or a salt; D represents a coupling component residue having a metalizable hydroxyl group at the position adjoining to the azo group. Use of these metal complex dyes makes it possible to dye metal-tanned leather with good permeability and excellent color fastness to rubbing and color fastness to light.

Growing community of inventors

Moriguchi, Japan

Minako Terasaki