| 摘要 |
PURPOSE:To prepare a silver-containing black ink suitable for a staining agent, a high-grade printed matter, by kneading a silver-containing black pigment recovered from a waste photographic film or a waste photograhic fixing solution, a resin and a solvent. CONSTITUTION:At least one silver-containing black pigment selected from an ash obtained, by the incineration of a waste photographic film containing silver or its mixture with a silver-containing precipitate recovered from a waste photographic fixing solution, in an oxidizing atomosphere for several hours, and a dried silver- containing precipitate powder obtained by heating a waste photographic fixing solution at 80-100 deg.C with addition of an anion such as nitric acid or sodium sulfide, combining with a silver ion, and drying the black silver-containing precipitate produced, a resin such as an acrylic resin or a cellulose resin, and a solvent such as toluene or ethyl acetate, are kneaded for several hours by means of a ball mill. |
