To obtain distinct fingerprints with a simple and convenient apparatus and a method by burning a sublimable dye compsn. which contains a sublimable dye and a combustible substance and does not soften at the burning temp. in the air to thereby sublime the dye.
This compsn. comprises 10-70 wt.% sublimable dye (e.g. a color dye, a fluorescent brightener, or an ultraviolet absorber), 10-50 wt.% combustible substance (e.g. woodflour, a charcoal powder, a pyrethrum extraction residue, used tea leaves, or coffee grounds), and 10-30 wt.% binder (e.g. starch or carboxymethylcellulose), does not soften at its burning temp. or lower, and is formed into plates or sticks. A nonionic disperse dye having high vapor pressure and thermal stability is pref. as the dye. Pref. fluorescent brighteners are oxazole compds. coumarin compds., naphthalimide compds., etc. Pref. ultraviolet absorbers are benzotriazole compds., benzophenone compd., cyanoacrylate compds., etc.
HIRANO TOSHINORI
TAKIMOTO HIROSHI
Next Patent: WATER-INSOLUBLE RED ANTHRAQUINONE DYE AND PREPARATION THEREOF