| 摘要 |
A colourless pigment which fluoresces yellow in ultra-violet light comprises a colourless organic plastic and a b -aminophthaline having the general formula <FORM:1092689/C4-C5/1> in which R1 denotes a hydrogen atom, a hydroxyl group or a methyl group and the radicals R2 and R3 denote hydrogen atoms or together denote one of the radicals <FORM:1092689/C4-C5/2> and <FORM:1092689/C4-C5/3> Organic plastic carriers may include polyvinyl chloride, polyacrylonitrile, polyacrylic esters or ureaformaldehyde or melamineformaldehyde resins. The fluorescent material may be made by condensing products of iminophthalimide with 2-methylpyridine, 2-methylquinoline or 2,6-dimethylquinoline. The concentration of b -quinophthalines in the whole mixture may be 0.1 to 3%, preferably 0.5 to 2% by weight. In an example a solution of one or more of the b -quinophthalines in a solvent miscible with water (e.g. dimethylformamide, N - methylpyrrolidone, tetrahydrofurane, or ethylene glycol monoethyl ether) may be added to an aqueous dispersion of the plastic. The mixture is then heated while stirring to approximately 85 DEG C., the pigment then being filtered off. To produce compositions which fluoresce in colours other than yellow, a small amount of a prior art substance, such as 4-aminonaphthalic acid n-butylimide, which fluoresces in another colour may be added to the plastic and b -quinophthaline. Reference is made to known pigments consisting of a mixture of polyvinyl chloride and 9,10-dichloroanthracene or di-hydroxyterephthalic esters and also the pigment o-hydroxybenzaldazine. The pigments can be used as marking inks, for warning signs and traffic signs, or for articles to be sorted automatically. |
