| 摘要 |
PURPOSE:To facilitate the concentration control of trace quantity of gelatine, by adding an aqueous solution of tannic acid to a plating liquid containing the gelatine as a smoothing agent and absorbing and filtering a produced colored precipitate by a filter having a specific sieve opening and then, observing insoluble matter sticking to the filter. CONSTITUTION:In a quantitative determination of trace quantity (1-3ppm) of gelatine contained as a smoothing agent of a plating liquid used in a process of manufacture of copper foil etc. for a printing circuit, 1wt% aqueous solution of tannic acid is added to a fixed quantity of the plating liquid and said solution is shaken thoroughly and it is left as it is for 30min. Hereafter, a produced precipitate is filtered under suction by a membrane filter or a filter such as a glass filter paper etc. having <=5mu sieve opening and the filter stuck with insoluble matter is compared with colored paper which has been colored preliminarily by a standard solution and then, the concentration of the gelatine is controlled at the proper concentration by knowing the concentration of the gelatine in a sample. Measurement may be performed by the determination of reflectance or infrared absorption in stead of visual observation. |
