首页>
外国专利>
1. In the process of making special paper, after any acid or shaving treatment, the words on the paper shall be altered and some words or signs shall be displayed at the bottom of the paper to indicate its intention to make it disappear
1. In the process of making special paper, after any acid or shaving treatment, the words on the paper shall be altered and some words or signs shall be displayed at the bottom of the paper to indicate its intention to make it disappear