| 摘要 |
PURPOSE:To enhance dimensional stability, by giving sulfonic groups to the surface of a film or sheet comprising a crosslinked aromatic high molecular weight compound as a main material through sulfonation, thereby providing the surface with an absorbance for a specified wavenumber. CONSTITUTION:A film or sheet comprising a crosslinked aromatic high molecular weight compound as a main material is immersed in fuming sulfuric acid or sulfuric anhydride per se, and is immersed in a liquid diluted with an organic solvent such as chloroform and carbon tetrachloride to effect sulfonation at a temperature of -30-70 deg.C, thereby giving sulfonic groups to the surface of the film or sheet to produce a planographic plate material. In the infrared spectrum of the surface of the plate material, the ratio of the absorbance in an intense band around a wavenumber of 1200 to the absorbance in a band attributed to the sulfonic group in the vicinity of a wavenumber of 1050 must be at least 0.6.
|
