Thermal process for applying hydrophilic layers to hydrophobic substrates for offset printing plates

摘要

PCT No. PCT/EP94/04218 Sec. 371 Date Sep. 20, 1996 Sec. 102(e) Date Sep. 20, 1996 PCT Filed Dec. 19, 1994 PCT Pub. No. WO95/18019 PCT Pub. Date Jul. 6, 1995This invention relates to a process for preparing printing plates which are used in offset printing. The process produces a plate which comprises a substrate film in which a thin durable hydrophilic layer has been applied thereto. In the process, the substrate film is first microroughened by pressure blasting so that the surface roughness, RA, is in the range 0.3 to 1.5 mu m. Subsequently, a durable, firmly adhering hydrophilic layer is applied to substrate by plasma-spraying an oxide powder with a particle size of 1 to 40 mu m onto the substrate. This process produces a plate whose surface is not greasy or grainy.