| abstract |
A polyvinyl acetal is described which contains 4 to 40 mol-% vinyl alcohol units, 1 to 20 mol-% vinyl acetate units, 0 to 85 mol-% vinyl acetal units derived from an aldehyde free of OH groups and 1 to 85 mol-% vinyl acetal units derived from an aldehyde containing OH groups. The polymer is suitable as binder for photosensitive mixtures, in particular for the preparation of printing plates and photoresists. The layers obtained therewith can be developed with neutral or weakly alkaline, purely aqueous solutions and produce printing plates with a high print run performance and good ink receptivity. |