Photopolymerizable elastomeric mixture and recording material containing this mixture, for producing ozone-resistant flexographic printing forms

A process for producing an ozone-resistant flexographic printing form, comprising the steps of:

• a) preparing a photopolymerizable layer comprising an elastomeric binder;
• an olefinically unsaturated compound polymerizable by free radicals;
• and a photoinitiator to form a mixture;
• wherein the mixture comprises at least one polyglycol ether of the general formula I:
• ##STR4## in which R.sub.1 and R.sub.2 are (C.sub.1-3)alkyl;
• R.sub.3 is hydrogen or (C.sub.1-3)alkyl
• A, B, C, and D can be identical or different and are selected from oxa-n-alkylene or oxa-isoalkylene and wherein
• l+m+n+o is 3 to 40:
• by (1) an extrusion process comprising extruding the mixture in a single screw or twin-screw extruder with subsequent final forming in a polishing stack or calender;
• or (2) forming a layer out of the mixture using a roller head process or (3) dissolving the mixture in an organic solvent, followed by cross-linking at elevated temperature and then pressing into a layer;
• b) applying or laminating the photopolymerizable layer prepared in step a) to a carrier,
• c) imagewise exposing the photopolymerizable layer with actinic light to produce polymerized and non-polymerized areas,
• d) removing the unexposed and non-polymerized areas of the photopolymerizable layer with a developer solvent to form a developed flexographic printing form, and
• e) drying the developed flexographic printing form to form an ozone resistant flexographic printing form.