Photohardenable mixture

Claim 1

Positive working, tonable, photohardenable mixture, comprising a binder or mixture of binders, at least one photohardenable compound, a photoinitiator system and optionally at least one additional, not photohardenable, plasticizing compound, characterized in that the photohardenable mixture, to reduce the temperature-dependence of the toning process, contains : (a) 10 to 80 weight-% of at least one ethylenically unsaturated photopolymerizable compound based on the total dry weight of the photohardenable mixture; (b) 20 to 90 weight-% of binder or mixture of binders based on the total dry weight of the photohardenable mixture, wherein, with use of a single binder, its glass (second order) transition temperature does not exceed 70°C and, with use of a mixture of binders, the glass transition temperature of each individual binder does not exceed 80°C, the binder, or in the case of a mixture of binders, at least one of the binders is thermoplastic and is based on acrylate and/or methacrylate and the binder or at least one binder of the mixture of binders possesses a sufficient content of salt-forming acid groups to establish a concentration of at least 2 weight-% of these groups in the binder or mixture of binders; (c) at least one multivalent metal compound selected from groups IIA-IVA, IIB-IVB and VIIB of the Periodic Chart (Hollemann-Wiberg, Anorganische Chemie 81 - 90 edition, appendix) in amounts such that at least 10 weight-% of the salt-forming acid groups present in the binder or mixture of binders are cross-linked and (d) 0.01 to 15 weight-% of a photoinitiator system based on the total dry weight of the photohardenable mixture.