Polymerisable compounds with high polymerisation depth

Composition comprises at least one polymerizable binder, and a photoinitiator mixture comprising (a) at least one diacyl-germanium compound (I), (b) at least one alpha -diketone, and (c) at least one accelerator. Composition comprises at least one polymerizable binder, and a photoinitiator mixture comprising (a) at least one diacyl-germanium compound of formula (I), (b) at least one alpha -diketone, and (c) at least one accelerator. R1, R2 : 1-4C alkyl or 2-4C alkenyl (both linear and optionally substituted by at least one polymerizable group); R3, R4 : H, halo, 1-4C alkyl or -O-1-4C alkyl; R5-R7 : 1-20C alkyl, 1-20C alkenyl, 1-20C alkoxy or 1-20C alkenoxy (all linear, optionally interrupted by at least one -O, -S or -NR8 and optionally substituted by at least one polymerizable group), H or halo; and R8 : H, 1-20C alkyl, 1-20C alkenyl, 1-20C alkoxy or 1-20C alkenoxy. An independent claim is also included for producing a composite, comprising providing the above composition, and completely or partially curing it.