Radiation-curable compositions containing photoinitiators linked by a covalent bond

A process for preparation of a radiation-curable acrylate compound, comprising reacting a compound A containing at least 2 acrylic groups with a benzophenone derivative wherein said benzophenone is not copolymerizable by free-radical copolymerization and wherein said benzophenone comprises at least one primary or secondary amino group;

• wherein said benzophenone derivative reacts with said compound A by Michael addition to an acrylic group of said compound A;
• wherein no more than 50 mol % of the acrylic groups in said compound A exist as Michael adducts with said benzophenone:
• wherein said benzophenone derivative is one of the formula:
• ##STR13## in which R is a phenyl radical or R.sup.1, and R.sup.1 is a radical:
• ##STR14## where the radicals R.sup.2 to R.sup.6 independently denote H, a C.sub.1 -C.sub.4 alkyl or C.sub.1 -C.sub.4 alkoxy group, and at least one, but not more than three, of the radicals R.sup.3 to R.sup.6 is a group X, and X is C.sub.1 -C.sub.30 aliphatic or aromatic group containing a primary amino group or a secondary amino group.