Patent ID: 7528205

Claim:
A photoradical generator comprising a compound (a) having a seven-membered ring imide structure-containing group represented by the following formula (2): wherein, R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 and R 8 respectively represent a hydrogen atom or a substituent and may be a cyclic structure in which they are bonded to each other; “X” represents a monovalent chemical structure having a part of a non-aromatic skeleton containing a hydrocarbon skeleton directly bonded to “N” of the seven-membered ring imide structure-containing group and a part containing a hydrogen-donating atom; when groups selected from the group consisting of R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 and R 8 are bonded to each other to have a cyclic structure, the cyclic structure is a structure that can keep a twist of two aromatic rings contained in a biphenyl structure contained in said formula.