Photoactive compounds for use with narrow wavelength band ultraviolet (UV) curing systems

A method of polymerizing a polymerizable compound comprising at least one ethylenically unsaturated double bond, comprising exposing said compound to ultraviolet radiation in the presence of a photoinitiator compound having the Formula (I) ##STR9## wherein A is --CO-- or --CO--CO--;

• Z is (H,H), --CH.sub.2 --, --S--, --O--, --CO--, --NR.sub.9 --, or a bond bridging the two aromatic rings,
• each R.sub.1 and R.sub.2 is independently selected from the group consisting of H, with the proviso that both R.sub.1 and R.sub.2 are not H;
• ##STR10## with the proviso that Z is not (H,H) when at least one of R.sub.1 or R.sub.2 is morpholino, ##STR11## with the proviso that when Z is --S-- and X is oxygen, then at least one of R.sub.1 and R.sub.2 is not phenoxy or toluyloxy and with the proviso that when Z is --S-- and X is sulfur, then at least one of R.sub.1 or R.sub.2 is not thiophenyl or substituted thiophenyl;
• and
• X--R.sub.7 with the proviso that R.sub.7 is not arylalkyl;
• X is O or S;
• each R.sub.3, R.sub.4, R.sub.5, and R.sub.6 is independently selected from the group consisting of --H, --Cl, --Br, --NO.sub.2, --CN, --OH, C1 to C8 alkyl, C6 to C8 aryl, C7 to C24 alkylaryl or alkylaryl or arylalkyl, C1 to C8 alkoxy, C6 to C18 aryloxy, C7 to C24 alkylaryloxy or arylalkoxy, C1 to C8 alkylthioether, --COOH, and --COOR.sub.7 ;
• and
• each R.sub.7 is independently selected from the group consisting of C1 to C8 alkyl and C7 to C24 alkylaryl or arylalkyl.

A method of polymerizing a polymerizable compound comprising at least one ethylenically unsaturated double bond, comprising exposing said compound to ultraviolet radiation using a narrow wavelength band excimer lamp emitting a narrow radiation wavelength band between about 250 to about 350 nanometers (nm) in the presence of a photoinitiator compound having the Formula (I) ##STR13## wherein:

• A is --CO-- or --CO--CO--;
• Z is (H,H), --CH.sub.2 --, --S--, --O--, --CO--, --NR.sub.9 --, or a bond bridging the two aromatic rings,
• each R.sub.1 and R.sub.2 is independently selected from the group consisting of H, with the proviso that both R.sub.1 and R.sub.2 are not H;
• ##STR14## and X--R.sub.7 ;
• X is oxygen or sulfur;
• each R.sub.3, R.sub.4, R.sub.5, and R.sub.6 is independently selected from the group consisting of --H, --Cl, --Br, --NO.sub.2, --CN, --OH, C1 to C8 alkyl, C6 to C8 aryl, C7 C24 alkylaryl or arylalkyl, C1 to C8 alkoxy, C6 to C18 aryloxy, C7 to C24 alkylaryloxy or arylalkoxy, C1 to C8 alkylthioether, --COOH, and --COOR.sub.7 ;
• and
• each R.sub.7 and R.sub.8 is independently selected from the group consisting of C1 to C8 alkyl and C7 to C24 alkylaryl or arylalkyl.