| abstract |
Described are storage-stable aqueous non-sedimenting photoinitiator suspensions comprising (a) a mono- or bis-acylphosphine oxide of formula (I) wherein R 1 is C 1 -C 20 alkyl; C 2 -C 20 alkyl interrupted by one or more O atoms; C 1 -C 20 alkoxy; phenyl-C 1 -C 4 alkyl; or phenyl which is unsubstituted or substituted by C1-C20 alkyl, C1-C12 alkoxy, halogen, cyclopentyl, cyclohexyl, C2-C12 alkenyl, C2-C18 alkyl interrupted by one or more O atoms and / or phenyl-C1-C4 alkyl; or R 1 is biphenylyl; R 2 is an aromatic group or has the same meaning as R 1; R 3 and R 4 are independently C 1 -C 12 alkyl, C 1 -C 12 alkoxy or halogen; and R 5 is hydrogen, C 1 -C 12 alkyl, C 1 -C 12 alkoxy or halogen; (b) a dispersing agent; (c) water which is particularly suitable in photopolymerizable aqueous compositions containing ethylenically unsaturated monomers. |