Photoinitiator combinations comprising
at least one compound of formula (I)
##STR1##
wherein
R.sub.1 is C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 alkoxy or halogen;
R.sub.2 is hydrogen, C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 alkoxy or
halogen; R.sub.3 is, for example, C.sub.1 -C.sub.20 alkyl, cyclopentyl,
cyclohexyl, phenyl-C.sub.1 -C.sub.4 alkyl, naphthyl or biphenylyl or an
O-, S- or N-containing 5- or 6-membered heterocyclic ring; and at least
one compound of formula (II)
##STR2##
wherein
R.sub.1 and R.sub.2 are as defined above; R.sub.9 is, for example, C.sub.1
-C.sub.20 alkyl, cyclopentyl, cyclohexyl, phenyl-C.sub.1 -C.sub.4 alkyl,
naphthyl, biphenylyl or an O-, S- or N-containing 5- or 6-membered
heterocyclic ring; and R.sub.10 is, for example, C.sub.1 -C.sub.20 alkyl,
C.sub.2 -C.sub.20 alkyl interrupted by one or more O atoms, cyclopentyl,
cyclohexyl, phenyl-C.sub.1 -C.sub.4 alkyl, naphthyl, biphenylyl or an O-,
S- or N-containing 5- or 6-membered heterocyclic ring; are reactive
photohardeners causing only a low degree of yellowing in the cured
substrates.
Combinaciones de Photoinitiator que abarcan por lo menos un compuesto de ## del ## STR1 del fórmula (i) en donde R.sub.1 es C.sub.1 - C.sub.4 alkyl, C.sub.1 - C.sub.4 alkoxy o halógeno; R.sub.2 es hidrógeno, C.sub.1 - C.sub.4 alkyl, C.sub.1 - C.sub.4 alkoxy o halógeno; R.sub.3 es, por ejemplo, C.sub.1 - C.sub.20 alkyl, cyclopentyl, cyclohexyl, phenyl-C.sub.1 - el alkyl C.sub.4, naftílico o biphenylyl o un O -, s o 5 n-containing o el anillo heterocíclico 6-membered; y por lo menos un compuesto de ## del ## STR2 del fórmula (ii) en donde R.sub.1 y R.sub.2 están según lo definido arriba; R.sub.9 es, por ejemplo, C.sub.1 - alkyl C.sub.20, cyclopentyl, cyclohexyl, phenyl-C.sub.1 - alkyl C.sub.4, naftílico, biphenylyl o un O -, s o 5 n-containing o anillo heterocíclico 6-membered; y R.sub.10 es, por ejemplo, C.sub.1 - C.sub.20 alkyl, C.sub.2 - el alkyl C.sub.20 interrumpido por unos o más átomos de O, cyclopentyl, cyclohexyl, phenyl-C.sub.1 - alkyl C.sub.4, naftílico, biphenylyl o un O -, s o 5 n-containing o anillo heterocíclico 6-membered; son los photohardeners reactivos que causan solamente un grado bajo de amarillear en los substratos curados.
