| 摘要 |
A multi-functional photoinitiator of formula (I)wherein Q is a heteroatom selected from Si, Ti, Zr and Sn or any two independently selected such heteroatoms linked by a covalent bond or a by C1-16 (preferably C1-9) alkylene group, n is at least 2 and n+m=the functionality of Q, each R<1 >is the same or different and is a non-photoinitiator group; each group PI is the same or different and is a photoinitiator group.Each -A<1>- is the same or different and is selected from linking groups of formula -(A<2>)p-Z- wherein p has an average of from 1 to 10, preferably from 3 to 5 and the groups -A<2>- are either (a) each independently selected from C2-4 alkyleneoxy groups; or (b) each independently selected from groups of formula -O-(CH2)qCO- wherein q is from 3 to 5, and Z is selected from -O-, -S- and -NR<6>- where R<6 >is C1-6 alkyl.
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