| abstract |
The invention relates to photopolymerizable compositions comprising as a photoinitiator a borate of formula I or I '; wherein: R1 and R2 and R3 are, for example, and independently of one another, phenyl or another aromatic hydrocarbon, with or without heteroatoms, the radicals of which are unsubstituted or substituted, or the radicals R1 and R2 form bridges to produce structures of formulas II, IIa or IIb. Provided that no more than two of the radicals R1, R2 and R3 are identical, and any one of at least two of the radicals R1, R2 and R3 are aromatic hydrocarbon radicals or phenyl radicals that are substituted at both ortho positions, or at least one radical R1, R2, or R3 is a sterically bulky aryl radical, and the remaining radicals of R1, R2, and R3 are aromatic hydrocarbon radicals or are phenyl radicals, which are substituted in at least one ortho position; R4 is, for example, phenyl or alkyl of 1 to 20 carbon atoms, and G is a radical that can form positive ions. |