Benzophenone derivatives of formula I
R
1
, R
2
and R
3
are each independently of the others hydrogen or C
1
-C
4
alkyl, cyclopentyl or cyclohexyl;
R
4
, R
5
and R
6
are each independently of the others hydrogen, C
1
-C
4
alkyl, cyclopentyl or cyclohexyl;
R
7
and R
8
are each independently of the other hydrogen, C
1
-C
4
alkyl, cyclopentyl or cyclohexyl; with the provisos that
(i) at least one radical R
1
, R
2
, R
3
, R
4
, R
5
, R
6
, R
7
, R
8
is other than hydrogen;
(ii) when all radicals R
4
, R
5
, R
6
, R
7
and R
8
are hydrogen and only one radical R
1
, R
2
, R
3
is C
1
-C
4
alkyl, that radical must be in the meta-position of the phenyl ring; and
(iii) when all radicals R
1
, R
2
, R
3
, R
7
and R
8
are hydrogen and two of the radicals R
4
, R
5
and R
6
are hydrogen and the remaining radical R
4
, R
5
or R
6
is C
1
-C
4
alkyl, that alkyl radical is not bonded in the para-position on the phenyl ring; are found to be especially suitable in photocurable compositions in respect of solubility, reactivity and a low level of yellowing.
式 I 的
二苯甲酮衍
生物
R
1
, R
2
和 R
3
各自独立地为氢或 C
1
-C
4
烷基、环戊基或环己基;
R
4
, R
5
和 R
6
各自独立地为氢、C
1
-C
4
烷基、环戊基或环己基;
R
7
和 R
8
各自独立地为氢、C
1
-C
4
烷基、环戊基或环己基;但前提是
(i) 至少一个基 R
1
, R
2
, R
3
, R
4
, R
5
, R
6
, R
7
, R
8
不是氢;
(ii) 当所有基 R
4
, R
5
, R
6
, R
7
和 R
8
为氢且只有一个基 R
1
, R
2
, R
3
为 C
1
-C
4
烷基时,该基必须位于苯环的元位置;以及
(iii) 当所有基 R
1
, R
2
, R
3
, R
7
和 R
8
是氢,R
4
, R
5
和 R
6
为氢,其余自由基 R
4
, R
5
或 R
6
是 C
1
-C
4
烷基,该烷基不键合在苯环的对位上;就溶解性、反应活性和低黄化程度而言,它们特别适用于光固化组合物。