Hybrid photoinitiators

1. A compound of the formula I

m is 1 or 2;

R 1 , R 2 , R 4 and R 5 independently of one another are hydrogen, C 1 -C 4 alkyl, C 5 -C 7 cycloalkyl, phenyl, C 1 -C 4 alkoxy, C 5 -C 7 cycloalkoxy or phenoxy;

R 3 , if m is 1 has one of the meanings as given above for R 1 , R 2 , R 4 and R 5 ;

R 3 , if m is 2 is a divalent group;

R 6 is hydrogen or C 1 -C 4 alkyl;

R 7 is hydrogen, and if R 6 is hydrogen then R 7 may additionally be C 1 -C 4 alkyl;

R 8 is group A or B

X is —O—, —O—CH 2 — or —O(CHR 14 )—;

n is 0-10;

provided that

(i) if n is 0, and X is O, then R 8 is a group A,

(ii) if n is other than 0, then X is O and R 8 is the group A,

R 9 and R 10 independently of one another are hydrogen or C 1 -C 4 alkyl;

R 11 and R 12 independently of one another are C 1 -C 4 alkyl or form together with the C atom to which they are attached a 5 to 7 membered saturated carbocyclic ring;

R 13 is hydrogen, C 1 -C 4 alkyl, C 5 -C 7 cycloalkyl, 2-tetrahydropyranyl or Si(C 1 -C 4 alkyl) 3 ;

and

R 14 is a group A′

R′ 13 has one of the meanings as given for R 13 or is the group C

2. The compound according to claim 1 , wherein m is 1.

3. The compound according to claim 1 , wherein

m is 1;

R 1 , R 2 , R 4 and R 5 are hydrogen;

R 3 has one of the meanings as given above for R 1 , R 2 , R 4 and R 5 ;

R 6 is hydrogen or C 1 -C 4 alkyl;

R 7 is hydrogen;

R 8 is group A or B

X is —O—, —O—CH 2 — or —O(CHR 14 )—;

n is 0 or 1;

provided that

(i) if n is 0, and X is O, then R 8 is a group A,

(ii) if n is other than 0, then X is O and R 8 is the group A,

R 9 and R 10 are hydrogen or C 1 -C 4 alkyl;

R 11 and R 12 are C 1 -C 4 alkyl;

R 13 is hydrogen;

R 14 is a group A′ and

R′ 13 has one of the meanings as given for R 13 or is the group C

4. A photopolymerizable composition comprising

(A) at least one ethylenically unsaturated photopolymerizable compound and

(B) at least one photoinitiator compound of the formula I according to claim 1 .

5. The photopolymerizable composition according to claim 4 , which additionally to the component (B) comprises at least one further photoinitiator (C), or further additives (D), or at least one further photoinitiator (C) and further additives (D).

6. The polymerizable composition according to claim 4 , which comprises 0.05 to 15% by weight of the at least one photoinitiator compound based on the total composition.

7. The polymerizable composition according to claim 4 , which comprises 0.1 to 10% by weight of the at least one photoinitiator compound based on the total composition.

8. A process for the photopolymerization of monomeric, oligomeric or polymeric compounds containing at least one ethylenically unsaturated double bond, which comprises adding to the monomeric, oligomeric or polymeric compounds at least one photoinitiator compound of the formula I according to claim 1 and irradiating the resulting composition with electromagnetic or particulate radiation.

9. A process which comprises utilizing the photopolymerizable polymerizable composition according to claim 4 wherein the process is for the preparation of pigmented and nonpigmented paints and varnishes, powder coatings, printing inks, adhesives, sealings, potting components, dental compositions, foams, moulding compounds, composite compositions, glass fibre cable coatings, screen printing stencils, for producing three-dimensional objects by means of stereolithography, and as image recording material, photoresist compositions, decolorizing materials, decolorizing materials for image recording materials, and for image recording materials using microcapsules.

10. The process according to claim 9 wherein the process is for the preparation of pigmented and nonpigmented paints and varnishes, powder coatings, screen printing inks, inks for offset-, flexo- or inkjet printing, printing plates, adhesives, sealings, potting components, dental compositions, foams, moulding compounds, composite compositions, glass fibre cable coatings, screen printing stencils, for producing three-dimensional objects by means of stereolithography, and as image recording material, photoresist compositions, decolorizing materials, decolorizing materials for image recording materials, and for image recording materials using microcapsules.

11. A coated substrate coated on at least one surface with the composition according to claim 4 .

12. A polymerized or crosslinked composition obtained by curing the polymerizable composition according to claim 4 .

13. A process for the preparation of the compound of the formula I as defined in claim 1 , which comprises acylating a OH functionalized α-hydroxyketone of the formula III

wherein

X is —O—, —O—CH 2 — or —O(CHR 14 )—;

n is 0-10;

R 6 is hydrogen or C 1 -C 4 alkyl;

R 7 is hydrogen, and if R 6 is hydrogen then R 7 may additionally be C 1 -C 4 alkyl; with phenyl glyoxylic acid or a derivative of a phenyl glyoxylic acid of the formula IVa or IVb

R 8 is group A or B

R 9 and R 1 independently of one another are hydrogen or C 1 -C 4 alkyl;

R 11 and R 12 independently of one another are C 1 -C 4 alkyl or form together with the C atom to which they are attached a 5 to 7 membered saturated carbocyclic ring;

R 13 is hydrogen, C 1 -C 4 alkyl, C 5 -C 7 cycloalkyl, 2-tetrahydropyranyl or Si(C 1 -C 4 alkyl) 3 ;

R 14 is a group A′

R′ 13 has one of the meanings as given for R 13 or is the group C

wherein

R 1 , R 2 , R 4 and R 5 independently of one another are hydrogen, C 1 -C 4 alkyl, C 5 -C 7 cycloalkyl, phenyl, C 1 -C 4 alkoxy, C 5 -C 7 cycloalkoxy or phenoxy;

R 3 , if m is 1 has one of the meanings as given above for R 1 , R 2 , R 4 and R 5 ;

R 3 , if m is 2 is a divalent group; and

Y is a OH, Cl or Br, optionally in the presence of a base.