Polymeric photoinitiators

1. A polyalkylether photoinitiator of the general formula I

R 1 (A 1 ) r -(R 2 ((—CH 2 CH 2 O) t A 2 ) m -O) o —(R 3 ((CH 2 CH 2 O) t A 3 ) n -O) p —R 4 (A 4 ) s   I

wherein R 2 and R 3 are independently at each occurrence identical or different, linear or branched alkylene or cycloalkylene groups; wherein R 2 and R 3 may be substituted with one or more substituents selected from CN; azides; esters; ethers; amides; halogen atoms; sulfones; sulfonic derivatives; NH 2 or Nalk 2 , where alk is any C 1 -C 8 straight chain alkyl group, C 3 -C 8 branched or cyclic alkyl group;

R 1 and R 4 are independently at each occurrence identical or different, linear or branched alkyl or cycloalkyl groups or aryl groups or are independently at each occurrence selected from H, OH, CN, halogens, amines, amides, alcohols, sulfones and derivatives thereof, sulfonic acid and derivatives thereof, sulfoxides and derivatives thereof, carbonates, isocyanates, nitrates, acrylates, polyethylenes, polypropylenes, polyesters, polyamides, polyacrylates and polyurethanes; and when R 1 and R 4 are alkyl and aryl groups, each of R 1 or R 4 may be substituted with one or more substituents selected from CN; OH; azides; esters; amides; halogen atoms; sulfones; sulfonic derivatives; NH 2 or Nalk 2 , where alk is any C 1 -C 8 straight chain alkyl group, C 3 -C 8 branched or cyclic alkyl group;

o and p are each a real number from 0-5000 provided that o+p>0;

m and n are each a real number from 0-10,

provided that m+n>0;

r and s are each a real number from 1-5;

t is an integer from 1-100; and

A 1 , A 2 , A 3 and A 4 are identical or different photoinitiator moieties.

2. The polyalkylether photoinitiator according to claim 1 , wherein A 1 , A 2 , A 3 and A 4 are linked to R 1 , R 2 , R 3 , and R 4 , respectively, via a spacer group.

3. The polyalkylether photoinitiator according to claim 2 , wherein the spacer group is selected from the group consisting of alkylene, cycloalkylene, aryl, and alkylene ether groups.

4. The polyalkylether photoinitiator according to claim 1 , wherein R 2 =—CH 2 CH 2 , in which one or more H atoms may be replaced by A 2 .

5. The polyalkylether photoinitiator according to claim 1 , wherein R 3 =—CH 2 CH 2 , in which one or more H atoms may be replaced by A 3 .

6. The polyalkylether photoinitiator according to claim 1 , wherein R 2 =—CH(CH 3 )CH 2 —, in which one or more H atoms may be replaced by A 2 .

7. The polyalkylether photoinitiator according to claim 1 , wherein R 3 =—CH(CH 3 )CH 2 —, in which one or more H atoms may be replaced by A 3 .

8. The polyalkylether photoinitiator according to claim 1 , wherein R 1 =OH.

9. The polyalkylether photoinitiator according to claim 1 , wherein R 4 =H.

10. The polyalkylether photoinitiator according to claim 1 , wherein A 1 , A 2 , A 3 and A 4 are identical or different photoinitiator moieties selected from the group consisting of benzoin ethers, phenyl hydroxyalkyl ketones, phenyl aminoalkyl ketones, benzophenones, thioxanthones, xanthones, acridones, anthraquinones, fluorenones, dibenzosuberones, benzils, benzil ketals, α-dialkoxy-acetophenones, α-hydroxy-alkyl-phenones, α-amino-alkyl-phenones, acyl-phosphine oxides, phenyl ketocoumarins, silane, maleimides, and derivatives thereof.

11. The polyalkylether photoinitiator according to claim 10 , wherein A 1 , A 2 , A 3 and A 4 are identical or different photoinitiator moieties selected from the group consisting of 2-hydroxy-2-methyl-propiophenone, benzophenone, thioxanthone, benzil, anthraquionone, camphorquinone, benzoin ether, acylphosphine oxide, silane, and derivatives thereof.

12. The polyalkylether photoinitiator according to claim 11 , wherein A 1 , A 2 , A 3 and A 4 are identical photoinitiator moieties.

13. The polyalkylether photoinitiator according to claim 1 , wherein A 1 , A 2 , A 3 and A 4 are at least two different photoinitiator moieties.

14. The polyalkylether photoinitiator according to claim 12 , wherein at least one of A 1 , A 2 , A 3 and A 4 is a benzophenone photoinitiator moiety.

15. The polyalkylether photoinitiator according to claim 14 , wherein at least A 2 and A 3 are benzophenone photoinitiator moieties.

16. The polyalkylether photoinitiator according to claim 1 , wherein o and p are each from 0-3000.

17. The polyalkylether photoinitiator according to claim 1 , wherein m and n are each an integer from 0-8 provided that m+n>0.

18. The polyalkylether photoinitiator according to claim 1 , wherein m=1 and/or n=1.

19. The polyalkylether photoinitiator according to claim 1 , wherein m=1, n=0 and the ratio o:p is at least 1:1000.

20. The polyalkylether photoinitiator according to claim 1 , wherein r and s are each from 1-4.

21. The polyalkylether photoinitiator according to claim 1 , having a molecular weight between 5 kDa and 10,000 kDa.

22. A method for curing a matrix composition, said method comprising the steps of:

a) mixing the polyalkylether photoinitiator according to claim 1 with a matrix composition;

b) curing the mixture obtained in step a) by exposing it to UV radiation.

23. A matrix composition obtained via the method of claim 22 .