D1479 stable liquid BAP photoinitiator and its use in radiation curable compositions

1. A radiation curable composition for optical fiber comprising a liquid bis(acyl)phosphine of formula (I):

and at least one free-radical polymerizable component;

wherein each of Ar 1 , Ar 2 and Ar 3 is independently selected from the group consisting of a phenyl group, a methylphenyl group, an ethylphenyl group, a dimethylphenyl group, a trialkylphenyl group, an isopropylphenyl group, a tert-butyl phenyl group, a methoxy phenyl group, a dimethoxyphenyl group, an ethoxy phenyl group, a diethoxy phenyl group, an isopropoxy phenyl group, a thiomethoxy phenyl group, a naphthyl group, a thiophenyl group and a pyridyl group; and

wherein said liquid bis(acyl)phosphine of formula (I) is liquid at 20° C. and is stabilized as a composition comprising less than about 1.0 wt. % water.

2. The radiation curable composition of claim 1 , wherein each of Ar 1 , Ar 2 and Ar 3 is independently a trialkylphenyl group and wherein the trialkylphenyl group is a 2,4,6-trimethylphenyl group.

3. The radiation curable composition of claim 1 , wherein the phosphine is bis(2,4,6-trimethylbenzoyl)phenylphosphine wherein Ar 1 is a phenyl group and each of Ar 2 and Ar 3 is a 2,4,6-trimethylphenyl group.

4. An optical fiber coating composition, which is the radiation curable composition of claim 1 , wherein the optical fiber coating composition is selected from the group consisting of a primary coating, a secondary coating, an ink coating, an upjacketing coating, a buffer coating and a matrix coating.

5. The radiation curable composition of claim 1 , further comprising a liquid bis(acyl)phosphine oxide of formula (II):

wherein each of Ar 1 , Ar 2 and Ar 3 is independently a selected from the group consisting of a phenyl group, a methylphenyl group, an ethylphenyl group, a dimethylphenyl group, a trialkylphenyl group, an isopropylphenyl group, a tert-butyl phenyl group, a methoxy phenyl group, a dimethoxyphenyl group, an ethoxy phenyl group, a diethoxy phenyl group, an isopropoxy a phenyl group, a thiomethoxy phenyl group, a naphthyl group, a thiophenyl group and a pyridyl group.

6. The radiation curable composition of claim 5 , wherein each of Ar 1 , Ar 2 and Ar 3 is independently a trialkylphenyl group and the trimethylphenyl group is a 2,4,6-trimethylphenyl group.

7. The radiation curable composition of claim 5 , wherein the phosphine oxide is bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, wherein Ar 1 is a phenyl group and each of Ar 2 and Ar 3 is a 2,4,6-trimethylphenyl group.

8. A radiation curable composition selected from the group consisting of an optical fiber coating composition and a coating composition capable of radiation cure on concrete and a coating composition capable of radiation cure on metal comprising at least one free-radical polymerizable component and a combination of at least two photoinitiators wherein at least one photoinitiator is liquid bis(2,4,6-trimethylbenzoyl)phenylphosphine and at least one photoinitiator is bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide.

9. The radiation curable composition of claim 8 , wherein the combination of bis(acyl)phosphine and bis(acyl)phosphine oxide are liquid at a temperature of about 15° C. or greater.

10. The radiation curable composition of claim 9 , wherein liquid bis(2,4,6-trimethylbenzoyl)phenylphosphine and bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide are present in a ratio of about 1:1 as measured by HPLC.

11. The radiation curable composition of claim 1 , wherein the composition is curable by UV light generated by a conventional UV light source.

12. The radiation curable composition of claim 1 , wherein the composition is curable by light generated by a LED light source.

13. The radiation curable composition for optical fiber of claim 1 wherein said liquid bis(acyl)phosphine of formula (I) is stabilized as a composition comprising less than about 0.75 wt. % water.

14. The radiation curable composition for optical fiber of claim 1 wherein said liquid bis(acyl)phosphine of formula (I) is stabilized as a composition comprising less than about 0.5 wt. % water.

15. The radiation curable composition for optical fiber of claim 1 wherein said liquid bis(acyl)phosphine of formula (I) is stabilized as a composition comprising less than about 0.25 wt. % water.

16. The radiation curable composition for optical fiber of claim 1 wherein said liquid bis(acyl)phosphine of formula (I) is stabilized as a composition comprising less than about 0.2 wt. % water.

17. The radiation curable composition for optical fiber of claim 1 wherein said liquid bis(acyl)phosphine of formula (I) is stabilized as a composition comprising less than about 0.15 wt. % water.

18. The radiation curable composition for optical fiber of claim 1 wherein said liquid bis(acyl)phosphine of formula (I) is stabilized as a composition comprising less than about 0.1 wt. % water.