Abstract: Disclosed are cationic photocurable compositions with improved shelf life stability. The thermally stable compositions comprise at least one cationically polymerizable compound, for example an epoxy compound, at least one onium salt photoinitiator and at least one compound selected from the group consisting of the organic phosphorus stabilizers and the hindered nitroxyl stabilizers. Also disclosed is a cationic photoinitiator composition comprising at least one onium salt photoinitiator and at least one compound selected from the group consisting of the organic phosphorus stabilizers and the hindered nitroxyl stabilizers.

Abstract: Optical fiber coating compositions which comprise at least one ethylenically unsaturated polymerizable compound and a photoinitiator blend, wherein the blend comprises (a) bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide and (b) 2,4,6,-trimethylbenzoylethoxyphenylphosphine oxide in an (a):(b) weight:weight ratio of between about 1:10 and about 1:8; or (c) bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, (d) 2,4,6,-trimethylbenzoylethoxyphenylphosphine oxide and (e) 2-hydroxy-2-methyl-1-phenyl-1-propanone in a (c):(d):(e) weight:weight:weight ratio between about 3:1:14 and about 4:1:16; or (f) bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide and (g) 2-hydroxy-2-methyl-1-phenyl-1-propanone in a (f):(g) weight:weight ratio of between about 1:3 and about 1:5 exhibit fast photospeed, very low color and fast photobleaching. The photoinitiator blends have low volatility, high shelf life stability and high compatibility with resins and monomers. The photoinitiator blends are for example liquid and easy to use.

Abstract: Disclosed is a process for photocuring certain thick layer ethylenically unsaturated systems with a light emitting diode (LED) light source. The thick curable compositions are thick coatings, gel coats, composites and adhesives. The photoinitiator is at least one bisacylphosphine oxide or monoacylphosphine oxide. The process provides for excellent surface cure and through cure.

Abstract: Optical fiber coating compositions which comprise at least one ethylenically unsaturated polymerizable compound and a photoinitiator blend, wherein the blend comprises (a) bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide and (b) 2,4,6,-trimethylbenzoylethoxyphenylphosphine oxide in an (a):(b) weight:weight ratio of between about 1:10 and about 1:8; or (c) bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, (d) 2,4,6,-trimethylbenzoylethoxyphenylphosphine oxide and (e) 2-hydroxy-2-methyl-1-phenyl-1-propanone in a (c):(d):(e) weight:weight:weight ratio between about 3:1:14 and about 4:1:16; or (f) bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide and (g) 2-hydroxy-2-methyl-1-phenyl-1-propanone in a (f):(g) weight:weight ratio of between about 1:3 and about 1:5 exhibit fast photospeed, very low color and fast photobleaching. The photoinitiator blends have low volatility, high shelf life stability and high compatibility with resins and monomers. The photoinitiator blends are for example liquid and easy to use.

Abstract: Disclosed are cationic photocurable compositions with improved shelf life stability. The thermally stable compositions comprise at least one cationically polymerizable compound, for example an epoxy compound, at least one onium salt photoinitiator and at least one compound selected from the group consisting of the organic phosphorus stabilizers and the hindered nitroxyl stabilizers. Also disclosed is a cationic photoinitiator composition comprising at least one onium salt photoinitiator and at least one compound selected from the group consisting of the organic phosphorus stabilizers and the hindered nitroxyl stabilizers.