Patent ID: 7309550

Claim:
A photosensitive composition comprising: at least one aliphatic polyether urethane (meth)acrylate oligomer having an average of about 2.0 (meth)acrylate groups per molecule, wherein the aliphatic polyether urethane (meth)acrylate oligomer is present in an amount of about 50 to 75% by weight of the total composition; at least one reactive diluent selected from the group consisting of: mono-(meth)acrylate esters, di-(meth)acrylate esters, poly-(meth)acrylate esters, and mixtures thereof, wherein the reactive diluent is present in an in amount of about 20 to 50% by weight of the total composition; and a mixture of two or more photoinitiators, wherein at least one photoinitiator is selected from the group of aromatic α-ketocarboxylic acid esters and at least one photoinitiator is selected from the group consisting of: benzoin and benzoinether derivatives, benzyl ketal derivatives, α,α-dialkyloxyacetophenone derivatives, α-hydroxyalkylphenone derivatives, α-aminoalkylphenone derivatives, acylphosphine oxide, acyl phosphine sulfides, α-ketocarboxylic acids and their esters, aromatic α-ketocarboxylic acids and their esters, O-acyl-α-oximino ketone derivatives, benzophenone and its derivatives, Michler's ketone, thioxanthone and its derivatives, metalocene compounds, bisimidazole and their derivatives, and polymer-bond compounds in amount of about 0.1 to 10% by weight of the total composition, wherein the photoinitiator provides reduced yellowing of the composition after curing.