Patent ID: 8426021

Claim:
An optical fiber coated with a radiation curable primary coating and a radiation curable secondary coating composition wherein said radiation curable secondary coating composition comprises a secondary coating oligomer blend; wherein said secondary coating oligomer blend comprises an alpha oligomer, a beta oligomer, and a gamma oligomer; wherein said alpha oligomer is urethane-free and is prepared by reaction of: an acrylate compound selected from an alcohol-containing acrylate or alcohol-containing methacrylate compound, an anhydride compound, an epoxy-containing compound, and an alpha oligomer catalyst selected from the group consisting of triphenylphosphine (TPP), tritoluylphosphine, phosphonium salts, tertiary amines, triethylene triamine catalysts, 1,4-diazabicyclo[2.2.2]octane (DABCO), metal catalysts, chromium (III) acetate, carboxylic acid metal salts, tin catalysts, stannous alkoxides, stannous acrylates, and titanium catalysts, wherein said beta oligomer is different from said alpha oligomer and is prepared by reaction of the following reagents: hydroxyethyl acrylate; one or more diisocyanates; a polyester polyol or a polyether polyol having a number average molecular weight in the range of from 300 g/mol to 10,000 g/mol; and a beta oligomer catalyst selected from the group consisting of dibutyl tin dilaurate; metal carboxylates; sulfonic acids; amino-base catalysts; organo-base catalysts; alkoxides of zirconium; alkoxides of titanium; ionic liquid phosphonium salts; ionic liquid imidazolium salts; and ionic liquid pyridinium salts; and wherein said gamma oligomer is an epoxy diacrylate; wherein said composition further comprises a single slip additive or a blend of slip additives; wherein said secondary coating composition is coated on said optical fiber with a glass drawing tower operated at a line speed of from about 750 m/min to about 2100 m/min, and wherein the cured secondary coating exhibits the following properties after initial cure and after one month aging at 85° C. and 85% relative humidity: a % RAU of from 80% to 98%; an in-situ modulus of between 0.60 GPa and 1.90 GPa; and a Tube Tg, of from 50° C. to 80° C.; wherein said beta oligomer is present in said radiation curable secondary coating composition in an amount ranging from 15.0 wt. % to 31.39 wt. %, based on the total weight of the coating composition.