Patent ID: 11964906
Assignee: COVESTRO (NETHERLANDS) B.V.
Field: Basic materials chemistry (Chemistry)
Classification: CPC C | IPC C

Claim 12:
13. A radiation curable composition for coating an optical fiber comprising:
a urethane acrylate oligomer which is the reaction product of an isocyanate, a polyol, and a (meth)acrylate monomer;
a reactive diluent monomer;
optionally, one or more additives; and
a Norrish Type I photoinitiator; wherein the Norrish Type I photoinitiator possesses:
(a) a potential excited triplet state with an ionization potential from 3.0 electron volts (eV) to 3.90 eV, wherein the ionization potential is calculated in accordance with molecular modeling B3LYP/6-31G(d) in combination with Koopman's Theorem (IP=−εHOMO); and/or
(b) a normalized rate of polymerization at 150 degrees Celsius (° C.) of between 0.35 and 0.9, wherein the normalized rate of polymerization at 150° C. is the maximum polymerization rate (in mmol/kg sec) of a mixture at 150° C. divided by the maximum polymerization rate of the mixture at 25° C., wherein the mixture comprises 1 part by weight of the Norrish Type I photoinitiator and 99 parts by weight of ethoxylated nonyl-phenol acrylate, and the polymerization rate is determined via an RT-FTIR method, wherein the RT-FTIR method is conducted while employing an ATR crystal with a 60 micron film, and a Dr. Honle D-bulb with an irradiance of 20 mW/cm2.