^4fDual Cationic and Free Radical UV Curable Optical Fiber Coating System

摘要

^7fThis report deals with a UV curable optical fiber coating system consisting of dual cure chemistries. The coating system comprising of a cationic curable primary coating and free radical curable secondary coating is reported. The UV curable functional groups in the primary coating are vinyl-ether groups and in the secondary coating are acrylate groups. The primary coating is based on a hydrocarbon oligomer with a controlled microstructure. The secondary coating is a standard commercial urethane-acrylate formulation. Detailed data on cure behavior, physical and optical properties of this novel primary coating will be presented. Some of the key properties are: 1. Low UV cure energy provides high vinyl ether conversion 2. UV cure speed unaffected at elevated temperatures 3. Low modulus at high percent conversion 4. Low modulus down to Tg of -55癈 Film studies encouraged us to examine the performance of the dual coating system on-fiber. In the fiber draw experiments the new primary coating was applied with a conventional urethane-acrylate secondary coating, using both wet-on-dry and wet-on-wet techniques at fast line speeds. The new coating system was a drop-in replacement for a conventional primary coating in making a single mode telecommunications grade optical fiber, using a 25-meter draw tower. The single mode fiber was evaluated and passed several key GR-20 tests.