| 摘要 |
PURPOSE:To obtain a curable resin composition which can give a cured product which can show a sufficiently low modulus even at low temperatures and improved in water resistance and heat resistance, by mixing a specified urethane acrylate oligomer with a monofunctional acrylate. CONSTITUTION:This composition contains 30-70wt% urethane acrylate oligomer having a polytetramethylene ether structure of a number-average MW>=1,000 between respective urethane bonds and 70-30wt% monofunctional acrylate of the formula (wherein n is a positive integer and R1-R5 are each H or CH3). Said urethane acrylate oligomer can be obtained by reacting, for example, a diisocyanate with polytetramethylene ether glycol of a number-average MW>=1,000 and a hydroxyalkyl acrylate. Said curable resin composition is suitable as an optical fiber cladding material because it does not increase optical transmission loss. |
