Resin composition for a coating for an optical fiber, and coated optical fiber and optical fiber unit using the same

摘要

A resin composition for a coating for an optical fiber which comprises a radical polymerizable oligomer (A) and a radical polymerizable monomer (B), wherein (A) comprises a radical polymerizable oligomer (A1) with Mn of 600 to 1600 formed by reacting compounds (1) to (3) below: (1) an aliphatic polyol compound with Mn of 50 to 600, (2) a polyisocyanate compound with a ring structure, and (3) a compound with a hydroxyl group and a radical polymerizable unsaturated group; and a radical polymerizable oligomer (A2) formed by reacting compounds (4) to (6) below: (4) an aliphatic polyol compound with Mn of 800 to 10,000, (5) a polyisocyanate compound, and (6) a compound with a hydroxyl group and a radical polymerizable unsaturated group; a mass ratio (A1)/ (A2) is 20/80 to 80/20, and a concentration of urethane linkages within the resin composition is 1.85 to 3.00 mol/kg.