Ultraviolet-curable resin composition and optical fiber
In an ultraviolet-curable resin composition for an optical fiber coating, the polarity parameter E T (30) of the resin composition is 47 to 61.
1. An ultraviolet-curable resin composition for an optical fiber coating, wherein a polarity parameter E T (30) of the resin composition is 47 to 61, wherein the polarity parameter E T (30) is determined by dissolving a betaine dye having a structure represented by a following formula (1) in the resin composition, measuring a maximal absorption wavelength λmax, and calculating according to the following expression:
E T (30)=28591/λmax [nm]
2. The ultraviolet-curable resin composition according to claim 1 , wherein the polarity parameter E T (30) is 51 to 61.
3. The ultraviolet-curable resin composition according to claim 1 , comprising a urethane (meth)acrylate oligomer, a monomer, and a photopolymerization initiator.
4. The ultraviolet-curable resin composition according to claim 3 , wherein the monomer comprises a nitrogen-containing monomer, and a content of the nitrogen-containing monomer is 15% by mass or less based on a total amount of the resin composition.
5. The ultraviolet-curable resin composition according to claim 4 , wherein the nitrogen-containing monomer comprises a heterocycle-containing (meth)acrylate or an N-substituted amide monomer.
6. An optical fiber comprising:
an optical transmission medium comprising a core and a cladding;
a primary resin layer being in contact with the optical transmission medium and covering the optical transmission medium; and
a secondary resin layer covering the primary resin layer,
wherein the secondary resin layer is a cured product of the ultraviolet-curable resin composition according to claim 1 .
7. The optical fiber according to claim 6 , wherein the polarity parameter E T (30) is 51 to 61.
8. The optical fiber according to claim 6 , wherein the ultraviolet-curable resin composition comprises a urethane (meth)acrylate oligomer, a monomer, and a photopolymerization initiator.
9. The optical fiber according to claim 8 , wherein the monomer comprises a nitrogen-containing monomer, and a content of the nitrogen-containing monomer is 15% by mass or less based on a total amount of the resin composition.
10. The optical fiber according to claim 9 , wherein the nitrogen-containing monomer comprises a heterocycle-containing (meth)acrylate or an N-substituted amide monomer.