Granted Patent B2

US 12,643,973 · App. 18/029,404 · Granted Jun 2, 2026

Inventor: Yuya Homma (Osaka, JP)

Assignee: SUMITOMO ELECTRIC INDUSTRIES, LTD.

C08F290/067C03C25/1065C03C25/326C09D175/12G02B6/02395

Abstract

Claims (23)

1 . An optical fiber comprising:

a glass fiber including a core and a cladding;

a primary resin layer covering the glass fiber so as to be in contact with the glass fiber; and

a secondary resin layer covering the primary resin layer;

wherein the secondary resin layer includes a cured product of a resin composition for secondary coating of the optical fiber, the resin composition comprising:

a photopolymerizable compound including a urethane (meth)acrylamide; and

a photopolymerization initiator,

wherein the urethane (meth)acrylamide has a (meth)acrylamide group at at least one end of a urethane bond, and

wherein a Young's modulus of the secondary resin layer is 800 MPa to 3000 MPa at 23° C. +2° C.

2 . The optical fiber according to claim 1 , wherein the urethane (meth)acrylamide includes a urethane oligomer having a (meth)acrylamide group at one end of a urethane bond, a urethane oligomer having (meth)acrylamide groups at both ends of a urethane bond, or a mixture of the urethane oligomers.

3 . The optical fiber according to claim 2 , wherein the urethane oligomer having a (meth)acrylamide group at one end of a urethane bond includes a urethane oligomer having a (meth)acrylamide group at one end of a urethane bond and having a (meth)acryloyloxy group at the other end.

4 . The optical fiber according to claim 1 , wherein the urethane (meth)acrylamide has a number-average molecular weight of 500 to 6000.

5 . The optical fiber according to claim 1 , wherein a content of the urethane (meth)acrylamide is 5 parts by mass to 60 parts by mass based on 100 parts by mass of a total amount of the resin composition.

6 . The optical fiber according to claim 1 , wherein the photopolymerizable compound further includes a (meth)acrylic acid ester.

7 . The optical fiber according to claim 6 , wherein the (meth)acrylic acid ester includes a (meth)acrylate having a bisphenol skeleton.

8 . A method for producing an optical fiber, the method comprising:

applying a resin composition to an outer periphery of a glass fiber including a core and a cladding; and

curing the resin composition by ultraviolet irradiation after the applying, wherein the resin composition comprises:

a photopolymerizable compound including a urethane (meth)acrylamide; and

a photopolymerization initiator,

wherein the urethane (meth)acrylamide has a (meth)acrylamide group at at least one end of a urethane bond, and

wherein a Young's modulus of a cured product of the resin composition is 800 MPa to 3000 MPa at 23° C.±2° C.

9 . The optical fiber according to claim 1 , wherein a glass transition temperature of the secondary resin layer is 70° C. to 105° C.

Assignments (1)

Priority Claims (1)

Continuity (1)

References Cited (85)