Polymer Composition, Plastic Optical Fiber, Plastic Optical Fiber Cable, and Method for Manufacturing Plastic Optical Fiber

A plastic optical fiber characterized in that the fiber has a transmission loss of not more than 400 dB/km and a core of a polymer composition comprising 5 to 100% by mass of a unit (A) of a lactone compound represented by a general formula (1) and 0 to 95% by mass of a unit (B) of (meth)acrylate as constitutional units, wherein the unit (A) of a lactone compound comprises a unit of an (S) isomer represented by a general formula (2) and a unit of an (R) isomer represented by a general formula (3) at a mass ratio of from 70/30 to 30/70,

• wherein, in the formulae (1) to (3), R1 represents a methyl group, an ethyl group, or a propyl group;
• and R2 and R3 independently represent a hydrogen atom, a C1-12 alkyl group that may be unsubstituted or substituted with one or more than two fluorine atoms, a phenyl group that may be unsubstituted or substituted with one or more than two alkyl groups, or a cyclohexyl group that may be unsubstituted or substituted with one or more than two fluorine atoms, or alternatively R2 and R3 may unite each other to form a 5- or 6-membered ring including the carbon atom to which R2 and R3 are bonded, where the 5- or 6-membered ring may be substituted with one or more than two fluorine atoms.

A method for manufacturing a polymer composition characterized by polymerizing a mixture of monomers comprising 5 to 100% by mass of a lactone compound (A) represented by a general formula (1) comprising an (S) isomer represented by a general formula (2) and an (R) isomer represented by a general formula (3) at a mass ratio of from 70/30 to 30/70, and 0 to 95% by mass of a (meth)acrylate (B) so that the mixture has a polymer content equal to or greater than 94%;

• and then subjecting the mixture to thermal melting under conditions of a temperature of Tc° C. (Tc≧Tg+40) (Tg denotes a glass transition temperature of the polymer composition) and of a pressure equal to or greater than 0.6 MPa,
• wherein, in the formulae (1) to (3), R1 represents a methyl group, an ethyl group, or a propyl group;
• and R2 and R3 independently represent a hydrogen atom, a C1-12 alkyl group that may be unsubstituted or substituted with one or more than two fluorine atoms, a phenyl group that may be unsubstituted or substituted with one or more than two alkyl groups, or a cyclohexyl group that may be unsubstituted or substituted with one or more than two fluorine atoms, or alternatively R2 and R3 may unite each other to form a 5- or 6-membered ring including the carbon atom to which R2 and R3 are bonded, where the 5- or 6-membered ring may be substituted with one or more than two fluorine atoms.

A method for manufacturing a plastic optical fiber characterized by subjecting a core to thermal melting under conditions of a temperature of Tc° C. (Tc≧Tg+40) (Tg denotes a glass transition temperature of a polymer composition) and of a pressure equal to or greater than 0.6 MPa wherein the core is formed of a polymer composition obtained by polymerizing a mixture of monomers comprising 5 to 100% by mass of a unit (A) of a lactone compound represented by a general formula (1) comprising a unit of an (S) isomer represented by a general formula (2) and a unit of an (R) isomer represented by a general formula (3) at a mass ratio of from 70/30 to 30/70, and 0 to 95% by mass of a unit (B) of (meth)acrylate so that the mixture has a polymer content equal to or greater than 94%.