Radiation polymerizable composition, cured layer of same, optical fiber containing cured layer and method for producing same

A primary coating layer of an optical fiber, the primary coating layer being formed from a radiation polymerizable composition comprising:

• (A) a urethane oligomer comprising a structure represented by formula (I) below:
• wherein R is a vinyl group and * is a bond;
• (B) one or more compounds of:
• (i) maleic anhydride,
• (ii) a compound represented by formula (II) below:
• wherein R1 is a single bond or an alkanediyl group comprising 1 to 6 carbon atoms, and
• R2 is a hydrogen atom, a hydroxy group, or a group represented by formula (II-1) or formula (II-2) below:
• wherein R3 is a hydrogen atom, an amino group, a carboxy group, a hydroxy group, an alkyl group, or an alkoxy group, and * is a bond, and
• wherein R4 is a hydrogen atom, an amino group, a carboxy group, a hydroxy group, an alkyl group, or an alkoxy group, and * is a bond, or
• (iii) a compound represented by formula (III) below:
• wherein R5 is an alkanediyl group comprising 1 to 6 carbon atoms;
• and
• (C) a radiation polymerization initiator.

A method for producing an optical fiber comprising a primary coating layer, comprising:

• disposing a radiation polymerizable composition on at least part of a surface of a glass fiber;
• and
• curing the radiation polymerizable composition by radiation irradiation, wherein the radiation polymerizable composition comprises:
• (A) a urethane oligomer comprising a structure represented by formula (I) below:
• wherein R is a vinyl group and * is a bond;
• (B) one or more compounds of:
• (i) maleic anhydride,
• (ii) a compound represented by formula (II) below:
• wherein R1 is a single bond or an alkanediyl group comprising 1 to 6 carbon atoms, and
• R2 is a hydrogen atom, a hydroxy group, or a group represented by formula (II-1) or formula (II-2) below:
• wherein R3 is a hydrogen atom, an amino group, a carboxy group, a hydroxy group, an alkyl group, or an alkoxy group, and * is a bond, and
• wherein R4 is a hydrogen atom, an amino group, a carboxy group, a hydroxy group, an alkyl group, or an alkoxy group, and * is a bond, or (iii) a compound represented by formula (III) below:
• wherein R5 is an alkanediyl group comprising 1 to 6 carbon atoms;
• and
• (C) a radiation polymerization initiator.