PURPOSE: To prevent reduction of the optical transmission performance due to heat deterioration during melting by blending a fluoroalkyl methacrylate (co)polymer with a specified percentage of mercaptan and using the resulting resin composition as the material of a clad for a core contg. methyl methacrylate as the principal component.
CONSTITUTION: Mercaptan contg. ≥1 -SH groups, especially ≥2 -SH groups in one molecule as a heat stabilizer is added to a homo- or copolymer of F-contg. monomers represented by formulae I , II [where X is H, F or Cl, each of R1 and R2 is H, CH3, C2H5 or CF3, each of (m) and (l) is 1W10, and (n) is 1W6] or a copolymer of ≥70wt% said F-contg. monomer with ≤30wt% other copolymerizable vinyl monomer. The amount of mercaptan to be added is 0.1W5pts.wt. per 100pts.wt. homo- or copolymer. A heat resistant optical transmission fiber consisting of a clad made of the resulting resin composition and a core contg. methyl methacrylate as the principal component is manufactured. Thermal decomposition is not caused during melting, preventing the formation of bubbles which deteriorate the transmission performance, and superior adhesive strength of the core to the clad is obtd.
NISHIDA KOUJI
TAWARA YASUTERU
