| 摘要 |
PURPOSE:To obtain the entitled optical fiber superior in light transmission characteristics, by continuously polymerizing starting materials pretreated in prescribed manners, forming polymethyl methacrylate having a specified stereoregularity, and using it for a core material. CONSTITUTION:(i) A monomer consisting essentially of methyl methacrylate is degassed in reduced pressure and/or stripped, and heat treated at about 110 deg.C to remove oxygen and peroxide contained, (ii) said monomer, a polymn. initiator composed of an azo compd., and a chain transfer agent are treated by means of distillation, ultrafiltration, etc. to remove ultrafine particles contained, (iii) then, they are fed into a polymerizing reactor, and continuously polymerized to form a polymer having <=1.1 syndiotactic parts/heterotactic parts ratio (area ratio obtd. by measuring an alpha-methyl signal by NMR). (iv) Next, said polymer is used as a core material, and a polymer lower in refractive index than this polymer is used as a sheath material to prepare optical fibers. |
