Polybutylene terephthalate having low carboxyl group concentration and loose tube for optical fiber comprising the same

摘要

A loose tube for an optical fiber comprising a polybutylene terephthalate. The polybutylene terephthalate has a terminal carboxyl group concentration of 10 eq./10.sup.6 g·polymer or less and an intrinsic viscosity [&eegr;], measured at 25° C. in orthochlorophenol, of 0.9 to 1.4 dl/g.