| 摘要 |
PROBLEM TO BE SOLVED: To provide a polybutylene terephthalate resin compsn. for an optical fiber loose tube which shows excellent resistance against hydrolysis and which hardly causes defective products due to contamination of dies or eye mucus. SOLUTION: This resin compsn. for an optical fiber loose tube consists of polybutylene terephthalate (A) having the following properties. The polybutylene terephthalate contains butylene terephthalate oligomers by <=0.30 wt.%, and when it is heat treated at 150 deg.C for 60 min, the amt. of the volatilized gas produced is <=10 ppm. It has <30 eq/ton density of molecular end carboxyl groups, and 1.0 to 1.2 intrinsic viscosity [η] calculated from the soln. viscosity measured at 25 deg.C in orthochlorophenol.
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