| 摘要 |
The present invention is a polyester block copolymer composition for flexible boots which comprises: a resin component comprising a polyester block copolymer [A] that contains a polybutylene naphthalate component as a hard segment and a polyoxytetramethylene glycol component having a number-average molecular weight of 1,100-1,400 as a soft segment and has a soft-segment content of 30-60 mass% and a polyester block copolymer [B] that contains a polybutylene terephthalate component as a hard segment and a polyoxytetramethylene glycol component having a number-average molecular weight of 1,200-1,800 as a soft segment and has a soft-segment content of 30-60 mass%, the copolymers [A] and [B] being contained in a specific ratio; and a polyfunctional epoxy compound [C] incorporated in an amount of 0.05-3 parts by mass per 100 parts by mass of the resin component. With the composition, it is possible to provide flexible boots which show satisfactory flex fatigue resistance when used in high-temperature environments and which keep flexible when used in low-temperature environments. |
