PURPOSE: To improve especially thermal aging resistance and durability, by a method wherein a tubular molded body such as a tube or a hose superior in mechanical and sliding properties at the time of a high temperature is manufactured by molding copolymer polyester containing a structural unit expressed by a specific formula.
CONSTITUTION: This tubular molded body is made into a molded product of copolymer polyester comprised of a structural unit of polyester formed of p- hydroxybenzoic acid expressed by a formula I, a structural unit formed of 4, 4-dihydroxy biphenyl expressed by a formula II, a structural unit formed of ethylene glycol expressed by a formula III and a structural unit formed of terephthalic acid expressed by a formula IV. On this occasion, the structural units (I+II) and (I+II+III) are made respectively 80-93mol% of the (I+II+III) and 20-7mol% of the (I+II+III). Then a matter whose mol ratio of the structural unit I/III becomes 78/22-93/7 and logarithmic viscosity becomes 1.0-3.0dl/g is used as the copolymer polyester.
GOTO NORIAKI
INOUE SHUNEI
