| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide, in a tubular molded item of a pipe or a pipe joint that is in need of the biodegradability, a tubular molded item that maintains the biodegradability as well as ensures sufficiently the impact resistance and also the adhesiveness between pipes themselves and a pipe and a pipe joint. <P>SOLUTION: This tubular molded item from a biodegradable resin and of a thickness of from 1 mm or more to 15 mm or less is manufactured by molding only predetermined one molding material containing a resin composition having as the principal component the lactic acid polymer that includes a constitutional unit of D-lactic acid and that of L-lactic acid, has a ratio of the constitutional unit of D-lactic acid of 5 mass% or less or of 95 mass% or more, and has the high crystallizability. By cooling to inhibit the crystallization on both outer surface parts so that this molded item may have the part with a relatively lower crystallinity on the outer surface parts and may have the part with a relatively higher crystallinity on the inside of the pipe wall. <P>COPYRIGHT: (C)2012,JPO&INPIT |
