PURPOSE: To improve long life such as pressure-resisting creep property by grafting a polyethylene having specified density and melt index with a silane compound followed by forming into a pipe in the uncross-linked state, and cross-linking the resulting polyethylene by the reaction with a silanol condensation catalyst and/or a water releasing material.
CONSTITUTION: A polyethylene having a density of 0.933-0.939g/cm3 and a melt index of 0.1-0.4g/10min is grafted with a silane compound and formed into a pipe in the uncross-linked state while the intermixture of water, silanol condensation catalyst and water releasing material is avoided as far as possible to prevent cross-linkage. After the molding, the resulting polyethylene is reacted with a silanol condensation catalyst and/or a water releasing material (those in which water is adsorbed to porous material powders such as alumina), and cross-linked. Hence, a hot water supply polyethylene pipe having well-balanced flexibility, short period strength and long period performance can be manufactured with good molding property.
NAKASHIBA AKIO
HASE FUMIO
MITO KAZUNORI
SHIBABUCHI TOSHIO
NAKAOKA MIKIO
MITSUI PETROCHEMICAL IND
SHINWA SANGYO KK
| JPS5837391A | 1983-03-04 | |||
| JPS6329701A | 1988-02-08 | |||
| JPS57127187A | 1982-08-07 |