METHOD FOR MANUFACTURING SILANE-CROSSLINKED PIPE MADE OF POLYETHYLENE

摘要

PROBLEM TO BE SOLVED: To provide a method for manufacturing a silane-crosslinked pipe made of polyethylene which is excellent in durability, appearance and extrusion moldability, and is suited for a cold and hot water pipe.SOLUTION: The method for manufacturing the silane-crosslinked pipe made of polyethylene, in which a polyethylene satisfying specified requisites is used as a base resin, includes: a process (1) of melting, kneading and reacting a mixture of 0.5 to 10 pts.wt. of organic unsaturated silane compound, 0.01 to 5 pts.wt. of organic peroxide and 0.005 to 10 pts.wt. of a silanol condensation catalyst while heating the mixture in an extruder to extrude the melted, kneaded and reacted mixture in a pipe shape; and thereafter, a process (2) of heating the extruded pipe-shaped material to subject to silane crosslinking according to the silanol condensation reaction, wherein, in the extruder, (A) the mixture is fed to the front of a silane graft reaction zone at a temperature lower than the one-minute half-life period temperature of the organic peroxide by 10°C or more and (B) the melting, kneading and silane graft reaction of the mixture are simultaneously performed in the silane graft reaction zone.