PURPOSE: To develop a thermoplastic resin pipe as well as its production method and facilities having a sufficient reliability even in the application to a pipe to be laid underground for sewage or the like by remarkably enhancing a flat rigidity of a composite pipe containing a corrugated pipe.
CONSTITUTION: A two-layer composite pipe 3 made of corrugated composite parts A and straight socket composite parts B is molded in a mold by contact bonding an intermediate layer pipe 2 alternately consisting of corrugated parts 23 and straight parts 24 to an outer peripheral surface of a straight inner layer pipe. The outer peripheral surface of the two-layer composite pipe is heated to a predetermined temperature. The surface is coated with a half- melted outer layer pipe 4 in a vacuum atmosphere. In this manner, a three-layer composite pipe 5 firmly contact bonded under the managed conditions of heat and pressure difference is molded. The three-layer composite pipe 5 is cut at the straight composite part and expanded in bore to a required shape as a socket for producing an article. In this manner, though an outer diameter difference exists between the corrugated part and the socket part, the uniform and firm contact bonding of the outer layer pipe to the intermediate layer pipe ensures a high-efficiency production of an article having a high flat rigidity, no wrinkle, and a smooth and beautiful appearance.
SHIOMI ICHIRO
NAKANO RYOICHI
NAGASE SADAO
MIZUTANI YOSHIAKI
BAN HISAYOSHI
MITSUBISHI CHEM CORP