| 摘要 |
<p>PURPOSE: To prevent the deformation of a molded object caused by heat stress and to make a protective layer peelable by extruding the protective layer composed of a thermal resin substantially transparent at temp. below its m.p. to apply the same to the surface of a continuous molded object made of a thermoplastic resin while holding the surface temp. of the molded object to below the m.p. thereof. CONSTITUTION: A protective layer composed of a thermoplastic resin transparent at temp. below its m.p. is extruded to be applied to the surface of a continuous molded object made of a thermoplastic resin while the surface temp. of the molded object is held to below the m.p. of the thermoplastic resin. For example, the surface temp. of a high density polyethylene pipe 1 is cooled to 109 deg.C lower than the m.p. of 122 deg.C, thereof and guided to a crosshead die 4 while thermal transfer printing 2 is applied to the surface of the pipe. High density polyethylene is supplied to the crosshead die 4 from a second extruder and a protective layer 3 of 109 deg.C is formed by a mold cavity 41 to be laminated to the surface of the thermal transfer printing 2. At this time, cooling air is ejected to the gap between the surface of the high density polyethylene pipe 1 and the introducing port 42 of the crosshead die 4 from cooling pipes 5, 5... to adjust the degree of the lamination of the molded object 1 and the protective layer 3.</p> |
