| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a mold for extrusion molding capable of controlling the occurrence of streaks in extrusion molding of cylindrical tubes made of a synthetic resin. <P>SOLUTION: A cylindrical resin passage 13 is secured by an inside mold 11 and an outside mold 12. A spiral area 14, a communicating area 15 and a parallel area 16 are demarcated in the resin passage 13, and the mold 1B for extrusion molding is constituted so that a molten resin is supplied and extruded to mold cylindrical tubes continuously. The shear rateγ<SB>w</SB>of the molten resin, expressed by an equation (1), is≤300 s<SP>-1</SP>on the inner peripheral surface 12a of the outside mold 12a and the outer peripheral surface 11a of the inside mold 11a in the parallel area 16. <P>COPYRIGHT: (C)2007,JPO&INPIT</p> |
