Tearable tube formed from fluororesin

[0061]A fluororesin tube was produced by melt extrusion molding with a tetrafluoroethylene-hexafluoropropylene copolymer (FEP) (FEP-130J manufactured by Du Pont-Mitsui Fluorochemicals Co., Ltd.) used as a fluororesin. In melt extrusion molding, a single screw extruder including a mold and having a cylinder diameter of 30 mm was used to perform tube molding by a sizing plate method at a screw rotation speed of 2.0 rpm and a die temperature of 330° C., thereby preparing a fluororesin tube (original tube) (before expansion) having an inner diameter of 0.5 mm, an outer diameter of 1.2 mm and a wall thickness of 0.35 mm. In the mold that was used, leg portions were provided in a flow path of a molten resin, the leg portions each had a width of 5 mm and length of 10 mm (length of the branched flow path), the number of the leg portions was 8, and the distance between a mold outlet and the leg portion on the molt outlet side was 10 mm.

[0062]Next, the resulting original tube was inserted into a

[0063]Except that as a fluororesin, a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA) (PFA 950 HPplus manufactured by Du Pont-Mitsui Fluorochemicals Co., Ltd.) was used in place of the tetrafluoroethylene-hexafluoropropylene copolymer (FEP), the same procedure as in Example 1 was carried out to prepare a fluororesin tube (original tube) (before expansion). Further, expansion was performed in the same manner as in Example 1 to obtain a fluororesin tube having an inner diameter of 1.25 mm, an outer diameter of 1.65 mm and a wall thickness of 0.2 mm (after expansion).