| 摘要 |
PROBLEM TO BE SOLVED: To upgrade a vulcanization by molding a resin coating layer in a shape having at least one strip of protruding or recess strip extending in a rib state in a lengthwise direction of a hose along an outer periphery of an extrusion molded unvulcanized rubber hose in the case of extrusion molding the layer on the outer periphery of the hose, thereby reducing a contact area between adjacent resin coating layers. SOLUTION: A mandrel 18, an inner surface rubber layer 12 and a reinforcing layer 14 are first passed through a crosshead of an outer surface rubber extruder, an outer surface rubber layer 16 is extrusion molded on an outer periphery of the layer 14, and then passed through a crosshead of a resin extruder to extrusion mold a resin coating layer 46 on an outer periphery of the layer 16. In this resin coating step, the layer 46 is molded in a shape having a plurality of protruding strips 48 extended at a predetermined pitch in a circumferential direction in a rib state in a lengthwise direction of the hose along an outer periphery. Here, a protruding height of the strip 48 is desirably 0.2 to 5 mm. The layer 46 may be considered to provide a plurality of recess strips 50 extended in a lengthwise direction on an outer periphery at a predetermined pitch in a circumferential direction. |
