MANUFACTURE OF CYLINDER FOR PROTECTING FORESTED SEEDLING

摘要

PROBLEM TO BE SOLVED: To manufacture the cylinder for protecting the forested seedling which can be manufactured at a low cost and transmits the sunshine uniform in all directions in the cylinder even when the cylinder body is made translucent so as to transmit the sunshine inside. SOLUTION: An internal mold 1 which is sectioned in a regular polyhedral shape having an even number of vertexes and an external mold 2 which has a hole 20 in a sectional shape a little larger and similar to the internal mold 1 and a projection streak 21 projecting inward at the corner parts of the hole 20 are used; and a thermoplastic resin which exits from an extruder and is in a soft fused state is drawn passing through the gap between the hole 20 and internal mold 1. Further, the cylindrical thermoplastic resin in the soft fused state which has exited from the extruder can be drawn passing through the hole while sucked outwardly.