Patent ID: 8262956

Claim:
A thin container production method to produce a thin container having a thickness in a range of 0.3 to 0.7 mm by injection molding of a polylactic acid resin, characterized in that a molten resin of a polylactic acid resin impregnated with supercritical carbon dioxide in a range of 0.5 to 2.5 percent by mass relative to the total amount is injected into a plurality of cavities corresponding to the thin container disposed in a mold, and each of opening and closing of a gate to each cavity is performed by an electromagnetic on-off valve for producing a plurality of thin containers by one injection operation, and a time period required for the molten resin of the polylactic acid injected into each cavity to reach a distal end of the cavity from the gate is measured, and a time of opening of the gate to each cavity by the electromagnetic on-off valve is controlled based on the measured time period.