| 摘要 |
A process for forming a container blank with flexible fold lines from polylactic acid sheet material. In the process, a sheet of polylactic acid material suitable for use as a container blank is placed between a forming tool and a substantially flat surface. The temperature of the forming tool is maintained at a point between the softening temperature and the melting temperature of the polylactic acid sheet. Then, a high frequency electric field is created between the forming tool and the flat surface so as to heat a portion of the polylactic acid sheet sandwiched therebetween, while pressing the forming tool into the sheet to a depth of at least 25% of the thickness of the sheet and forming bulges in the sheet adjacent to opposite sides of the tool. Next, the polylactic acid sheet is allowed to cool while maintaining the same in a substantially flat condition. Thereafter, a container is formed using the creased polylactic acid sheet. |
