METHOD FOR BLOW MOLDING A HOT-FILL CONTAINER WITH INCREASED STRETCH RATIOS

摘要

A method of manufacturing a hot-fill container (1) by means of blow molding a preform (16) provided with a wall and a closed bottom (19), said method comprising the steps of:
heating the preform (16) at a temperature greater than the glass transition temperature of the plastic;introducing the such heated preform (16) within a mold (32) provided with a mold base (36) and sidewalls (34A, 34B), which sidewalls are heated at a predetermined temperature;blow molding the preform (16) to form the container (1) for subsequent hot-fill applications;

wherein:
the wall of said preform (16) has a lower end segment (24) of increased thickness and the bottom (19) has a thickness lower than the lower end segment (24),the preform (16) is subjected to a length stretch ratio comprised between 3.4 and 3.9, and a hoop stretch ratio comprised between 3.5 and 3.9.

主权项

1. A method of manufacturing a hot-fill container (1) from a plastic preform (16) by means of blow molding said preform (16), wherein said container (1) is provided with a base (7) including a high standing ring (8) and a central outwardly-inclined invertible diaphragm (9), wherein said preform (16) has an open neck (2), a wall (18) and a closed bottom (19), said method comprising the steps of:
heating the preform (16) at a temperature greater than the glass transition temperature of the plastic; introducing the such heated preform (16) within a mold (32) provided with a mold base (36) and sidewalls (34A, 34B), which sidewalls are heated at a predetermined temperature; blow molding the preform (16) to form the container (1) for subsequent hot-fill applications;characterized in that:
the wall (18) of said preform (16) has a main segment (22) of substantially cylindrical shape and a lower end segment (24) of increased thickness adjacent the bottom (19), whereby said lower end segment (24) is stretched to form the high standing ring (8) of the container (1), and the bottom (19) has a thickness lower than the lower end segment (24) whereby the bottom (19) is stretched to form the invertible diaphragm (9) of the container (1), the preform (1) is subjected to a length stretch ratio comprised between 3.4 and 3.9, and a hoop stretch ratio comprised between 3.5 and 3.9.