HEAT AND PRESSURE-RESISTANT SELF-SUPPORTING CONTAINER AND PRODUCTION THEREOF

摘要

PURPOSE: To prevent the heat creep of a bottom part at a time of heating and sterilization and to obtain excellent heat and pressure resistance and impact resistance by providing a thick-walled thermally crystallized part to a bottom central part and stretching the bottom part other than the central part in high stretching magnification not only to reduce the wall thickness thereof but also to orient and crystallize the bottom part and providing a plurality of trough parts and foot parts to the peripheral part of the bottom part. CONSTITUTION: Stepped parts 8, 9 are formed between the body part 3 and shoulder part 5 of a container 1 as well as between the body part 3 and bottom part 4 thereof and a thick- walled thermally crystallized part 10 is provided to the central part of the bottom part 4. The bottom parts 11, 12 other than the thermally crystallized part are formed so as to form difference in level 13 from the thermally crystallized part 10 to be stretched in high stretching magnification to be reduced in thickness and oriented to be crystallized by thermal fixing. As a result, the heat-resistant creep of the whole of the bottom part can be enhanced and a plurality of trough parts 11 and foot parts 12 are provided to the peripheral part of the bottom part. At this time, since the resin of the bottom parts other than the thermally crystallized part is drawn out to be formed into the foot parts, the reduction of the wall thickness of the foot parts can be prevented. Since the thermally crystallized part 10 of the central part of the bottom part is upwardly depressed, when the content of a bottle is heated and sterilized, the self-supporting stability of the bottle is kept.