| 摘要 |
<p>PURPOSE:To reduce the production of cracks, uneven thickness and sag to the outside, by a method wherein a projection is formed at the tip when a bottom is molded by melting one end of a polyester tube for closure. CONSTITUTION:A tube is made from polyester whose main repeating unit is ethylene-terephthalate, both ends thereof being open which are heated to a molding temperature. When one end of them is closed by fusion-welding in a mold formation into a bottom and the other is molded into a desired neck shape, a projection is provided at the end of the bottom for closure by fusion-welding.</p> |
