| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a cap and a manufacturing method for the same, which prevent the cap from coming off from a mouth piece of a bottle when an inner pressure of the bottle increases and enable a highly precise setting of the value of the inner pressure to be released. <P>SOLUTION: The cap 10 made of a rolled material has a top face 11 and a side face 12 almost vertically extending downward from the circumferential edge of the top face 11, and is fitted on the mouth piece of the bottle. At least one vent hole 21 is formed on the side face 12 to extend circumferentially thereon. The vent hole 21 has a length equivalent to 4% or more to 15% or less of the circumferential length of the side face 12 so that a straight line passing through the axis of the cap 10 and parallel with the rolling direction of the rolled material makes an angle of less than 30° with a straight line passing through the center of the extending direction of the vent hole 21 and the axis on the surface of the top face 11 in a flat view of the top face 11. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
