| 摘要 |
PROBLEM TO BE SOLVED: To improve sealability by forming a protruding line rising upward on a top face of a plug, also placing the protruding line from an outer periphery to the center of the top face, and having the protruding line and the top face inside the protruding line caught in a sealing material of a cap at the time of capping. SOLUTION: A protruding line 2 rising upward is formed on a top face 11 of a plug 1 of the plastic bottle from an outer periphery toward the center of the top face 11. At the time of capping, the protruding line 2 and a top face 12 inside the protruding line 2 are caught by a sealing material 3 of a cap to improve sealability at the time of capping. That is, when the plug 1 falls inside, the protruding line 2 is caught by the sealing material 3, thereby preventing its deformation and securing sealability. Since a part 31 of the sealing material 3 engaged with top face 12 is compressed and increased in strength, function for catching the protruding line 2 is improved, thereby more reliably preventing the deformation. |
