Method of applying roll-on closures

In the process of pasteurizing a carbonated beverage contained in a bottle, the bottle consisting essentially of a thermoplastic resin which is deformable when subjected to an elevated temperature equivalent to pasteurization, the bottle being formed to include a finish portion defining the mouth of the bottle, a method of maintaining the configuration of the finish of the bottle during exposure to the elevated temperature, the method comprising the sequential steps of:

• providing a metal closure having a substantially flat top wall defining a continuous peripheral edge and a downwardly extending skirt depending from the peripheral edge of the top wall,
• applying the closure to the bottle to cause the skirt to come into contact with the finish portion of the bottle to position the closure in place on the bottle without interlocking the skirt and the finish portion,
• deforming the top wall of the applied closure to define a bottle mouth configuration-maintaining member extending downwardly a predetermined distance into the mouth of the bottle in spaced relation to the radially outwardly situated closure skirt, and
• interengaging the skirt of the applied closure and the finish portion to hold the configuration-maintaining member within the mouth of the bottle to resist radially inward movement of the finish portion of the bottle during exposure of the bottle and closure assembly to the elevated pasteurization temperature and to retain the closure in place on the bottle, whereby the configuration of the finish portion of the bottle is maintained to prevent unwanted leakage from the bottle and closure assembly during pasteurization.