Easily openable container lid with resealability and method of producing the same

Abstract

An easily unsealable container closure having re-sealing performance and comprising a closure member having an opening portion that has been formed in advance, and an unsealing tab which is so fitted to the outer surface side of the closure member as to cover the opening portion and is hermetically adhered to the periphery of the opening portion, wherein the unsealing tab includes a flexible tab member and a plug member integrally adhered to the tab member and is so formed as to be fitted to the opening portion of the closure member, and the flexible tab member is hermetically fixed to the periphery of the opening portion in the closure member so as to be torn off. The container closure offers re-sealing performance which can be repetitively effected to temporarily seal again the once unsealed opening, and further offers excellent re-sealing performance, unseal indication function and easy-to-unseal performance.

Description

TECHNICAL FIELD [0001] The present invention relates to an easily unsealable container closure and a method of producing the same. More particularly, the invention relates to an easily unsealable container closure which is a partially unsealable container closure having re-sealing performance enabling the opening to be temporarily sealed again such as enabling the opening that is once unsealed to be temporarily sealed again and to a method of producing the same. BACKGROUND ART [0002] Easily unsealable container closures (easy-open lids) have been widely used as food container closures such as of food cans and beverage cans, and can be classified into the container closures of the partially opening type which are chiefly used as closures for beverage cans for containing various kinds of beverages such as coke, beer, juices, etc. and the container closures of the fully opening type which are chiefly used as closures for canned foods and cans containing instant noodles, snack cookies, ...

AI Technical Summary

Benefits of technology

[0038] In the easily unsealable container closure of the invention, further, the adhesion between the sealing portion and the closure member is torn off or is weakened near both ends of the folding line which is a boundary line between the sealing portion and the folding portion of the flexible tab member prior to pulling the plug member from the opening portion. For example, the flexible tab member has the sealing portion and the folding portion that are adhered and fixed together near both ends of the folding line. This tears off the adhesion of the sealing portion near the portion where the plug member starts being pulled earlier than the pulling of the plug member, enabling the flexible tab member to be torn off with a decreased force at the time of pulling the plug member and, hence, requiring a generally decreased force for the unsealing.

[0039] In the easily unsealable container of the present invention, it is desired that the plug member is a plastic plug member formed by the injection forming or the compression forming, or is a metal plug member formed by the press forming. In particular, it is desired that the plastic plug member is made of a resin composition of an olefin resin and at least the one selected from a thermoplastic elastomer and a rubbery composition, having a heptane elution amount at 25° C. of not larger than 150 ppm, a deformation ratio (JIS K 6723) at 100° C. of smaller than 30%, and a compressive permanent strain (JIS K 6262) at 70° C. of in a range of 50 to 95%, making it possible to maintain the sealing at the time of high-temperature filling or retort sterilization and, further, imparting repetitive elasticity necessary for the re-sealing after the container closure is unsealed.

[0040] It is desired that the hardness at normal temperature of the resin composition constituting the plug member is in a range of 80 to 95 as measured by using a type-A durometer indentater and is in a range of 50 to 75 as measured by using a

Problems solved by technology

However, it is a widely accepted common sense that the easily unsealable containers are

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